Initial range tests, 2.4GHz, 1W tx, range video - RC Groups
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Jan 12, 2009, 09:35 PM
Registered User

Initial range tests, 2.4GHz, 1W tx, range video

Hi Guys,
I received my 1W 2.4GHz and rceiver from range video, I ordered it on thursday and it arrived in NY today (Monday). This guy must have a top rate order processing and shipping department So I had to do a baseline range test:

-antennas that came with the rx/rx (little stick verticals 3dBi??)
-mostly line of sight down a strait road
-transmitter hanging from a tree branch vertical
-receiver about 4 inches above the roof of my car with antenna also vertical
-I drove away from the transmitter while watching the TV in my car and my trip odomoter.

-under 0.5 mile was mostly full quieting
-1/2 mile to 1 mile was noisy but probably usable
-above 1 mile probably too noisy.

I am going to order some decent receive antennas and a yellow yacket diversity. I will post some range results when I get the stuff.

-I am assuming my stick antenna is 4dBi that I can change to a 6dBi and not worry about over my head at high altitude. So that 2dBi
-add the yellow jacket receiver (add divirsity and hopefully a couple of dB of sensitivity after all it costs 5 times the lawmate but I don't know the specs)
-add a 8dBi patch on one input of the diversity rcvr (8-3 = 5dBi)
-add a 15 dbI yagi on the other (15-3=12dBi)

My RF link calculator says the 1 mile goes to 5.4 miles with the above assumptions. At the long range, only the yagi is selected.

Any comments about my plans to buy the 8dBi patch, 15dBi yagi and yellow yacket please post. Cost aside, is the yellow yacket the best?

Also.... I need a signal strength indicator on the lawmate receiver... Where can I tap into the lawmate for RSSI?
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Jan 12, 2009, 10:04 PM
Registered User
I found the RSSI pin. I should have googled it before I posted. It is pin 9. This will take some of the variability out of my range tests.

I read the A/B switch does not do anything as the case was reused but it is conected to a trace and smd component so it has to do something.
Anyone know what the a/b switch does?
Jan 13, 2009, 06:50 AM
Registered User
yellow yacket??? i meant Jacket
Jan 13, 2009, 10:23 AM
JettPilot's Avatar
How far do you want to go ? You do not want the higher gain vertical antenna on your plane unless you are going to extreme range, because the video will cut out badly when you bank and its not vertical.

With a 14 dbi receiving antenna, your range will be far beyond your RC system, and you will have good video to several miles. I would not put the disadvantage of the higher gain antenna on the plane itself unless I really needed it. You will really hate the dropouts everytime you turn.

Your antenna selection on the yellow jacket sounds very good, either a 14 dbi yagi or a 14 dbi patch works very well with the 8 dBI patch for close in work. The yellow jacket is a great receiver, but the picture quality does not seem as quite as good as the lawmate receivers, the yellow jackets picture is a little washed out in comparison, and the colors do not seem quite as good. But the diversity part of the yellow jacket works so well, you will really like using it.

Jan 13, 2009, 03:03 PM
Registered User
Thanks JP
I plan a couple of miles for now... Probably more when I get board. I will probably get an FMA co pilot when I move the stuff form the easy star to a telemaster. I will set it up for shallow turns as to stay vertical. Hopefully the RVOSD can save my bacon if I do bank too much. It is ordered.

I ordered the yellow jacket, 15dBi yagi, 14dBI patch and 19dBi dish. I could not find a 6dBi rubber duck with sma normal polarity. I will post results with RSSI verses distance when it all comes.

Call here is AA2PY... yours? I was really into AMSATS mode J for a few years - 144 up and 432 down.... now not really active
Jan 14, 2009, 09:45 AM
JettPilot's Avatar
Hi Russ,

With the 14 dbi antennas I have been to 15 miles, there is noise in the video, but its very usable. With the 19 dBI dish, you should be able to get close to 30 miles pretty easy. I tried both a 14 dbi patch, and a 14 dbi yagi, they seem to have about the same performance. Dont forget your 8 dBI circular patch for close in, that is a really nice one to have do you dont need to constantly point the antenna in the pattern.

I use copilots, and they are required items for me, signal loss happens, and you absolutely want the plane to level by iteslf when the receiver goes into failsafe. A telemaster is a really nice flying airplane that will carry a lot of weight, a friend of mine has one and its perfect for long range FPV. Good luck, I am anxious to see your project. BTW, advanced class ham here also 73

Jan 14, 2009, 10:21 AM
Registered User
I will find something around 8dBi for close in. I will keep you posted as I get the project going. We are starting slow with an wasy star and I wont even add teh RVOSD untill we move to the telemaster

advanced class ham here also
I beg you pardon "clear throat" extra here
Jan 14, 2009, 11:53 AM
Registered User
Daemon's Avatar
Keep in mind also that range testing from inside a car will always produce
relatively poor results with both 2.4Ghz and 900Mhz, since you're inside
a metal box, which will produce blockage and/or severe multipathing.

Jan 14, 2009, 04:50 PM
Registered User
since you're inside
a metal box
The reciever and antenna were tie wrapped to my roof rack. I guess the reflections from the car roof caused an error in my test. I probably really wont know until I get something in the air.

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