WA Radio Scanner Users' Group

I was thinking earlier tonight about how to connect an aviation-style headset to a handheld amateur transceiver - either one of the Quanshengs or an Icom IC91AD...

After a bit of googling around, this looks to be a bit more challenging than I had originally thought, since the aviation headsets are built in a specific way (

One of the things I'd come across was someone's suggestion to just use one of those "personal hands-free" type earplug and lapel mike combinations. The poster reckoned the lapel mike had a "surprisingly good" noise cancelling ability, then the aviation headset just goes over the earplug.

Another option was this DIY box on this website which looks a bit complicated (and maybe a bit too much effort for a one-off...)

So ... just on the off-chance, does anyone know of a "quick and simple" way of doing what I'm looking for?

What sort of jack is on the end of the aviation headset? What impedance is the mike? I have a PC mono headset I use on my icom which has an electret (condenser) mike and it's wired up just using the appropriate connectors.. (ie no extra components) I have more or less the same for the FT-1802 which doesn't require any extra circuitry.. just the matching plugs and sockets. Also adapted a nokia "handsfree" doohickey just as a mike/PPT (not using the earpiece.. I hate those things)

Edit: Also, what sort of mike socket is on the quansheng?

robbage wrote:What sort of jack is on the end of the aviation headset?

I believe they're 6.5mm phono plugs, but I'm not 100% certain. I also don't know what the expected impedance is. I'm having a bit of trouble finding any of that out... I did find that the Icom manual says this for the mic/speaker connectors:

Edit: Also, what sort of mike socket is on the quansheng?

Both radios have one of those moulded 2.5mm / 3.5mm dual plugs... The speaker/mic I have for the Icom, despite having the same connectors as the one for the Quansheng doesn't work in the Quansheng - and vice versa. So they must be wired up differently or have different impedances...

Yeah I found the Quansheng pinout later on. http://highfields-arc.6te.net/construct ... heng51.htm
I can't see why the headset can't be plugged in with a suitable adaptor.. if the impedance is incorrect then it will just sound bad or not work at all. Does the headset have PTT? With a stereo 6.5mm there aren't enough connections for a conventional configuration of mike, speaker, PTT and ground.
A 6.5mm line socket is a fairly standard item. That with 2.5mm and 3.5mm stereo jacks should be enough to try it out.
According to this http://homepage.ntlworld.com/rg4wpw/hm46.html the Icom is wired the other way around with the 2.5mm and 3.5mm doing opposite jobs.

robbage wrote:Yeah I found the Quansheng pinout later on. http://highfields-arc.6te.net/construct ... heng51.htm

Thanks for that, I hadn't managed to get around to finding any info about the Quanshengs, I'd started with the Icom and worked from there.

robbage wrote:I can't see why the headset can't be plugged in with a suitable adaptor.. if the impedance is incorrect then it will just sound bad or not work at all. Does the headset have PTT?

That I'm not sure about, I don't think there's a PTT on the headset itself, I think that's controlled from elsewhere (i.e. the control column in the aircraft) - I shall have to ask one of our tame pilots we keep around here

robbage wrote:With a stereo 6.5mm there aren't enough connections for a conventional configuration of mike, speaker, PTT and ground.

I'm fairly sure the headset has two 6.5mm plugs, one for the headphones and one for the microphone.

robbage wrote:A 6.5mm line socket is a fairly standard item. That with 2.5mm and 3.5mm stereo jacks should be enough to try it out.

Yeah - that was my first thought, just getting suitable adapters and see what happens - then I started to see the wiring diagrams for the Icom and thought to myself "this looks like it might involve more than just using an adapter from one size plug to another"

robbage wrote:According to this http://homepage.ntlworld.com/rg4wpw/hm46.html the Icom is wired the other way around with the 2.5mm and 3.5mm doing opposite jobs.

Isn't that odd ...

Zebedee wrote:

robbage wrote:I can't see why the headset can't be plugged in with a suitable adaptor.. if the impedance is incorrect then it will just sound bad or not work at all. Does the headset have PTT?

That I'm not sure about, I don't think there's a PTT on the headset itself, I think that's controlled from elsewhere (i.e. the control column in the aircraft) - I shall have to ask one of our tame pilots we keep around here

If not then an inline switch or something. I have a PTT that you hold like you would a hammer and then press down with your thumb.. like some camera exposure thingies.

Zebedee wrote:Yeah - that was my first thought, just getting suitable adapters and see what happens - then I started to see the wiring diagrams for the Icom and thought to myself "this looks like it might involve more than just using an adapter from one size plug to another"

Doesn't look like it.. the mike doesn't get it's ground from the sleeve like the headphone. The sleeve is PTT.

Zebedee wrote:

robbage wrote:According to this http://homepage.ntlworld.com/rg4wpw/hm46.html the Icom is wired the other way around with the 2.5mm and 3.5mm doing opposite jobs.

Isn't that odd ...

Not really The great thing about standards is...
Anyway.. if you want me to wire something up, let me know

the intercom doesnt have a PTT, it is voice activated.

the PTT is for Communications between the pilot and ATC

Nafenn wrote:the intercom doesnt have a PTT, it is voice activated.

the PTT is for Communications between the pilot and ATC

The PTT is the one on the control column I assume.

If the headphones are VOX activated, there must be some kind of switching mechanism - when the incoming audio is above a certain threshold it activates ... ?

Any idea whether there's any documentation on how it all works?

Zebedee wrote:The PTT is the one on the control column I assume.

If the headphones are VOX activated, there must be some kind of switching mechanism - when the incoming audio is above a certain threshold it activates ... ?

Any idea whether there's any documentation on how it all works?

uhhh... there is an intercom switch, and a squelch knob

thats all i know, there might be more info in the aircraft manual... will look it up if i get a chance

That'd be good, thanks

Zebedee wrote: I believe they're 6.5mm phono plugs, but I'm not 100% certain. I also don't know what the expected impedance is. I'm having a bit of trouble finding any of that out...

Don't know if this is a industry standard for aviation headsets, but the aviation headsets that Altronics sells have an impedance of 300 ohms each wired in parallel.

http://www.altronics.com.au/index.asp?a ... m&id=C9063

and there's also this

http://wsanders.net/blog/static.php?pag ... 527-095119

Blinky wrote:Don't know if this is a industry standard for aviation headsets, but the aviation headsets that Altronics sells have an impedance of 300 ohms each wired in parallel.

Thanks Blinky - I'm fairly sure there are two aviation standards, from what I've been reading ... basically "Military" and "Everything Else"

Blinky wrote:http://www.altronics.com.au/index.asp?a ... m&id=C9063
and there's also this
http://wsanders.net/blog/static.php?pag ... 527-095119

Yeah I saw that wsanders.net link last night and looked fairly interesting. And I never knew Altronics sold aviation headsets!

And just to add to the insanity ... We seem to have a non-standard plug size

Looking at this document, the plugs are 6.5mm and 5.3mm - I've never even *heard* of that second one before