[HBR] Walt's latest receiver

[Bill Higgs]

Walt, good to hear that your new toy is playing well. Good luck with the matching transmitter project! The earliest editions of the ARRL SSB for the Radio Amateur had a couple of exciters using tuned circuits only, usually somewhat lower in frequency. However, an IF bandwidth is an IF bandwidth, and the BC-453 cans give a good one when properly tuned. You'll need double conversion, of course, and some good filtering to keep the transmitted birdies down. A bit of audio filtering in the mic amp will ease your task, and you should have a dynamite sounding rig when you're done.

BTW, If the receiver in question is the one using the BC-221 panel, I have a download of the pic on my computer. I'll e-mail it to you directly.

I've gotten back to my own HBR-? after a several month hiatus (looks as though it may wind up with 16 tubes, but not an HBR-16 circuit - a few diodes but NO transistors). Current area of construction is the RF amplifier. I'm going to try the 6BZ6 with the circuit in Orr's Radio Handbook, but I may revert to the 6BJ6 as the pin basing is the same in this configuration. Anyone on the group tried this? Also, I'm going to try toroids in lieu of airwound coils; two challenges here: Q is apt to be a bit lower, and you have less control of coupling between the primary and the secondary. Advantages are that they conserve a great deal of space. A breadboarding of the tuned circuit with my dual capacitor and 60 turns on a T50-2 toroid yielded a tuning range of about 3.5 - 7.8Mhz, with a good peak (lacking a dip meter, I couple a signal generator to the circuit and then read the peak voltage with an RF probe - works for me). As I am using the band imaging technique (80 is the image of 40 with an IF of roughly 1.8Mhz, I may find I need a bit of extra selectivity. It'll depend on the final loading of the circuits. Hopefully, I can get some B+ to it by the weekend, and start testing.

73,

Bill Higgs, NT4C