Thread Tools
Old Oct 28, 2011, 08:18 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
^That's the right stuff. I got my crimper at RadioShack, believe it or not. Works fine. Not racheting or anything, but that's ok by me. The only problem is that it doesn't crimp the center pin. I use my L-COM crimper for that but you can solder it, no problem.

Usually the easiest thing to do is type "RG58/U SMA male jumper" into EBay's search engine. That will come up with a bunch of cables you can buy and just cut in half. No crimper needed. I also sell them on my website in 48" lengths with two SMA male ends on them for use making your own DIY antennas.

-Alex
RCG Plus Member
Sign up now
to remove ads between posts
Old Oct 29, 2011, 02:40 PM
The Flying Farmer is offline
Find More Posts by The Flying Farmer
^Its what I do^ - FPVholic
The Flying Farmer's Avatar
Bump
Anyone?
Is this cable and a FME female connector 50ohm? I can't tell. Again this is for a 1900Mhz for cell network
Old Oct 29, 2011, 02:45 PM
The Flying Farmer is offline
Find More Posts by The Flying Farmer
^Its what I do^ - FPVholic
The Flying Farmer's Avatar
Cable with fme connector
Old Oct 29, 2011, 09:16 PM
p3jpaavi is offline
Find More Posts by p3jpaavi
Registered User
Hi i think I have all the parts what are needed to build this antenna. I have couple questions still.

Picture 1 : Does it work if I take the plastic shield away when it goes true the reflector and solder it to reflector and to the two cable ends ?

Picture 2 : I will solder the to cable ends to the ground and the middle of the cable to the "singnal wire" ?
Old Oct 31, 2011, 09:25 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by The Flying Farmer View Post
Bump
Anyone?
Is this cable and a FME female connector 50ohm? I can't tell. Again this is for a 1900Mhz for cell network
Yes, that's 50 Ohm cable.

-Alex
RCG Plus Member
Old Oct 31, 2011, 09:26 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by p3jpaavi View Post
Hi i think I have all the parts what are needed to build this antenna. I have couple questions still.

Picture 1 : Does it work if I take the plastic shield away when it goes true the reflector and solder it to reflector and to the two cable ends ?

Picture 2 : I will solder the to cable ends to the ground and the middle of the cable to the "singnal wire" ?
Picture 1: Yes. It will work ok.

Picture #2: Yes. Simple as that.

-Alex
RCG Plus Member
Old Nov 03, 2011, 05:12 PM
Kahnx is offline
Find More Posts by Kahnx
Registered DSer
Kahnx's Avatar
I'm currently building my first bi-quad. at 1040MHz.

IBCrazy, you mentioned that you can reduce the size of the reflector (to a minimum of the size of the bowtie) with some loss of gain. How much would you expect to loose at the minimum size? and would this increase the size of the side lobes (for better landing)? Would a minimum size reflector reduce a bi-quad back to the level of, say a std patch?

Thanks

Roger.
Old Nov 04, 2011, 09:19 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
The reduction of the reflector can drop the gain as low as 9dbi. The problem is that most of this drop appears in the back of the antenna, not the sides. If that is acceptable, then go for it. However, I find using the standard BiQuad works better for me, so I leave the full reflector.

-Alex
RCG Plus Member
Old Nov 04, 2011, 03:45 PM
rbcodell is offline
Find More Posts by rbcodell
Registered User
Hi Alex. I would like to try the CP biquad on 910 mhz. Did you post this somewhere? Are you using a length of coax to get the 90 degree phase shift?
Regards
Richard
Old Nov 05, 2011, 07:30 PM
Kahnx is offline
Find More Posts by Kahnx
Registered DSer
Kahnx's Avatar

Bi-Quad build failure - and hints pls?


I've just finished building my first bi-quad at 1040MHz.

Tested it for the first time and it is terrible. The commercial 8 dbi it is intended to replace has heaps better reception in a basic 'reception signal pointed through my house' test. When there's no signal left at all on the bi-qaud, the patch picture is perfect. Humph!

I've attached a couple of photos of the antenna, focussing on my ordinary soldering skills. Nonetheless, the centre conductor and shield conductors are not touching at the intersecting lines of the bowtie, and there is no bridging of solder. At the edge of it's range it does exhibit some polarisation effect.

Can anyone see an obvious error or otherwise make a suggestion on improving it? Thanks in advance. Roger.
Old Nov 05, 2011, 08:34 PM
bakchos is offline
Find More Posts by bakchos
WannaBeLikeJoshTheSlowJet
bakchos's Avatar
Quote:
Originally Posted by Kahnx View Post
I've just finished building my first bi-quad at 1040MHz.

Tested it for the first time and it is terrible. The commercial 8 dbi it is intended to replace has heaps better reception in a basic 'reception signal pointed through my house' test. When there's no signal left at all on the bi-qaud, the patch picture is perfect. Humph!

I've attached a couple of photos of the antenna, focussing on my ordinary soldering skills. Nonetheless, the centre conductor and shield conductors are not touching at the intersecting lines of the bowtie, and there is no bridging of solder. At the edge of it's range it does exhibit some polarisation effect.

Can anyone see an obvious error or otherwise make a suggestion on improving it? Thanks in advance. Roger.
Looks like cold joint, you need to get that wire hotter and the solder will create a better joint.
Old Nov 06, 2011, 05:38 PM
Zahnarzt is offline
Find More Posts by Zahnarzt
Earth's Mightiest Hero, KC9TBO
Zahnarzt's Avatar

Finally Done


Here's my finished 900MHz BiQuad. Amazing what a can of Krylon can do. I hot glued the sheet metal to some foam board, so it's nice and light and can be easily mounted to my antenna tracker with heavy duty 3M velrco-like material. Haven't tested it on the actual plane yet.
Old Nov 07, 2011, 08:30 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by rbcodell View Post
Hi Alex. I would like to try the CP biquad on 910 mhz. Did you post this somewhere? Are you using a length of coax to get the 90 degree phase shift?
Regards
Richard
The build for the CP version is in the Video Aerial Systems forum on FPVLAB.

I even made a how to video for it: http://fpvlab.com/forums/showthread....e-Quad-antenna

-Alex
RCG Plus Member
Old Nov 07, 2011, 08:32 AM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by Kahnx View Post
I've just finished building my first bi-quad at 1040MHz.

Tested it for the first time and it is terrible. The commercial 8 dbi it is intended to replace has heaps better reception in a basic 'reception signal pointed through my house' test. When there's no signal left at all on the bi-qaud, the patch picture is perfect. Humph!

I've attached a couple of photos of the antenna, focussing on my ordinary soldering skills. Nonetheless, the centre conductor and shield conductors are not touching at the intersecting lines of the bowtie, and there is no bridging of solder. At the edge of it's range it does exhibit some polarisation effect.

Can anyone see an obvious error or otherwise make a suggestion on improving it? Thanks in advance. Roger.
Polarization maybe? Do you have the bowtie flat or is it stacked like an "8"? The BiQuad absolutely rocks. It's not very easy to build, though... I'd double check all my connections and be sure that the coaxial cable did not melt when soldering. You might have a short there.

-Alex
RCG Plus Member
Old Dec 15, 2011, 09:58 PM
p3jpaavi is offline
Find More Posts by p3jpaavi
Registered User
Hey,

a question I mounted my antenna to tripod. What i did is that I drilled a hole to the antenna plate an mounted it there to the tripod using the tripod mount screw. Does this affect my range ?
Last edited by p3jpaavi; Dec 15, 2011 at 10:36 PM.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log How To Build a BiQuad RX antenna Talajouy FPV Talk 21 Dec 23, 2010 12:52 AM
Question DIY Biquad antenna for a 900mHz Moosthegoose FPV Talk 5 Jan 14, 2010 04:37 AM
Discussion Antenna tutorial JIMOOO FPV Talk 1 Feb 25, 2007 01:04 AM
Discussion looking for a DIY tutorial. TonyBAMF Beginner Training Area (Aircraft-Electric) 8 Jan 10, 2006 05:56 PM
I need help to DIY flywire antenna for 36 MHZ RX GoodHeli Radios 5 Aug 24, 2003 09:05 PM