KC0QNB
Member
Back in the late '70s early '80s, a lot of radio users had to update their equipment to narrow band, now I read that there is a new narrow band spec from 25kHz down to 12.5kHz, anybody know what the pre 1980 wide band spec was?
That change was in the late 50s-early 60s, not the 70s or 80s. Channel spacing was 30 kHz with 60 kHz separation between adjacent assigned frequencies, i.e. 154.310, 154.340, 154.370, 154.400, 154.430, etc. and adjacent assigned frequencies would have been 154.310, 154.370, 154.430, etc.
It became 15 kHz, i.e. 154.310, 154.325, 154.340, 154.355, 154.370, 154.385, 154.400, 154.415, 154.430, etc., with 30 kHz separation between adjacent assigned frequencies.
Soon it will change again to 12.5 kHz spacing and 25 kHz separation for analog, and 6.25 kHz spacing with 12.5 kHz separation where applicable for digital. Check the VA STARS system for the layout of their freqs for their vhf high band trunking. That'll give you an idea where it's all going.
Us old guys remember this kind of thing because we were still wet behind the ears when it was happening.
In your spare time you would narrow band Twin V's with the conversion kits. I bet there are some wideband Permakey filters still around in some shop.