[BC] NRSC - Harmonics above 5 MHz

[Burt I. Weiner]

The problem with using a calibrated communications type of receiver 
or spectrum analyzer at 1 KM is the antenna.  You need to know the 
antenna factor.  Antennas are not a flat device, especially when your 
looking over several octaves.  Each antenna will come with its own 
unique calibration curve.  Basically, any sample device will be 
something other than flat when you're talking about a spread over 
several octaves.

an aside: One of the neatest and inexpensive receivers (on eBay) is a 
HP 3586B.  Typically $200 to $300.  This is a Selective Level 
Voltmeter.  This is exactly what a Potomac FIM-41 is - a tuneable, 
Selective Level Voltmeter.  The HP 3586B tunes from 10 Hz (Yes, ten 
Hertz) to 32 MHz and is a precision device.  The problem is -- you 
still need a calibrated antenna to make field intensity 
measurements.  Potomac came up with a really clever way to 
standardize the loop and receiver together in the FIM series.

Burt

At 10:00 PM 2/9/2007, you wrote:

>However, a FIM-41 only goes to 5 MHz...  if you are doing a station
>at the top end of the band you need a communications receiver or
>analyzer to do a proper harmonic and spurious measurements above 5 MHz...
>
>Robert

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at earthlink.net
K6OQK