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[Geo]

Hi
Before some days i read a thread about an old BFO metal detector. It uses a rf choke with name AF-555.
Does someone know something about it? I am interesting for the inductance of the choke. I remember that before 20.... 25 years we used this choke at AM transistor transmitters.

Regards

[amtech2005]

help

Geo , Some old BFO'S were high as 500. khz, could this choke be around 555. khz ? And some chokes were used with I.F. Frequency 455 khz for a.m. radio Band. Maybe was for a Russian BFO ? I saw a post of an old russian detector looked like there were some big chokes on the circuit board , I am searching for that post again . Maybe Between 80. u.h. or 2.5 m.h. Sorry for all the maybe Please show some photos............Eugene

[Geo]

Hi Eugene.
I attach the pfoto of the pcb and you will see the JAF1 and JAF2. It works at 1Mhz!!!!! but it dont interesting me
Regards

[amtech2005]

help

glad you posted that schematic, pretty sure it is exactly 2.5 millihenry choke

[Geo]

Hi Eugene
Thanks for your answer.
I believe that don't exceed the 1mH......This is the reason that i am looking for the choke data
Regards