Having several receivers at hand, Collins, Hammurland, Tentec, &
Rhode-Schwarz, some which when the RF gain is reduced the S meter moves up
scale and some when the RF gain is reduced the S meter then indicates the
amount of AGC action, I prefer the ones which when RF gain is reduced the S
meter indicates the remaining AGC action. It seems that the total dynamic
range is preserved in this condition.
With the Collins, when the RF gain is reduced the S meter moves up scale.
The 60 over 9 signal still indicates 60 over 9 on peaks and the overload
remains as the AGC can't handle that level of signal, although the
background noise is now masked by the reduce RF gain and bias applied to the
IF stages. With the Hammurland when the RF gain is reduced some amount, the
S meter falls back to some level representative of the signal driving the
AGC on the RF and IF stages. Same true for the Paragon II and Omni VI Plus.
As to the Rhode-Schwarz, well you name it, it will do it.
I find it very effective to adjust the RF gain such that with no signal
present except man made and atmospheric noise to such value that the S meter
indicates about S-1 or S-2, no more. I hear folks all the time saying that
they can't copy a signal because of a S-9 line noise. That indicates to me
that they simply need to reduce the RF gain to allow the AGC to do what it
does best. On the other hand, if the RF gain on the radio that swings the S
meter up scale is adjusted to get rig of the noise, it also get rid of the
In all receives above, at max RF gain a 50 uV signal will give a S-9 meter
reading except for the Collins where the reference is 100 uV for S-9.
I guess we want it both ways plus one more.
----- Original Message -----
From: "Toby Pennington" <email@example.com>
To: "Discussion of Ten-Tec Equipment" <firstname.lastname@example.org>
Sent: Thursday, February 09, 2006 6:13 PM
Subject: Re: [TenTec] S meter and RF gain
> Bill, there is nothing to get. I am merely stating that I would like the
> RF gain to be independent of the S meter and prefer it to work like it
> in the 1.xxx version of software, instead of the way it works in the O2
> the 2.0 firmware.
> This best suits my method of operating. I have operated rigs like the Pro
> and found myself having to continually run the RF Gain up to get S meter
> reading and then back down with the Rf gain. In the case of the Pro 3
> RF gain had to be turned down considerably to be able to do QSK cw. (Not a
> very good rig for QSK cw) Sold it!
> This is my preference of the way the RF gain and the S meter should work.
> Toby W4CAK
> ----- Original Message -----
> From: "Bill Tippett" <email@example.com>
> To: <firstname.lastname@example.org>
> Sent: Thursday, February 09, 2006 6:17 PM
> Subject: [TenTec] S meter and RF gain
>> <<< With the new RF gain S meter interaction, the S meter is
>> always correct if the signal is above the RF gain setting>>>
>> >IF THE SIGNAL IS ABOVE THE RF GAIN SETTINGS..... This is
>> precisely my point, if the signal is NOT above the rf gain
>> setting then NO s meter reading is available, whether
>> accurate or not, having the s meter to read actively all the
>> time gives you an idea of what the relative strength of the
>> other stations signal is and you can quickly give him a report.
>> But Toby...if you set RF Gain just above the noise level,
>> ANY signal above the noise level STILL reads correctly. If
>> the signal is IN the noise, then the meter is useless anyway.
>> I think you're missing the point that you set Gain just so
>> the meter rests AT the noise level with no signal. Any signal
>> stronger than the noise will still read correctly. I'm
>> repeating myself but hopefully you got it this time. OK?
>> 73, Bill W4ZV
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