Morton Jim@LLL-MFE.ARPA (05/01/85)
I ordered a Heath TNC as soon as the catalog came out and it was an
"official" product. Recieved my kit Thurs the 25th. (i picked mine
up at my local store)
The kit is nice. Uses a taped roll of resistors, diodes and caps
to speed assembly. I took about six hours to glue the thing together and
make cables for my terminal and radio. The kit comes with a connector and
cable for the connection to the radio but none for the terminal.
I had some bad parts - most were locally replaceable. The first was
a bad 7912 -12V regulator that liked 18 volts better than 12 . The second
was a
MC1458 op amp in the output to my transmitter. This was pretty easy to
find as the last step in calibration (audio level and tone null) would not
work right. the idea of this cal step was to hook a scope onto the audio
output and adjust the level with ptt on. then turn off ptt and adjust a
null control for minimum level. then set the proper audio level key down
to make sure. Well my op-amp was a better oscilator than amplifier so
no matter how i adjusted things, the level stayed the same. Being curious,
i looked at the input of the op-amp and saw evrything o.k. so i swapped
the chip and viola ! i am on the air.
My last problem regards the Non - volatle ram. I can not seem to program
it. I will consult heath and probably get a new chip or some such.
anyway... i have had a contact with the thing... seems to work
although i need a better antenna and more power ( i am running a whopping 3 W)
I can hear a lot of stations that can not hear me.
Heath did provide good instructions for hooking the unit to various
radios including my ICOM IC02AT which required a transformer on the XMIT
side of things.
All in all i am happy and satisfied with what i got.
Jim Morton WA6FWW
415-423-2374 days