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PPP May 18th 07 04:28 PM

Field strength meters
 
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!


Richard Clark May 18th 07 06:43 PM

Field strength meters
 
On 18 May 2007 08:28:40 -0700, PPP wrote:

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!


Antenna, rectifier, capacitor - in that order. Cost, roughly $1.

73's
Richard Clark, KB7QHC

Wimpie May 18th 07 09:58 PM

Field strength meters
 
On 18 mayo, 17:28, PPP wrote:
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!


Hi,

It seems that your interest is professional measurements.

You may contact www.dare.nl. Mostly known as an EMC test house, they
also make several products for EMC measurements. They have a light
powered (via fibre) wide band field strength meter (RadiSense 18
GHz). You can find the product on their web site under the tab EMC
products.

Best regards,

Wim
PA3DJS




Richard Fry May 19th 07 06:15 PM

Field strength meters
 
With the right accessories for it including its calibrated antenna(s),
and deep pockets, the Z-Technology R-507 Portable Field Strength
Meter will get you from 0.3 MHz to 1 GHz with +/- 2 dB accuracy
traceable to NIST.

The calibrated antennas allow a direct readout in units of dBmW,
dBµV, or dBµV/m.

http://www.ztechnology.com/

RF


nx7u May 19th 07 10:53 PM

Field strength meters
 
The simplist route to measuring microwave field strength is a spectrum
analyzer and a standard-gain horn antenna.
You can then convert from the dBm measurement of the spectrum analyzer
to dBuV/m by using the calculated gain of the horn antenna, accounting
for the loss in any interconnecting coaxial cables/waveguides.
You can even build your own standard gain antenna, see http://www.w1ghz.org.
Or try eBay.



On May 18, 8:28 am, PPP wrote:
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!




Sal M. Onella May 23rd 07 05:03 AM

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.



Owen Duffy May 23rd 07 09:30 AM

Field strength meters
 
"Sal M. Onella" wrote in
:

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,


There are both EMC receivers and Spectrum Analysers intended for field
strength measurement, and modern digital system allow the antenna
response to be stored in the instrument and field strength automatically
calculated for different freqencies.

My FSM software (http://www.vk1od.net/fsm/) which is designed for making
field strength measurments using a conventional SSB comms receiver, an
antenna, a known attenuator, and a PC. FSM can read a file of Antenna
Factor vs Frequency and calculate a spline interpolation for the
frequency of measurement to (along with other factors) calculate the
received field strength in dBuV/m. I would be very surprised if any
modern digital instruments don't do likewise, either directly in the
instrument or in PC based analysis software, though there is a great
advantage in indication of field strength directly on the instrument.

In a recent test, the radiocomms regulator here loaded such a table of
modelled AF for an untuned loop antenna system
(http://www.vk1od.net/SmallUntunedSquareLoop/ssulNEC.htm) into a R&S EMC
receiver and made swept measurements using the loop over HF, and compared
them to the results from measurements using a R&S active loop (AF about
20dB lower than the passive loop). The difference of the medians was less
than a dB which speaks well for the NEC model!

Field strength is a bit of black magic to most hams.

Owen

AndyS May 26th 07 12:02 PM

Field strength meters
 
Andy writes

I did a quick google using " Field strength meter 18 Ghz" and found
numerous hits, including companies like L.C., Mayes, and PM just
to name three.

Lots of people make them.... you just gotta look. The google
search engine works well.

Andy W4OAH


Sal M. Onella May 28th 07 06:19 AM

Field strength meters
 

"Owen Duffy" wrote in message
...
"Sal M. Onella" wrote in
:

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,


There are both EMC receivers and Spectrum Analysers intended for field
strength measurement, and modern digital system allow the antenna
response to be stored in the instrument and field strength automatically
calculated for different freqencies.


Thanks, Owen,

I read online that there were EMC receivers that would store the AF curves,
but I happened not to read that there were spec-ans that would, too. I
haven't done that work in over ten years and we rarely had state-of-the-art
gear. (Can you say, "Singer NM-25"?)

Glad to know it's all getting easier.

Now, if we just could hook an X-Y plotter up to it ... Relax, I'm just
kidding!




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