- If you are willin to add resistors (attenuation) in the circuit, I recommend just a simple 10k pot for each. Then you could have anything from NOMessage 1 of 6 , Apr 27, 2012View SourceIf you are willin to add resistors (attenuation) in the circuit, I recommend just a simple 10k pot for each. Then you could have anything from NO attenuation, to lots of attenuation.Better yet, 1k to ground and 10k pot will give anything from 1:11 -> 1:1 and no chance of a setting with no audio. Of course it is a LOT easier to package a resistor or 2 in a connector than a pot. If you are using audio isolation transformers, then you already have a box for the attenuator.I've never used a soundcard TNC with an HT. I've don this many times with radio's Data jack or Mic jack. The PTT interface (using a com port) and extra wiring usuallly drives an external box - good for the atennuators and isolation transformers though.
--- On Fri, 4/27/12, Bob Harris <knineudx@...> wrote:
From: Bob Harris <knineudx@...>
Subject: Re: [aprsisce] UZ7HO Soundmodem
Date: Friday, April 27, 2012, 8:22 AMAndre,
Thanks for the confirmation of my thinking.
I hadn't thought about a need for an attenuator, so I have added some 10K and 1K resistors to my shopping list. Would some attenuation also possibly be needed when using soundmodem and a pc with the data port on a mobile radio (e.g. a Yaesu FT-8800)?
On 4/24/2012 10:35 AM, Andre wrote:
On Tue, 24 Apr 2012 15:59:03 +0200, Bob Harris <knineudx@...> wrote:
That's a neat program. Has anyone interfaced a hand held transceiver (e.g. Yaesu VX-150) to a computer and Soundmodem? I know the various TNC manufacturers (e.g. Kantronics and Byonics) say to put a resistor between PTT and Mic and Kantronics also says to add a capacitor.
If it is a combined ptt line then yes you need a resistor between the ptt circuit and the mic plug of the ht and also a small capacitor between the MIC-ptt junction and the soundcard out of the PC, also adding a 10 db attenuator in the mic line might be needed, that should be placed between the capacitor and the sound out of the pc, a simple voltage devider of a 10k and 1k resistor with the 1k to ground should work.--Bob Harris (K9UDX)