Transmitting problems

[ozbendigo]

Hi everyone

 

I found the forum while looking for a solution to my radio problem.

 

I fly an Airborne Edge X 2002 Microlight with an Icom A22E hand held radio and Raptor A22 intercom and headsets. (+ Black Widow antenna)

 

Reception is very good but my transmission is terrible.

 

Transmission reported at the weekend in the circuit as less than 1. Volume is great, but sounds like electrical interference with very faint audio in the background.

 

I am at a loss to know where to start. If anyone has an idea I would be pleased to hear from them

 

Cheers John

 

 

[skeptic36]

Hi John,

 

to the forums.

 

I can't help with your problem, but there has been a lot of discussion about aerials here , maybe you will be able to glean something from there.

 

Regards Bill

 

 

[Guest Andys@coffs]

So from what you've told us:-

 

a) rx is Ok

 

b) Tx (inferred) Signal strength is Ok

 

you can probably ignore the antenna

 

So heres what I would do:-

 

1) have someone with another radio at a reasonable distance on the ground.

 

2) Choose a frequency in advance that you know is unused in your area. Use the PCA charts and the ERSA to ensure that any frequency you use isnt related to Airports or Pilot Activated Airport lighting or area frequency or anyother ATC function. Agree the frequency with the person in 1)

 

3) When they are at a reasonable ground distance to test the radio (anything around 1-2kms will be fine I would have thought, 1km is adequate.

 

4) test on the ground (Engines off) with full suystem have them respond in terms of audio readibility and also signal strength. The later is determined without a strength meter by the amount of background noise in the signal. A keyed radio that immediately makes the reciever with Squelch off change from background hiss to nothing is probably a 5 and when the background hiss only marginally reduces a 1 for the extreme ends.

 

5) repeat 4) again but this time with the intercom and headsets etc out of circuit, That is just using the handhelds internal speaker and microphone.

 

6) If the difference between 4 and 5 is huge then the problem lies with the intercom and headsets. If almost no difference then the fault lies with the radio. Note this isnt defiitive, there is a possibility, though remote, that the external audio and or microphone circuits on the radio are faulty, but as they say "if you hear hooves think horses not zebras in Australia" In otherwords this type of radio failure is likely remote. If you want to discount it entirely substitute your radio with another of its type to see if the fault remains. If unsure if your radio and the external circuitry will even work together (and I cant imagine for a moment that an A22 wont work with external circuitry) then substitute an alternate brand/mode of radio.

 

7) repeat 4 with engine on. If difference between this 4) and last 4) then the problem is likely engine interference related.

 

Report back your findings

 

Andy

 

 

[ozbendigo]

Thanks Andy

 

I will give that a try and report back. Radio reconditioned and test by ICOM last year, so it should be OK.

 

Cheers John

 

 

[ozbendigo]

Thanks Bill

 

I have had a good look at aerials discussion and found some very useful information there. I will get back to the forum when I have had a run through Andy's suggestions

 

Cheers John

 

 

[Guest Kevin the Penniless]

The antenna needs to present a correct 'load' to the transmitter. If you have a SWR meter (VHF) you need to check the match is reasonable (say less than 2:1). Antennas on some aircraft leave a lot to be desired. By the way, I am (was) a radio techo in my early working life.

 

 

[ozbendigo]

Andy, Bill and Kevin

 

Thanks for your advice. I ran through the check list offered by Andy, using two identical radios and an obliging mate. Nothing much changed, swapped the radios around, changed a lead no difference, tried different headsets, different PTT and repositioned the aerial@$#@!!

 

Today as a last resort dragged out the old 1/4 wave wire aerial mounted it on the trike - hallelujah - reading you 5 John!!!!!

 

Thanks again for your help, thanks to the guys in the Bendigo circuit for putting up with my numerous radio checks.

 

So where to go with the "Black Widow" aerial? I will talk to the supplier and see if they have any suggestions.

 

Cheers John