SV-COM radio a bit weak

[madb1rd]

Folks,

I've been flying with the SV-COM radio for about 120 hours now on a new RV-3 and am wondering about transmission and reception range expectations. Generally I cannot receive ATIS transmission from more than about 15-20 miles with the SV-COM even with the unit in no-squelch mode. I've not tested how far it will transmit though. And I've had a couple of instances where close proximity ship to ship transmissions did not work at all, as if I was on the wrong frequency, but I wasn't. So I'm wondering about the best approach to sort out the cause, or if I should be concerned at all. If I should be concerned than the culprits are either the antenna, the coax or the radio. Before I go digging under the hood I was wondering what others are seeing with respect to reception ranges.

 

[Dynon]

Yeah, you should be getting much more than that. Do you know how well/far you're transmitting to other people? Antenna , coax, and connections are definitely the places to start here. Ground plane issues would more likely affect transmission.

 

[madb1rd]

The unit is on an RV-3, with a RAMI bent whip antenna (AV-17). I measured the SWR on it yesterday and it was 1.44 at 136.975, 1.40 at 126.500 and 2.65 at 118.000. It rises from 1.5 to 2.65 from 119.000 to 118.000.

The max power it puts out is 6.4W in the low frequency range, 6.0W mid range and it's down to 3.5W on the high end. I had a piece of RG-142 (solid core RG-400) that I tried to see what happens and the numbers are about the same.

I'm waiting on some RG-400 to arrive so I can replace the cable and then go test fly it. We'll see how that goes, after that I'm not sure what to test. I'll let you know how the RG-400 replacement goes.

 

[RobertHamilton]

Those are good numbers. Given your testing, you may want to contact our tech support folks, get an RMA, send in the radio, and we will test it for you.

-Robert

 

[madb1rd]

Hi Robert,

OK, an update. I got to fly it today. Max range being able to just barely hear ATIS from a large airport is about 30 miles, and it doesn't get user audible until about 12 miles. Transmission range is good inside 15 miles but decays pretty fast much further than that.

The other issue it has always had has been the volume is not strong enough. I have it hooked up to a sigtronics two place unit and I have to have the volume of both the radio and the intercom up to full blast and have the headset volume full up to be able to hear. And this is true of both Lightspeed Zulus I have. And the problem is there with the intercom on or off.

On the radio weakness I could try swapping the antenna out but that requires taking my other RV apart and it seems like the antenna is working like it should. I did do some turns and belly up to see where it was weakest and the gear prop do degrade it some when where the signal is really weak. When the signal is good (closer) they do not effect the reception.

Do I just call your support line to get the repair information? What is the turn around time on that, typically?

 

[Dynon]

Yes, get in touch with our support department at 425-402-0433 or support at dynonavionics dot com. We endeavor to turn things around in 10 business days or less.