[K3] RE: S Meter

[mikerodgerske5gbc]

I'll second the comments below.

By the way, I don't want to incur the cost of a P3 to "fix" the RF Gain PAIN.
I'm just having to live with it.


ate: Wed, 06 Mar 2013 10:30:51 -0500
From: drewko <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] K3 S-Meter
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

Don,

I always seem to have my RF gain adjusted by ear to below where the
s-meter will deflect on a particular signal. So I will most always
have to readjust the gain to see an s-meter reading. The RF gain can
be adjusted much lower than the signal's meter deflection point but
still have an audible signal. A moderate strength signal can still be
heard when the RF gain has been turned down to the point where the
s-meter incicates s9+40 db.

The more I think about it the less useful it seems to have the meter
deflect upward with a lowered RF gain setting. Does anyone find this
action useful for tuning in a signal?

I know that I would be fiddling around with the RF gain control a lot
less if the s-meter display was not affected by the gain control. Why
not make the s-meter "absolute mode", which is independent of the
attenuation setting, also independent of the RF gain control? That
seems more consistent and logical to me.

73,
Drew
AF2Z


73
Mike R


Play me some fiddle, but no stinkin' violin!

Amateur/Ham Radio KE5GBC
HF & Echolink mobile
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[k6dgw]

I must be missing something in this recurring "RF Gain" thread.  In the
"olden days" before product detectors [think SX-28], for CW, you turned
AGC off, AF gain to max, and used the RF gain.  The BFO produced a
constant signal that activated the AGC if it was on, and with the RF
gain at max, the received signal was way too high at the mixer compared
to the BFO level which was constant.  The S-meter didn't work for CW and
that funny sounding new mode called SSB.

Today, I run my K3 with RF gain at max, AF gain controls the volume, AGC
is on ... SLOW for SSB, FAST for CW ... all the time.  After all the
comments in this thread, I've tried "riding the RF gain" with AGC off on
very weak signals.  CW signal readability doesn't change.  If I could
barely copy him with AGC on, I can equally barely copy him without AGC.
  The only effects I can find are:  1) I'm fiddling with the controls a
whole lot more and if QSB occurs he disappears until I manage to bring
up the gain; and 2) A strong station that appears in the passband is
really really loud in the cans.

I leave my P3 set with dBm on the ordinate.  Except on RTTY, the P3
averaging prevents the apparent peaks from actually matching the peaks
on the S-meter and I kind of like to see the real baseline noise level
at the receiver input.

Based on this thread, I must be doing something really wrong.  My K3's
AGC does a super job of controlling the RF gain, far better than I can
do manually, and my S-meter works in all modes.  Explanations on what
I'm missing are welcome.

My "rememberer" remembers a receiver that had both a real RF gain
control and an IF gain control separately.  I don't remember the name
however.  I'll look in Fred Cady's book this afternoon and see if the K3
HW AGC is actually applied to the RF stage [not sure there is one], the
first mixer, or just the first IF amp chain.  I remember audio-derived
AGC ... it was OK for phone, not so much so for CW.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2013 Cal QSO Party 5-6 Oct 2013
- www.cqp.org

On 3/11/2013 3:08 AM, Mike Rodgers wrote:

> By the way, I don't want to incur the cost of a P3 to "fix" the RF Gain PAIN.
> I'm just having to live with it.


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