[App_rpt-users] Hamtronics receiver issue with AllStar RTCM

Skyler F electricity440 at gmail.com
Sun Mar 27 19:04:13 EDT 2016

Ok, so JP1 is just for the squelch amp? the RX levels are fine. When I
ignored squelch, I could easily get a 3khz tone to show at 3khz on the menu.

On Sun, Mar 27, 2016 at 4:23 PM, Tim Sawyer <tisawyer at gmail.com> wrote:

> Try adding JP1 in the RTCM. This gives some gain to the squelch noise amp.
> If that works you'll want to turn on the RTCM's BEW (#17 on the main
> menu). If it's not on that menu you'll need to download the proper firmware
> and upgrade. This help radios with low out of band discriminator noise not
> false the squelch on voice peaks. There 3 settings 0) off, 1) on, and 3) on
> with more aggressive locking.
> But first make sure you can calibrate the squelch with JP1 in. Otherwise
> your SOL and there's no reason to upgrade. In that case you'll have to buy
> some other radios for your voters.
> On Sun, Mar 27, 2016 at 2:12 PM, Skyler F <electricity440 at gmail.com>
> wrote:
>> For a voter project, we got the hamtronics VHF receiver pretuned to the
>> repeaters input frequency. The idea is to use hamtronics receivers for
>> every voted receive site for equivalent audio characteristics.
>> http://www.hamtronics.com/r303.htm
>> When hooked up to the discriminator on the hamtronics board, I could not
>> get the RTCM to calibrate squelch. It usually told me the audio was too low
>> weather the RX level was bumped up or down. I then hooked it up to a
>> motorola SM50 and it calibrated shortly after adjusting RX levels.
>> So... I hooked a cheap sound card up to audacity, and took a look at the
>> spectrum of each receiver. The hamtronics obviously looks like it lacks
>> high frequency noise on the discriminator output.
>> Here is the SM50 discriminator out:
>> amsatnet.info/SM50.png
>> Here is the hamtronics discriminator out:
>> amsatnet.info/HAMTRONICS.png
>> Here is an audio sample comparing them (you can probably guess which
>> radio is first):
>> amsatnet.info/Sm50_hamtron_DISC.wav
>> Does anybody else have experience with hamtronics receivers?
>> Thanks,
>> Skyler KD0WHB
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> --
> --
> Tim

Skyler Fennell
electricity440 at gmail.com
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