Help is here if you need it...

[Guest mcoates]

Greetings, as the owner of XCOM avionics i have amassed a fair bit of knowledge on VHF radio systems in aircraft with about 1300 XCOM customers and about 500 Microair customers (when we sold them).... If you need help just ask, regards Michael Coates XCOM Avionics

 

 

[Yenn]

Michael.

 

I am surprised you havn't been swamped with queries.

 

I have a problem with handhelds in the Corby. I use an Icom IC -22E and also a Vertex VXA-150. Both radios are very poor in transmission when used in the plane with a headset and PTT. but used outside the plane are perfectly good. It seems to be interference from the planes electrics, which are basically standard Jabiru. The radios are not both installed together and they both use their own battery power and antenna.

 

I have today re routed the leads from the regulator to the heavy cable feeding the starter, rather than running them into the cockpit and havn't been able to test if there is any improvement.

 

The VXA-150 picks up a lot of noise from the Garmin 12XL, but the icom is OK.

 

My thought is that the main problem comes from the DC feed from the regulator or the magneto kill wires, all of which are shielded wire.

 

Any thoughts on the problem would be appreciated.

 

 

[Guest mcoates]

Hello Yenn,

 

firstly to break the ice and start the information process handheld radios are designed as exactly that, handheld radios.

 

Handheld radios work best if you are standing on the edge of a runway and talking to an aircraft in circuit, that is what they are designed to do and in many cases is actually illegal to use them in an aircraft because they are not approved.

 

Having said that I know of many that are installed in aircraft as a primary radio and actually working quite well.

 

The only two brands that I have experience with are the vertex and also the ICOM which you mention above. The vertex is quite a nice radio but you cannot put it within about 2 m of the GPS. I've spoken at great length of the vertex people at Oshkosh and they keep telling me the same thing as I've told you above.. these are not aircraft radios they are handheld radios!

 

The only ICOM I have successfully had working in an aircraft is the old IC200 handheld which is one of the older style handheld radios which was actually built extremely well, I still have my original one purchased the least 15 years ago and it is still working well despite the fact that the battery is only last about 30 seconds, we mainly use this radio to test back to all the XCOMs as part of our final production testing.

 

The best way to get a handheld working in a conventional aircraft is to use an external aerial, ideally the aerial will have double shielded coax between the handheld radio and the aerial itself. This helps reduce interference and other problems.

 

Also, the headset adapter plugs which are made also notoriously unreliable and many of them do not have adequate shielding which means as soon as you press the push to talk button the handheld is pumping RF which should be going out through the aerial straight into your headset jacks and headset cables usually producing sounds which are not nice to listen to.

 

The Jabiru engine is particularly bad because of the quality of regulator they use. The Jabiru engine regulator is from a Kubota lawn tractor, in the lawn tractor and environment the regulator is only required to recharge the battery, in a Jabiru installation however it not only requires a battery recharge but it also needs to run many other accessories like the radio, transponder, GPS, strobe system, landing light etc unfortunately the little Kubota regulator is in deep water when this happens and it starts to get hot as too much current is being drawn through the regulator, what happens then when the regulator gets hot is anyone's guess but we have tested them and is in voltage spikes of up to 60 V coming through the regulator that is why it is vitally important to keep the regulator as cool as possible, ideally in clean air from outside the engine compartment.

 

The best thing you can probably do is to replace the standard regulator with the PowerMate regulator from Claus, you can probably buy these through this website, through our website or directly from Claus who advertises in the AUF mag but either way regardless of the regulator they need to be kept in free air flow if possible to keep them cool.

 

In summary, don't use a hand-held inside an aircraft unless it is a long way away from the GPS unit and is running an external aerial for the best results, make sure the aerial coax is the best quality you can get and preferably isdouble shielded. The latest coax is available from Dick Smith and Jaycar does not have braided shielding but instead has aluminium foil which lasts about 10 minutes once it has been crimped, and finally when you transmit try and keep your headset wires away from the aerial to stop RF coming back in. I hope this helps

 

 

[Yenn]

Thanks Michael.I will try with the aircraft aerial, and also get one of Klaus's regulators.I had used the Icom in my Thrueter with a Klauss Grim regulator.

 

Ian Borg

 

 

[ZULU1]

Icom ICA 3/22 series

 

I manufacture intercoms and headsets in SA, we use the entire Icom range and Vertex standard here for trike usage. The main reson being no requirements for Radio station licences. They all perform well.

 

The Jabiru motor as correctly quoted emits horrible "electrical noise" and should you be operating your handheld from the supply (top socket) then it is desirable to install aregulator line choke arrangement. The ICA 22 will state an error message if over 15 vdc.

 

If you use a standard headset as you advise it will not perform well as your installation without a microphone pre amp. We fit them for our PPG customers.

 

Obviously an external antenna goes without saying and a rf bead looped in the cable to the radio from the headset intercom assembly will reduce rf ingeress. As Michael advises the BNC cable on the external antenna is critical.

 

All in all we use them (including the ICA6/24 series) without an real problems.

 

Good Luck

 

Paul ZULU1

 

 

[Paul Willett]

Michael,

 

I have an XCOM760 - works beautifully, with one, and one only exception. For some reason I lose comms regularly with Brisbane Tower (120.5) when within 3nm of them (overflying at 1500FT normally). The 120.5 aerials are on the top of the control tower - my aerial is on the top of my aircraft. I have a good solid metal ground plane connection, and I have had the aerial (non-aviation style whip antenna) snipped to the optimum length by an Avionics Tech. My aircraft is all metal.

 

Ideas? (I have considered shielding, but it is the same in varying turning attitudes and distances)

 

No problems with other Towers - AF, CG, MC, RK, CS, AY, BK, MB etc. etc.

 

 

[Yenn]

Michael

 

An update on my problems. For some reason the vertex now works well even with a GPS within 600mm of it, nothing has changed. The problem with the Icom I traced to a faulty soldered joint in the Icom connector, had to break the plastic shield as it wouldn't unscrew but it is fixed now.

 

Your comment about handhelds beeing only for use beside the runway to talk in the circuit doesn't square with Icom advertising and the fact that Icom and Vertex both provide a headset adaptor as standard.

 

Ian Borg

 

 

[Guest Andys@coffs]

Michael

 

<Tounge in cheek>

 

The more involved ICOM Hand helds now include VOR reception with radial tracking functionality (actually have done for years now) . Of course thats included so that the instructor who has just turned his student loose solo can easily navigate his way to the right runway to stand beside, it was obviously never intended for inflight operation.... :<)

 

</Tounge in cheek>

 

Anyway on a more serious note any intentions to make your XCOM able to produce a digital or analogue radial output and perhaps even DME for a VOR/DME station in the NAV VHF band.

 

Shouldnt have thought it would be too difficult to do given that the radio already can recieve in that range and their is obviously computing power available to drive the front panel? Would make a nice point of differentiation between yours and theirs. If ICOM can make it work in a handheld then its obviously not beyond the realms of the possible.

 

For me at present choosing between yours and theirs is going to be about the best $ deal as I dont see many points of relevant differentiation at the moment and support for both is probably about the same I would suspect. The ability to do a firmware upgarde remote from the factory / support center is a differentiator, assuming the software feature set is evolving. Last I looked I dont actually remeber seeing any firmware upgrades available from the website. That said, how does that affect the TSO status?

 

Regards

 

Andy

 

 

[Admin]

Note Michael Coates is no longer able to reply to posts as he has been banned from the forums.