The 'rules' (as they were learned to me when I was an eng. student, back in
the late 70's) were :
- no space between the figure and unit when the unit is abbrevated (so
136.5kHz)
- abbrevated units in capital otherwise not (so 12V and 12 volt)
- no multiples for units (so volt, ampére, watt, not volts, ampéres, watts)
- RF, LF, IF etc : in capitals without dots

BTW : terms LF, HF ,RF, IF etc... are mixed up frequently :

RF = radio frequency (regardless of the exact frequency)
IF = intermediate frequency (idem dito)
So a receiver can have a RF of 136kHz and an IF of 70MHz.

Frequency ranges :
VLF = 3kHz - 30kHz (very low frequencies)
LF = 30kHz - 300kHz (low frequencies)
MF = 300kHz - 3MHz (medium frequencies)
HF = 3MHz - 30MHz (high frequencies)
VHF = 30MHz - 300MHz (very high frequencies)
UHF = 300MHz - 3GHz (ultra high frequencies)
SHF = 3GHz - 30GHz (super high frequencies)

So despite what one often reads both the 73kHz and 136kHz ham bands are LF
and not VLF.

At 12:54 8/05/00 +0200, you wrote:

To All from PA0SE

On my question about the proper way of writing units in English/American I
received the following reply from the Editor of RadCom.

73, Dick, PA0SE


Hello, Dick.

It is RadCom style to use the following:

10V or 10 volt(s), 5A or 5 amp(s), 2W or 2 watt(s).
With IF, RF and AF, capital letters and no dots.
With frequency, no gap between the number and the units, ie
800Hz, 136kHz, 21MHz.

Steve White, G3ZVW

In The Netherlands we write 5 A, but 5 ampère, 10 V but 10 volt. So in
general the unit is written with a capital when abbreviated but with a
lower case when written in full. And with a space between figure and unit.

What is correct in English or American, 3 V or 3V?.  Same question for 10
amp, 10amp, 10Amp, 10Amps?, etc.

And what about rf or RF? if, IF, i.f. or I.F. (intermediate frequency)
etc.?

73, Dick, PA0SE