WTB Counter, A simple Build your own kit 32Mhz versi

[Fred Finster]

     How to use the K1MG Frequency Counter with Tube radios.

     I just hooked the input with a micro jumper lead to the Grid resistor
     of the tube following the one with the plate I wanted to check.  I did
     not worry about the circuit loading of the tube following where I
     wanted to measurce the preceding VFO amplifier where the tuned circuit
     was at the doubling frequency of the local oscillator.  I just wanted
     to measure frequency.   Choosing where to pick off the connection
     point for the Frequency Input to the Counter is not hard.  Some times
     on the Grid resistor you might have - 2 to -10 Volts DC voltage with
     RF voltage you can see on a scope on the 0.5V per division, Other
     times you can put it on the 100 ohm range Cathode Resistor in the tube
     circuit.  I just caution putting on the Plate Circuit,  It detunes the
     plates tuned circuit and the DC voltage level is high.  Use the
     coupling capacitor to the Grid Resistor of the Next tube to block the
     High DC voltage.  Measure at the Grid Resistor of the next tube.

     If you want to measure at the output,  look for the meter circuit
     which has a resistor divider and 1/2 wave diode rectifier near the
     final Tube.  Here is a low level of RF energy you can measure with the
     Frequency Counter.   Other wise just wrap the wire or make a coil near
     the output tuned circuit and pick up the RF energy from the air.  I
     wrapped the alligator clip around the long wire antenna and that
     worked for me.


     I would suggest getting the 1000V 0.1uf capacitor in series before
     checking a 600V plate circuit!  It already has a transistor emitter
     follower amplifier.  For higher input RF voltage peak to peak swings
     Several volts you could include a series 100K ohm resistor to limit
     voltage peaks   100K/1K  would be a divide by 100 circuit.  a 10V peak
     to peak swing would give a 100mv swing at the input to the transistor
     emitter follower amplifier.


     Fred Finster  WB7ODY


     A long while ago, I followed some website to your and read your
     article about all the wonderful radio stuff left behind by your
     grandfather.  I really enjoyed reading and learning.  Find
     it interesting that you e-mail me now.


     ps.   Does anybody know of a website, that gives technical
     instructions for trouble shooting various circuits in a Tube Radio.
     As an example above like I explained how to connect a frequency
     counter to various places in a tube circuit.  I am looking for
     examples of how to connect various pieces of test equipment to trouble
     shoot a radio problem.  For peaking tuned Plate circuits on say Tube
     V1,  I would go to following Tube V2 grid resistor and place a scope
     probe.  Then the 20pf capacitance of the scope probe and 1 Meg Ohm DC
     impedance would not affect tube V1 tuning of the coil slugs.  I would
     also place the frequency counter input lead there to see what
     frequency I was peaking on the scope.  The oscillator 6.352 Mhz or the
     doubled 12.704 Mhz frequency.


______________________________ Reply Separator _________________________________
Subject: Re: WTB Counter,  A simple Build your own kit 32Mhz versi
Author:  Allen & Matt <mattall at CWNET.COM> at INTERNET
Date:    6/29/98 3:01 PM


Hi Fred--

This simple 32MHz counter sopunds like just the ticket!

But, The specs say the RF input impedance is only 1K ohm,
with 15pF capacitance.

How do you avoid excessive circuit loading when using
with tube equipment? Did you build-up an emitter follower
or some-such?

Our Best to You and Yours,

Rev. Allen
--
* * * * * * * * * * * * * * * *
73 de Allen, KJ6XH, and Matt                  West Sacramento, CA
               email:     mattall at cwnet.com
               http://users.cwnet.com/mattall

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --