[BC] Ed Burkhardt...

[Burt I. Weiner]

I met Ed many years ago.  He discovered that I was making off-air 
frequency measurements in the Southern California area.  The first 
time he called I answered the phone with my normal, "Come In", and 
all I heard on the other end was, Burkhardt here".  After a long 
pause by both of us he went on to introduce himself.  After that we 
talked quite often on the phone up to the time of his passing.

They way you can evaluate noise when doing FM frequency measurements 
is to determine how quite or clean the carrier becomes when listening 
to it beat against a transfer oscillator with modulation removed.  If 
the carrier is very quiet, 60 dB or better it will appear pretty much 
as a clean CW beat.  If there is any noise such as hum or his, it 
will make the zero-beat broaden out.

Part of Ed's  setup used a General 1109A "synchroscope" that he had 
modified.  This is a comparison scope with the second anode lead in 
the center of the screen.  He would feed an audio tone into one side 
of the scope, the audio tone being the result of a standard beating 
against the unknown incoming signal, and a transfer oscillator into 
the other side of the scope to to produce a Lissajou pattern.  He 
would adjust the transfer oscillator until the Lissajou pattern would 
stand still and then read the frequency of the transfer oscillator to 
determine the exact difference between the standard signal and the 
incoming signal.  I have copies of his modifications to the GR-1109A 
that he made.  Ed and I were always exchanging notes and ideas on how 
to go about measurements.

I felt very sad when Ed passed away.  We never got a chance to meet 
face to face and have a good laugh at each other's expense.  I know 
we both would have enjoyed that.  Just after he passed away I spoke 
to his wife.  We talked for quite a while and she sent me a picture 
of Ed.  I will always remember the times I answered the phone only to 
be greeted with a long pause followed by, "Burkhardt here".

I also use a scope as a beat indicator and sometimes using a Lissajou 
pattern.  See:  http://www.k5cm.com/k6OQK%20FMT%20NEW.htm

Burt

>From: Broadcast List USER <Broadcast at fetrow.org>
>
>The late Ed Burkhart in the Baltimore-Washington-Richmond and beyond
>markets used a similar method, though he viewed it on an
>oscilloscope.  He would count the rotation of the Lissajous figure on
>the scope, which showed the frequency high or low.  I really don't
>know how he did it, but he did it well.
>
>For AM, he measured carrier frequency.
>
>For FM, he measured carrier frequency, Pilot frequency and level, SCA
>carrier(s) frequency and level.
>
>He also measured noise, kind of roughly, but you could be sure that if
>he put a note on the bottom of your post card that you should check
>noise on something, you had better do it.  I used him at an AM, and
>four FMs over the years.
>
>He lived on a hill north of Richmond, VA, from what I understand, with
>a fairly short tower, and a room full of stuff in a room on the back
>of his house.