|Oct 31, 2014, 09:58 AM|
Joined Sep 2013
433mhz what can i expect?
flying today with my 250 size quad with 1.3ghz video(800mw) and ezuhf 4ch receiver on it ..
my tx is a ezuhf powered by 2s li-ion(so slightly lower voltage then recommended)
set at full power(switch)
i was flying low over the fields at a non populated area i was about 500meter far and 3meters high , suddenly the motors stopped(fail-safe is my guess)
my video signal was still very good till it dropped in high weeds offcourse .
luckely i had a lost model alarm on board ,i never would have found it again without this.
guess it is very normal this happend but i expected my video becoming much worse before the rc control cut out .
any comments ?
(i was checking bounderies of my system and like i said i expected to loose video much fater then rc , no houses otr people in the area and failsafe programmed so it cuts off so it was no daneger to anyone...)
|Oct 31, 2014, 12:39 PM|
Joined Sep 2013
no recordings , it feld like it went into failsafe for a brief moment and i might regained connection wthin a second or 2 but because i was so low and i didn't pushed full throttle it went into the high weeds .
i just passed over some water , i know it isn't to good for radio contact but the video didn't suffered from it .
should i be able to fly 500meteres out at only 3 meter high? i heard of a rule 10:1 (distance vs height) but not sure wheter this is frequency dependant?
either way i was 500:3 .......
i'm looking further into rssi displayed , no video captured.
it actually feld like i was dragging a line which got caught for a moment (nose went up a bity and then the quad dropped , i think i got control again went it crashed (no damage) but i'm not sure , i am sure i didn't hit anything as nothing but high weeds where there and i was flying 2 meters above it.
|Oct 31, 2014, 12:45 PM|
Yes, you should be able to retain control anywhere you have video, and should be able
to fly 3m up at 500m out.
Most likely you're experiencing some sort of onboard interference that's reducing the range of your ezUHF.
ezUHF has a micro-power range test. Set a baseline range with just the receiver powered (ideally
with just a battery), and then repeat the range test with everything else on your quad powered up.
If you experience a significant reduction in range, de-power various components until you isolate
what is killing your range.
|Nov 01, 2014, 08:40 PM|
Joined Sep 2013
found the issue!
boy is my face red
did some tests & found a very obvious reason which i looked over...
i fly fpv from in my car , doors&windows open .
video receiver is on the car roof but i'm in the car with my tx....no further explanation needed i gues.....
|Nov 02, 2014, 12:16 AM|
I've flown from inside a vehicle many times, but I do make sure
the UHF antenna is high enough that it has clear LoS out of the window openings.
Here's a flight done from inside my truck in the winter.
In fact two of us were flying from the same vehicle.
and another during the summer on the move
I've done range tests with my UHF Tx outside the vehicle, and
UHF Rx inside the vehicle out over 30 miles, so it's not like the car itself
is the problem. I still suggest that you utilize your micro-power range
test mode to make sure you don't have some onboard source of interference
that is cutting your range.
|Nov 02, 2014, 03:15 AM|
Joined Sep 2013
ok , i will do more testing , i'll look into cutting the tx power to rangecheck.
what i did first was unplug esc, video and power the rx with a battery and connected a servo on motor ch.
stick up and servo went to one side , took my bike and went down the road , approx 1mile with lots of houses between tx and rx no failsafe .
then plugged back in all gear and drove my car down the road (with tx inside , after only 70meters it went into failsafe , tx was on passenger seat this time.
while i was flying the steering wheel and probably the whole front of the car was blocking the rx so i think theres a good chance the car was the issue .
i should putmy ezuhf tx on top of the car too while flying , would a long trainer cable to my controller (futaba T8fg) be any problem, i guess not?
|Nov 02, 2014, 10:19 AM|
I use a transponder. It does however get away from the KISS principle, but keeps the higher energy UHF away from my radio, video, and interference. On a tripod, I have mounted in a radioshack project box a frsky rx shooting PPM into a hawkeye deluxe 1 watt transmitter. I will actually be putting two frskys in there, so I can choose between single stick or conventional transmitters on any given day. It also has a low voltage alarm and large number volt display on unit. Works a treat.
For your situation, it would work great. Place the tripod outside on the highest thing near your car.
|Nov 02, 2014, 12:57 PM|
Even with your UHF Tx in the passenger seat, it should *not* lose the signal at 70m.
You've got some other issue, but are creating correlation without causation by
adding too many variables to your tests. Put the Tx somewhere with clear LoS to the car
at or above waist height (do not put it on the ground. That'll create multi-pathing)
Do the micro-power range test with the Rx powered by a battery sitting on the dash of your
car and drive until it loses signal (drive till the lights on the Rx stop blinking).
Then repeat the test with Rx installed in your quad and everything powered up, with it also
sitting on the dash of your car.
I suspect you'll find the range of the 2nd test (with all else being equal) will be significantly
reduced. That indicates something on the quad itself is interfering with the UHF Rx.
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