[arm-allstar] Radioless nodes, hoping someone can help

[Patrick Perdue]

Hi Jed:

Last I heard, which was a few months ago, his kids were in hospital with 
COVID, and he planned to resume sales at the start of 2022. Obviously, 
this hasn't happened. If anyone else has more info, I'd love to know 
about it as well.


I have one of these. The box itself is a great design, with an amp 
powerful enough to drive a passive speaker with plenty of volume, even 
for my broken ears.

What I don't like, however, is the microphone he ships with it. It's 
garbage! It's one of these $15 Chinese Icom HM-118 knock-offs. Chris 
uses the Icom RJ45 pin-out. He uses that particular microphone because 
it has it's own DTMF generator, and that's about the only good thing 
about it. There is some electronic bridging going on, so it picks up 
tons of bus noise from the system it's connected to. The microphone 
element doesn't line up with the holes in the case, so it has a very 
hollow sound. I ended up using an Icom HM-207, then switched to an Icom 
HM-154. The HM-207 is the same microphone that ships with the IC-2700, 
IC5100 and some others. Though it has buttons, the radio itself does the 
processing, so no DTMF control with that microphone, but it sounds 
sooooooo much better.

The microphone I ended up using, the genuine Icom HM-154 (there are 
knock-offs of that, too, and I have one), isn't great out-of-the-box 
either. I took mine apart and drilled the hole out around the element. 
It has a tiny little pinhole that just wasn't letting enough sound 
through. I like the audio I've got now, but, again, no DTMF control. I 
just use the Node Remote app on my iPhone to control it. Since I only 
use headphones with this box, as I would annoy everyone in the house 
with as much volume as I now need for speakers, I wrote a small script 
to unmute the local audio of my microphone when I key up, then mute it 
again when I unkey, so I can have a good idea of how my audio sounds, at 
least in terms of level and avoiding the problematic popping p problem. 
This is not something you would want to do in normal situations.


So, having said that, I'm interested in what others are doing for a 
reasonable radioless node configuration. The Yellow Box radioless nodes 
are gone now, so that isn't an option anymore. You could, I suppose, 
wire a modified sound fob to an Alinco EMS-57 (not one of the clones... 
I have one of those, too, and it's awful) for reasonable audio and DTMF 
control.

Lots of folks are using the USB dongle that ships with the Mpow 071 
headset in combination with microphones and speakers, since it is just a 
CM-108 chip. The volume down button on the dongle activates PTT on a 
node with no modification needed. A couple of ways to do this without 
modifying any hardware:

Find a one-piece TRRS microphone that plugs directly into the dongle (I 
don't know of models, but I know they exist), then route the output of 
your node through the Raspberry Pi's built-in audio jack through 
outstreamcmd in rpt.conf and a small modification to /boot/config.txt. A 
couple of disadvantages here. First, the audio will be ever so slightly 
more latent than the output of the fob directly. Second, the Pi's 
built-in audio jack isn't good for passive speakers, even with the 
volume cranked all the way in alsamixer.

Since the Mpow dongle only has a single TRRS jack, if you don't want to 
use the included headset, you'd either have to do this, or use an 
appropriate splitter cable to split microphone and audio output to their 
own jacks. More cables, more mess, more things to break, especially in a 
mobile setup.

Perhaps something more interesting could be done by taking the dongle 
apart, and integrating it plus a microphone and speaker/jack output into 
a hand-held microphone, such that you only have to plug one cable into 
the Pi if you just want to use it with no frills. Still wouldn't give 
you DTMF control, though.
I heard of someone starting a project of building a radioless node into 
a gutted Motorola radio, with everything self-contained. I wonder if 
that ever went anywhere. Something like that would be good on a desk or 
in a car, provided you've got a place to mount it. I know others have 
wired things into old dispatch consoles and the like as well.

On 3/27/2022 10:31 AM, "Jed Barton via ARM-allstar" wrote:
> Hey guys, Hope everyone is doing well. Got a question.  Thinking of
> putting a radioless node together.  I was thinking about getting 1 of
> the nodes from allstarnodes.com.  Whoever owns that site, they haven't
> returned any emails from a few of us now, and I got refunded when I
> tried to get 1 of his nodes.  So does anyone know what might be going
> on with that, and are there any other sources who could do the same
> thing?  He had a really nice little box that I was quite impressed
> with.  Any thoughts?
> Looking to have a radioless node in my shack, and my friend is looking
> to have 1 in his vehicle.
>
>
> Cheers,
>
> Jed
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