Sorry it has been so long since I posted. Life has been, well, challenging to say the least. And you know, when life serves you lemons, make lemonade. It just takes a while to peal that many lemons ;-)
Pressley - Sangamo
Pressley - Sangamo
I have had this radio for quite a while. It was obviously a kit radio. I had asked Alan Douglas about it and he indicated that the Sangamo components were probably a Sangamo IF strip kit. The kit was probably from 1924.
A posting at the ARF website had a link to this site:
http://www.duanesradios.info/html/press ... odyne.html
The radio chassis I had looked exactly like the one in the picture of Mr. Pressley at the bottom of the page. Note that my radio used Stromberg C. interstage transformers.
It was well built, but I cant say if it was assembled in a shop or by an amateur since it had been worked on later. Obviously some of the solder joints were very unprofessional in particular the mounting of the large metal-can cap to the chassis rail. It had been installed in a cabinet robbed from another radio, probably a 5 tube TRF (this radio is that small). The cabinet is much deeper than necessary, but part of the radio's history so that is where the chassis remains.
The most significant problem was the failure of the secondary of the first audio (imagine that) and, of course, that can-cap. The windings were replaced in the interstage transformer and everything else cleaned and checked out. It had been assembled with round tags under the chassis power/antenna connections that exactly matched the schematic on the web page above. So setting it up was simple - except the part missing from the schematic referred to as the loop. This was a loop antenna but with a tap (where?) used in conjunction with the band switch.
Well, the previous owner may or my not have had the radio running but he did provide a small coil or rather RF transformer that I used in the loop position. It alone provided enough signal to receive the stronger stations. With a 15 foot long antenna I was able to receive all local stations and the stronger ones in multiple spots on the dial. With a ground added to either post 1 or 2, depending on the band switch position, the first tuning stage provided some selectivity and gain. Otherwise it was pretty much one dial tuning with the IF filament control used to get the oscillator running and the second one for audio gain. This would have been the simplest of the supers that I have to operate and provided good sensitivity in a comparison with the 10 tube units that I have restored. I'm really glad that I got it off the shelf and got it running.
Well, the previous owner may or my not have had the radio running but he did provide a small coil or rather RF transformer that I used in the loop position. It alone provided enough signal to receive the stronger stations. With a 15 foot long antenna I was able to receive all local stations and the stronger ones in multiple spots on the dial. With a ground added to either post 1 or 2, depending on the band switch position, the first tuning stage provided some selectivity and gain. Otherwise it was pretty much one dial tuning with the IF filament control used to get the oscillator running and the second one for audio gain. This would have been the simplest of the supers that I have to operate and provided good sensitivity in a comparison with the 10 tube units that I have restored. I'm really glad that I got it off the shelf and got it running.
Below: As found. Note the set of Deforest tubes. all of them were good!
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