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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Re: Eico dip meter - Help!!
Summary: It's really quite simple...
Message-ID: <4052@kitty.UUCP>
Date: 24 Sep 90 23:12:53 GMT
References: <3110@vela.acs.oakland.edu> <4049@kitty.UUCP> <3113@vela.acs.oakland.edu>
Organization: Recognition Research Corp., Clarence, NY
Lines: 35

In article <3113@vela.acs.oakland.edu>, swood@vela.acs.oakland.edu ( EVENSONG) writes:
> Hey! The 710 is the very animal that I have. (Eico 710, 8 bands from
> .4-250 MC)
> 
> Any one have any hints on how to create and tweak coils for this animal?  
> Pretend I don't know anything about building resonant coils for dip meters,
> and you won't be far from off.

	Get some 0.75" OD plexiglass tubing and cut it in 2.5 inch lengths.
You'll have to use some ingenuity in fabricating pins to fit the socket
on the end of the grid dip meter.  Heavy solid wire, like some tinned
12 AWG may be about right.

	The grid dip meter is tuned *solely* by the inductance of the
coil; there is obviously no bandswitch on the instrument.  While the
3 lower frequency coils may be tricky since they are tapped and I cannot
estimate the turns, the higher frequency coils from 2.9 MHz to 250 MHz
should be easy to build.

	Just start with winding a coil based upon the description in
my previous article.  All you need to test is a sensitive frequency
counter.  Set the scale on the grid dip meter to a given frequency.
Take the test leads from the counter and loosely wrap a turn around
the coil form for inductive coupling.  Merely add or remove turns on
the coil until the grid dip meter calibration matches the reading
on the frequency counter.

	These coils, by the way, are not exactly hi-Q, so I wouldn't
sweat your fabrication technique.

	I can't do much more than tell you the above.

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
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