View Single Post
  #6   Report Post  
Old May 23rd 07, 05:03 AM posted to rec.radio.amateur.antenna
Sal M. Onella Sal M. Onella is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 442
Default Field strength meters


"PPP" wrote in message
oups.com...
Hi,

From my search, I found two companies that manufacture field strength

meters: Potomac Instruments and Z-Technology. I was wondering if there
are others. It seems that these companies do not go past 3Ghz.

We are interested in measuring field strength all the way up to 18Ghz.
Does anyone know of any manufacturers that do this?

An alternative would be to use spectrum analyzers with the right
antenna, but I'm not aware of any spectrum analyzer that measure field
strength. From my lab experience, we were mostly dealing with dBm. I
did not see any option for V/m. Plus, they are very expensive. Thanks!

I've never had a spectrum analyzer measure field strength directly, although
maybe the Test & Measurement science is getting close. The missing link is
"antenna factor" (AF) which accounts for the db gain, usually negative, for
the antenna you're using. In my experience, every time we needed
quantitative measurements of field strength, we rented (or the government
lab sent us) one or more antennas and their calibration curves. AF unit is
dB/m.
See http://www.ce-mag.com/99ARG/Williams97.html for a neat explanation of
the conversion process to field strength.

I implied that T&M science might be able to yield field strength directly.
This would be by storing the calibration curves for selected (stock)
antennas in the instrument itself, much as we have been storing settings,
traces, etc, for many years. Dunno if anybody's doing it. I could have
used it a time or two.