One of my 2001 Christmas presents was a Ten-Tec 1253 regen receiver. I wasn't able to find much information about this receiver on the web, but was interested by what I did find. In the end, this turned out to be one of the most fascinating regen receiver projects I'd ever built.
I worked on this a a leisurely pace over three days of my Christmas vacation. Like I expect from Ten-Tec kits, it was fun to put together. The final product looks nice, performs well, and has a solid feel. The quality of the enclosure isn't matched by any other sub-$100 kit I've come across.
The speaker is mounted the same way as the speaker in the 1340 transceiver. In that rig, I'd noticed some buzzing of the aluminum frame at certain frequencies. I found a solution to this problem (which I also later used on my 1340).
Take some narrow electrical tape (3/8" or so--if you don't have narrow use a sharp knife to split a nearly empty roll of electrical tape down the middle giving you two narrow strips). Run some around the hole that holds the speaker and fold over both sides of the hole. The speaker will now rest against the tape. Then apply tape along all four edges on the side that will go against the enclosure. Be neat because you can see this area through the speaker grill. Tighten things down and you shouldn't have any buzzing.
The only other problem I encountered was with mounting the battery holder. I was happy with the appearance of all the wires I'd run for the bandswitch. Installing the battery holder would have forced me to stuff all these wires beneath a mounting plate. So I decided not to install the batter holders. Instead, I plan to mount this in a separate enclosure with the ARRL standard mobile power connector on it. All of my low-power projects can be connected (through an adapter cable) to this type of connector. This way I can use the batteries to listen to my 1253, or use it as part of a portable station with the Tuna Tin 2, or I can hook up the 1340 transceiver. To me, the added flexibility of an external battery pack is worth the extra space.
The 1253 is a well designed, solid performing regen receiver. Like all regens, it has its quirks and its strengths. It is very sensitive when you set the controls properly. I've found it easy to tune, even on CW and SSB signals. The audio is loud and clear.
But the most fascinating thing is the bandswitching. Small inductors are diode switched with voltage from a counter IC. This lets you step through the bands using a single push-button. Along with the varactor tuning, this gives a simple, small, and reasonably stable (at least in a 'normal' shack) tuning circuit. I'll probably copy some of these ideas in future homebrew projects
The only thing I've even thought about modifying is the audio. It would be nice to have more audio selectivity when copying CW signals. There's plenty of audio power to allow some simple filtering in the audio stage. But since I'm building a number of receivers to play around with, I plan to build an outboard audio filter.
Overall I've been impressed with this radio. I think it's an excellent regen for the QRP shack.
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