[Elecraft] Interface and Ham Radio Deluxe

[Joe Subich, W4TV]

> If you connect directly to mic/speakers on both the PC and Radio be
> very careful. The PC speaker output can over drive the audio if you
> put it straight to the microphone of the rig and I would always
> advise using isolating transformers. You can spot people who have
> gone the 'straight through to mic input' route when they overdrive
> their audio and produce very wide signals.

An isolation transformer does not solve the excessive level problem.
For that you need an attenuator or voltage divider.  Typically one
would connect a 4.7K or 10K resistor in series between the sound card
output and the mic input and a 470 or 1000 Ohm resistor from the mic
input to the mic ground.  That 20dB is about right for the sound card
line/speaker output to an electret mic input.  Substitute 47K or 100K
for dynamic mic inputs or use a 500/1000 Ohm pot with the wiper to
the mic input instead of the fixed shunt resistor.

73,

    ... Joe, W4TV


On 10/13/2013 4:38 AM, Dave wrote:
> If you connect directly to mic/speakers on both the PC and Radio be very
> careful.  The PC speaker output can over drive the audio if you put it
> straight to the microphone of the rig and I would always advise using
> isolating transformers.  You can spot people who have gone the 'straight
> through to mic input' route when they overdrive their audio and produce
> very wide signals.
>
> A better option is to use Line in/Line out on the PC and interface to an
> accessory socket that takes constant line levels.  not lookied at the
> KX3 data inputs yet but if they are provided use them...
>
> Personally, I have used a US Interface Navigator.  It provides excellent
> interfacing on both audio and computer connections.  HRD is a bit
> expensive if you want the latest version, I well remember when it was
> free and there were a group of peopkle testing it and sugesting
> improvements and identifying bugs...
>
> Dave (G0DJA)
>
> ----- Original Message ----- Sent: Sunday, October 13, 2013 3:58 AM
> Subject: Re: [Elecraft] Interface and Ham Radio Deluxe
>
>
>> Dale,
>> I like and use a SignaLink USB and like it. However, almost any of the
>> popular interfaces will work. Or, you could just use the mic and
>> headphone connectors on your PC and run cables to the mic and
>> headphone connectors on the KX3. That can work also.
>
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