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20 dB Attenuator for GSM Field Meter

I have a digital field strength meter covering the 800MHz to 2.5GHz
range To it is connected, via SMA cable, a log periodic antenna. The
available reading only goes to 1999 uW/m2. I would like to place a
20dB attentuator in-line with the antenna to increase this by a factor
of 100.

Can anyone please suggest what circuit or components to use? Is
something like this all I need?

http://www.radio-electronics.com/in...gn/attenuators/attenuator-resistor-values.php

Can I assume the meter's input impedance is 50 Ohms?

Richard Jones
 
J

Jasen Betts

Jan 1, 1970
0
I have a digital field strength meter covering the 800MHz to 2.5GHz
range To it is connected, via SMA cable, a log periodic antenna. The
available reading only goes to 1999 uW/m2. I would like to place a
20dB attentuator in-line with the antenna to increase this by a factor
of 100.

Can anyone please suggest what circuit or components to use? Is
something like this all I need?

http://www.radio-electronics.com/in...gn/attenuators/attenuator-resistor-values.php

If only it was that simple! at 800 to 2.5Ghz layout is going to be critical if
you want a flat response over that range.

At the first online supplier I checked 3GHz attenuators seem to start at
around $40 for upto 10dB, 20dB is twice as much.
Can I assume the meter's input impedance is 50 Ohms?

If it's not it'll probably written somewhere near the input
TV uses 75 ohms, but most other things are 50 ohms.
 
I have a digital field strength meter covering the 800MHz to 2.5GHz
range To it is connected, via SMA cable, a log periodic antenna. The
available reading only goes to 1999 uW/m2. I would like to place a
20dB attentuator in-line with the antenna to increase this by a factor
of 100.

How is the actual measurement instrument protected against direct
radiation penetration ?

Sure, you can insert various attenuators along the line, but if the
signal source will penetrate directly in to the equipment from the
air, you are in trouble.
 
F

Fred Abse

Jan 1, 1970
0
I have a digital field strength meter covering the 800MHz to 2.5GHz range
To it is connected, via SMA cable, a log periodic antenna. The available
reading only goes to 1999 uW/m2. I would like to place a 20dB attentuator
in-line with the antenna to increase this by a factor of 100.

Can anyone please suggest what circuit or components to use? Is something
like this all I need?

http://www.radio-electronics.com/in...gn/attenuators/attenuator-resistor-values.php

Can I assume the meter's input impedance is 50 Ohms?
SMA are 50 ohms, hence yes.

Use a Pi-section attenuator, theoretical values are 61.11 ohms, 247.5
ohms, 61.11 ohms.

Good luck with getting it to stay resistive up to 2.5GHz.
 
L

Lund-Nielsen, Jorgen

Jan 1, 1970
0
Am 04.04.2013 12:29, schrieb Jasen Betts:
At the first online supplier I checked 3GHz attenuators seem to start at
around $40 for upto 10dB, 20dB is twice as much.


Naaa,

Minicircuits DC-6GHz SMA Attenuatos, regardless of the AttenFactor
are around 12$/Piece..!

have a look:

<www.minicircuits.com/pdfs/VAT-20.pdf>

Jorgen
 
D

DecadentLinuxUserNumeroUno

Jan 1, 1970
0
I have a digital field strength meter covering the 800MHz to 2.5GHz
range To it is connected, via SMA cable, a log periodic antenna. The
available reading only goes to 1999 uW/m2. I would like to place a
20dB attentuator in-line with the antenna to increase this by a factor
of 100.

Can anyone please suggest what circuit or components to use? Is
something like this all I need?

http://www.radio-electronics.com/in...gn/attenuators/attenuator-resistor-values.php

Can I assume the meter's input impedance is 50 Ohms?

Richard Jones


http://www.minicircuits.com/pdfs/K1-LAT+.pdf

http://www.surplussales.com/rf/RFAtten-4.html


A really nice one!
<http://www.ebay.com/itm/NICE-MCL-BW...803?pt=LH_DefaultDomain_0&hash=item3cd07e44ab>
 
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