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UHF in Urban Environments

#1
So I got the Orangerx openlrs 100mw rx and module a few weeks back. I uploaded the openlrsng firmware sucessfully. They worked perfectly for about 10 flights, until randomly they just stopped communicating. I had no servo control and every time I would plug the battery in the servos would start overheating. It was just really weird. So I grudgingly bought another rx and module, since the flytron openlrs wasn't in stock and I can't afford any other UHF system. Once again I downloaded the firmware and It was working fine until I encountered a lockout about 100m out in a semi-urban environment that just about destroyed my whole plane. After I fixed it I went to fly again in the same spot to see if it was interference that caused the lockout. I ground tested it about 500m and everything worked fine. However, when I flew I could only get 75m tops before I got locked out. I tried a new location. This one was a bit more isolated and I got maybe 200m no problems (that's the farthest I flew). So could interference be locking me out at the more urban place? It is strange because I had never been locked out before even in the same spot. Other than that I would highly recommend avoiding orangerx openlrs because is is just so unreliable. I think rc equipment hates me. I never have consistent success, and I can never fully diagnose my problems.
 

xuzme720

Dedicated foam bender
Mentor
#2
You should be getting much more range on a LRS system. Got any pics of your setup? Maybe there's something there causing the problem.
 
#3
Well if there is something wrong it isn't visible to the naked eye. I'm thinking that maybe there is just a ridiculous amount of interference in that specific area. However, that troubles me because I flew 700m there one time no problem. Then I was flying fpv (going about 500m no problem) when I encountered a lockout. And after that I could only get 50m in that spot whether I was using fpv or not. I have 2 orangerx recievers and I get the same results with both. So weird. I just want to know if anyone has experienced this with the same product or any other UHF.
 
#6
stock dipole on rx and dragon link half wave dipole on tx. I'm going to change my center frequency to around 450 mhz and see what happens. I'll report back tomorrow.
 

vk2dxn

Senior Member
#7
If you are using frequency hopping I would suggest not picking 450 as your center frequency. Try something lower in the simplex portion of the 70cm band. Avoid anything close to repeater inputs or outputs. Google the 70cm band plan for your country to give you a better understanding of how the band is used
 

vk2dxn

Senior Member
#10
I am not sure of how the channel spacing is set up in the firmware but I would try to set them at least 25khz apart. You really need to know how the band is occupied in your area so you can set up your frequencies.
I don't know how good the band pass filtering is in the RX but I would aim to have your channels at least 25khz away from an occupied frequency
 
#11
I tried many different frequencies in the 400 - 460mhz range with no success. I have no idea what the problem is. I'm about ready to quit.
 

KJ4CCH

Senior Member
#13
best watch out using such transmitter in an urban environment. plus with the 100 mw you might want to consider building a different antenna.

I also am looking into openlrs / orangelrs (cant afford to much with a part time job.) I just need to figure out how to wire it all in hahaha. Here is a picture of a band plan by the ARRL.

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make sure you are away from repeaters...even though you might only be transmitting a few miles, you might occasionally start causing interference. 70cm simplex is pretty quiet in most places, most people talk on repeaters. oh and stay away from the satellite stuff.

i really dont think all these LRS products should be put on the 70 cm band. 1.25 meters would be great, i never EVER hear anyone using anything on that band.