HD-15 PSK Interface

[Brian Carling]

I have one of these Heath phone patches for sale of anyone 
else would like to try the conversion. It makes an extra 
nice PSK31 interface with that VU meter for monitoring 
the signal levels.

Brian, AF4K

On 17 Feb 2005 at 9:12, Bob Macklin wrote:

> I was asked about this yesterday but I did not see my response show
> up.
> 
> I used to operate TTY back in the 60s witha real TTY machine. A Model
> 15.
> 
> After returning to ham radio after a 30 year absense I heard about
> PSK31. I downloades WinPSK and gave it a try. I also read about making
> an interface with isolation transformers.
> 
> I am a Heath collector. I decieded I could make a decent PSK interface
> using a Heath HD-15 phone patch. But I knew very little about the
> phone patch at the time I started. I bought a pair of small 500ohm to
> 8ohm audio transformers from Ocean States Electronics.
> 
> I pulled the original transformers made to work with a phone line out
> and replaced them with the small audio tranformers. I removed the
> nulling circuit as it is not needed. I commected the Rx transformer
> with the 8ohm winding to the speaker and the 500ohm winding going to
> the sound card LINE IN. I used the switch on the HD-15 to connect the
> Tx output to either the speaker or the audio transformer. I connected
> the second transformer with the 8ohm winding connected to the computer
> speaker output. The secondary was connected to the Hi-Z and Lo-Z
> outputs to the Tx. Since I have a SB-401 I used the Hi-Z connected to
> the phone patch input on the SB-401. I don't like messing with the mic
> input.
> 
> The HD-15 switch and level controls were connected pretty much like
> the original circuit. I have the VU meter connected to the output of
> the Tx level control.
> 
> I can copy PSK QSOs that I cannot even hear. I am very impressed with
> this technology. It does not take much bandwidth and the cost of the
> software is right.
> 
> Bob Macklin
> K5MYJ/7
> Seattle, Wa.
> 
> "REAL RADIOS GLOW IN THE DARK"

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