"Leon" wrote in message
oups.com...

wrote:
I am trying to get some slug-tuned coils. I tried 4 different
electronics stores and searched online. So far I can't find them. I
found a few online, but not at the right uH value. I need them to make
a notch filter to block out a radio station (or summat) that is
interfering with channel 2 and 4 on my TV. The schematics and complete
info are on this page:

http://www.dewtronics.com/tutorials/...ter/df222.html

The last resort would be to buy an kit online for the notch filter, but
it has lots of extra parts to make versions that I don't need. The
coils I need a

3.5 turn slug-tuned coil with aluminum core - 0.16 to 0.24 uH
5.5 turn slug-tuned coil with aluminum core - 0.06 to 0.09 uH

I can't even seem to find very many inductors of any kind that are
under 1 uH in value.
Anybody know where I can get these slug-tuned coils or what
substitution I can make? I need to be able to vary the inductance so I
can tune it to the right frequency to block out from my TV signal.
Right now I don't know exactly what exact frequency it is, just that
it's between 55 mhz and 72 mhz.

Toko makes that type of coil - S18 series, IIRC.

Leon


Not being completely familiar with your situation (haven't read any replies
either) - am just asking - might you consider (or have you) - a coax stub
tuned filter? Put an appropriate "T" connector on the back of your set -
place your actual TV antenna coax or whatever you're using on one side and a
length of coax or equivalent of what you're using on the other side and cut
it (the side NOT connected to your antenna) til it cuts out the
interference. I had problems with a 2 way radio set up once and ended up
doing that - took some cutting til I got to the right length, but BINGO - no
more problem. I'm not sure if this would work in your situation - the system
was more for 2 way radio issues - but easy enough to try without "hunting"
for parts. Maybe it will work! I read about these in books, I've used one
myself as I said. But oddly, I hardly ever hear of others using them.

There is a length you will have to start at - but I don't have the paperwork
I had - in front of me to figure out the starting length. Maybe someone else
here can toss in the frequency or formula. I've not used it in quite some
time and it's TOO early in the AM for me to think. It seems to me (but don't
quote me), it was a 1/4 wave of the frequency you're "correctly" receiving -
not the "interference".

If the station is nearby - maybe the "engineer" can be of help. Usually -
they are. If it is "cable" TV you have - maybe contact the Cable TV
company - you "could" have leakage on your line.

Hope this might help - sure less aggrivating than trying to run down parts!

L.