Saturday 16 July 2016

Clansman Manpacks for Amateur Use - Part 2

In my previous post we discussed the unusable for amateur radio sets from the Clansman range, and the 'rare' but usable radios.

This time, we'll move on to the most suitable of the series, but starting with the 'least' suitable of them!

PRC-350



The PRC-350 is a 2W FM radio covering 36 to 57MHz in 25kHz steps. This means it covers the 6m band. Sadly, the current 6m bandplan uses 10kHz steps, which means only a few of the -350's channels coincide with a usable amateur frequency, and the FM calling channel is not one of them! It also uses a special 15v battery that is not compatible with any of the other radios. However, its does use the standard Clansman audio ancilliaries, and its antennas are the same as those of the more useful PRC-351. It does however have an internal 160Hz subtone generator which means it will work with non-clansman radios. As with the other radios we will talk about in this post, it also has dual audio connections. Originally, this was so that the operator could use the radio, usually with a headset, whilst a handset was available for the officer! There is also a mini-BNC antenna connector that allows this radio to be used with external antennas for increased range.


PRC-351


Of the VHF FM Clansman radios, the PRC-351 is understandably the most popular and most usable. Antenna compatible with the 350, battery and audio ancilliaries compatible with the PRC-320, it is a 4W FM set covering 30 to 77MHz in two seemless switching ranges at 25kHz channel steps. This means that although just like the 350 it is difficult to use on 6m, there are more channels usable on 4m, and this includes the calling channel on 70.450MHz. It is also possible, with a simple but tricky to carry out modification, capable of being made to cover a bit of the FM portion of the 10m band, by using a switch to 'fool' the synthesizer!

As with the 350, the 351 has an external antenna connection, in this case a proper BNC. This can be used with a number of Clansman antennas, which we will discuss later, or of course amateur antennas. But its main advantage is to connect it to a clip on 20W amplifier.

PRC-352 - The 351 plus 20W Amp

Adding on the 20W amplifier to the 351 redesignates it the PRC-352. At this point, the various whip antennas can no longer be used and an external antenna is required, but range is considerably increased. I myself have used my 352 and the Ground Spike Antenna to contact Bob M1BBV up on the summit of Ingleborough in the Yorkshire Dales, from Emley Moor, a distance of about 45 miles.


You may notice my PRC-352 above has another unit on top - a 4W SURF. We will mention these later. For amateur use, there is no advantage in having a SURF unit, if anything, they will actually reduce your signal!

PRC-320



The PRC-320 is the most popular of the Clansman manpack series, and with good reason. Build like the proverbial brick outhouse, the 320 is a 30W HF transceiver, capable of CW, AM and SSB opertion in 100Hz steps from 2MHz to 30MHz. Due to its rather agressive VOGAD mic amp, its 30W sounds more like 100W! Its built in manual ATU can match the radio to almost any antenna, although its best suited to capacitve (ie short) antennas. Only capable of USB 'as is', a relatively simple mod can add LSB capability. It does have a few curiosities in its operation, the chief of which is a 2kHz offset (the side-step) on SSB operation. Battery and audio ancilliaries compatible with the 351. However, unless you intend to use it only with resonant antennas, the 2.5m whip and the antenna gooseneck adapter are essential accessories. A tuning guide plate is attached to the radio body which shows what ATU settings are needed for various antennas, or what lengths of antenna wire for dipoles. A pair of clansman antenna wire spools, and a dipole center,  are pretty much also essential accessories.

Prices for these vary considerably. A thick fin version is sometimes available, with reinforced protective fins over the controls, but commands a higher price. Budget radios can be had for less money, but expect some fins to be missing.

In the next post in this series, i'll talk about the antenna, battery and audio ancillaries suitable for use with the PRC-320, 351 and 352 radios.





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