[BC] Frequency Measurement detector...

[Broadcast List USER]

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.

New or fill-in overnight Jocks were interesting.  Some tried to talk  
him into giving them the Hotline number.  Some refused to believe  
someone was calling them on the Hotline to ask for dead air.  When  
that happened and he could not convince the jock he was on the level,  
I would get a call the next day and got to write a note to the jock  
telling him or her to OBAY.  Sometimes that resulted in a late night  
call to the PD who would dress down the jock.

We agreed to let the jocks give away a prize if they had one anytime  
in their shift.  "We are going to shut up for just a moment to a few  
minutes.  The first caller to get through when we play the next song  
gets a..."

We even used that for extended maintenance intervals.  This was very  
interesting when I was working at a top rated Top-40.  The jock would  
announce, sometimes several times, that we would be going off at  
Midnight, or 2 AM, or whatever, and that the first caller, of up to  
first nine callers to get through would win a ... whatever.

I would always walk down to the studio and tell the jock to give a  
Legal ID and play a song.  It just amazed me that all nine Request  
Lines would be lit in a second, even if we were off the air for five  
or six hours.  These were people who would dial the first 9 digits of  
the Request Line number and hover a finger over the last digit.  I am  
guessing those days are over!

--chip

On Nov 19, 2010, at 4:31 PM, broadcast-request at radiolists.net wrote:

> Message: 25
> From: "Burt I. Weiner" <biwa at att.net>
>
> The most common and reliable method for off-air frequency measuring
> is what is called the heterodyne method.  In this case you tune a
> receiver to the desired signal and then zero-beat the signal with a
> local signal generator connected to the receivers antenna input
> through whatever padding is required.
>
> Zero Beat is an oft misunderstood term.  True Zero Beat is when there
> is no (zero) beat note, essentially D.C.  From a practical standpoint
> you would tune the local signal generator for zero beat while
> watching the S-Meter on a receiver.  As you approach zero beat you
> will hear the resultant heterodyne tone becoming lower and lower
> until it's either below the ability for the receiver to reproduce it
> or your ear to be able to discern the beat note.  At this point you
> can look at the S-Meter and see it start to swing back and
> forth.  The closer you get to true zero beat the slower the S-Meter
> wavers until you bring it to a stand still.  You then measure the
> local signal generator using a counter or a dial reading, depending
> on the type of Interpolation or Transfer Oscillator used.
>
> In the case of the Heterodyne Method, the receiver is only used as a
> detector and only needs to do two things:  Allow you to hear and
> identify the station and to give you a display of the signal strength
> for the sake of being able to let you see zero beat.  I've used
> everything from a good car radio to a SP-600JX and now my receiver of
> choice is a HP-3586B Selective Level Meter.
>
> I used to measure two stations that were both on 1340 kHz.  Both were
> over 100 miles away and equally interfered with each other.  There
> was so much interference on the frequency that watching the S-Meter
> was useless.  By having the one I was measuring modulate their
> transmitter with a 1000 Hz tone I was easily able to measure that
> individual station by determining Zero Beat by ear.
>
> Burt