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Philco 38-62 Sensitivity - Printable Version

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Philco 38-62 Sensitivity - dconant - 12-05-2025

Hello, Don't know if this is a sensitivity issue or not. I can receive stations in the middle of the dial pretty good but both both ends seem to be quite dead. Any idea what might be going on? The set has been recapped and aligned. All tubes test good. Schematic is here. https://philcoradio.com/library/download/service%20info/wiring%20diagrams/vol2/split/Part9-Philco%20Wiring%20Diagrams%20Vol.%202.pdf

Thanks, 
Dan

RE: Philco 38-62 Sensitivity - RGK20m3 - 12-05-2025

What are you using for an antenna? My limited experience is that it is nearly impossible to have an antenna that covers the entire band. Closest I have is a 2 turn counter phase loop on my 38-7XX
I use a tuned coupled milkcrate loop on my 38-690 that really works well, and really helps when connected to the 38-7

RE: Philco 38-62 Sensitivity - Vlad95 - 12-05-2025

This is most likely the result of poor tuning of the input path. The tuning procedure is described in detail in the document you attached in the "Tuning Compensators" section.

I also strong recommend adjusting the oscillator tuning range after the first stage of IF tuning. Compensator #8 adjusts the low-frequency range to 520 kHz, and compensator #3B adjusts the high-frequency range to 1720 kHz. After this, you can proceed to adjusting the maximum sensitivity to 1600 kHz using compensator #3A and to 580 kHz using compensator #10. Since the settings are interrelated, it is recommended to repeat the tuning process several times for both low and high frequencies to achieve the best results.

RE: Philco 38-62 Sensitivity - dconant - 12-06-2025

Well I guess I messed up. I did an alignment again with very little difference but then I realized the band switch was in the SW position. When switched to AM the whole band came to life. I just assumed I was on the AM band since I was receiving AM stations. So now the question is why am I getting mid band stations on the SW band?

My antenna is just a long wire about 100 feet long stretched between trees with a ground rod driven in the ground about 50 feet from the house. Works quite well on these old radios.

Dan

RE: Philco 38-62 Sensitivity - RGK20m3 - 12-08-2025

Wish I could have that setup; condo rules prohibit it.

RE: Philco 38-62 Sensitivity - Vlad95 - 12-08-2025

My antenna at my previous home in Ontario
I'm planning to install one here again this summer.