[App_rpt-users] Hamtronics receiver issue with AllStar RTCM

Bryan Fields Bryan at bryanfields.net
Sun Mar 27 19:08:50 EDT 2016

On 3/27/16 5:12 PM, Skyler F 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.

> 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.

> Does anybody else have experience with hamtronics receivers?

Yes, I have a number of them in place and find they work perfectly with the
RTCM.  It can give about 2v P-P on the discriminator pin, and has the high
frequency compute the RTCM squelch needs.

My prime setup is here:

Note you'll want to put a cap in line, as the discriminator is DC coupled in
the hamtronics.  Can you put a scope on the discriminator line and measure the
voltage?  You might have a problem with the receiver.

Bryan Fields

727-409-1194 - Voice
727-214-2508 - Fax

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