[christge9]

Philco 52-541 - Was wondering if someone could tell me how many turns the loop antenna has? Mine is missing.

[David]

Looking at the sch you could use a ext ant, sorry unable to answer your question.    

[Radioroslyn]

>Looking at the sch you could use a ext ant

Not so much. The circuit needs to have the loop in circuit to form the tuned circuit connected to the input of the mixer. I don't think there is anything particularly special about the loop except the size and the inductance. If you happen to have a spare loop from another set that fits give it a go. If your spare was use with 365 pf tuning cap then it should fine as is. You can check it's resonant's by how well it receives at the high end. If the ant trimmer doesn't have a peak remove a turn from from the loop.
Or
http://www.sparkbench.com/loopante2.html


GL
Terry

[w4rtc]

Mine has 16 turns of about # 26 gauge enamel wire. It is wound flat, like ribbon cable, wound to fit the  inside of. The cabinet
Joe

[christge9]

Thanks Terry, I tried a generic loop (from tubes and more) with poor results, and one from a GE J64 which was better, but I think not right.

Thanks Joe, I'll give that a try. SAMS diagram quoted a value of 3.1 ohms.

[christge9]

For anyone interested, this was resolved using 16T of #29 wound around a cardboard form (shaped to the cabinet opening). I secured the windings with varnish to brown packing paper, which looked authentic.

Measured 3.1ohms, 0.227mH; which was right in the middle of what the resonance calculator determined (using ends of tuning cap range).

Performance was great, and even worked well without an external antenna.