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 3. GQ EMF EF Meter RF Spectrum Power Analyzer
 Radio Amateur 14Mhz Band tests		  New Topic  Reply to Topic
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johnm1000

United Kingdom
2 Posts
Posted - 03/05/2021 :  10:51:44  Show Profile  Reply with Quote
I am trying to measure my field strength for the new regulations on EMF. It seems that the GQ EMF-390 cannot do that.
But spec said 0.01Ghz up to 10Ghz..
Pity as I just bought one!
Regards,
John
Regards
John
Reply #1

EmfDev

2143 Posts
Posted - 03/05/2021 :  13:35:50  Show Profile  Reply with Quote
Hi John, did you use RF Browser? What reading did you get on RF Browser?
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Reply #2

johnm1000

United Kingdom
2 Posts
Posted - 03/09/2021 :  06:11:14  Show Profile  Reply with Quote
Yes used the RF Browser. I only got about 5mW/m2 even at 14.2Mhz 100W and 10ft from the antenna. I have tried using the software to download the RF browser data but it does not seem to be recorded. Also only power and no frequency information so I cannot be sure it is not my mobile phone or the wifi.. Not sure the GQ meter works for lower frequencies. I also tried it on 433Mhz at 10W into 1/4wave. Hard to get close to antenna but at about 20ft away the wifi was clearly stronger..
I cannot see that I could prove to the inspector that I am within the new licence limits for radiation. I have till mid April before the new licence ammendments come into force. All radio operators civil/military etc are going to have to comply. Any ideas welcome.
Regards
John
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Reply #3

Damien68

France
780 Posts
Posted - 03/09/2021 :  07:17:59  Show Profile  Reply with Quote
it is radiated power you are looking for?
If it I think the best is to evaluat it with modelisation and calculation based on your antenna diagramm, configuration and Tx power. Done by an radio amateur it should be admissible by the authorities in case of control.

or with a RF detector specialy calibrated to 20m band.
otherwise you will only have one chance to be wrong especially since we are on the edge of the bandwidth and bandwith qualification is not defined and must not be at all at -3dB.
Mastery is acquired by studying, with it everything becomes simple
Edited by - Damien68 on 03/09/2021 08:30:02
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Reply #4

Damien68

France
780 Posts
Posted - 03/09/2021 :  08:40:54  Show Profile  Reply with Quote
Or try to find reference setup with similar configuration. and get value as it's.
it is above the good liver that you can have to be able to show.
Mastery is acquired by studying, with it everything becomes simple
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Reply #5

EmfDev

2143 Posts
Posted - 03/09/2021 :  13:29:58  Show Profile  Reply with Quote
Damien68 is correct and you can just calculate the power density using the parameters of your antenna. The EMF390 is not specifically calibrated in 14.2 MHz frequency range.
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Reply #6

WigglePig

27 Posts
Posted - 03/29/2021 :  06:02:58  Show Profile  Reply with Quote
quote:

I cannot see that I could prove to the inspector that I am within the new licence limits for radiation. I have till mid April before the new licence ammendments come into force. All radio operators civil/military etc are going to have to comply.


You will not need to "prove compliance" but just that you have made a reasonable assessment and the expected levels are below the published exposure limits. The best and easiest way of doing this is to make calculations using the published OfCom and RSGB calculator spreadsheets; if these do not give a positive outcome (they are quite pessimistic) then a more detailed assessment will be required.

Measuring the levels you are generating will be extremely difficult with the equipment available to the typical radio amateur, even with the appropriate test equipment it is not easy.
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