View Full Version : Hand Held Radio for Aviation?


Cherokee_N7471W
20th Nov 2010, 00:32
Hello fellow aviators,
Have any of you satisfactorily used an ICOM A24 with an intercom and headsets?

I purchased my A24 at the 2005 EAA fly-in at KOSK. I've used it on the flight line, and have had it running nearly daily in my truck for years... and have been pleased...

Now my #2 Nav/Com quit, so I wanted to use my A24 as a back up.... This is the first time I tried it with a headset.... ICK!!!!!!

I installed the ferrite beads per ICOM and it still does not work consistently.

For the more technically inclined,
1.) The A24 manual lists the phone output as 8 Ohms and the microphone as >100K Ohms. That sounds about right for HiFi… but I would expect something like 600 Ohms for General aviation<?>!
2.) I have 3 headsets (Sigtronics, Pilot, and MarvGoldman) and a portable intercom (Sigtronics SPCC-2). The Sigtronics headset did work with the OPC-499 adapter and rubber duck antenna with external PPT switch. The other two headsets and the SPCC-2 all “Growl”.
3.) I do not believe this is RF rectification because:
a. I have the ferrite beads installed,
b. I had this radio on the bench to check it with avionics tech. The check was made with the A24 terminated in a proper 50 Ohm non reactive resistive load (a Can-tenna which does not radiate much!!) HP frequency counter, modulation test set… etc. Yet the problem occurred even in this RF sparse controlled environment. Thus it seems to me that the A24 was not designed properly for proper impedance matching to general aviation headset in the first place.

SOOOOO! Has anyone had success with an intercom – ICOM A24 mating? Has anyone had ICOM actually fix this issue?:ugh:

Thank you
Walt.
SEL & Glider
EAA, AOPA



austerwobbler
20th Nov 2010, 07:56
I have a i'come A24 which clips in a holster on the instrument panel in my Auster, runing on genuin icom head set adaptor leads to a 9v battery intercom and a ptt switch on the controll stick,and I have a externally mounted arieal on the top of the roof. Works fine with all the different headsets I have used in .
And it works ok if you put a single headset straight to the radio missing out the intercom.

Austerwobbler :ok:

Zulu Alpha
20th Nov 2010, 12:33
There have been lots of problems with the A6 and I believe the A24 to be similar. ICOM aren't interested, so you have a chocolate teapot as far as a backup radio.

One thing to check: Are you using the PTT on the side of the radio or a seperate one connected to it.
I believe the one on the side turns on the internal mic and you need to use an external PTT to get your headset mic to work.

see here for more details http://www.pprune.org/private-flying/207268-icom-a6-a24-problems-headsets.html

2high2fastagain
20th Nov 2010, 15:24
Zulu,

Looks like ICOM ight have surrendered on this one. Their website seems to stipulates the handhelds for ground use only..

Aviation/Airband Radio : Icom UK - radio transceivers, receivers and navigation products (http://www.icomuk.co.uk/categoryRender.asp?categoryID=3754)

Having said that, I'm pretty sure that an A24 was fitted to a microlight I had a ride in recently and it seemed to work fine with both sets of headsets. I'm sure the microlight boys can post some answers here for you (as well as austerwobbler).

Zulu Alpha
20th Nov 2010, 20:05
Their website seems to stipulates the handhelds for ground use only.

Yes but they do supply a headset adapter with the radio. If you try and use it then the feedback makes it useless, whether on the ground or in the air.

I recommend looking at Vertex handhelds. They are made by Yaesu and I'm very pleased with mine.
The A6 is also fine but I only use it when on the ground at our strip

IO540
20th Nov 2010, 20:56
Their website seems to stipulates the handhelds for ground use only..

Morons.

There is a nice handheld in this month's Flying mag which does an ILS also - the SP-400 (http://sportys.com/pilotshop/product/14807). No idea if it works with a headset. No doubt that one is "illegal" for anything whatever, too ;)

2high2fastagain
20th Nov 2010, 23:35
You have to ask why you'd have a VOR navigation function if you are only using the A24 on the ground. Mind you, it would certainly be entertaining using VOR tracking in the car instead of a satnav. Could start a whole new trend...

SNS3Guppy
21st Nov 2010, 01:14
I recommend looking at Vertex handhelds. They are made by Yaesu and I'm very pleased with mine.

Likewise. I have the Vertex Standard VXA-710, which is a handy size for a flight bag.

Any of the handhelds are weak and less than ideal for use; don't expect a lot from them. Yaesu (Vertex Standard) makes good ones. The Vertex series are a little less user friendly than other units, but they do have more options.

GyroSteve
21st Nov 2010, 07:12
The Icom A6 and A24 both have feedback problems when used with an external headset. They are widely used in microlights - but only because Icom have a strangelhold on the UK market and because earlier Icoms (like the A3) were very good ......

The reason they work on microlights is that they are normally connected to a proprietary intercom (Lynx, Flycom etc) and the intercom manufacturers put fixes in their system to get around the feedback issues.

Vertex airbands are very good, not widely used in the UK as they are not CE certified.

IO540
21st Nov 2010, 08:57
I have the Icom A22 and it has maybe 10-20nm range on its antenna, and almost as good as the main radios when connected to a normal rooftop VHF antenna, using a bit of 50 ohm coax with BNCs both ends.

I got a little loop installed in the plane when it was new, to enable the connection of the radio as described above.

Mickey Kaye
21st Nov 2010, 17:48
Vertex 220

Brilliant piece of kit

mikehallam
22nd Nov 2010, 19:46
It's my main Rans S6 radio & I have no qualms about the Vertex 220, but their other models [according to posters various] can be dogs. Price is/was good too from the Far East. There is said to be service available in the U.K.

[ Vertex VXA 220 Service/ spares access U.K.
Nabishi UK Ltd, 16c Upton Road, Tilehurst, Reading,
Berkshire RG30 4BJ.
'phone 0118 943 3311 for sales or assistance.]

The 220 will run off a fused 12volt supply - just like the older Icoms did. So less hassle there.

mikehallam

Mickey Kaye
23rd Nov 2010, 17:32
You can also get a Car Cig lghter charger off ebay for the Vertex 220 its about 4 quid delivered. Having said that the inbuilt battery gives hours and hours of use (must be well over 24) and you can also get a higher capacity battery pack again of ebay for about a tenner and god know how long that will last for.

Cherokee_N7471W
5th Dec 2010, 01:23
First thank you all for your posts to my start of this thread.

I read them with interest. I then downloaded the manuals for the A24 (ICOM America) and A24E.

I see the warnings in the A24E manual (“E” for European I presume<?>) not for use in flight/only for ground use!!!!
Now WHY<?>!!!! Would anyone buy a receiver for VORs that is to be used only on the ground!!! How utterly absurd. My personal opinion is a paper cover for a known but denied problem.

I also note that in the A24 manual the microphone impedance is listed at greater than 100,000 Ohms, while the manual I down loaded for the A24E has an apparent error. That is the index indicates SPECIFICATIONS on page 31 and OPTIONS on page 32, whilst I find options on both pages without specifications.

I also searched other manufactures of Aviation Audio components and found the Microphone impedances ranging from 50 Ohms to 2200 ohms. This would indicate the A24 was not built to general aviation standards (I compare with YAESU’s posted Microphone impedance value of 150 Ohms for the VXA-710/300/220).

Of additional interest, the specification for the ICOM A23 is 150 Ohms, and their A210 panel mounted transceiver is specified as 600 Ohms…. These seem right on the mark.

Where are my Ham radio operators and electronics engineers? Tell me, what results might one expect if connecting a ~470 Ohm microphone to a transceiver with a >100,000 Ohm microphone circuit? Something like I (and others?) experience with the A24? Something like loading the microphone circuit down (I remember about 4 volts when we were bench checking ) until if fails or sets up oscillations?

Cheers
Walt (for Silvaire1 Walt stands or Want A Luscombe Too!)

Cherokee_N7471W
5th Dec 2010, 14:34
Fellow aviators,
Below is the post I sent to ICOM service. Please respond to me if you have approached ICOM in regards to the A24 and Headset/Intercom issues, and tell me of your experience.

Cheers
Walt.

----------------------------------------



Greetings Mike, Fred, Carl, {ICOM Services et al},

Ref: Trouble tickets ABHI215195 & ABHI1651A4
Telcon:15 Nov 2010 Mike
Telcon:22 Nov 2010 Carl
Telcon: 01 Dec 2010 Carl


Carl,
Per our last telephonic conversation on 1 December 2010, I have researched the microphone impedance’s published for general aviation audio circuits. With two exceptions all I found fell between the range from 50 to 2200 Ohms. [The two exceptions were both in regard to ICOM products; the manual for the A24 indicates >100K Ohms, and on the site http://www.mypilotstore.com/MyPilotStore/sep/5427 (http://www.mypilotstore.com/MyPilotStore/sep/5427) indicates >100K Ohms for the ICOM A14, however the ICOM manual for the A14 indicates 150 Ohms. Thus you might contact MyPilotStore and have them correct what appears to be a typo.]

Thus, I continue to believe that the A24 has an inherent design issue regarding the microphone impedance (>100,000 Ohms) relative to the industry range of 50 to 2200 Ohms.

Per our conversation I asked that you elevate this issue to you next level (Mr. Greg Hake was the name I noted). I repeat that request in this post.

Below I list my references that you might check the veracity of my findings and note my due diligence.

V/r
Walt

Aviation Microphone data summary
RTCA/DO-214, Audio Systems Characteristics and Minimum Performance Standards for Aircraft Audio Systems and Equipment, dated March 2, 1993.
FAA: TSO-C139 - Aircraft Audio Systems and Equipment
Manufacturer
Model
Impedance Ohms
ICOM
A24
>100K
ICOM
A23
150
ICOM
A210
600
ICOM
A14
150 or 100K: I found two different values depending on the source. The ICOM manual had the 150 value.
BOSE
A20
Microphone (Electret) Bias required: 8 to 16 VDC through 220 to 2200 Ohms.
NARCO
VHF760
Microphones - Electret > 100mV into 200 Ohm
David Clark
H10-13.4
Mic Impedance: 50 ohms +/- 20%
David Clark
H10-20
Mic Impedance: 50 ohms +/- 20%
David Clark
H10-30
Mic Impedance: 50 ohms +/- 20%
David Clark
H20-10
Mic Impedance: 50 ohms +/- 20%
David Clark
H10-60
Mic Impedance: 50 ohms +/- 20%
YAESU
VXA-710
Ext. Mic, Impedance: 150 Ohms
YAESU
VXA-300
Ext. Mic, Impedance: 150 Ohms
YAESU
VXA-220
Ext. Mic, Impedance: 150 Ohms
PS Engineering
PM 1000 FAA TSO Approved Intercom
Headphone Impedance: 150-1000 W typical, Aircraft Radio Impedance: 1000 W typical
sennheiser-aviation
HME 26
150 - 2,200Ω (terminating)
valavionics
VAL_AP_100
600 ohms
www.ps-engineering.com/faq.shtml (http://www.ps-engineering.com/faq.shtml)
You need to be sure that any headset or helmet equipped with such a plug uses general aviation microphone (150 ohm) and headphone (150 to 600) impedance. Military systems are often 8 ohm, and incompatible with civil aviation units.
http://www.ps-engineering.com/docs/PSE_Brochure.pdf (http://www.ps-engineering.com/docs/PSE_Brochure.pdf)
Aircraft Radio Impedance 510Ù
http://www.capitalavionics.com/tip_0909.asp
and for a microphone audio circuit, between 150-600 ohms (measuring DC voltage).

Cherokee_N7471W
5th Dec 2010, 14:46
Austerwobbler,

Thank you for your post. SO far you are about the only one who has responded in the positive for the ICOM A24 with intercom & headsets.

So, Please be so kind as to give me the specifics of your intercom (manufacture, model) and your Headset(S).

Since I have already spent my money with ICOM, I'm still looking for ways to make my Intercom/headset work with my A24... Perhaps you already have a tolerable solution.

V/r
Walt

magpienja
5th Dec 2010, 16:04
Quite a few of the guys I fly with (microlights) seem to be able to use them successfully with intercoms and for VHF comms,

Why not as the same question on the BMAA forum, BMAA Forum (http://forums.bmaa.org/)

I'm sure you will get the info you req there.

Nick.

Cherokee_N7471W
9th Dec 2010, 23:12
I have seen Luscombes over the years and not paid much attention to them until about 1996 when I bumped into an owner doing some maintenance on his (brake cables not hydraulics). We ended up with me on the ground adjusting so he could set in side and feel the heal brakes. So he gave me a ride…. What a hoot!!! {it had the ‘big’ 85 HP upgrade!} Luscombes were near the top of my list ever since. I finally was made an offer on an AA-1 (friend of a friend lost medical) so ended up with that. It is also a surprisingly simple aircraft. It has worked out well for me, as it is a bit faster than most in the 100HP class, and technically IFR. However, until I can upgrade some avionics (ergo the desire to have the A24 hand held working on board) I keep it CVAU flying.

So, I have now requested twice to have the tech-support supervisor at ICOM America call or email me. I have heard nothing. How can I (we) get any satisfaction from the ICOM Goliath when I (we) are but little Davids who have already fatten Icom’s bottom line and have limited resources?

Cheers
Walt.

Cherokee_N7471W
11th Dec 2010, 17:21
Fellow Aviators, ICOM did at least respond to my latest post(below) however, They still do not address the issue I raise of microphone impedance matching. Where are my electronic techies? I ask for your feedback and support.

Thank you
Walt.
===================================
My post back to ICOM, with thread below:

Mike Hilton,
Thank you for responding.
I have it in my notes that we spoke on 15 Nov 2010. Please refer to ABHI215195, ABHI1651A4, & AC9G412126.
MH:“Not all radios and headset combinations have issues with RF feedback
that you mentioned.”
WRP:>> Mike, I did not specify RF feedback; You have assumed RF feedback. But continuing the discusison; you are correct in that some headsets do work, I have one headset (Sigtronics S-45) that does appear to work with my A24/opc499. However, my other two (a FlightCom Classic 40XL, the third is in the aircraft so I do not have the model here) do not**. The most critically for my application the A24 exhibits oscillation in the mic circuit with my Sigtronics SPCC-2 intercom in line. Yet all three of my headsets work when individually mated with my panel radios in my aircraft, and all three of my heads sets work in all combinations with the SPCC-2, and all three headset work in combination with the SPCC-2 and the aircraft radios. The only issue is “pickiness” about the A24’s mic tolerances.
** (not an RF feedback as this has been tested with the A24 terminated properly in to a non-reactive 50 Ohm load (can-tenna)).

MH: “Also, Icom America can only support US products and
the "E" designation indicates that this is a European radio. “
WRP:>> Mike, I forwarded the post regarding the “E” model from a forum, my A24 is the north American A24 purchased directly from the ICOM booth at the EAA fly-in at KOSK Wisconsin USA.
>>>>POINT: I am not alone in experiencing non-RF feedback issues, and
>>>>POINT: both the north American and European manuals specify a mic impedance of >100,000 Ohms. This is not consistent with general aviation. Please research TSO -C139 >>>> RTCA/DO-214, Audio Systems Characteristics and Minimum Performance Standards for Aircraft Audio Systems and Equipment, dated March 2, 1993.
>>>>POINT: ICOM is selling an aviation product which is not designed to the commercial standards of general aviation. {Please check other manufactures, and your own [ICOM] A14,A23, & A210 aviation products; the listed mic impedances are 150, 150 and 600 Ohms respectively. }

MH: “That being said, you may still be able to use the information on our web site in
the Knowledge Base. To get there, first go to our home page at:
www.icomamerica.com (http://www.icomamerica.com) and then, click on "Support". Next, click on
"Knowledge Base" and you will see a search engine on the following page.
In the field labled "KB Number", type in this number: 64AJ571413 and
click on the "Go" button. Click on the link under "Attachments" and you
will see a solution to this issue. I hope that this will help.”
WRP:>> Thank you, however, this was the solution given to me a year ago, and twice more by your offic and now yet again::: I installed the ferrite beads over a year ago, and again emphasize that the oscillation persists even on bench checks when the RF was properly terminated into a non-reactive non-radiating resistive load and the RF benign environment was confirmed with a spectrum analyzer and signal strength meter.
SO…. Talk to me about mic circuit designs, and impedance matching…
1.) Please confirm that your manuals are correct in stating the A24 has a mic impedance of >100,000 Ohms.
2.) Please confirm to me that you have verified general aviation microphone impedances standards and state you findings. (Check my earlier posts, I’ve already summarized my findings and sent them to you)
3.) Given a miss match of say 50, 150, (470 ohms driven with 8 to 16 vdc might be ideal?) or 600 Ohms to 100,000 Ohms, what would an electronics engineer predict? ?? A circuit so far out of match that it will not function and in some cases produces an oscillation? Yet a few headsets with a 2K or so impedance might provide enough loading to function….?
4.) If this is beyond your expertise or your authority to comment please have an engineer or management respond.

V/r
Walt





----- Original Message -----
From: avionics@<hidden>
To: "walt peterson15" <walt.peterson15@<hidden>>
Sent: Friday, December 10, 2010 11:20:45 AM
Subject: ICOM Technical Support Ticket # AC9G412126
Good Morning.......
Thanks for your e-mail.
Not all radios and headset combinations have issues with RF feedback
that you mentioned. Also, Icom America can only support US products and
the "E" designation indicates that this is a European radio. That being
said, you may still be able to use the information on our web site in
the Knowledge Base. To get there, first go to our home page at:
www.icomamerica.com (http://www.icomamerica.com) and then, click on "Support". Next, click on
"Knowledge Base" and you will see a search engine on the following page.
In the field labled "KB Number", type in this number: 64AJ571413 and
click on the "Go" button. Click on the link under "Attachments" and you
will see a solution to this issue. I hope that this will help.
Best Regards;

Mike Hilton
Technical Support Representative
ICOM America, Inc.
2380 116th Ave. NE
Bellevue, WA 98004
Ph. (425) 454-7619
Fax (425) 637-8417
Walter Peterson
walt.peterson15@<hidden>
Description
EMAIL
BODY: Carl, Fred, Mike,
Below is a post I remember seeing and found again. It seems I am not the
only ONE!
Walt
========================================================================
=
Has anyone got one of the new Icoms to work with a headset?
------------------------------------------------------------------------
--------
I am in the market for a handheld transciever for use in our Chippy, so
bought an Icom A-6E with OPC499 haedset adaptor. Worked fine without the
headset, but on fitting the OPC499 and headset, it just gave feedback
whistle on transmit. So I took it back to the dealer.
He got another A-6E out of stock, another OPC499, and a new headset -
same result. Tried different headsets - same result. Same OPC499 and
headsets worked fine with an A-3 transceiver the dealer had in stock.
I got a refund from the dealer, and e-mailed Icom who said they were
aware of the problem (RF feedback) and had a fix. Someone off the
'Flyer' forum who had the same problem had Icom apply the fix to his
A-6E. But when he got it back, it still had the same problem.
Has anyone out there got an A-6E or A-24E that works OK with a headset?
SSD