|[AMRadio] HD-15 PSK Interface|
macklinbob at msn.com
Thu Feb 17 12:12:38 EST 2005
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
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
"REAL RADIOS GLOW IN THE DARK"
More information about the AMRadio mailing list
This page last updated 17 Dec 2017.