Re: [Elecraft] K1 AGC time constant

2006-04-05 Thread Rick Dettinger
In practice, RF gain is rarely backed down by K2 users -- the AGC
system has a very pleasant sound and very wide dynamic range. This
could easily be achieved with the K1, too. But you could incorporate a
manual RF gain control if you wanted to. Finding a place on the K1's
front panel is another story.

Wayne

It wouldn't be to difficult to put a panel mount RF Gain pot in place of the
AF Gain control.  A run of RG174 to the attenuator relay would give front
panel RF gain control at the expense of the AF gain control.  A trimmer pot
would need to be located on the RF board to allow for set and forget AF gain
adjustment like in the Wilderness Nor Cal 40A.  Some traces would need to be
cut on the RF board.  I am thinking about this as I like to turn the AGC off
and use RF gain control.  A possible disadvantage would be degraded signal
to noise ratio on the higher bands.
73 - Rick - K7MW

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Re: [Elecraft] K1 AGC time constant

2006-04-05 Thread Rick Dettinger
Hi Ralph - I received an off list post from a member  who recommended
changing C31 to .22uf and C67 to .01uf .  Said it made a big improvementin
the AGC action.  Have not tried it yet but I think I will next time I have
the covers off. 73 - Rick - K7MW- Original Message -
From: "Ralph Tyrrell" <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, April 05, 2006 9:59 AM
Subject: Re: [Elecraft] K1 AGC time constant


> I did the exact same thing you did Rick. Same RS cap
> and AGC did not speed up as I had hoped.
> Also wonder what other might have done?
>
> 73, TY, W1TF, K1 # 1423
>
> --- Rick Dettinger <[EMAIL PROTECTED]> wrote:
>
> > I changed C31 on the RF board to 1uf  but it still
> > seems very slow.  When I
> > remove an S9 siginal  (50uv) it takes about 15
> > seconds for the S meter to
> > decay to one bar.  I used a non polorized
> > electrolitic cap as that is what
> > they had at RS.  It is physically larger than the
> > original cap but there is
> > plenty of room.  I am not sure what a non polorized
> > electrolitic capacitor
> > is but there are no polarity marks,  which I haven't
> > seen before.  Should I
> > try a smaller value for C31? Thanks - Rick -
> > K7MW
> >
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Re: [Elecraft] K1 AGC time constant

2006-04-05 Thread Tom Althoff
Ron ZL1TW and I have played with the AGC on the K1...here's a cut and paste
from one of our exchanges earlier this year.

My mod adds a .47 cap in series with the AGC On-Off line so that by turning
the AGC "off" I can return to the longer recovery time (which I never choose
to do).

Not sure if the 22K between 9 and 10 of RP3 really did anything..I just left
it in.

My K1 effectively has a pair of .01 rf bybass caps in the AGC circuit in
place of the original caps.

Tom K2TA

---
<<<<< So I'm running .22 at C31.01uf at hmmm C67?...the one at the mixer
chip.
22K across Pins 9 and 10 of RP3.  (this is slightly less than your 47K
across the same terminals).

Lastly, I have the .47 in series with the AGC ON-OFF line.

I must say there wasn't as dramatic change going from the .22 to the .01 as
there was going from the 2.2 to the .22 but it is definitely better and as
you say...probably can't hope for much more than that.>>>>>>>>
__
- Original Message - 
From: "Ralph Tyrrell" <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, April 05, 2006 12:59 PM
Subject: Re: [Elecraft] K1 AGC time constant


> I did the exact same thing you did Rick. Same RS cap
> and AGC did not speed up as I had hoped.
> Also wonder what other might have done?
>
> 73, TY, W1TF, K1 # 1423
>
> --- Rick Dettinger <[EMAIL PROTECTED]> wrote:
>
> > I changed C31 on the RF board to 1uf  but it still
> > seems very slow.  When I
> > remove an S9 siginal  (50uv) it takes about 15
> > seconds for the S meter to
> > decay to one bar.  I used a non polorized
> > electrolitic cap as that is what
> > they had at RS.  It is physically larger than the
> > original cap but there is
> > plenty of room.  I am not sure what a non polorized
> > electrolitic capacitor
> > is but there are no polarity marks,  which I haven't
> > seen before.  Should I
> > try a smaller value for C31? Thanks - Rick -
> > K7MW
> >
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>
>
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Re: [Elecraft] K1 AGC time constant

2006-04-05 Thread Ralph Tyrrell
I did the exact same thing you did Rick. Same RS cap
and AGC did not speed up as I had hoped.
Also wonder what other might have done?

73, TY, W1TF, K1 # 1423

--- Rick Dettinger <[EMAIL PROTECTED]> wrote:

> I changed C31 on the RF board to 1uf  but it still
> seems very slow.  When I
> remove an S9 siginal  (50uv) it takes about 15
> seconds for the S meter to
> decay to one bar.  I used a non polorized
> electrolitic cap as that is what
> they had at RS.  It is physically larger than the
> original cap but there is
> plenty of room.  I am not sure what a non polorized
> electrolitic capacitor
> is but there are no polarity marks,  which I haven't
> seen before.  Should I
> try a smaller value for C31? Thanks - Rick -
> K7MW
> 
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[Elecraft] K1 AGC time constant

2006-04-03 Thread Rick Dettinger
I changed C31 on the RF board to 1uf  but it still seems very slow.  When I
remove an S9 siginal  (50uv) it takes about 15 seconds for the S meter to
decay to one bar.  I used a non polorized electrolitic cap as that is what
they had at RS.  It is physically larger than the original cap but there is
plenty of room.  I am not sure what a non polorized electrolitic capacitor
is but there are no polarity marks,  which I haven't seen before.  Should I
try a smaller value for C31? Thanks - Rick - K7MW

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