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Old Jul 23, 2010, 07:23 AM
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1.2-1.3Ghz Tx/Rx All infos on one page - updated: 27/10/2013

Hi Folks,

About time I update this super old thread with the latest standards.

So you want to do some FPV on 1.2Ghz and you're looking for answers? You've come to the right place!

For those who don't want to read all the details here are 3 configurations that just work perfectly on a legal frequency 1280Mhz:

CONFIG 1: an ultra-small aircraft / close range



Link



CONFIG 2: Normal airplane / Quad and around 3-4km (depends on your noise floor)


Link

Use stock antennas or Circular Polarisation Omnis on both TX and RX

Fan or Skew Planar wheel


CONFIG 3: Normal airplane / Quad and long range




Link

Tx Antenna: Circular Polarisation Omni

Fan or Skew Planar wheel

Rx Antenna:

Crosshair or Pepperbox or Helical


For these 3 configs you will need a receiver:

Get a lawmate



I have been using one since day one 5 years ago and it's still kickin' it's the least you should use (not the digital ones bundled with the fox 800)

or look at the RECEIVERS section below and pick a better one.



ANTENNAS

First you have to know that there are Linear polarisation Antennas and Circular Polarisation Antennas

Linear Polarisation:

+ Tough antennas (you can step on it and still fix it)
+ Cheap
+ Very easy to DIY

- Signal getting weak when plane is banking
- Prone to multipathing (more interferences)

Circular Polarisation:

+ Very good signal in all kind of situation, the best you can get.
+ Handles low altitude way better than Linear
- Fragile
- Not Easy to DIY
- Expensive (the good ones)
- not easy to install on aircraft because of its shape

Don't get me wrong linear polarisation is still a good solution in some situations, for example for ground FPV most guys use a dipole on their car + patch because if the car tumbles the antenna can handle it. A dipole + yagi will bring you very far.


LINEAR POLARISATION:

Monopole:

Stock fox-800 (for TX or RX):

Dipole: better then Mono

Make yourself a Vee Antenna: Link to DIY.


On the Rx side if you want to go for long range:

Patch: Biquad: Yagi:


CIRCULAR POLARISATION

The omnidirectional ones (TX or RX):






Long Range Rx Antennas
:

Helical DIY Tutorial (not easy)
Crosshair DIY Tutorial (go for it)

Pepperbox No tutorial / High Performance


For near space attempts:The Gattling (400$!!!)

Or

a Helical in a Satelitte dish (Yep that's Insane):


Lost in antenna choice? Watch this Video from the master (before he invented the pepperbox) and read following Guide:



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Old Jul 23, 2010, 07:24 AM
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TRANSMITTERS

UNDER CONSTRUCTION

FOX-800

Price:56USD including shipping
Buy
Weight: 23 grams or .81oz once uncased
Frequencies (Channel:Mhz): 4:1080 / 5:1120 / 6:1160 / 7:1200 / 8:1240 / 9:1280 / 10:1320 / 11:1360

+ Best Bang for your Buck
+ Tough
+ LCD Screen and easy channel switching
- looses power with voltage (you can add a voltage reg if you want for long range projects, but I didn't)
- The Rx sold with it is rather crap (sensitive to UHF signals and overall interferences)

Many reports showing this one is very good, up to 2-3 kms Stock configuration
Real Power output: 500mw

Hints:

- You must uncase it, no risk of overheat
- Tx is smaller and is more powerful then the fox-700 See Vs Test here
- Frequency choice made with a button not a jumper


LAWMATE 1W v1



+ Powerful
+ Does not loose power with voltage
- Overheating problems (watch out! don't leave it unattended or fly under heavy sun)
- Audio quality is rather crap
- channel change with dip switches
- Not Sold anymore

THE LAWMATE 1W v2



Price:80USD + shipping
Buy
Frequencies (Channel:Mhz): 1:1080 - 2:1120 - 3:1160 - 4:1200 - 5:1010 - 6:1040 - 7:1240 - 8:1280Mhz

+ Powerful
+ Does not loose power with voltage
- Video level may need to be adjusted
- channel change with dip switches
- expensive!

RECEIVERS


RMRC (one extra for the saw upg, version)


Frequencies (Channel:Mhz): 1:1258 - 2:1280 - 3:1320 - 4:1360
Price:50USD + shipping
Buy

Price:80USD + shipping (Saw Upgraded Version)
Buy

+ Rather good Quality
+ Supports 1258Mhz (other US legal Channel, must be used with a compatible RMRC TX)
- Only 4 channels supported
- No LCD



DPCAV COMTECH + 1258Mhz (one extra if you mod it with a better SAW filter)


Price:56USD + shipping
Buy
Frequencies (Channel:Mhz): 1:1258 - 2:1280 - 3:1320 - 4:1360

+ Very Good Quality
+ Supports 1258Mhz (other US legal Channel, must be used with a compatible TX)
- Only 4 channels supported
- No LCD

STANDARD DIGITAL RX


Price: You get it bundled with the Fox800
Buy
Frequencies (Channel:Mhz): 4:1080 - 5:1120 - 6:1160 - 7:1200 - 8:1240 - 9:1280 - H:1320 - C:1360

+ The Cheapest
+ LCD
- very sensitive to UHF signals
- Quality Control
- Some have old F-connectors

In a nutshell: Don't use it if you have a Long Range system or at least with good separation between the Rx and your RC Transmitter (2 meters +). Some may work up to 3kms but some are just crap so it's kinda a lottery.

LAWMATE++ (too many pics in the post)


Price:37USD + shipping
Buy
Frequencies (Channel:Mhz):
(Switch A) 1080-1120-1160-1100-1140-1180
(Switch B) 1080-1120-1160-1200-1010-1040-1240-1280

+ Average Quality (some units have issues).
+ Rather cheap
+ numerous channels
- Channel switching using dip switches
- No LCD
- No 1258Mhz

Not the star of the fpv community but I cannot blame mine as it always worked OK (5kms)


KNOB TYPE RECEIVER



Price: Don't you dare buy this trash!
Frequencies (Channel:Mhz): Drifting

- Very bad quality

Don't use one to Fly!


GENERAL QUESTIONS

TO BE CONTINUED
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Old Jul 23, 2010, 08:39 AM
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I recommend useing a "lawmate" video rx

over those that comes with the combo

edit it also works well with that $27 one
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Old Jul 23, 2010, 09:23 AM
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Quote:
Originally Posted by iacei View Post
Other reliable combos:


Hints:

- 6-7-8 Channels seem to work the best
- Rx has a 17Mhz Saw filter which is good (no need to make the Saw filter mod)

Chart containing the available frequencies
Did you notice if this hint applies only to Sunsky units, or both Sunsky and BOB units?
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Old Jul 23, 2010, 09:29 AM
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Only for the sunsky.

In fact the BoB Rx seems to have a classic SAW filter which would be interesting to mod but I di d not find someone who did it on the bob.
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Old Jul 23, 2010, 09:46 AM
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Oh, sorry I meant specifically the part about channels 6-8, but I assume that is Sunsky as well.

Maybe I should have tried the Sunsky instead of the BOB but I though they were the same at 1st.
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Old Jul 23, 2010, 01:15 PM
GOK
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I have recently purchased the sunsky 1.2 Ghz 800mw system. We did a ground test with a friend. Vtx 5th floor of a building on the skirts of a hill, Vrx drove away with a car. We had clear video without any interference at 2.8km LOS. This of course was without and RC equipment around. Stock antennas out of the box, no patch, no diversity etc. This was on channel 8.

GOK
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Old Jul 25, 2010, 02:08 PM
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Nobody is talking about this one ?
http://www.dinodirect.com/1-2GHz-Min...0.html?cur=EUR
It's fixed on 1080mhz.
I've ordered one, hope to have it in a week
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Old Jul 25, 2010, 04:29 PM
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Give us feedback when you test it. I think Renatoa reported it is a good one.
.
Did a test today to check some things:
I confirm the custom Vee is way better then the stock rubber duck antennas
I did not see a big difference between the lawmate rx and the Fox one (not on a very long distance though)
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Old Jul 25, 2010, 05:58 PM
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After shipping the Sunsky one is almost the same price as a Lawmate, isnt it? Why you get the Sunsky over the LM in this case... the extra "300mw" (if they are really there). I thought LM was about the best you can get if you dont mind 5v power. Or does LM not have the legal channels (USA)???
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Old Jul 26, 2010, 01:58 AM
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the lawmate is 12 volts
and is a much better video rx

all channels are available with the lawmate video rx



Quote:
Originally Posted by Derek_S View Post
After shipping the Sunsky one is almost the same price as a Lawmate, isnt it? Why you get the Sunsky over the LM in this case... the extra "300mw" (if they are really there). I thought LM was about the best you can get if you dont mind 5v power. Or does LM not have the legal channels (USA)???
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Old Jul 26, 2010, 02:45 AM
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Quote:
Originally Posted by Derek_S View Post
After shipping the Sunsky one is almost the same price as a Lawmate, isnt it? Why you get the Sunsky over the LM in this case... the extra "300mw" (if they are really there). I thought LM was about the best you can get if you dont mind 5v power. Or does LM not have the legal channels (USA)???
Where do you find a Lawmate Tx/Rx for 65USD shipped?

I had a Lawmate Tx/Rx for more then 100USD shipped and the Tx was good but a bit fragile.
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Old Jul 26, 2010, 05:52 AM
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Oh, sorry, I rechecked the lawmate is about $30 after shipping. But still, $30 difference for a 'better' Rx and Tx, if you dont mind 5v?

I say 'better' becasue I do not have a Lawmate, I just have asked several of the veteran FPV'rs here and ALL of them I asked told me Lawmate was the way to go. Granted they also are mosly using the 2.4 channels. And When I asked David22, he at least uses a LM RX. (Thanks David for your advice)

BUT, I also do not have a Sunsky unit. I have only 2 BOB units, which for me are working out to be a waste of money. Range just really sucks, not even counting that I am getting local interference at my favorite field (but not the BOB's fault I guess). I wish I would have tried Sunsky, as they seem to be better units. Kmart is getting 1 mile with stock omnis? JEALOUS
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Old Jul 26, 2010, 06:24 AM
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If you do not reach good ranges with 2 Bob units I guess there is something wrong with your setup. A sunsky would not help you out here.
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Old Jul 26, 2010, 07:14 AM
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It not just me. At least one experienced member (IBCrazy) has the same problem with BOB only 1000' with stock units. Check his posts if you want more info, he is pretty knowledgeable, more than I am. I have not tagged along in the BOB dedicated thread lately, so there may be more, or IBCrazy and myself may be alone in this.

I also get much surperior range in the exact same airframe with a cheap FOX style 900mhz system. The BOB fades at 1000' for me very badly, as it did for him. I get a lot of interference here in the city, too, which is not entirely the BOBs fault but could be intensified by a presumed poor receiver sensitivity of the BOB. I have not yet dared to find the limit of my 900 sytem, but I have gone at least 2000' on 500mw.

Another discussion on BOB is that it has an F type RF connector, 75ohm, where most of use use SMA. This poses another albeit minor problem with (possibly) mismatched impedance and connector/adapter losses. Check my thread on multipath for a little discussion on that. I am not sure what Sunsky has? SMA hopefully?

I really dont think it is a airframe systems problem as I have tried various configurations with proven equipment (at least what works for others on this forum). I am not saying the BOB is bad, I am just saying it hasnt worked as well as a 700mw unit should in a rural area. I have not seen very many people say it is working great for them (but I have not searched thoroughly) but I do seem to keep finding good posts the Sunsky system. I would never had thought they were different, but perhaps they are.

I also tried it in a completely different airframe with totally different and very simple/mimimal electronis with the exact same results. I will need more testing to confirm, but it just looks like I might have got a bad draw as far as quality control goes.

EDIT: I just spent a bit looking through the thread. I have not found any consensus, but maybe just one out of every few units is really good? I really dont know but there do seem to be quite a few people happy with the BOB.
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