TheRadioBoard

In an earlier post I posed a question about making a trap for a radio that did not use an external antenna ... only an internal ferrite antenna.

After some excellent advice and feedback, I was able to find a solution. It is very simple, and you might say it's a no-brainer ... but it took some experimenting to get it to finally work.

The radio I am trying to build the trap for is my Ferrite Fox #4 ...



Note in the picture where the ferrite rod is, and the size of the rod.

Now here is the same radio with the trap in place ...



The trap consists of a high-Q ferrite loopstick and a remotely wired 365pf variable capacitor. The loopstick is placed so that it is centered on the coil portion of the interior ferrite loop antenna.

With this setup, I can tune the trap to the strongest station I can hear and it dissappears from the dial. I can tune the stations on either side of the trapped station just fine.

I'm stoked !!! Many thanks to Mike Tuggle for the great feedback on traps. I hope this device finds homes with others that need a similar trap

Cheers,

Tony

Great work.
You often see arrangements with the trap on the same rod, but I could never see how that could work very well.

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Nice work!

I did a similar thing on a test set:







Enjoy!

Mike

_________________
I like the K-I-S-S Principle: "Keep It Sane & Simple"
http://www.peeblesoriginals.com

Hey Mike ... that's a pretty elaborate "Test Set"

My test setups usually involve alligator clip leads and perf board !!

Will your test radio pick up stations with only the internal antenna ??

Traps seem to work a bit differently when the rig uses a strictly internal ferrite antenna as opposed to a ferrite coil with an external antenna feed.

I would expect that tuning your trap would pull the main tuning off a bit ... do you recall if that was the case ??

Tony

..

Tony,

Your sets are really nice looking, and bet they work well.



The set will pick-up a few, on the internal loopsticks.
However, it's not really intended to be used that way.
It's mostly used to test detectors, etc. . .



To be honest, I've not noticed that type of interaction, that much.
However, I suspect it does affect tuning,
but I'm used to peaking all the variables
to gain maximum tuning for each station.

Glad to share, and appreciate the sharing of your's and others.

Mike

_________________
I like the K-I-S-S Principle: "Keep It Sane & Simple"
http://www.peeblesoriginals.com