Microair transmit issue in new Jabiru

[rankamateur]

Some devices must not give a stuff about interference! The bloke unloading my shed kit yesterday was using a remote control on the Hiab and I couldn't sit in the ute within 100 yards of him for noise on the UHF with the squelch turned right up.

 

 

[Roscoe]

I guess you checked the pin in the end of the antenna ( radio end ) not crimped properlymike

Mike had a look at the Radio end of the Antenna Cable today and yes,not crimped properly and BNC loose. Cant do anything on weekend but will get fixed and reconect

 

 

[Roscoe]

And assumed that Radio Tech checked this when Radio removed. Radio will be reconnected after another Bench check asap and i will let you know how it goes.

 

 

[Roscoe]

What he said, exactly the same for me.....Id also agree that DC sag under Tx is something I'd be quickly testing for. With the Aircraft running see if you can measure with a DC voltmeter the supply voltage to the transceiver (at the 25 pin D connector) on Rx and also again during Tx........an older analogue voltmeter may be a better tester than an LCD voltmeter for this one...... I personally would be surprised if the jab antenna could cause distortion on Tx especially if the SWR shows good fwd to reflected power ratios so IMHO changing antennas would be the last thing I looked at not one of the first and only if I can prove a fault but cant fix because I cComant get to it.....

 

Have you changed headsets recently? I asked previously about avionics changes and you said nope, but if you've added ANR headsets or changed brands etc then that's a change I would want to know about... All headsets should offer the same interface characteristics but in reality they don't and that's why there is a mic gain adjustment on the side of the radio (not really an end user adjustable device rather a tech adjustable with test equipment)

 

BTW is the problem only in the aircraft when its running? or is it present on the ground with avionics on but motor off....

 

Andy[/Q

 

Andy the Com Antenna Cable runs UNDER the floor back to the Rudder correct?

 

So,if down the track another Antenna was fitted then an underbelly Antenna would do the job if the existing encased Rudder Antenna was faulty or badly connected.

 

Do you think that is an option rather than having to remove the Rudder?

[Roscoe]

Roscoe you would just leave the aerial in the tail it is just aluminum fibre glassed onto the vert fin of you chose to not use it againSo many jabirus use this in fact probsbly 99% so it could be fixed for sure it is just wire screwed to a strip of alloy

 

Comant aerials cost around 400 with coax. Mount to roof or underneath they come straight for the roof of bent for underneath

Thanks for that, so the Fin has to come completely off to get access to the Antenna?.....And have you heard of A Jab Antenna problem before?......appreciate y our input Deb

 

 

[RKW]

Roscoe, do you have a separate intercom in your Jab? If you do, the problem may be in the intercom and not the radio.

 

 

[Roscoe]

Roscoe, do you have a separate intercom in your Jab? If you do, the problem may be in the intercom and not the radio.

Yes separate intercom but no difference with intercom turned off.

 

 

[Roscoe]

If as stated before, you have a good SWR I can't see another antenna making any difference. I would test the operation with the original micro air headsets to eliminate that option - can't see the aerial causing distortion.Have had one installation giving "broken/distorted/blocking " transmissions - radio checked OK on bench, SWR checked mid range OK, put back in aircraft and worked fine. My conclusion, although unable to prove it, a bad connection on one of the coax connectors. Might be worth checking or reterminating them.(as referred to previously by AVOSET)

Frank yes as mentioned in another thread, i have just located a poor crimping issue at the Radio endof the Antenna coax.

Will keep you posted.

 

 

[coljones]

Has your tech tested another, known good, radio in the plane to prove out the total installation. If the other radio works you can then limit the search to the radio itself and the connectors. If the other radio doesn't work in situ you can then contemplate pulling the plane apart, buying new antennas, rewiring, new battery etc.

 

 

[frank marriott]

Roscoe,

 

You could be on track with that loose connector.

 

Ref another aerial - (I have 2 VHF radios thus 2 aerials) - the second aerial (ground independent) is mounted inside behind the rear bulkhead and with the aircraft being fibreglass you cannot tell whether I am using com one or two. I think marginally better reception from the fin when gaining ATIS 40 to 50 miles out but that could well be slightly better sensitivity in one radio over the other, so personally I would not be mounting external aerials - but as I say that is a personal choice, I don't like aerials sticking out like an afterthought but either way works.

 

 

[Roscoe]

Has your tech tested another, known good, radio in the plane to prove out the total installation. If the other radio works you can then limit the search to the radio itself and the connectors. If the other radio doesn't work in situ you can then contemplate pulling the plane apart, buying new antennas, rewiring, new battery etc.

Good call, yep tday tested handheld connected to the Antenna coax and tested fine. Stay tuned!

 

 

[Roscoe]

Good call, yep tday tested handheld connected to the Antenna coax and tested fine. Stay tuned!

But also found crimping issue at Radio end of Antenna coax prior to test

 

 

[Roscoe]

You just take off the rudder so a few hinge pins and the rudder cable to get to the factory installed aerial. Probably a 5 minute job but not much to see when doneif the aerial is faulty it can ONLY be the coax, plug attachment or the way in which the screw attaches the coax wire to the aerial

 

i saw a radio tech set one up and he tuned it by adding a piece of coax about 40cm long to the bottom alloy piece and fed it back into the fin

 

The factory ones donT have this so it is not abserlutely necessery

Mine is a factory build but I am hopeful since finding the bad coax crimping tday at the radio end that we may be on to the problem. And thanks for Fin removal comments. Last resort hopefully

 

 

[Roscoe]

Thannks

 

Roscoe,You could be on track with that loose connector.

Ref another aerial - (I have 2 VHF radios thus 2 aerials) - the second aerial (ground independent) is mounted inside behind the rear bulkhead and with the aircraft being fibreglass you cannot tell whether I am using com one or two. I think marginally better reception from the fin when gaining ATIS 40 to 50 miles out but that could well be slightly better sensitivity in one radio over the other, so personally I would not be mounting external aerials - but as I say that is a personal choice, I don't like aerials sticking out like an afterthought but either way works.

Thanks Frank. Will let everybody know next week when Radio reconnected following fixing of the crimping at the Radio end of the coax. Fingers crossed

 

 

[Kyle Communications]

My experience with Microair say it will be the radio not the antenna install

 

 

[Roscoe]

My experience with Microair say it will be the radio not the antenna install

Gday, what problems did you have?

 

 

[Kyle Communications]

I have had quite a few micro air radios in the workshop here.....all seem to have similar problems and don't seem to be fixed over old and new models

 

Just my observations not throwing any mud

 

Mark

 

 

[Roscoe]

I have had quite a few micro air radios in the workshop here.....all seem to have similar problems and don't seem to be fixed over old and new modelsJust my observations not throwing any mud

 

Mark

Thanks Mark, what sort of probs are we talking about, mine is under warranty

 

 

[Kyle Communications]

They go out of lock and get fixed on 148 mhz and thy will even transmit there. You can get it back into lock and it will work fine for a few weeks then jump out of lock again...if you don't understand much about rail the radio is controlled by frequency circuits and these need to be locked together if one slips out of lock then the radio ends up in the never never. Other issues have been no or bad audio ...never been able to solve it it is too intermittent. Got customers to send the radio back to manufacturer and they either sent them a new radio or replaced the main pcb. While its under warranty then don't stress about it.

 

 

[Roscoe]

They go out of lock and get fixed on 148 mhz and thy will even transmit there. You can get it back into lock and it will work fine for a few weeks then jump out of lock again...if you don't understand much about rail the radio is controlled by frequency circuits and these need to be locked together if one slips out of lock then the radio ends up in the never never. Other issues have been no or bad audio ...never been able to solve it it is too intermittent. Got customers to send the radio back to manufacturer and they either sent them a new radio or replaced the main pcb. While its under warranty then don't stress about it.

Mark thanks for that info. Appreciate your input

 

 

[Camel]

Just a question for you radio experts, my Microair radio generally works fine except when I fly past Coffs Harbour and abeam the airport I get radio interference and sound like several commercial radio station broadcasting on Coff tower freq, has happened several times but not with other radios in other aircraft, any ideas ? Seems it picks up more than it should. Has not happened anywhere else.

 

 

[Roscoe]

What tyoe

 

Just a question for you radio experts, my Microair radio generally works fine except when I fly past Coffs Harbour and abeam the airport I get radio interference and sound like several commercial radio station broadcasting on Coff tower freq, has happened several times but not with other radios in other aircraft, any ideas ? Seems it picks up more than it should. Has not happened anywhere else.[/QUOtype What type of Aircraft?

[Camel]

What tyoe

Do you mean type ?

 

Has dual frequency monitoring.

 

 

[Roscoe]

Do you mean type ?Has dual frequency monitoring.

Sorry yes i meant what type of aircraft?

 

 

[Camel]

Sorry yes i meant what type of aircraft?

Jabiru 230