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Old Feb 13, 2012, 02:51 PM
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Originally Posted by Chairwolf View Post
Markus,

I've been thinking about doing this on my next antenna build. I could probably make a tiny washer out of a piece of copper or brass, using a drill press, by just drilling the proper size hole, trimming the O.D. to the rough shape, and then mounting the piece in the drill chuck on a screw and sanding or filing it round.

But I'm wondering if anyone knows of a source of pre-made small washers of the size we'd need to use on RG316 cable?

Thanks,

Bob
I bought a box of such washers here in Switzerland from "Bosshard AG". They are called "Flat washers without chamfer brass". There are so many confusing numbers on that (presumably stupid SAP generated) packingslip that I'm unable to give you a partnumber. There is a print on it saying it's according to "DIN 125A". If I remember correctly, I odered them online in their webstore.

The Slip says that the "origin" is china, so eventually you get them elsewhere too.

HTH

Markus
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Old Feb 13, 2012, 08:50 PM
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Hugo just sent me a tutorial for the Windmill, Fan and Turbine. They use a single center post which will be much easier to solder that micro Frsky feed wire to than the central blob of the SPW. We will see.

Richard
Old Feb 13, 2012, 08:56 PM
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I think it'll work this time!!
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Originally Posted by markus123456 View Post
I bought a box of such washers here in Switzerland from "Bosshard AG". They are called "Flat washers without chamfer brass". There are so many confusing numbers on that (presumably stupid SAP generated) packingslip that I'm unable to give you a partnumber. There is a print on it saying it's according to "DIN 125A". If I remember correctly, I odered them online in their webstore.

The Slip says that the "origin" is china, so eventually you get them elsewhere too.

HTH

Markus
Hmmmm, good to know, but it sounds like the shop in my back yard might be able to get them to me faster!
Old Feb 14, 2012, 09:28 AM
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Originally Posted by Chairwolf View Post
Markus,

I've been thinking about doing this on my next antenna build. I could probably make a tiny washer out of a piece of copper or brass, using a drill press, by just drilling the proper size hole, trimming the O.D. to the rough shape, and then mounting the piece in the drill chuck on a screw and sanding or filing it round.

But I'm wondering if anyone knows of a source of pre-made small washers of the size we'd need to use on RG316 cable?

Thanks,

Bob
Easier solution: Brass tubing. Get some brass tubing that tightly fits the coaxial cable and then use the build method I did in the cloverleaf video. The brass collar will hold the elements in place making it easy to solder. If you look at my professional units, you will see this is how I build them

-Alex
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Old Feb 14, 2012, 01:58 PM
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I think it'll work this time!!
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Originally Posted by IBCrazy View Post
Easier solution: Brass tubing. Get some brass tubing that tightly fits the coaxial cable and then use the build method I did in the cloverleaf video. The brass collar will hold the elements in place making it easy to solder. If you look at my professional units, you will see this is how I build them

-Alex
I'll take you up on that. How 'bout sending me a couple of 900mhz units for,um, "observation!"
Old Feb 14, 2012, 02:13 PM
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I can send you a few collars. As you can imagine I have hundreds of them

-Alex
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Old Feb 14, 2012, 03:17 PM
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I think it'll work this time!!
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Originally Posted by IBCrazy View Post
I can send you a few collars. As you can imagine I have hundreds of them

-Alex
Great, thanks! Maybe I'll bum a few if you have them in your pocket when we fly together sometime this spring. BTW, I was in L'burg just this morning for an hour or 2. Too bad I didn't have time to fly. Maybe next time!

-Bob
Old Feb 15, 2012, 08:14 AM
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Stop by any time. I need somebody to pull me out of the shop from time to time. I swear I spend all of my free time in there these days. I keep 2 planes in the car at all times in case I see something I want to fly while driving around.

-Alex
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Old Feb 25, 2012, 11:27 PM
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My attempt at a 5.8Ghz skew-planer. This antenna was much easier to build then the cloverleaf.

This is the second antenna I have built and I think this one came out better then the cloverleaf I built first.

I used a printed PDF protractor and MM ruler to take all the measurements.


Old Feb 26, 2012, 12:11 AM
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looks good, in your first picture, though seems your lobes are a bit flat? maybe around 35 degrees?

my first one was also like that, once i got the 45, and compared it to the old one, it was unreal how off i was...i never used a jig!! lol

When i dry fit my lobes together in a small jig i made from a scrape piece of EPP foam, i traced out the 45 on another piece of foam and size it up while placing it behind!
I found this really easy to get you angles! Then once satisfied! put some flux on the already tinned ends/centre with a tooth pick, tin your iron and touch the 3 or 4 ends in the centre ,(which ever you are building) form the bottom! That should make a nice solder joint!

Mine are not perfect, i think the skew wheel is a bit flat! I need to make make a set for a friend and another skew for myself!

I finally got my 7'' monitor yesterday and tested it with these antennas, its like night and day comparable to the stock whips...i left the RX on the table in the kitchen, and walked to the other side of the house in another room, and never dropped out once! even when i was shaking it. It got a touch snowy/static for a split second! I honestly could not believe it!

My Big TV has to be very sensitive or something. When i tested them on it, if i shook either of the antennas i would get a black out screen.

I can not wait to try these on a Plane or my Quadcopter...

Now i just need to find where to get some of those 90 degree adaptors so i can lay my RX flat on the aircraft!

where did you get them ebay!? if so ,got a link!?

Thanks
Old Feb 26, 2012, 12:03 PM
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yeah, here are adapters:
http://www.ebay.com/itm/SMA-90-Degre...item1c23720a7b

but if you are building it anyway, why not just start with a cable that already has a 90 deg end on it already?
something like this:
http://www.ebay.com/itm/Cable-RG174-...item2eadbd556a
(although I don't remember if RG174 is a good cable to use or not, but at this short of a distance, I'm not sure it matters much.)
Old Feb 26, 2012, 12:11 PM
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Originally Posted by yzguy View Post
yeah, here are adapters:
http://www.ebay.com/itm/SMA-90-Degre...item1c23720a7b

but if you are building it anyway, why not just start with a cable that already has a 90 deg end on it already?
something like this:
http://www.ebay.com/itm/Cable-RG174-...item2eadbd556a
(although I don't remember if RG174 is a good cable to use or not, but at this short of a distance, I'm not sure it matters much.)
Yea i would, but i have a few normal ones, never thought on it back when i ordered them.

174 is not the greatest. i use RG316
http://www.ebay.com/itm/150701624632...ht_3037wt_1185

have 3-4 more on the way!

Ill get these
http://www.ebay.com/itm/280604124507...9#ht_739wt_952
Old Mar 01, 2012, 02:10 PM
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Building the antenna - Soldering it all together
Now this is the hard part. Soldering this without overheating the coaxial cable is difficult.

First, mark the centers of the pinwheel blades. Now place them over top of each other 90 degrees apart. Each of the blades should set at a 45 degree angle from the "X".........

Ok, How do tell if I overheated coax? Wire gets softer?
Old Mar 01, 2012, 02:19 PM
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LHCP or RHCP


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I will try to answer questions here:

...........

Q: Is this right hand or left hand polarized?
A: It depends on which way you bent the pinwheel. It is the opposite direction of your hand. If you curl your fingers in the direction of the bend coming off the center pin with your right hand, the antenna is left hand polarized. Both Old Man Mike's and mine are LHCP.

Q: Why left hand polarized?
A: It's just how it came out. I didn't choose before designing it.
.......

-Alex

So It doesn't matter? If I use LHCP or RHCP as long as both are same polarization? There's no setting on tx or rx? Well on 5808 type Vtx / rtx?
Old Mar 01, 2012, 04:21 PM
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So It doesn't matter? If I use LHCP or RHCP as long as both are same polarization? There's no setting on tx or rx? Well on 5808 type Vtx / rtx?
From a link quality standpoint of view it does not matter, and no you don't have to set anything on the tx or rx. It's just how the antenna radiates the waves. If you look from behind the antenna into the direction it goes away, RHCP is like screwing a screw into something. LHCP is like takeing it out.

One thing is important though. ALL CP antennas known to me that you can buy commercially are RHCP. RHCP is how the industry assures that antennas from different manufacturers match eachoter. At least RHCP is always the default. So it's a good idea to make yours RHCP if you ever consider to buy a CP antenna somewhere.

HTH

Markus
Old Mar 01, 2012, 04:23 PM
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Building the antenna - Soldering it all together
Now this is the hard part. Soldering this without overheating the coaxial cable is difficult.

First, mark the centers of the pinwheel blades. Now place them over top of each other 90 degrees apart. Each of the blades should set at a 45 degree angle from the "X".........

Ok, How do tell if I overheated coax? Wire gets softer?
The best cable is cable with teflon insulation, and you can't overheating that with regular soldering. The cheap cables with (I belive ABS) insulation are not only delicate, at least for 5.8Ghz they are totally unuseable.

Markus
Old Mar 01, 2012, 04:42 PM
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Originally Posted by markus123456 View Post
The best cable is cable with teflon insulation, and you can't overheating that with regular soldering. The cheap cables with (I belive ABS) insulation are not only delicate, at least for 5.8Ghz they are totally unuseable.

Markus
Ok thanks. Dpcav here I come again. He he radio shack guy today said its got a 6 in it when I asked for rg316 50 ohm....he showed me rg6.... He he I guess I should give him 1/2gold star for tryin he he

Should Ive posted this in the IBCrazy fpv thread? I have some questions on fpv Vtx/vRx, and this antenna....?
Last edited by boxhead530; Mar 01, 2012 at 04:53 PM. Reason: which thread to post?
Old Mar 01, 2012, 09:33 PM
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Which IBCrazy FPV thread are you referring to? I browse them all

In any case RG316 is what you need. You can find it all over the place from FPV vendors these days. It's not terribly expensive. Just don't use RG58 or RG174 for 5.8GHz. it will not work very well.

-Alex
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Old Mar 01, 2012, 09:54 PM
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Originally Posted by IBCrazy View Post
Which IBCrazy FPV thread are you referring to? I browse them all

In any case RG316 is what you need. You can find it all over the place from FPV vendors these days. It's not terribly expensive. Just don't use RG58 or RG174 for 5.8GHz. it will not work very well.

-Alex
Ya got so many, but I trying to stick to what I'll be using, what I'll be planning and what ever your doing he he

Radio shack today:
Me: do you rg316 50 ohm coax?
Radio shack guy: after looking in 3 different places...uh we got some rg6, it's got a 6 in it...
Me, walking over to the pullout bins: ah, no thanks, I'll look at the rg316 sma to bnc....(18$, I'll wait).
Old Mar 02, 2012, 06:28 PM
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Made a skew planar, a bit crooked, but I have run out of RP-SMA leads, so that'll do for now at least until I get a set from Markus
I am looking forward to testing to see how much it outperforms my cloverleaf on the rx. When flying out in the open, I have found the pair of cloverleaf's work beautifully, but lately I have been flying in a paddock on the edge of the suburb I live in, about 40m from our units, and have been getting bad interference (multipathing I am guessing). I am hoping the SPW will help with this. Feel free to comment on my antennas, I know they aren't the best, but hopefully will do for now
Old Mar 02, 2012, 06:52 PM
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Hi IbCrazy.

Based on that :

" If I use a .040" ( 1mm) wire do I need the lobes be slightly small them ?"

Best.
FRED

Quote:
Originally Posted by IBCrazy View Post
TexasAggie - You might find the little hooks help a lot. They won't harm anything at 1.3GHz. I make them as long as the feedpoint gap so the overall lobe lenght is consistent.

The lobes should be .5% longer than 1 full wavelength depending on the wire thickness you use. Wire thickness will change resonant wavelength, so the little details will change. Generally the thicker the wire, the higher the resistance (I know this sounds backwards but we're talking RF, not DC). My calculations were done with .035" wire. if you use thinner wire (say .030 or .025) you will need the lobes to be slightly longer than my calculations.

-Alex
Old Mar 02, 2012, 07:15 PM
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Made a skew planar, a bit crooked, but I have run out of RP-SMA leads, so that'll do for now at least until I get a set from Markus
I am looking forward to testing to see how much it outperforms my cloverleaf on the rx. When flying out in the open, I have found the pair of cloverleaf's work beautifully, but lately I have been flying in a paddock on the edge of the suburb I live in, about 40m from our units, and have been getting bad interference (multipathing I am guessing). I am hoping the SPW will help with this. Feel free to comment on my antennas, I know they aren't the best, but hopefully will do for now
Sammy,

They look nice, and shape and proportions also look very ok to me.

The problem with 5.8Ghz is that a nice looking antenna does not mean that it's a good working antenna as it's very very difficult to build one that resonates where planned and that resonates good. As a matter of fact, bending one of those horizontal parts of the lobes up or down by a tenth of a milimeter easily can make the difference between a 1.2 or 2 SWR. Now how would one want to predict this without the ability to measure?

So for what you can do, those antennas look beautifull. The colour you used lowers the resonant frequency, but what the heck, since we don't know if they are above of where they should be or not - it probably does not matter!

Markus
Old Mar 02, 2012, 07:19 PM
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Sammy,

They look nice, and shape and proportions also look very ok to me.

The problem with 5.8Ghz is that a nice looking antenna does not mean that it's a good working antenna as it's very very difficult to build one that resonates where planned and that resonates good. As a matter of fact, bending one of those horizontal parts of the lobes up or down by a tenth of a milimeter easily can make the difference between a 1.2 or 2 SWR. Now how would one want to predict this without the ability to measure?

So for what you can do, those antennas look beautifull. The colour you used lowers the resonant frequency, but what the heck, since we don't know if they are above of where they should be or not - it probably does not matter!

Markus
Hmm shoulda painted them red for fast lol! Cheers Markus, I want to get out and test them, but weather is a bit crap here. If you wouldn't mind me scratching your brains some more, could you please see my problems here? https://www.rcgroups.com/forums/show...postcount=4172 Cheers Mate!
Old Mar 02, 2012, 07:26 PM
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hi everyone, a quick noob question: would it be ok to use the rg6 cable for a 5.8ghz system
Old Mar 02, 2012, 07:36 PM
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hi everyone, a quick noob question: would it be ok to use the rg6 cable for a 5.8ghz system
No because the impedance does not match. RG6 is 75ohms, we need 50 ohms. Apart from this they are also not rated up to 5.8Ghz, but the same holds true for RG316. This does not matter if you keep the cable very short though, however not so with the impedance!

If you have problems to source RG316 cables to try your own antenna, search ebay. There are many people selling apropriate patch cables you could use as a base.

Markus
Old Mar 02, 2012, 08:34 PM
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thanks Markus, i see now what your talking about.
Old Mar 02, 2012, 08:57 PM
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Originally Posted by asaloca View Post
Hi IbCrazy.

Based on that :

" If I use a .040" ( 1mm) wire do I need the lobes be slightly small them ?"

Best.
FRED
For 1.3GHz and .040" I'm coming out to 99.8% of 1 wavelength assuming a relative humidity of 75%.

-Alex
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Old Mar 07, 2012, 11:58 AM
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at what length do i cut my RG316 cable? 2-3-6inches long??

ive got my Skew-Planer and Cloverleaf all bent up ready to solder to the cables,

and im confused as to how long they can be cut at
I understand the tips, for soldering,,
ive got two RG316 cables with male female connectors mounted,

can i measure from the female case looks like its almost flush,,

and how long/short do i cut it at for either one,,
both are for 1.3 system antennas

thank you very much,
jp
Old Mar 07, 2012, 05:38 PM
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Cable length is irrelevant. Any length you want works fine.

-Alex
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Old Mar 07, 2012, 05:40 PM
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Originally Posted by ibcrazy View Post
cable length is irrelevant. Any length you want works fine.

-alex
thank you alex
Old Mar 07, 2012, 05:56 PM
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Originally Posted by markus123456 View Post
The best cable is cable with teflon insulation, and you can't overheating that with regular soldering. The cheap cables with (I belive ABS) insulation are not only delicate, at least for 5.8Ghz they are totally unuseable.

Markus
Teflon has many wonderful properties, but make sure not to burn it, inhale any smoke from it, or get scraps of it into a fire. It starts to decompose into nasties around 500 deg F and lots of folks run soldering irons at 600-750 deg F.
Old Mar 07, 2012, 08:02 PM
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Teflon has many wonderful properties, but make sure not to burn it, inhale any smoke from it, or get scraps of it into a fire. It starts to decompose into nasties around 500 deg F and lots of folks run soldering irons at 600-750 deg F.
I wondered why grandmas birdys died.....he he

Got everything except sma- rp connecters, but have started soldering things up, got dip switch wired and ready to solder to vRx,the SPW will have good Clarence on ground base...so no answer from fpvhobby, about Vtx antenna ground, so will wait to put the CL antenna on in, I've came up with a ping pong ball cut to have second piece different color to look like a eyeball, and battery leads, antenna will give it the eyeball on a stalk look he he..for mQX other small cp helicopters
Old Mar 13, 2012, 01:53 AM
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Would these cables work for a 5.8 ghz skew planar wheel build?

http://www.ebay.com/itm/400270118235...9#ht_500wt_976
Old Mar 13, 2012, 03:32 AM
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Originally Posted by TheQuadLaser View Post
Would these cables work for a 5.8 ghz skew planar wheel build?

http://www.ebay.com/itm/400270118235...9#ht_500wt_976

Yes and no, they are great to have the 90 on one end for your CL, and they do look as if they are rg316.

But...they are male. You need Female?
I have bought these on 2 occasions now!
Great seller!
http://www.ebay.com/itm/150701624632...ht_3037wt_1185

Note. After looking at the ones i get, they also say Male...But shows the female?

I also have these on the way so i can set up my CL and TX more of a low profile on my Wing and Quad

RP-SMA male JACK RP-SMA female PLUG right angle adapter
http://www.ebay.com/itm/280604124507...9#ht_739wt_952

All i know on my 5.8 200Mw there is male, so i get the female cables.
Old Mar 13, 2012, 07:17 PM
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Thank you for the links eastcoast. I am making antennas for my Fatshark goggles, and Fatshark video transmitter, which both have female sma connectors on them so I need male connectors. Are most other transmitters/recievers not that way?
Old Mar 13, 2012, 08:36 PM
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Cord length?


Hi,

I've been reading the first 15 pages of this thread.
I don't think anyone mentions anything about the antenna cord length?

Some seem to solder the antenna directly to the SMA contact.
And others leave some cord and solder the antenna on that.

Is there a general rule here?
(I have heard that cord length must match frequenzy, but that was in another context.)

I'm using a 1280MHz system and will make a "Skew-Planar Wheel Antenna" for the RX and a "Cloverleaf Antenna" for the TX.
I'm using this receiver: Link - 1.3GHz receiver

Thanks!
/Windman
Old Mar 13, 2012, 10:42 PM
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Originally Posted by TheQuadLaser View Post
Thank you for the links eastcoast. I am making antennas for my Fatshark goggles, and Fatshark video transmitter, which both have female sma connectors on them so I need male connectors. Are most other transmitters/recievers not that way?
Ok kool no drama! i was assuming it was for the normal 5.8 200Mw
http://www.hobbyking.com/hobbyking/s...dProduct=15295

Which is what i have and they have the Male SMA on them

So id say the ones you linked look like they are RG316 so they should be fine.
Old Mar 14, 2012, 05:51 AM
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Originally Posted by Windman View Post
Hi,

I've been reading the first 15 pages of this thread.
I don't think anyone mentions anything about the antenna cord length?

Some seem to solder the antenna directly to the SMA contact.
And others leave some cord and solder the antenna on that.

Is there a general rule here?
(I have heard that cord length must match frequenzy, but that was in another context.)

I'm using a 1280MHz system and will make a "Skew-Planar Wheel Antenna" for the RX and a "Cloverleaf Antenna" for the TX.
I'm using this receiver: Link - 1.3GHz receiver

Thanks!
/Windman
DO NOT SOLDER IT TO THE CONNECTOR. Doing so violates the nearfield of the antenna, and this will change the parameters of the antenna to the bad.

Markus
Old Mar 14, 2012, 10:11 AM
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DO NOT SOLDER IT TO THE CONNECTOR. Doing so violates the nearfield of the antenna, and this will change the parameters of the antenna to the bad.

Markus
Thank you for your answere Markus,

But it really didn't answere my question about if the cord length matters?
And if there is a general rule or maby an equation that applies.

Thanks
/Windman
Old Mar 14, 2012, 10:20 AM
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Thank you for your answere Markus,

But it really didn't answere my question about if the cord length matters?
And if there is a general rule or maby an equation that applies.

Thanks
/Windman
No, the lenght of the coax cable itself does not have influence on the impedance, even though some people think so. However, coax (especially RG316 which is not rated for 5.8Ghz) has damping, so you should keep it short, as short as you can. In case of RG316, I found that starting with about 10cm bad effects kick in, so try to stay shorter. I found 6cm to be pretty ideal as the tx/rx is then out of the near field, the antenna is still stiff enough even for high speed and the damping effect can be negletted.

Markus
Old Mar 14, 2012, 10:54 AM
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Mmmmmmm!
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Oh gosh, almost forgot. Markus, how's it going with the antennas? It's been a long long time since I ordered them, surely the queue can't be THAT long. If it is you should be a very rich person right now.

Now, I did make my own, but I did pay for these and a pair made by someone who knows how to actually make these would come in handy now that I have several quads and cameras.
Old Mar 14, 2012, 11:17 AM
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Hey IBCrazy or Hey markus 123456?
What is near field?
What I've done, is on rx, put two 5mm rg 316 leads to two sma/sma-rp connecters. For a panel and a SPW. This make 10 mm...am I messing up reception? Badly? Should I just get a tee? I did not want wait, or order more stuff (no one in Chico, Ca. Has 50 ohm cable or sma connecters, that I've seen)
Old Mar 14, 2012, 11:22 AM
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Originally Posted by WiseDuck View Post
Oh gosh, almost forgot. Markus, how's it going with the antennas? It's been a long long time since I ordered them, surely the queue can't be THAT long. If it is you should be a very rich person right now.

Now, I did make my own, but I did pay for these and a pair made by someone who knows how to actually make these would come in handy now that I have several quads and cameras.
Your antennas are packed in their box and ready to ship. I finished them late yesterday evening. They will ship tomorrow as I'm not at home today and did not had the time to ship this morning. Regarding the queue and becoming rich, there is also another explanation. There were some orders with pretty complicated and time consuming antennas. I had to build some of them eight!! times before I was happy with the result. Call me stubborn, but nothing leaves my place if I'm not happy with it.

Markus
Old Mar 14, 2012, 11:25 AM
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Awesome! Well alrighty, kudos to you for making sure you ship out products you're happy with. If you're not happy with them, chances are your customers won't be either when a bit of money is involved! Now to buy more video transmitters and one that's compatible with my Fatshark goggles, if I can find the Tx in stock anywhere at a reasonable price, grr.
Old Mar 14, 2012, 11:34 AM
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Originally Posted by boxhead916 View Post
Hey IBCrazy or Hey markus 123456?
What is near field?
What I've done, is on rx, put two 5mm rg 316 leads to two sma/sma-rp connecters. For a panel and a SPW. This make 10 mm...am I messing up reception? Badly? Should I just get a tee? I did not want wait, or order more stuff (no one in Chico, Ca. Has 50 ohm cable or sma connecters, that I've seen)
I'm a bit confused as to what you did. Are you sure you talk 10mm and not 10cm? It would be ten times the difference in lenght.... Hearing you talk about a tee connector worries me. You can't connect two antennas to ONE receiver. You would need two of them and a diversity. Ok, you CAN connect two antenans to the same receiver (even more identical ones) as this would form an antenna array, but then you would have to match the impedance of those antennas back to 50 ohm. Ohms law says that if you connect "resistors" in parlalell, the resulting value is 1/(1/r1 + 1/r2 ... +1/ rn)) so if you connect two 50 ohm antennas, the resulting impendance is no longer 50 ohms but only 25.

The near field is the area around an antenna which is about one wave lenght in radius. Objects that are in this nearfiled will change the radiation pattern of the antenna. That's because the velocity factor of such objects is different from the otherwise surrounding air. An effect like light going through a lense comes into play. Needless to say that conductive objects are even worse.

HTH

Markus
Old Mar 14, 2012, 12:18 PM
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Ah, I get word fast and brain slow...
Yes, 2 pieces 5mm long to two different sma's
No, only one antenna at a time, I forgot most electricity rules, but thought two antenna at same time without diversity would create more multi path problems,
So the different antenna connecters would be for wider range of different rx antennas, one at a time, of the four antennas I have, three bought for one I made, the sma's are different.
The one I made has sma -rp, the ones I bought have sma and sma-rp...
I was wondering about reception interference from the 5mm lengths of rg316 from board to connectors?
On test to tv, clear on test with myvu's I had a black vertical line moving horizontal across. Slow.
Myvu's connected to disc player or iPhone was clear, but I don't have any 16 volt caps on rx wiring yet.
Old Mar 14, 2012, 05:31 PM
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Quote:
Originally Posted by markus123456 View Post
No, the lenght of the coax cable itself does not have influence on the impedance, even though some people think so. However, coax (especially RG316 which is not rated for 5.8Ghz) has damping, so you should keep it short, as short as you can. In case of RG316, I found that starting with about 10cm bad effects kick in, so try to stay shorter. I found 6cm to be pretty ideal as the tx/rx is then out of the near field, the antenna is still stiff enough even for high speed and the damping effect can be negletted.

Markus
Great answere!
It sounds like you know what you are talking about, so I'll take your word for this

Ebay next....

Thanks!
/Windman
Old Mar 14, 2012, 09:42 PM
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I would love some advice on my tx and rx antenna setup!

I have a 1.3GHz system. Tx is 400mW.
I will be using it on a quad for some aerial photo/video.
I will not be flying extremely far away, but maby up to 1000 meters (maximum).

I have two receivers with SAW filter modification and an Eagle Tree ground station with diversity.

What would be the best antenna setup?
I'm planning on using a "Cloverleaf Antenna" for the tx, and a "Skew-Planar Wheel Antenna" for the rx. Would this be a good setup?
And what would be a good choice for the 2nd receiver?
I have a patch antenna, but I think it is to directional for my purpose?

Thanks
/Windman
Old Mar 17, 2012, 01:29 AM
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Thanks for the instruction!

another successful student.....
Old Mar 19, 2012, 11:27 AM
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Quote:
Originally Posted by Windman View Post
What would be the best antenna setup?
I'm planning on using a "Cloverleaf Antenna" for the tx, and a "Skew-Planar Wheel Antenna" for the rx. Would this be a good setup?
And what would be a good choice for the 2nd receiver?
I have a patch antenna, but I think it is to directional for my purpose?

Thanks
/Windman
I would start without diversity for now. When you are ready for diversity a helical or a Crosshair is a good choice. The beam is pretty wide on a 3 turn helical (about 130 degrees or so). I personally fly a 3 turn helical on a tripod. No diversity, no tracking, none of it.

-Alex
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Old Mar 25, 2012, 10:33 AM
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Just measured my ant with the new DIY VSWR meter.
I noticed there is a great variation with frequency. I actually had perfect 1:1 on a certain frequency and as bad as 3.5 on another ( all on a 1.2 VTX ).. I just donīt know what freq it is LOL... any DIY freq counters out there??
Old Mar 31, 2012, 11:59 PM
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Originally Posted by tascheri View Post
Just measured my ant with the new DIY VSWR meter.
I noticed there is a great variation with frequency. I actually had perfect 1:1 on a certain frequency and as bad as 3.5 on another ( all on a 1.2 VTX ).. I just donīt know what freq it is LOL... any DIY freq counters out there??
You could look up the specs for your transmitter to find the frequency.
Old Apr 05, 2012, 09:36 AM
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I am just about to build my antenna for 1.2GHz and I am just wondering - presented concept is based on 1/4 - 1/2 - 1/4 wavelengths.

Will this work also in 1/8 - 1/4 - 1/8 setup? The aim is simply to make it smaller for the 1.2GHz frequency...
Old Apr 06, 2012, 10:38 AM
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In a word, no. You must use 1 wavelength loops.

-Alex
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Old Apr 06, 2012, 01:21 PM
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I just saw your video of the easy way to make the cloverleaf using the hooks and legs method. Have you come up with an easier way of making this antenna?
Old Apr 07, 2012, 09:20 PM
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I have several easy ways to build this. One is my "bullet jig". It uses a wooden bullet inside a tube with magnets. Make it really easy to make.

However, I usually use not jig at all. I see all these fancy jigs and laugh because they're all guessing I use some fancy jig. My jig is my two hands

-Alex
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Old Apr 08, 2012, 04:11 AM
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Quote:
Originally Posted by IBCrazy View Post
I have several easy ways to build this. One is my "bullet jig". It uses a wooden bullet inside a tube with magnets. Make it really easy to make.

However, I usually use not jig at all. I see all these fancy jigs and laugh because they're all guessing I use some fancy jig. My jig is my two hands

-Alex
Could you please give the links of your easy build videos? Thanks!
Old Apr 08, 2012, 10:28 PM
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Sure: Check the first post: https://www.rcgroups.com/forums/show....php?t=1388264
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Old Apr 09, 2012, 04:03 AM
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Originally Posted by IBCrazy View Post
Thank you!

P.S. Also one of the videos in that post were removed.
Old Apr 09, 2012, 03:18 PM
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Pat K

What about a ground plane?


Hi all,
I have been playing with 4nec2 software for a while to see how to increase gain for the SPW. It seems that adding a ground plane underneath the SPW can boost the gain to about 5dBi.
Of course the antenna cannot get any signal under 5deg elevation but who really flies underground...
For low altitude flying, the antenna would just need to be tilted by 10deg in the good direction to offer 4-5dB over 30deg in elevation and almost 120 deg in azimuth.

Is it a software artefact or can we get even further with our beloved omni antennas?

Here is the file for those who want to play with the software, together with the 4nec2 output at my frequency 5645MHz:
Last edited by Papat; Apr 10, 2012 at 06:05 AM.
Old Apr 09, 2012, 08:53 PM
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I just wish I knew what it is.... I bought it online locally and it has no branding on it...but using my lawmate RX I figured most of the freqs. looks like the center freq is VERY close to my target. 1080 Mhz. Now I have to make another for 1200 just because I bought a Lawmate that only does 1.2G... faulty unit...

Quote:
Originally Posted by volto View Post
You could look up the specs for your transmitter to find the frequency.
Old Apr 10, 2012, 03:34 AM
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Hi Alex,
I found an article about making SPW antenna here:
Antena Skew Planar Wheel: ACTUALIZADO CON PRUEBAS COMPLETAS DE LABORATORIO


Arc Angle = 90°
Pitch Angle = 50°

It is a bit different. Does it have the same performance with your SPW antenna here?

Thanks
Old Apr 10, 2012, 06:07 AM
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Pat K
Alex, Markus, any opinion on this finding? Could it be a route to explore?
For instance, I have no clue whether this would work in CP.
Pat

Quote:
Originally Posted by Papat View Post
Hi all,
I have been playing with 4nec2 software for a while to see how to increase gain for the SPW. It seems that adding a ground plane underneath the SPW can boost the gain to about 5dBi.
Of course the antenna cannot get any signal under 5deg elevation but who really flies underground...
For low altitude flying, the antenna would just need to be tilted by 10deg in the good direction to offer 4-5dB over 30deg in elevation and almost 120 deg in azimuth.

Is it a software artefact or can we get even further with our beloved omni antennas?

Here is the file for those who want to play with the software, together with the 4nec2 output at my frequency 5645MHz:
Last edited by Papat; Apr 10, 2012 at 06:13 AM.
Old Apr 10, 2012, 06:16 AM
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Originally Posted by Papat View Post
Alex, Markus, any opinion on this finding? Could it be a route to explore?
Pat
Pat,

Obiviousely if you can increase gain on the SPW this way, that could be beneficial as I agree that most people don't fly from the top of a mountain. One of my flying sites is on a hill though, so there it might not be an ideal aproach but in many many cases this could be interesting.

I'm truly held busy currently with lots of things in paralell, I will definately have a look. You may better post this in the CP Antenna developement thread though. See here:

https://www.rcgroups.com/forums/show...5&goto=newpost

HTH

Markus
Old Apr 10, 2012, 08:12 AM
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Originally Posted by markus123456 View Post
Pat,

Obiviousely if you can increase gain on the SPW this way, that could be beneficial as I agree that most people don't fly from the top of a mountain. One of my flying sites is on a hill though, so there it might not be an ideal aproach but in many many cases this could be interesting.

I'm truly held busy currently with lots of things in paralell, I will definately have a look. You may better post this in the CP Antenna developement thread though. See here:

https://www.rcgroups.com/forums/show...5&goto=newpost

HTH

Markus
Thanks for your feedback Markus, I will post it on the other thread.
What is interesting with this ground plane (if it really works!) is that it does not require any modification of the SPW itself. Then it is easy to install or remove the ground plane depending on the flying site.
Old Apr 10, 2012, 03:23 PM
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Just built my first 5.8GHz Skew Planar and Cloverleaf antennas. Was very challenging to tin welding wire. Is there any trick you guys use to tin those wires? This is the wire i used: Carbon Steel Mig Solid Welding Wire.

Old Apr 10, 2012, 04:59 PM
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Is that MIG wire dirty/corroding?

Cleanliness of the metal is very important, along with a good flux and/or flux cored solder.
Try to get some 60/40 tin/lead flux cored solder, like this
http://uk.rs-online.com/web/p/solders/0555235/

Don't rub away the copper flash on the outside of the MIG wire as the base metal underneath is carbon steel and it does not solder at all well.
A Scotchbrite pad or similar is good enough for preparing the wire.

HTH

Nigel.
Old Apr 10, 2012, 06:18 PM
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Quote:
Originally Posted by Devonboy View Post
Is that MIG wire dirty/corroding?

Cleanliness of the metal is very important, along with a good flux and/or flux cored solder.
Try to get some 60/40 tin/lead flux cored solder, like this
http://uk.rs-online.com/web/p/solders/0555235/

Don't rub away the copper flash on the outside of the MIG wire as the base metal underneath is carbon steel and it does not solder at all well.
A Scotchbrite pad or similar is good enough for preparing the wire.

HTH

Nigel.
I'm not sure if it is corroding, but i noticed that it gets darker than it used to be. I kept the pieces in dry place in a plastic bag for few weeks before soldering.

I guess that was my mistake. I did rub the copper from the MIG wire which makes things even worse.

I've got pretty much same 60/40 solder with 2.2% flux.

I didn't clean the pieces before soldering. Maybe that was my mistake.
Old Apr 15, 2012, 04:00 PM
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Dear Antenna Gurus,
I'm planning to make SPW for a FrSky receiver to extend bidirectional (telecommand and telemetering) link range.
Since it has 2 antennas, should I make two SPWs or just one SPW with a stock antenna are good enough?
If I build just one, I'll put it on top fuselage right next to the canopy.
If I have to build two, I'll put them on wing top or even wing bottom facing ground with 10-12" separation.
What's your suggestion? Does cloverleaf better suit for this purpose?
Old Apr 15, 2012, 05:22 PM
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The advantage of Circularly Polarised antennas is the ability to significantly reduce multipath signals.

In your case, 2 Skew-Planar's would be best, one oriented upwards and one oriented sideways (90 degrees difference).
This way, you will eliminate the 'nulls' and hopefully, the built in diversity will choose the best one for reception.

At the same time, to make best use of your system, you should equip your Tx with a C-P antenna (maybe a Skew-Planar also or even a C-P patch/helical if you can keep it pointed toward the aircraft).

Let us know of any improvement you notice.

Nigel.
Old Apr 15, 2012, 08:42 PM
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Thanks for quick reply.
I'm currently building Sky Surfer V4 for my future FPV platform and planning to put RP-SMA plug to U.fl pigtails (http://www.ebay.com/itm/320847624761...84.m1497.l2649) before joining the fuselage.
I can put two SPWs with 90 degree offset - one at upper fuselage right next to the canopy
and another at left side of fuselage under the wing near COG point.
(I'll put VTX near tail in the future.)
Is there any spacing requirement between two SPWs? I'm worrying about the reflection.
Last edited by flybabo; Apr 16, 2012 at 05:17 AM.
Old Apr 16, 2012, 03:54 AM
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Because the antennas will be quite close, 'as far apart as possible' will have to be good enough.

Nigel.
Old Apr 25, 2012, 11:14 PM
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:( uugh


I bought a Bluebeam 1.3G ant set from Readymade RC and they sent a pair for 5.8G.

I really have to open a support ticket to get the antennae I ordered???
Old Apr 27, 2012, 06:02 AM
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Hey, I had posted this elsewhere, but how would it go on a SPW?

"Hey does anyone know how well a windsurfer antenna reflector works?
I have read a few bits and pieces about people using it for RC 2.4GHz for FPV. Not sure whether its worth giving a go, but hey, it costs practically nothing, there's not much to lose (except my plane!)
http://www.freeantennas.com/projects...te2/index.html"

Im thinking it may have problems due to reflecting and antenna polarization. (would a right handed tx antenna then work with a left handed rx antenna with refector?)
Im not expecting it to work well at all, probs very dodgy, but RF stuff has caught my interest.
Old Apr 27, 2012, 11:44 AM
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It would distort the circularity significantly (since reflections reverse) as you noted. Why not build a helical or a Crosshair antenna?

-Alex
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Old Apr 27, 2012, 01:42 PM
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Just a recap

Readymade RC just shipped a replacement 1.3G set this morning wih return postage for the 5.8 set the sent by mistake. Now that's some awesome customer service! I WILL be a return customer for sure!
Old Apr 27, 2012, 05:00 PM
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I asked this in another smaller thread but it's slowly drifting off onto page three

Are these antennas installed backwards? I thought the CL was supposed to go on the Vtx and the SPW on the Vrx?



______________________________________________





http://www.readymaderc.com/store/ind...roducts_id=781
Old Apr 27, 2012, 05:23 PM
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Quote:
Originally Posted by IBCrazy View Post
It would distort the circularity significantly (since reflections reverse) as you noted. Why not build a helical or a Crosshair antenna?

-Alex
Hehe I was expecting an answer to build one of those, I was just curious about the reflector that's all. Thanks Alex
Old Apr 27, 2012, 08:20 PM
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Quote:
Originally Posted by turbodriven View Post
I asked this in another smaller thread but it's slowly drifting off onto page three

Are these antennas installed backwards? I thought the CL was supposed to go on the Vtx and the SPW on the Vrx?



______________________________________________





http://www.readymaderc.com/store/ind...roducts_id=781
Answer: Yes
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Old May 04, 2012, 11:04 AM
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hi ...
i looked and could not find what kind of gain this SPW antenna have ... anyone knows ?
i do know the CL has a gain of 1.2dbi
Old May 07, 2012, 08:24 PM
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i used 0.6mm steel wire making two SPW antenna, it really perform well in nearby airspace, but radiation fade out quite quickly. Previously the V may loose signal during banking and easy like noisy when move around. but now it is crystal clear in near by space, I see video signal down grade around 200meter away, and quickly loose signal with about another 100 meter. but regain it right back.

admittedly, my antenna is not perfect shape as designed, eg. the curve may not be perfect, and skew is not perfect 45degree and the feedpoint is not aligned perfectly. i am going to rebuild another few to have better connector alignment, etc.
what is the expected range for home brew SKPW?
and how critical are the dimension/angel/arc?

I am looking effective way to use home tools to calibrate steel wires (flex enough), make curve in right way and angle to be exactly angle
Last edited by modelerchina; May 07, 2012 at 08:37 PM.
Old May 08, 2012, 04:53 AM
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Quote:
Originally Posted by modelerchina View Post
i used 0.6mm steel wire making two SPW antenna, it really perform well in nearby airspace, but radiation fade out quite quickly. Previously the V may loose signal during banking and easy like noisy when move around. but now it is crystal clear in near by space, I see video signal down grade around 200meter away, and quickly loose signal with about another 100 meter. but regain it right back.

admittedly, my antenna is not perfect shape as designed, eg. the curve may not be perfect, and skew is not perfect 45degree and the feedpoint is not aligned perfectly. i am going to rebuild another few to have better connector alignment, etc.
what is the expected range for home brew SKPW?
and how critical are the dimension/angel/arc?

I am looking effective way to use home tools to calibrate steel wires (flex enough), make curve in right way and angle to be exactly angle
I would use a CL on the plane. The SPW is ideal as an rx antenna. If you build it by yourself and don't have measureing equipement to tune the antenna, ending up with a propper SWR on a SPW is difficult. The CL is less critical and SWR is very important on the tx side. Other than this your build "looks" ok. However, with HF, sometimes even a good looking antenna does not necesairly has to be a good one. However at the frequency your tx transmits, things are not THAT critical but still, use that SPW on the ground and make you a new CL for on the plane.

Markus
Old May 09, 2012, 10:22 PM
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i think SPW much easier to build, as I straight cross two wire and bend it, CL needs measure all the angles
Old Jul 21, 2012, 12:35 PM
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Heres a good website for antennas.
http://rcexplorer.se/page14/CPantennas/CPantennas.html
Old Jul 23, 2012, 07:46 AM
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Originally Posted by IBCrazy View Post
Now we need to bend the radius in our "S". I did this by taking my pliers and making small bends all the way around the 1/2 wavelength side until the end met with the middle of the antenna. The tip of the wire should meet the center at a ~105 degree angle. It will not (and should not) intersect at 90 degrees.

Do this to both wires. They should again be identical and should look like a figure "8".

Now take your figure "8" and twist one side 90 degrees along the central axis of the element. One radius should be flat and the other should be upright. Do this to both elements. They should be identical.

-Alex
when you measure the 1/4 and 1/2 wavelengths, are your calipers supposed to be outside the wire(outside the bends too) so the wire fits into the space between the caliper, or are you measuring from the middle of the wire, or the inside of the bend?
Old Jul 23, 2012, 01:52 PM
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Originally Posted by KillerCut View Post
when you measure the 1/4 and 1/2 wavelengths, are your calipers supposed to be outside the wire(outside the bends too) so the wire fits into the space between the caliper, or are you measuring from the middle of the wire, or the inside of the bend?
It is technically center to center. However, I would be sure to focus on getting the feed point gap as close as possible because this is where the real inaccuracy is seen in most DIY builds.
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Old Jul 23, 2012, 02:46 PM
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I am worried about getting it too close, because I got it soooooo close on my first try on these antennas and they did not work well. I can get it so I can barely fit a piece of paper in without being shorted if you want, but then most likely the antenna will suck again, So I purposely built my last ones with like a 1-2mm gap...
Old Jul 24, 2012, 11:20 PM
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Quote:
Originally Posted by KillerCut View Post
when you measure the 1/4 and 1/2 wavelengths, are your calipers supposed to be outside the wire(outside the bends too) so the wire fits into the space between the caliper, or are you measuring from the middle of the wire, or the inside of the bend?
if its center to center then one inside one leg and one outside the other will give consistent results
Old Jul 25, 2012, 06:49 AM
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if its center to center then one inside one leg and one outside the other will give consistent results
you are right. thats much easier.
Old Aug 03, 2012, 08:37 PM
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Tried my hand at a 5.8Ghz base-fed SPW antenna today. How's it look to you guys, any major issues? I used some copper wire with the hope that it wouldn't be too soft at this small size, and it seems pretty robust. The welding wire I had just wouldn't take solder.
Old Aug 03, 2012, 09:55 PM
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^Finally someone paid attention to my build video and did it the easy way. This will do just fine. Ideally the wire should be much thinner, but for a first antenna, this is excellent.

-Alex
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Old Aug 03, 2012, 11:21 PM
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Quote:
Originally Posted by Rocketman1092 View Post
Tried my hand at a 5.8Ghz base-fed SPW antenna today. How's it look to you guys, any major issues? I used some copper wire with the hope that it wouldn't be too soft at this small size, and it seems pretty robust. The welding wire I had just wouldn't take solder.
solder looks a bit cold on the top center..only the bottom...which makes me think that may be why you were having trouble getting it to stick to the welding wire..Are you using and iron or a gun? irons are much easier IMHO because they stay hot and you don't have a tendency to rush things, or hold them on too long waiting on the solder to flow causing the insulation to melt... dimensionaly it looks great to me, especially in the center where the elements meet up without any overlap. I have yet to master it...maybe this weekend...
Old Aug 03, 2012, 11:26 PM
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I use a good quality iron with temperature control, but I'll double-check the joint to see if it's cold. I don't think that was the issue with the welding wire though - the solder wouldn't flow even on the high 900-degree setting.
Old Aug 03, 2012, 11:35 PM
wilem is offline
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airplanes r made from aluminum
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Quote:
Originally Posted by Rocketman1092 View Post
I use a good quality iron with temperature control, but I'll double-check the joint to see if it's cold. I don't think that was the issue with the welding wire though - the solder wouldn't flow even on the high 900-degree setting.
wow, the only time i can't get solder to flow is when the wire is coated.. or the tin content is to high, i guess you already tried flux.. the copper wire should be fine anyway at 5.8. just dont step on it.
Last edited by wilem; Aug 05, 2012 at 10:37 PM.
Old Aug 23, 2012, 06:50 PM
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Hey guys, Im understand that a 3db loss occurs if I use Linear antenna on my plane and CP gear on the ground. What I dont understand is how much distance will this translate too. I know i cant get an exact number but how can I correlate 3db off of the overall db of the setup. I guess I am missing something because the 1.95 db of my clover leaf - 3 would be negative lol.... Im confused

Is my 900 clover going to be an issue on my Radian Pro?
Old Aug 23, 2012, 09:34 PM
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I think you lose 3db just because of circular polarization.... or something like that...
Old Aug 23, 2012, 10:25 PM
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Quote:
Originally Posted by elliott000 View Post
Hey guys, Im understand that a 3db loss occurs if I use Linear antenna on my plane and CP gear on the ground. What I dont understand is how much distance will this translate too. I know i cant get an exact number but how can I correlate 3db off of the overall db of the setup. I guess I am missing something because the 1.95 db of my clover leaf - 3 would be negative lol.... Im confused
As I understand it:

The 1.95 has to do with the quality of the antenna. The -3 has to do with polarization as KillerCut said. it goes something like this;

linear to in polarized linear = 0 loss
CP to in polarized CP = 0 loss
CP to linear = -3 loss or vis versa
linear to out of polarized linear [i.e. @ 90* to each other] = -26 [i.e. not much signal]
CP to out of polarized CP [ RH polarized to LH polarized] = -26 or so [WAG]

Null areas excluded I'll take a -3 loss which never gets worse than that, any day compared to the potential of up to a -26 loss because the antennas get perpendicular to each other in flight.

WAG = Wild Assed Guess as I don't know how bad LH CP to RH CP is

HTH

Richard
Old Aug 23, 2012, 10:56 PM
MASHTON is offline
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Quote:
Originally Posted by elliott000 View Post
Hey guys, Im understand that a 3db loss occurs if I use Linear antenna on my plane and CP gear on the ground. What I dont understand is how much distance will this translate too. I know i cant get an exact number but how can I correlate 3db off of the overall db of the setup. I guess I am missing something because the 1.95 db of my clover leaf - 3 would be negative lol.... Im confused

Is my 900 clover going to be an issue on my Radian Pro?
Antennas 101 - Polarization, Diversity & Gain Patterns (27 min 56 sec)
Old Aug 23, 2012, 11:57 PM
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thanks man, ive watched that video like 4 times, months ago when I was startiing out. never remembered the section 17 minutes in lol
Old Aug 24, 2012, 12:49 PM
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No Worries... I forget stuff a lot to.


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