question clansman radio fequencies

[sim60]

I was wondering if anybody could tell me the frequency range of the clansman sets, as I was watching the guys transmitting and receiving at Wartime in the vale and my dad has got various radio`s for listening only(as he does not want to transmit)but is struggling to find much to listen to, he can`t get out of the house for various medical reasons and it helps pass the time. Any ideas/hints/tips most appreciated.

Thanks Simon

Ps he used to listen to CB radio but that seems to of died a death

[g0ozs]

Simon

 

Depends on the set, and the amateur bands within its coverage.

 

HF (Short Wave):

HF sets (UK/PRC-320, UK/VRC-321, UK/VRC-322 and UK/PRC-319) operate from 1.5 to 30MHz using USB, AM and morse - as far as there are centres of activity 3.615MHz and 7.187MHz are the ones I know of for AM in particular. Actually the 319 has wider coverage up to 40MHz but not of anything that can be legally used.

 

 

The sets can be legally used by cadets on their assigned frequencies and by licensed radio amateurs on any amateur band within the range, and the main ones are

 

 

 

• 1.8-2.0 MHz
  
• 3.5-3.8 MHz
  
• 7.0-7.2 MHz
  
• 14.0-14.35MHz
  
• 21.0-21.450 MHz
  
• 28.0-29.7MHz
  

 

 

These bands are split in to segments for various kinds of transmission - in general morse code is at the low end and SSB speech is at the high end. Bands below 10MHz are generally used with lower side band (LSB) and above 10MHz with upper side band (USB) - Clansman sets in UK service only had USB so are more likely to be found above 10MHz unless the owners have converted them (which is fairly easy) or are prepared to be the odd ones out on 3.5 and 7MHz (which is not easy!).

 

In practice most UK stations use 3.5 and 7MHz for daytime traffic within the UK - 7MHz works better in the afternoon - and the bands from 14MHz upwards are better for long distance use.

 

UK amateurs are allowed to apply for a notice of variation to their licenses allowing secondary use of some military channels in the 5 to 6 MHz range. The channels are listed at:

 

http://thersgb.org/services/bandplans/html/rsgb_band_plan_jan_2014-1_files/sheet009.htm

 

 

 

VHF:

The UK/PRC-349 covers 36 to 46 MHz which includes no legal amateur band.

 

The UK/PRC-350 does 36 to 56MHz including the 50-52MHz amateur band and 51.5, 51.6 and 51.7 are probably among the most used as the amateur 20KHz channel spacing and the Clansman 25KHz spacing line up on these frequencies in a general purpose section of the band.

 

The UK/PRC-351, UK/PRC-352 and UK/VRC353 all cover 30 to 76MHz FM only. This includes the 50-52MHz band mentioned above and also the 70MHz band on which 70.450MHz is the centre of Clansman activity here in Suffolk and North Essex.

 

UHF:

The UK/PRC-344 is a UHF air band set covering 225 to 400MHz AM. There is no UK amateur band within that range

 

 

Band Plans:

The Radio Society of Great Britain and other national societies publish "band plans" to help Amateurs share the bands between different kinds of use. These are voluntary in the UK but widely followed so are helpful to a listener in finding the traffic that they want.

 

You may find the Radio Society of Great Britain (RSGB) band plans at

 

http://thersgb.org/services/bandplans/html/rsgb_band_plan_jan_2014-1.htm

 

helpful;

 

Regards

 

Iain

[g0ozs]

Also note the Vintage & Military Amateur Radio Society nets page at: http://www.vmars.org.uk/Regular_NETS_Details

[AlienFTM]

Simon

 

Depends on the set, and the amateur bands within its coverage.

 

HF (Short Wave):

HF sets (UK/PRC-320, UK/VRC-321, UK/VRC-322 and UK/PRC-319) operate from 1.5 to 30MHz using USB

 

SSB, Single Side Band, as opposed to Universal Serial bus. Otherwise, at first glance, what he said.

 

I may well be wrong (you could look it up). Single side Band:

 

Most of the radio signal is noise. With VHF, squelch can tune this out. Not so with HF. So, imagining the signal as a modulated sine wave, by eliminating the bottom half of the signal and mangling the top half to boost the signal to noise (mentally I have a vision of something akin to deriving the RMS value of a sine wave).

 

AM was also available for backwards compatibility with Larkspur and foreign sets (though istr the NORMAL setting on Larkspur was in fact Phase Modulation).

 

Or a meringue?

 

Edit: if this reads badly, sorry I got interrupted by work. How rude.

[g0ozs]

Alien

 

USB (Upper Side Band) and LSB (Lower Side Band) are both forms of single side band - the difference is which half of the AM signal is removed. Both sets have to use the same sideband for the received signal to make sense (if you get it wrong it works as a kind of speech inversion scrambler). Most NATO HF radios standardised on Upper Side Band for SSB so USB was synonymous with SSB on those sets and it was never necessary to worry about - other HF users do use both side bands and the Clansman sets are therefore incompatible with default Amateur use of lower side band below 10MHz unless modified. The reason for using LSB below 10MHz relates to a circuit design trick that allows a single set of (expensive) filters to be used that was common in the early days of SSB in the 1960s.

 

The RT320/1 (USB/LSB) and RT320/L (Yugoslav LSB only) commercial variants of the UK/PRC-320 HF manpack differed physically by having two sets of filters in the space occupied by the 100Hz frequency decade switch in the 320/1 or by swapping the USB filter for an LSB one in the 320/L.

 

Larkspur had phase modulation as a side effect of using frequency shift keying for teleprinter traffic - more or less the same hardware is used for both. From what I'm told PM works better with strong signals and less well than AM with weak signals, on HF. Unlike SSB it isn't much of a bandwidth saving and became obsolete when Collins and others developed the narrow filters needed for SSB in the late 1950s not long after Larkspur was designed.

 

Regards

 

Iain

[AlienFTM]

Alien

 

USB (Upper Side Band) and LSB (Lower Side Band) are both forms of single side band - the difference is which half of the AM signal is removed. Both sets have to use the same sideband for the received signal to make sense (if you get it wrong it works as a kind of speech inversion scrambler). Most NATO HF radios standardised on Upper Side Band for SSB so USB was synonymous with SSB on those sets and it was never necessary to worry about - other HF users do use both side bands and the Clansman sets are therefore incompatible with default Amateur use of lower side band below 10MHz unless modified. The reason for using LSB below 10MHz relates to a circuit design trick that allows a single set of (expensive) filters to be used that was common in the early days of SSB in the 1960s.

 

The RT320/1 (USB/LSB) and RT320/L (Yugoslav LSB only) commercial variants of the UK/PRC-320 HF manpack differed physically by having two sets of filters in the space occupied by the 100Hz frequency decade switch in the 320/1 or by swapping the USB filter for an LSB one in the 320/L.

 

Larkspur had phase modulation as a side effect of using frequency shift keying for teleprinter traffic - more or less the same hardware is used for both. From what I'm told PM works better with strong signals and less well than AM with weak signals, on HF. Unlike SSB it isn't much of a bandwidth saving and became obsolete when Collins and others developed the narrow filters needed for SSB in the late 1950s not long after Larkspur was designed.

 

Regards

 

Iain

 

There you go. every day is a training day.

 

I'd give you a Like, but apparently not on HMVF.

 

[sim60]

Thanks to everybody for taking the time and trouble of replying to my question. I have passed them onto my dad.

Thanks Simon