[Milsurplus] CTCSS???

[Morrow, Michael A.]

From: Toscano

> I believe a PRC77 has a CTCSS tone of 150.0Hz. Correct?
> Then my next question is will other interoperable manpack=20
> radios of the same vintage (specifically PRT4) have that
> tone as well?

The AN/PRT-4A (but not the AN/PRT-4) transmits 150 Hz tone.  Thus, you'd =
need to turn the squelch off on a AN/PRC-77 in order to hear a AN/PRT-4. =
 Likewise, the older RT-67, -68, and -70/GRC sets, and the AN/PRC-6, -9, =
and -10 sets, don't send 150 Hz tone.  At least the Vietnam-era =
AN/VRC-12 (43, 44, 46, 47, 48, 49, etc.) vehicular equipment could =
select "new" squelch (requires tone) or "old" squelch (requires carrier =
only).  I don't know why a similar feature wasn't designed into the =
AN/PRC-25/77.

I've found that my AN/PRC-25 and -77 sets work fine with current 6-meter =
FM ham sets if I set the ham set to send 151.4 Hz tone.  However, my ham =
equipment won't let the nominal 150 Hz sent from the AN/PRC-25/77 break =
the CTCSS when it is set for 151.4 Hz.  I set the ham set for carrier =
squelch operation on receive, with tone on transmission.

I guess the AN/PRC-77 and the AN/VRC-12 series of radios are now pretty =
much out of the US military inventory.  The had a good run, though, from =
the early 1960s on into the early 1990s.  Few other military radio sets =
have ever had that longevity in common active service.

Mike / KK5F