Meter to troubleshoot two-way radios

Thread Starter

sparkarcer

Joined Mar 10, 2017
3
Hi
Could someone recommend an affordable meter for testing two way radios broadcasting in the 70-90 Mhz frequency range. I mostly want to confirm the antennaes and cables are doing what they should be doing. I think radios are set at 5 watts output. (I need to do more than just an ohmmeter test on the 50 ohm coax shield and wire.) The system also uses a repeater which I would also like to diagnose. Not sure what the output power of repeater is.
Thanks for any recommendations.
 

DickCappels

Joined Aug 21, 2008
6,387
I doubt that you will have problems with your coax being too far off impedance-wise if you are using new coaxial cable.

An ohmmeter measures resistance, not impedance. You can probably rent a network analyzer for that.
 

Janis59

Joined Aug 21, 2017
1,179
Antennas, coax feederlines etc may be VERY accurately tested by 50$ Nano-VNA (e-bay, Wuhan factory :) no somewhere else but China). Ensures the one port-tests and two-port tests but not at active line.
 

DickCappels

Joined Aug 21, 2008
6,387
Excellent! I did not know such things existed. The last time I was around gear like that the price was many thousands, but that included the pen plotter and the floppy disc with the DOS-based software. :)
 

vu2nan

Joined Sep 11, 2014
148
Hi
Could someone recommend an affordable meter for testing two way radios broadcasting in the 70-90 Mhz frequency range. I mostly want to confirm the antennaes and cables are doing what they should be doing. I think radios are set at 5 watts output. (I need to do more than just an ohmmeter test on the 50 ohm coax shield and wire.) The system also uses a repeater which I would also like to diagnose. Not sure what the output power of repeater is.
Thanks for any recommendations.
A handy instrument would be a field strength meter.

You should be able to build one like this.

http://www.k2gq.org/init/static/files/RF_Field_Strength_Meter.pdf

An off-the-shelf unit like this would cost around $ 25.00.

2.jpg

- Nandu.
 
Last edited:

Janis59

Joined Aug 21, 2017
1,179
For field strength meter far more accurate data are giving the same price digital wonders TM195 (50 MHz-3,5 GHz) without of spectral analyzer and Go_EMF-390 what is zero Hertz to 10 GHz with in-built spectrometer (however only up to 2,5 GHz).
 

Janis59

Joined Aug 21, 2017
1,179
PS
Third option - the Digital Defined radio like blue 5$ SDR working 3 MHz-1,7 GHz or it 40x expensiver twin the Hack-RF-1 working 50 kHz-3.5 GHz. Just You see in the real tome ALL signals in spectrogram antenna is able to see, OKay You have no validated accuracy on signal stregth except the ratio between signals. However approximate signal strength is known there. However there are a just nightmare about right computer interfaces installing. Yet I am sure witness, it is possible.
 
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