08-25-2021, 04:37 PM
After a thorough alignment of the AM this radio is VERY good ! Last night I finished aligning the AM; first all the IF, then the oscillator tuning and the RF until it was working as well as it could on the standard tuning, picking up stations all up and down the dial. Since much of the alignment called for the signal coming in through the loop, and the chassis was out of the cabinet, I made a substitute loop. For anyone who comes after this thread, here is how I did it. It may prove useful to you also.
First I measured the loop in the cabinet. It was 18.75 inches by 10.25 inches, so each turn was (18.75 + 10.25) x 2 inches in circumference, or 58 inches. There were 3 complete turns, for a total length of 174 inches. I had a box that was 6 x 6 inches, for a total outside circumference of 24 inches. 174 / 24 = 7.25, so 7 and 1/4 wraps around the box would equal the proper length to emulate the loop. I used some 20 gauge insulated wire, and made the simulated loop, and it worked a treat ! I figure a similar process would work for other Philco radios which have those big loops of thick, bare, copper wire at the back of the cabinet. You will need to measure carefully so you can calculate the total length, then find a suitable form to wind it on, and wind on the exact length. I also left about 8 inch leads to connect to the antenna terminals. You can see the loop to the right of the radio chassis in the picture.
[Image: https://64.media.tumblr.com/453b2cb82755...08b7c7.jpg]
Once I had the AM alignment (and the SW) all done, and double checked the FM, I then set all the push buttons to stations I listen to a lot on the broadcast band, WSM 650, WLW 700, WSV 750, WLS 890, WRVA 1140, and WLAC 1510. The stations come in as well on their push button as they do with standard tuning. The picture above was taken today of the radio playing on FM. In the daytime the reception on AM in my radio room is not great, terrible actually, because of the interference from the TVA power lines, but the FM comes in clear, and with stations all up and down the dial. I am VERY pleased with the results ! Only one thing; I now realize that there is still a problem with the FM on the first 48-482 I restored. It should be a LOT better than it is, so I may go back and hunt down what that problem might be.
First I measured the loop in the cabinet. It was 18.75 inches by 10.25 inches, so each turn was (18.75 + 10.25) x 2 inches in circumference, or 58 inches. There were 3 complete turns, for a total length of 174 inches. I had a box that was 6 x 6 inches, for a total outside circumference of 24 inches. 174 / 24 = 7.25, so 7 and 1/4 wraps around the box would equal the proper length to emulate the loop. I used some 20 gauge insulated wire, and made the simulated loop, and it worked a treat ! I figure a similar process would work for other Philco radios which have those big loops of thick, bare, copper wire at the back of the cabinet. You will need to measure carefully so you can calculate the total length, then find a suitable form to wind it on, and wind on the exact length. I also left about 8 inch leads to connect to the antenna terminals. You can see the loop to the right of the radio chassis in the picture.
[Image: https://64.media.tumblr.com/453b2cb82755...08b7c7.jpg]
Once I had the AM alignment (and the SW) all done, and double checked the FM, I then set all the push buttons to stations I listen to a lot on the broadcast band, WSM 650, WLW 700, WSV 750, WLS 890, WRVA 1140, and WLAC 1510. The stations come in as well on their push button as they do with standard tuning. The picture above was taken today of the radio playing on FM. In the daytime the reception on AM in my radio room is not great, terrible actually, because of the interference from the TVA power lines, but the FM comes in clear, and with stations all up and down the dial. I am VERY pleased with the results ! Only one thing; I now realize that there is still a problem with the FM on the first 48-482 I restored. It should be a LOT better than it is, so I may go back and hunt down what that problem might be.
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