SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Oct 31, 2014, 09:58 AM
Registered User
Joined Sep 2013
97 Posts
Discussion
433mhz what can i expect?

hi,

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 ?

thanks

(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...)
fpvrook is offline Find More Posts by fpvrook
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 31, 2014, 12:13 PM
The Fixer
Martin Y's Avatar
Canada, ON, Milton
Joined Jan 2009
3,856 Posts
I'd be checking other than the ez unless you know for sure it was the control. Do you have rssi displayed or recorded the gs video?
Martin Y is online now Find More Posts by Martin Y
RCG Plus Member
Latest blog entry: Flyfly Fox Glider
Reply With Quote
Old Oct 31, 2014, 12:39 PM
Registered User
Joined Sep 2013
97 Posts
Quote:
Originally Posted by Martin Y View Post
I'd be checking other than the ez unless you know for sure it was the control. Do you have rssi displayed or recorded the gs video?
hi,

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.
fpvrook is offline Find More Posts by fpvrook
Reply With Quote
Old Oct 31, 2014, 12:45 PM
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,938 Posts
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.
Daemon is offline Find More Posts by Daemon
RCG Plus Member
Old Nov 01, 2014, 08:40 PM
Registered User
Joined Sep 2013
97 Posts
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.....
fpvrook is offline Find More Posts by fpvrook
Reply With Quote
Old Nov 02, 2014, 12:16 AM
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,938 Posts
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.
FPV - Cold snowy flight. (7 min 24 sec)

and another during the summer on the move
FPV - 13.5 mile flight cross country from vehicle (22 min 50 sec)


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.
Daemon is offline Find More Posts by Daemon
RCG Plus Member
Old Nov 02, 2014, 03:15 AM
Registered User
Joined Sep 2013
97 Posts
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?
fpvrook is offline Find More Posts by fpvrook
Reply With Quote
Old Nov 02, 2014, 10:19 AM
Registered User
Deadstick 8409's Avatar
Joined May 2010
1,023 Posts
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.
Deadstick 8409 is offline Find More Posts by Deadstick 8409
Reply With Quote
Old Nov 02, 2014, 12:57 PM
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,938 Posts
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.
Daemon is offline Find More Posts by Daemon
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion What would you expect behind the blue door? TDboy Sailplane Talk 8 Oct 31, 2014 05:43 PM
Question Your Opinion: Can we expect 2m foam jets or not? hklagges Large EDF Jets 12 Oct 03, 2014 09:31 PM
Discussion Hexi, Quad, what to get, and what to expect ydeardorff Multirotor Talk 5 May 14, 2014 04:12 PM
Discussion Change Sun 90mm 12 bladed fan, what can I expect? GregG Electric Ducted Fan Jet Talk 26 Feb 09, 2014 07:33 AM
Discussion What range can I expect/why can't I go as far as <insert name here> IBCrazy FPV Talk 85 Jun 03, 2011 02:54 PM