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steps

PostPosted: Tue Sep 12, 2017 5:21 pm
by Silage
Is there standard steps for PMR uhf /vhf frequencies?

Re: steps

PostPosted: Tue Sep 12, 2017 6:58 pm
by m0lsx
Yes each band has it's own band plan that includes the spacing between each channels centre frequency.

Re: steps

PostPosted: Tue Sep 12, 2017 7:07 pm
by Silage
What would they be? 25 or 12.5 etc?

Re: steps

PostPosted: Tue Sep 12, 2017 8:52 pm
by m0lsx
Yes & some times a mixture of more than one. This allows two different users to share a band in harmony..Or should. So if you look at 446 PMR, you will see commercial users on one set of frequencies & low powered licence free users on a different set of frequencies.
Each band has it's own plan & the steps are decided by number of factors. As the idea is that users should not interfere with each other. So power output, antennas permitted, mode of operation, density of licensed operators & other such factors all come into play.

Re: steps

PostPosted: Thu Sep 14, 2017 8:37 am
by Minus1
Assuming that by "PMR" you mean business radio (because OFCOM haven't noticed that having "PMR" as the abbreviation for both "Private Mobile Radio" and "Public Mobile Radio" is mind-boggingly stupid):

All bands will have standard steps.
Most business bands use 12.5 kHz, BUT some idiot thought that offseting some by 6.25 kHz was a good idea, so you need to use 6.25 kHz as most scanners cannot handle a fixed offset (because they don't have this offset stupidity in the US). So you waste 50% of your time scanning freqs that are not actually used. (If you have a scanner with copious memory - such as a Uniden UBCD3600XLT - you can set up your own systems to scan those bands more effectively)
(The EU thought that was a good idea for 446 MHz too, but that's EU bureaucrats for you…)
The ones that use 6.25 kHz offsets are:
139.50625-140.49375 with 148.00625-148-99375
143.00625-143.99375 with 154.00625-154.99375 (WPD digital in some areas)
Most, but not all, PMSE bands.

Some digital freqs use even dafter offsets of 3.125 kHz, but we won't go into that :rolleyes: