Noisy radio advice

[vk3auu]

Does your intercom have a voice operated turner-oner. Sound like the gain might be set a bit too high and is triggered by the added noise from the engine being picked up by the mike.

 

David

 

 

[Kev]

David,

 

No, my mike is not voice operated. The Rotax engines, in particular the 912 series are known for having a 'dirty' electrical supply. I am assuming that this is the problem, and that I just haven't found the correct way to eliminate it yet.

 

Kev.

 

 

[XC-Buzzard]

High Noise

 

Hi Kev, I had similar problems with my set, then I changed to Air Magic set, and even went further by Isolating Com's from Electrics, hooking it up to Battery on its own, this gave me great clarity, and no static or interference on recep or trx. wired a 1 amp fuse between battery and radio, just for added safety. Trike pilot,, L/ridge. Regards Lance..

 

 

[Guest Perry]

Folks,

 

My apologies for the delayed reply - I am a lizard drinking.

 

Good News - Ian has taken on the Airmagic range of products and shortly they will be available on line in Clear Prop - excellent news. If you are desparate, give Ian a call and I am sure he could have you sorted.

 

There should be a couple of units on display at Natfly this weekend at Ian's Stand.

 

As for the interfaces - Lynx has a lower end internal circuit that leads to higher noise. Due to the expense of the gear, we have built a retrofit for failed units to assure longer lifer at less expense than purchasing a new set. If you go Airmagic, your Lynx becomes a paperweight.

 

The Airmagic Chatterbox Mic is hot (or on all the time) but it has full ANR, so no nasties, just plain coms without the noise. Today I had a CFI in raptures with his helmet visor held up at cruise and no wind noise - this is an acheivement.

 

As for Xcom, we have not yet produced the fix for the Xcom for we have been unable to prise a unit away from an owner yet so that we can begin the fiddle - any takers?

 

We have the Microair working like never before with nil interference and coms for over 100NM 5/5!

 

Keep in touch.

 

Regards

 

Perry

 

 

[Guest Perry]

Hiya Kev,

 

I too had an Xcom unit once before Airmagic and sold it onto someone who was absolutely unwaivable on the product - Oh well he scored one for less than 50% cost.

 

I remember that I tried an Airmagic Powerbox noise filter inline on the supply to the Xcom that was powered from a Rotax 912S.

 

I must admit that it did suppress heaps of static noise and certainly improved the reception but it certainly did not come perfect.

 

Talk to Ian, he has some Powerboxes due for arrival shortly.

 

If you do have another go at your comms, I have found that a combination of the Vertex VXA220 with a Chatterbox and a Vee Rabbit Antenna to be pretty close to perfect.

 

Regards

 

Perry

 

 

[Kev]

Thanks Perry,

 

I'm kind of partial to the Xcom, if only for the dual watch facility. The interference is not too bad at the moment, but could certainly stand improvement. I might try putting the in-line noise filter on the power supply to the radio instead of the comms and see if that makes any difference (space is becoming limited around the area of the radio, though).

 

Safe flying

 

Kev.

 

 

[ZULU1]

Antenna

 

Hiya Kev

 

Just read your thread, I really have no experience at all with the Xcom as Perry advises on his previous thread. However after reading the instruction manual they have a transmit output of 6 watts. This for a trike is hectic and can lead to all kinds of problems with rf ingress when transmitting. This is compounded by a poorly grounded/installed antenna. For our Microair fix which I must confess is really, really good and the best I have seen in a panel mount. When testing in a trike I was asked to identify aircraft type !!! We turn the power down to 1,5 watts, readjust the mic gain as the chatterbox has its own mic amplifier, install a line choke filter (which we specifically designed for a clapped out 503 single ignition) and our Vee rabbit antenna. This was designed for the Airborne / Microair installation at Perrys request. I am not really an antenna boffin and asked our local radio hams to help..That was a year ago and over 300 sales later they are very popular in South Africa, Australia and now selling in the UK, all Quiks imported to South Africa get them fitted standard.

 

The expense for results obtained are worth the effort.

 

But suggest that you try the filter box first..then turn down the power. Maximum of 2 watts output. This will help the tx out. But i have never seen a radio so I have no idea how to do the adjustments ?? The Vee rabbit aids reception and prevents rf ingress from a GPS, Skydat and so on. You can expect transmissions in excess of 200kms easily with a Microair at 1,5 watts and more with a VXA220. So would imagine the Xcom to do the same ?

 

Ian will be able to help you out with all products from Clear Prop.

 

Cheers Paul (Air Magic)

 

 

[Kev]

Thanks for the advice Paul.

 

My transmissions appear to be clear, and I'm not sure without some help, how I would turn down the power output on the Xcom. What is a VXA220?

 

I have seen photographs of the Rabbit Vee antenna, and think that it would introduce problems when de-rigging the wing, so would prefer to avoid going that way at this stage. After saying that, I don't rig & de-rig very often, so it wouldn't be that much of an issue.

 

My current antenna is a Lynx one, and appears to be installed and grounded adequately.

 

Regards

 

Kev.

 

 

[ZULU1]

Vee Rabbit

 

Kev, I have absolutely no idea how to adjust an Xcom !! I have never even seen one before but Perrys trying to find one, so we can establish how to do this.

 

As regards the Vee Rabbit, they are a simple fitment with 4 cap screws and a small spanner and Allen key is provided with each kit. The cable is in two pieces and disconnect below the wing attachment. Ian will have some available for viewing at the Natfly stand.

 

Take a look at the pic on a UK Gemini. This bracket is designed for the smaller King Post.

 

Sorry a VXA220 is a Vertex Standard radio and rate them as the best used so far, also from Clear Prop, they like to be fed with 9,6 volts input which Clear Prop stocks the regulators also..

 

Cheers Paul

 

 

 

[XC-Buzzard]

Just a quick hello from the boys here at the ridge, Perry , Hi !!

 

 

[zodiac3813]

Hi Perry, just did a search for Airmagic filter, but came up with nothing... where did you buy it?

 

I'm having the same (or similar) problem with an Icom A200 in a Jabiru LSA. VERY scratchy/snap-crackle-pop on anything over 2600 RPM. Thought I'd found the problem after rectifying a very dodgy earth connection from battery to firewall, but it made no difference. As I say, clear as a bell with engine off or running below 2600 RPM. Transmission is unaffected: good at all RPM. VERY frustrating!

 

I tried borrowing an identical radio: problem persisted, therefore radio not at fault. Considering installing a seperate intercom, but I'd like to clear up this problem first. The only things I've added since buying the aircraft are landing light and EGT probe & guage'

 

Cheers, Jim.

 

 

[Guest EQ Gary]

radio problems

 

In order to test radio/ intercom problems you need to isolate each section.

 

Remove headset and do no engine running test with someone on another radio.

 

Just PTT with no headset.

 

Then repeat with engine on at a number of RPM's.

 

If you can hear any thing then it could be induced noise in the DC feed.

 

You need to then put a DC filter inline and also look at the single point ground connections in your aircraft,

 

When you fix all these problems you can then look at antenna and intercom problems, but get the radio correct first.

 

 

[zodiac3813]

Hi Gary & thanks for the reply. I've done engine off test broadcasts as well as with engine running. Reception (to another aircraft) is clear and 5/5 no matter what engine is doing. The snap-crackle-pop comes in above 2600 rpm. I was checking the list of things Jabiru replaced when the engine was rebuilt (70 hrs ago) and they appear to have used the original ignition harness. This may be next on my hit-list!

 

The problem is definitely not within the radio itself, as I have tried a different radio. The interference also comes through on a small hand-held (battery powered) through seperate headphones, but was cut out by squelch control. I am currently using the A200's in-built (crappy) intercom. Neither the radio nor the intercom have a readily adjustable squelch control.

 

I intend to fit a sigtronics or similar intercom, but would like to get rid of this noise in the meantime!

 

Cheers, Jim.

 

 

[zodiac3813]

Problem Solved!

 

Hey Guys!

 

I rang Jabiru about my interference noise... Jamie advised me to check a relay behind the panel, which has to be kept vibration-free, due to the fact that it contains metal bands which develop static electricity when they vibrate at certain frequencies.

 

Sure enough, I had anchored the relay to the firewall with velcro. After removing the velcro, I wrapped it in 1/2" foam and set it free again.... no more interference!

 

Thanks for your help,

 

Cheers, Jim.