Sensitivity Shootout .. 20 Various Radios

[majoco]

I find it very hard to believe that my Icom R7000 will lift the squelch at 0.07uV - that's under the basic front end noise value of -128dBm. Squelch lift is certainly not a reliable way of measuring receiver sensitivity. You didn't pay any attention to 'selectivity' but that has a great effect on sensitivity comparisons - the wider you open the door, the more the muck flies in. I'll have to assume that the station monitor that you used was correctly loaded with a 50ohm pad and had been recently calibrated. Most receiver sensitivity measurements are done on FM with a 30db quieting signal, not squelch lift. Every receiver that I have ever tested (and that's quite a few) used a 30dB pad between the sig gen and the receiver to keep background noise and spurious out of the front end. A service monitor is just a a 'go - no go' device. uV vs dBm are not any more 'precise', just the same level expressed in different ways.

 

[prcguy]

I agree that the squelch break point is meaningless and is not in any way a sensitivity measurement. The two accepted methods of measuring FM receiver sensitivity are 20dB quieting and 12dB SINAD.

Anyone with a CW signal generator and AC voltmeter can do a 20dB quieting measurement. You adjust the receiver audio output for a moderate high level of noise with no signal and increase the signal level until you reduce the receiver hiss by exactly 20dB. It might take a few tries to get the right scale on the AC voltmeter but otherwise its very easy and accurate.

The other method requires a modulated FM signal and a SINAD meter, which can be stand alone or built into a service monitor. Once the SINAD meter is calibrated you simply find the RF level that produces 12dB reading on the SINAD meter and your done.

Most people don't have access to a SINAD meter but many have a simple RF signal generator. Even if the absolute level is not calibrated on the signal generator you can usually rely on them for comparing two or more receivers to see which is more sensitive using the quieting method.

So, enough of this half way playing around and lets get to some actual sensitivity measurements!
prcguy

I find it very hard to believe that my Icom R7000 will lift the squelch at 0.07uV - that's under the basic front end noise value of -128dBm. Squelch lift is certainly not a reliable way of measuring receiver sensitivity. You didn't pay any attention to 'selectivity' but that has a great effect on sensitivity comparisons - the wider you open the door, the more the muck flies in. I'll have to assume that the station monitor that you used was correctly loaded with a 50ohm pad and had been recently calibrated. Most receiver sensitivity measurements are done on FM with a 30db quieting signal, not squelch lift. Every receiver that I have ever tested (and that's quite a few) used a 30dB pad between the sig gen and the receiver to keep background noise and spurious out of the front end. A service monitor is just a a 'go - no go' device. uV vs dBm are not any more 'precise', just the same level expressed in different ways.

 

[Project25_MASTR]

I agree that the squelch break point is meaningless and is not in any way a sensitivity measurement. The two accepted methods of measuring FM receiver sensitivity are 20dB quieting and 12dB SINAD.



Anyone with a CW signal generator and AC voltmeter can do a 20dB quieting measurement. You adjust the receiver audio output for a moderate high level of noise with no signal and increase the signal level until you reduce the receiver hiss by exactly 20dB. It might take a few tries to get the right scale on the AC voltmeter but otherwise its very easy and accurate.



The other method requires a modulated FM signal and a SINAD meter, which can be stand alone or built into a service monitor. Once the SINAD meter is calibrated you simply find the RF level that produces 12dB reading on the SINAD meter and your done.



Most people don't have access to a SINAD meter but many have a simple RF signal generator. Even if the absolute level is not calibrated on the signal generator you can usually rely on them for comparing two or more receivers to see which is more sensitive using the quieting method.



So, enough of this half way playing around and lets get to some actual sensitivity measurements!

prcguy

Do it enough and you can get within 1 dB of 12 dB SINAD by ear. Always best to do it with the meter though.


Sent from my iPhone using Tapatalk

 

[SCPD]

How about another radio to add to the list. Exact same everything as the radios above btw .. minimum squelch activation.

Uniden BCD536HP

127 MHz 0.14 uV
147 MHz 0.14 uV
155 MHz 0.15 uV
420 MHz 0.15 uV
447 MHz 0.14 uV
772 MHz 0.14 uV
868 MHz 0.15 uV

 

[prcguy]

So what's the 12dB SINAD or 20dB quieting on that one?
prcguy

How about another radio to add to the list. Exact same everything as the radios above btw .. minimum squelch activation.

Uniden BCD536HP

127 MHz 0.14 uV
147 MHz 0.14 uV
155 MHz 0.15 uV
420 MHz 0.15 uV
447 MHz 0.14 uV
772 MHz 0.14 uV
868 MHz 0.15 uV

 

[SCPD]

So what's the 12dB SINAD or 20dB quieting on that one?
prcguy

Answer .. probably about the same as the other radios at the top of this thread. If you love it so much .. go ahead and measure it.

Btw, that was almost funny, but not quite there yet.

 

[CanesFan95]

So, the lower the number, the better (more sensitive) the receiver is?

 

[N4GIX]

So, the lower the number, the better (more sensitive) the receiver is?

Yes. The number represents the amount of signal voltage (micro-volts) required to break the squelch or decode CTCSS or DCS.