Seven Years Later - Update on Aetna

I knew that Sue's radio was unusual  but it is more special than I had thought:

https://www.russoldradios.com/blog/old-radiosradioproject-update-iv

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UPDATE 12-16-2021
We now know the the Aetna model is 252P under Walgreens. It is a 4-tube  + ballast Tuned Radio Freq receiver from 1936. Most of the radios found in this cabinet are 550s, which is a superheterodyne rather than a TRF.  The super is relatively rare. The TRF is much more unusual.

Russ

I know that a lot of people have wondered what would happen if a person was to design a receiver - a TRF receiver, that had one high gain tube driving another and so-on. With this chassis it is easy to find out. Like the front end in a Zenith Stratosphere this chassis has a tuned 6D6 driving another, in this case a 6C6. Well, the answer is that LOTS of RF gain can get you - squealing, motorboating and eventually  - nothing. Even in the Strat, they had to turn off one of the 6D6s on some bands to keep the noise down to a controllable level. Unlike the Strat, or any super, this radio has no IF to narrow and amplify a specific freq so strong stations can be over powering to weak stations.

With this radio it is best to decide what kind of antenna you are going to use and align the radio to that antenna. A longer antenna will provide the noises mentioned above and a shorter one will make weak stations - weak. While the schematic in Riders says not to bend the plates on the tuning cap, linearity across the band is poor. Maybe someone already bent the plates or maybe they need some adjustment, but the spot (freq) you choose to  align to is going to be the sweet spot all else going down hill from there.

​No wonder they replaced this chassis with the 550 super. 

I thought that I took some chassis pics as we updated the radio with re-stuffed caps we found over the last 7 years. I'll try to find them.