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Old Oct 24, 2010, 05:35 PM
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barok's Avatar
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Originally Posted by Virgis21 View Post
It is located as it is shown in picture.. you can see 2 holes in the main rod and mount rig fits into those holes,so it is the way as shown in the picture now!

Virgis
ok..vertical..straight out not aimed up..will try..

thanks Virgis
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Old Oct 24, 2010, 07:58 PM
BEOWULF
North vancouver, B.C. Canada
Joined Apr 2008
18,592 Posts
here is a video of a yagi being tested non fpv to test landing behind the yagi

you should be able to see the positioning of the yagi as an example and what to expect, as flying around it for video

fpv testing with yagi (4 min 53 sec)


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Originally Posted by barok View Post
ok..vertical..straight out not aimed up..will try..

thanks Virgis
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Old Oct 25, 2010, 02:13 AM
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Hong Kong, Hong Kong Island, Central And Western District
Joined Jun 2008
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OMM - I didn't know that, will repost numbers with camera off then.
So the video signal occupies a twenty Mhz spectrum then?
As you can tell, I'm not much of an engineer, but I'm curious. I was wondering if you know of a website somewhere that explains how this works in layman terms?
Many thanks.

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Originally Posted by Old Man Mike View Post
When a transmitter is modulated by the video camera, the frequency spreads around the center frequency aproximately +/- 10 Mhz. Depending on how the fequency counter measures, it could be confused by the modulation. The best way to measure the center frequency is to disconnect the video camera from the transmitter when you make the measurement.

OMM
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Old Oct 25, 2010, 01:03 PM
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Hong Kong, Hong Kong Island, Central And Western District
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Ok - just tested the BEVRC-Lawmate 1.2G 1W without plugging in the camera.
OMM - you are correct the new frequency counter reading for the channel increases from 1260 to 1267-ish. All other channel readings remain the same.
Plugged the camera back in to see what channels could be actually received by the NGH-Lawmate portable 1.2G receiver. This unit and the BEVRC vtx can only communicate with 1080, 1120 and 1160 frequencies. The portable vrx can only pick up noise on 1200, 1240 and 1280.
Hope this is of reference value to those trying to decide vtx/vrx combinations. Thanks all for the suggestions.
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Old Oct 26, 2010, 10:33 AM
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USA, GA, Atlanta
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Hi Levendis -
I've been looking at getting the BEVRC-Lawmate 1.2G 1W.
So the vRX will receive 1280 but the vTX doesn't transmit 1280?
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Old Oct 26, 2010, 10:54 AM
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Originally Posted by blively View Post
Hi Levendis -
I've been looking at getting the BEVRC-Lawmate 1.2G 1W.
So the vRX will receive 1280 but the vTX doesn't transmit 1280?
I'm another Sunsky 1.2ghz 800mw happy camper. I just got mine in the mail after my BEVRC-Lawmate 1.2G 1W burned out after about an hour of use on the bench. The Lawmate transmitter was running extremely hot, even after I reworked the heatsinks (~185 deg F on the surface).

I have been running the Sunsky 1.2ghz 800mhz for about two hours and it is only about 90 degrees F and rock solid at 1281mhz on CH 9. By the way, since I still have the Lawmate receiver and the DPCAV RSSI meter attached so I checked the output. I have to have wireless bridges for my computer network because the walls interefere so much but using the Lawmate receiver and IBCrazy Vee antenna, the lowest RSSI reading I got was 95. In the same area with the Lawmate transmitter, I got an 85.

So, I'm going to buy another Sunsky transmitter since they're so cheap and another Lawmate Receiver for my second receiver (oracle diversity).

YMMV (your mileage may vary)

http://www.sunsky-online.com/view/13...6+receiver.htm
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Old Oct 26, 2010, 12:09 PM
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Amherst, VA
Joined Jun 2006
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I wrote a new RX antenna tutorial for this band. 11dbi BiQuad. Has pictures and all calculations including precalculated values for 1280 MHz: http://www.rcgroups.com/forums/showthread.php?t=1328260

Should take 1-2 hours to build.
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Old Oct 26, 2010, 01:11 PM
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Hong Kong, Hong Kong Island, Central And Western District
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The Bevrc-lawmate 1.2G 1W that I have seems unable to transmit at 1280, although as OMM suggested my frequency counter test may not be definitive, and that there are at least three other frequencies that can be used successfully. As many have said, it does get very hot in operation, but then so does the Lawmate 500mw unit, and it seems to work as long as one doesn't leave it on the ground, turned on, for too long. You should search for user feedback for the sunsky unit in this forum, but I haven't used one yet myself.
I have both the Lawmate vrx that came with the 1W vtx, and also their portable unit with internal battery. I've only used the portable unit so far, and can reliably use at least three channels, but not the remaining five. Seems solidly built, but with the limited equipment and time I have I can't prove what it cannot do.
The most frustrating bit is that not all FPV video equipment come with instruction documentation so it helps if one is more of a 'radio-nerd'.

Quote:
Originally Posted by blively View Post
Hi Levendis -
I've been looking at getting the BEVRC-Lawmate 1.2G 1W.
So the vRX will receive 1280 but the vTX doesn't transmit 1280?
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Old Oct 26, 2010, 03:45 PM
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Canada, BC, Victoria
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Quote:
Originally Posted by Levendis View Post
The Bevrc-lawmate 1.2G 1W that I have seems unable to transmit at 1280, although as OMM suggested my frequency counter test may not be definitive, and that there are at least three other frequencies that can be used successfully. As many have said, it does get very hot in operation, but then so does the Lawmate 500mw unit, and it seems to work as long as one doesn't leave it on the ground, turned on, for too long. You should search for user feedback for the sunsky unit in this forum, but I haven't used one yet myself.
I have both the Lawmate vrx that came with the 1W vtx, and also their portable unit with internal battery. I've only used the portable unit so far, and can reliably use at least three channels, but not the remaining five. Seems solidly built, but with the limited equipment and time I have I can't prove what it cannot do.
The most frustrating bit is that not all FPV video equipment come with instruction documentation so it helps if one is more of a 'radio-nerd'.

Good to know, thanks for the info! But let's keep in mind that you're speaking directly about the PORTABLE vrx, not the included Lawmate 1W vrx. From everyone I've talked to, including Zoltan @ NG, the included vrx does work receive all 8 channels, including 1280mhz, though not sure on the vtx side. I remember a thread somewhere where someone confirmed 1280 working on both with a scanner, but not sure where it is. It'd be nice if we could get some more test results! Just wanted to clarify for those that are mis-reading the posts.
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Old Oct 26, 2010, 10:29 PM
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Sydney, Australia
Joined Nov 2007
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the lawmate gear does transmit and receive on all channels!!
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Old Oct 28, 2010, 05:16 AM
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Kaunas, Lithuania
Joined Oct 2007
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here is a short flight to 5500m LOS.
with 1.2ghz lawmate 1W stock antenna in the air, and 8dbi patch on the ground.
rc was Dragon link.
I see the diference between Fatshark tx and lawmate. Lawmate gives more bright video but contrast is bad.
Can anyone explane those 3 knobs in lawmate tx to adjust video quality? which one is doing what? Thanks

5500m los (3 min 13 sec)


Virgis
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Old Oct 30, 2010, 01:59 PM
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USA, IA, North Liberty
Joined Mar 2008
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OK guys, I need some help. I received a 13dbi Yagi from eBay here:

http://cgi.ebay.com/1-2-GHz-13-dBi-Y...item414948c86e

It came broken and I contacted them and they shipped out another one. The replacement one is shorter by about 32 mm. I ran some calculations on my Yagi program and sure enough the difference between a 1200mhz and a 1280mhz was about 32mm! I contacted them and stated that they sent the wrong Yagi it was 1200mhz when I ordered a 1280mhz. They said that they are all the same and that 1200mhz is the center frequency.
Could any of you who got the 1280mhz Yagi measure from the center of the reflector to the center of the element furtherest away?

I'm including a picture of the 2 antennas.

The top one is the 1280mhz with the last element missing and the 4th element broken in half looking at it from the end.

Also if any of you are using the 1200mhz antenna, what is the same measurement?

Thanks.
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Old Oct 30, 2010, 02:16 PM
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South Africa, Eastern Cape, Port Elizabeth
Joined Sep 2010
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Ok guys.... question.

Will this yagi work on the 1.3G system from BevRC?
I see there is a "frequency overlap" with the 1.2G and 1.3G system.
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Old Oct 30, 2010, 02:19 PM
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Virgis21's Avatar
Kaunas, Lithuania
Joined Oct 2007
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Crist Rigotti,

I suposse to get mine soon, so will replay as I have it on my desk!

Virgis
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Old Oct 30, 2010, 04:09 PM
BEOWULF
North vancouver, B.C. Canada
Joined Apr 2008
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yes it should work

mine works with the fox tx useing 1240

I have also tested it out with 1360

Quote:
Originally Posted by Bakkie View Post
Ok guys.... question.

Will this yagi work on the 1.3G system from BevRC?
I see there is a "frequency overlap" with the 1.2G and 1.3G system.
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