Nov 062016
 

I found this 1950s-era Canadian military radio in an online Goodwill auction, of all places. It is missing its whip antenna, but a friend in Australia is helping me out with that. This one may be tricky to repair if it doesn’t already work, because all but one of the vacuum tubes are hermetically sealed into individual metal cans. The modular construction made these easy to repair in service, but I don’t have a stock of spare modules to draw from.

Oddly, the -3V battery pin is covered with a rubber plug. The plug seems to be firmly bonded to the rubber battery connector insulator, so I don’t want to pull it off until I’m sure that it doesn’t belong there. This is a mystery that I hope that other CPRC-26 fans can help me figure out.

It’s a bit surprising that this is my first CPRC-26. It just seems like a radio that I should have acquired many years ago, but it took me this long to get around to buying one.

The radio came with five out of six channel crystals installed, but two are duplicates. Unfortunately, none of them are for 51.0 MHz, the single most used channel for US ham radio operators who collect VHF low-band military FM radio gear. I think I’ve read that the CPRC-26 uses the same crystals as the US PRC-6 radio.

The handset is very similar to the US H-33/U handset, but with a bakelite piece bonded on the outside of the rubber PTT switch boot, and a different connector. The PTT switch piece is cracked, so I’ll need to repair or replace it.

Three of the bottom case screws are missing. They’re sealing type screws with little O-rings in recesses under the heads. The top of the case is secured with four clamps. Two of them had fallen off in shipping, but luckily I found them in the packing material before I threw away the shipping box.

  7 Responses to “Canadian CRT-1/CPRC-26 Radio”

  1. I have spare modules, if you nned them

  2. Mark,
    Interesting. The only sets listed with a 51.0 MHz frequency are the Type B and C which were not used, and the Type D. The Yellow dot indicates a Type D with the following channels: 50.0, 50.2, 50.4, 50.6, 50.8 and 51.0 MHz. The crystals in this radio are set to 51.8, 56.4 and 65.05 MHz (crystal frequency + IF of 4.3 MHz). And two of these frequencies are in pairs. Could this be the reason for the capped power pin?
    The manual lists the frequency range as between 47.0 MHz and 55.4 MHz.
    If you are interested, I most of the manuals. My e-mail address is cmp.truck@gmail.com. I can send you scanned copies.
    Ian
    VA6SSV

  3. I think that I remember reading that late versions had an all solid state audio module thus eliminating the need for the -3v bias.

    • Neat!

      I did end up pulling off the cap on the -3V pin. It wasn’t molded or glued in place as I originally thought; it was just crammed down tight on the pin, such that the seam wasn’t very visible under the years of gunk. SO maybe it was there for a reason, or maybe it was just crammed on there for no particular reason. Maybe I’ll learn more once I get around to studying my set’s electronics more carefully?

  4. Craig,
    Philips developed a solid state model for the Danish army. It is called the PRC-261 and had twelve channels rather than six.
    Mark,
    I am not a radio expert by any means, but if the top of the frequency range for this radio is 55 MHz, and this radio operates above this frequency, does this mean a modification was made to allow operating on 56.4 MHz and 65.05 MHz?
    Ian

    • I don’t know about this CPRC-26 yet. I have used other crystal-controlled radios outside of their specified ranges, such as an EF Johnson Fleetcom II that I repurposed for use on the US 440 MHz ham band back in the 1990s. The specified frequency range often isn’t a hard limit.

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