KXB3080 Manual - minor mistake but important for newbies?

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KXB3080 Manual - minor mistake but important for newbies?

Martin Gillen-2
I was just going out to buy equipment to build this when I noticed:

> Fine-tip temperature-controlled ESD-safe soldering station with 700 to 800°F tip
> (370-430°C). Recommend a spade tip approx. 0.05" (0.13 mm) wide. Do not use a
> high-wattage iron or soldering gun since this can damage pads, traces, or the parts
> themselves.

I know it's minor but 0.05" is more like 1.3mm than 0.13mm...

Looking forward to getting my 80m on the air!

73
Martin.
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Re: KXB3080 Manual - minor mistake but important for newbies?

Alexandra Carter
Weller WTCPT baby! Read the solder tutorial on the Elecraft site, it's
the best I've seen anywhere! 73 de Alex NS6Y

On Apr 3, 2006, at 11:34 AM, Martin Gillen wrote:

> I was just going out to buy equipment to build this when I noticed:
>
>> Fine-tip temperature-controlled ESD-safe soldering station with 700
>> to 800°F tip
>> (370-430°C). Recommend a spade tip approx. 0.05" (0.13 mm) wide. Do
>> not use a
>> high-wattage iron or soldering gun since this can damage pads,
>> traces, or the parts
>> themselves.
>
> I know it's minor but 0.05" is more like 1.3mm than 0.13mm...
>
> Looking forward to getting my 80m on the air!
>
> 73
> Martin.
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RE: KXB3080 Manual - minor mistake but important for newbies?

Ron D'Eau Claire-2
In reply to this post by Martin Gillen-2
Martin wrote:

I know it's minor but 0.05" is more like 1.3mm than 0.13mm...

-------------------------

Thanks Martin!! All the field testers, Wayne, Gary and I all missed it!

It's doubly embarrassing for me because I live in metric. Here in the USA
much of the scientific/technical stuff is all in metric and I normally
convert back to English units for something like this. Shoot, I even cook in
Metric. All my recepies are in grams and milliliters.

I peeked and see that we had it right in the KX1 manual too.

Ron (fumble-fingers) AC7AC


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K1 AGC time constant

Rick Dettinger-2
In reply to this post by Alexandra Carter
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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AW: KXB3080 Manual - minor mistake but important fornewbies?

Peter Zenker
In reply to this post by Ron D'Eau Claire-2

Because I am always free in my manual translations, the German manual of
KXB3080 says (retranslated)

"Recommended is a small solder tip in pencil form"



No metrics nor inches  :-)

Peter


-----Ursprüngliche Nachricht-----
Von: [hidden email]
[mailto:[hidden email]] Im Auftrag von Ron D'Eau Claire
Gesendet: Dienstag, 4. April 2006 06:58
An: 'Martin Gillen'; 'elecraft'
Betreff: RE: [Elecraft] KXB3080 Manual - minor mistake but important
fornewbies?

Martin wrote:

I know it's minor but 0.05" is more like 1.3mm than 0.13mm...

-------------------------

Thanks Martin!! All the field testers, Wayne, Gary and I all missed it!

It's doubly embarrassing for me because I live in metric. Here in the USA
much of the scientific/technical stuff is all in metric and I normally
convert back to English units for something like this. Shoot, I even cook in
Metric. All my recepies are in grams and milliliters.

I peeked and see that we had it right in the KX1 manual too.

Ron (fumble-fingers) AC7AC


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Re: KXB3080 Manual - minor mistake but important for newbies?

Martin Gillen-2
In reply to this post by Ron D'Eau Claire-2
Alex,

The local electronics store had WESD51D stations on sale when I went
looking last
year for the initial KX1 build... The Elecraft mowwwwjowwww was
working for me even
BEFORE I started building!

I'm holding out for the 'Low Static' Soldapullt now - they had to back
order it for me!

- Martin.

On 4/4/06, Ron D'Eau Claire <[hidden email]> wrote:

> Martin wrote:
>
> I know it's minor but 0.05" is more like 1.3mm than 0.13mm...
>
> -------------------------
>
> Thanks Martin!! All the field testers, Wayne, Gary and I all missed it!
>
> It's doubly embarrassing for me because I live in metric. Here in the USA
> much of the scientific/technical stuff is all in metric and I normally
> convert back to English units for something like this. Shoot, I even cook in
> Metric. All my recepies are in grams and milliliters.
>
> I peeked and see that we had it right in the KX1 manual too.
>
> Ron (fumble-fingers) AC7AC
>
>
>
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Re: K1 AGC time constant

Ralph Tyrrell
In reply to this post by Rick Dettinger-2
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 <[hidden email]> 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
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
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>
>
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Re: K1 AGC time constant

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" <[hidden email]>
To: <[hidden email]>
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 <[hidden email]> 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
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> >  http://mailman.qth.net/mailman/listinfo/elecraft
> >
> >
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> > Elecraft web page: http://www.elecraft.com
> >
>
>
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Re: K1 AGC time constant

Rick Dettinger-2
In reply to this post by Ralph Tyrrell
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" <[hidden email]>
To: <[hidden email]>
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 <[hidden email]> 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
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> >  http://mailman.qth.net/mailman/listinfo/elecraft
> >
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
>
>
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K1 VFO frequency range change

Rick Dettinger-2
In reply to this post by Rick Dettinger-2
I changed the VFO frequency range capacitor to 120 pf and now have a 178 khz
tuning range.  Since I only need 125 khz to reach the SKCC frequency  of
7120 khz, I may try a 100 pf capacitor.  I would like to know what types of
capacitors will work will here.  The 68 pf  capacitor is a disc ceramic and
the 120 pf  capacitor is a polystyrene type.  To make this change, I not
only needed to change the VFO capacitor, but also the 30m xtal and futz
around with the turn spacing on the VFO coil to get the proper VFO range.  I
do not find the 18 khz per revolution tuning rate to be difficult but it is
my nature to keep fussing.      73 - Rick - K7MW
----- Original Message -----
From: "Rick Dettinger" <[hidden email]>
To: <[hidden email]>
Sent: Monday, April 03, 2006 10:12 PM
Subject: [Elecraft] K1 AGC time constant


> 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
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
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Re: K1 AGC time constant [and how to radically improve K1 AGC]

wayne burdick
Administrator
In reply to this post by Tom Althoff
As the principle designer of the K1, I just love these AGC circuitry
discussions, and thought I'd better put in my 2.5 cents.

The K1's present AGC circuit, being AF-derived, is a compromise between
attack time and recovery time. This topic has been the subject of
scholarly efforts by Haward, DeMaw, and others, so I'll just summarize
by saying that the slow rise time of an AF-derived signal limits how
quickly you can respond to a large signal using a simple diode
detector. Nearly all low-cost QRP transceivers that have AGC at all use
this technique, including all of the ones I've designed (KX1, Sierra,
NC40, SST).

DSP can be used to emulate a faster response using various techniques,
including post-processing of the signal as it propagates through the
DSP's pipeline. But assuming one wants faster AGC without having to
write DSP code, a relatively simple hardware-based improvement is
possible. Actually implementing it is left to the reader, and here's
what you need to know.

If you look closely at the K2 Control board schematic, you'll see that
the K2's fast AGC is obtained using an "auxiliary" I.F. of around 150
kHz. This is 100 times higher in frequency than the audio signal that
the K1 uses to drive its AGC detector, eliminating the rise-time
problem. The same technique could be used in the K1. You could start
with the K2's AGC circuit (mixer, amplifier, and detector), perhaps
breadboarding it on a proto board. You could pick off the 4.915 MHz
I.F. signal from the output of the K1's crystal filter, routing this to
another '602/'612 that has its oscillator running at 5.068 MHz (a
common crystal frequency). As in the K2, you'd then need to amplify and
detect just the 150-kHz difference product coming out of the mixer.
Various circuit simplifications may be possible relative to the K2's
circuit, which also includes manual RF gain control, T/R swiching, and
AGC on/off control.

An important subtlety: optimal results might require gain-controlling
the auxiliary I.F. mixer at pin 2, using the same derived AGC signal
that drives pin 2 of the K1's RX mixer and product detector. This would
ensure that the aux I.F. mixer's gain is scaled downward at the same
rate as the product detector as signal voltage goes up. This was not
necessary in the K2 case, because the I.F. amp (MC1350) is the only
gain-controlled stage, and it is ahead of the auxiliary I.F. mixer.

If anyone tries this and succeeds in creating very fast AGC for the K1,
we'd be happy to publish it as an application note on the web site. Who
knows? It might even make a nice little option module. The entire
circuit, if done using SMD parts, could fit on a board placed
underneath the K1's RF board.

I'd do it myself, but I'm a bit busy  :)

73,
Wayne
N6KR


---

http://www.elecraft.com

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Re: Re: K1 AGC time constant [and how to radically improveK1 AGC]

Rick Dettinger-2
Thanks Wayne - I am ready to place my order for a  fast AGC option  module.
Without the battery option, I think I  have room.  Probably enough room for
a TUF 1,  K2 type mixer module also (just kidding, sorta).   Rick - K7MW
----- Original Message -----
From: "wayne burdick" <[hidden email]>
To: "Elecraft Reflector" <[hidden email]>
Sent: Wednesday, April 05, 2006 1:05 PM
Subject: [Elecraft] Re: K1 AGC time constant [and how to radically improveK1
AGC]


> As the principle designer of the K1, I just love these AGC circuitry
> discussions, and thought I'd better put in my 2.5 cents.
>
> The K1's present AGC circuit, being AF-derived, is a compromise between
> attack time and recovery time. This topic has been the subject of
> scholarly efforts by Haward, DeMaw, and others, so I'll just summarize
> by saying that the slow rise time of an AF-derived signal limits how
> quickly you can respond to a large signal using a simple diode
> detector. Nearly all low-cost QRP transceivers that have AGC at all use
> this technique, including all of the ones I've designed (KX1, Sierra,
> NC40, SST).
>
> DSP can be used to emulate a faster response using various techniques,
> including post-processing of the signal as it propagates through the
> DSP's pipeline. But assuming one wants faster AGC without having to
> write DSP code, a relatively simple hardware-based improvement is
> possible. Actually implementing it is left to the reader, and here's
> what you need to know.
>
> If you look closely at the K2 Control board schematic, you'll see that
> the K2's fast AGC is obtained using an "auxiliary" I.F. of around 150
> kHz. This is 100 times higher in frequency than the audio signal that
> the K1 uses to drive its AGC detector, eliminating the rise-time
> problem. The same technique could be used in the K1. You could start
> with the K2's AGC circuit (mixer, amplifier, and detector), perhaps
> breadboarding it on a proto board. You could pick off the 4.915 MHz
> I.F. signal from the output of the K1's crystal filter, routing this to
> another '602/'612 that has its oscillator running at 5.068 MHz (a
> common crystal frequency). As in the K2, you'd then need to amplify and
> detect just the 150-kHz difference product coming out of the mixer.
> Various circuit simplifications may be possible relative to the K2's
> circuit, which also includes manual RF gain control, T/R swiching, and
> AGC on/off control.
>
> An important subtlety: optimal results might require gain-controlling
> the auxiliary I.F. mixer at pin 2, using the same derived AGC signal
> that drives pin 2 of the K1's RX mixer and product detector. This would
> ensure that the aux I.F. mixer's gain is scaled downward at the same
> rate as the product detector as signal voltage goes up. This was not
> necessary in the K2 case, because the I.F. amp (MC1350) is the only
> gain-controlled stage, and it is ahead of the auxiliary I.F. mixer.
>
> If anyone tries this and succeeds in creating very fast AGC for the K1,
> we'd be happy to publish it as an application note on the web site. Who
> knows? It might even make a nice little option module. The entire
> circuit, if done using SMD parts, could fit on a board placed
> underneath the K1's RF board.
>
> I'd do it myself, but I'm a bit busy  :)
>
> 73,
> Wayne
> N6KR
>
>
> ---
>
> http://www.elecraft.com
>
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Re: K1 AGC time constant [and how to radically improve K1 AGC]

Tom Althoff
In reply to this post by wayne burdick
I think what Ron and I were shooting for was not a really fast AGC but more
of a "Not-so-gosh-darned slow" AGC.

Wayne...doesn't 9 to 15 seconds for the S-meter to drop seems excessively
long to you?  Especially for a QSK rig.

When I changed C31 from 2.2 to .22 the hang time seemed to approximate that
of the "slow" AGC setting of the K2.

The pop exists on strong signals with both the stock and the modified K1 but
did not seem any worse after the mod.

Is there ANY chance that a decimal point was moved between the design specs
and production runs so that C31 is supposed to be a .22 instead of a 2.2
ufd?

Those of use who see 9 seconds or more for the sensitivity to recover really
like the 1 to 3 second recovery time after the cap values are changed.
That's one great thing about Elecraft kits...you can make them perform just
as "badly" as personal preference merits.

I love my K1.   And if I hadn't of changed the AGC time constant I would
still love it.   I just love it a litte bit more now. 8-)

Tom K2TA

----- Original Message -----
From: "wayne burdick" <[hidden email]>
To: "Elecraft Reflector" <[hidden email]>
Cc: "Ralph Tyrrell" <[hidden email]>; "Tom Althoff" <[hidden email]>
Sent: Wednesday, April 05, 2006 4:05 PM
Subject: Re: K1 AGC time constant [and how to radically improve K1 AGC]


> As the principle designer of the K1, I just love these AGC circuitry
> discussions, and thought I'd better put in my 2.5 cents.
>
> The K1's present AGC circuit, being AF-derived, is a compromise between
> attack time and recovery time. This topic has been the subject of
> scholarly efforts by Haward, DeMaw, and others, so I'll just summarize
> by saying that the slow rise time of an AF-derived signal limits how
> quickly you can respond to a large signal using a simple diode
> detector. Nearly all low-cost QRP transceivers that have AGC at all use
> this technique, including all of the ones I've designed (KX1, Sierra,
> NC40, SST).
>
> DSP can be used to emulate a faster response using various techniques,
> including post-processing of the signal as it propagates through the
> DSP's pipeline. But assuming one wants faster AGC without having to
> write DSP code, a relatively simple hardware-based improvement is
> possible. Actually implementing it is left to the reader, and here's
> what you need to know.
>
> If you look closely at the K2 Control board schematic, you'll see that
> the K2's fast AGC is obtained using an "auxiliary" I.F. of around 150
> kHz. This is 100 times higher in frequency than the audio signal that
> the K1 uses to drive its AGC detector, eliminating the rise-time
> problem. The same technique could be used in the K1. You could start
> with the K2's AGC circuit (mixer, amplifier, and detector), perhaps
> breadboarding it on a proto board. You could pick off the 4.915 MHz
> I.F. signal from the output of the K1's crystal filter, routing this to
> another '602/'612 that has its oscillator running at 5.068 MHz (a
> common crystal frequency). As in the K2, you'd then need to amplify and
> detect just the 150-kHz difference product coming out of the mixer.
> Various circuit simplifications may be possible relative to the K2's
> circuit, which also includes manual RF gain control, T/R swiching, and
> AGC on/off control.
>
> An important subtlety: optimal results might require gain-controlling
> the auxiliary I.F. mixer at pin 2, using the same derived AGC signal
> that drives pin 2 of the K1's RX mixer and product detector. This would
> ensure that the aux I.F. mixer's gain is scaled downward at the same
> rate as the product detector as signal voltage goes up. This was not
> necessary in the K2 case, because the I.F. amp (MC1350) is the only
> gain-controlled stage, and it is ahead of the auxiliary I.F. mixer.
>
> If anyone tries this and succeeds in creating very fast AGC for the K1,
> we'd be happy to publish it as an application note on the web site. Who
> knows? It might even make a nice little option module. The entire
> circuit, if done using SMD parts, could fit on a board placed
> underneath the K1's RF board.
>
> I'd do it myself, but I'm a bit busy  :)
>
> 73,
> Wayne
> N6KR
>
>
> ---
>
> http://www.elecraft.com
>

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Re: K1 AGC time constant [and how to radically improve K1 AGC]

wayne burdick
Administrator
Tom,

The selected part really is 2.2 uF, which provides a long enough AGC
hold time to prevent annoying leading-edge effects during slow CW copy.
If you mostly listen to much faster CW, you can certainly drop the
value.

In any case, the decay time will be roughly proportional to the
strength of the incoming signal. Normally you won't see signals big
enough to result in a delay this long.

73,
Wayne
N6KR


On Apr 5, 2006, at 2:41 PM, Tom Althoff wrote:

> I think what Ron and I were shooting for was not a really fast AGC but
> more
> of a "Not-so-gosh-darned slow" AGC.


---

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Re: K1 VFO frequency range change

Mike Morrow-3
In reply to this post by Rick Dettinger-2
>I changed the VFO frequency range capacitor to 120 pf and now have
>a 178 khz tuning range.

That's why I've always termed this option as the "180 kHz" option rather than Elecraft's "150 kHz" characterization.

>Since I only need 125 khz to reach the SKCC frequency of
>7120 khz, I may try a 100 pf capacitor.

There's a lot more Morse activity above 7120 kHz.  To me, that's more than worth the additional VFO span.

You mentioned having changed out the 30m hetrodyne crystal, which I assume means that your 30m band tuning now starts near 10 MHz.  Reducing VFO span to, say, 125 kHz will mean that you'll only be able to cover about the first 20 kHz of the 30m band.

73,
Mike / KK5F
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Re: K1 VFO frequency range change

Rick Dettinger-2



> You mentioned having changed out the 30m hetrodyne crystal, which I assume
means that your 30m band tuning now starts near 10 MHz.  Reducing VFO span
to, say, 125 kHz will mean that you'll only be able to cover about the first
20 kHz of the 30m band.
>
> 73,

Mike / KK5F

Yes, I can copy WWV on 10 mhz now.  I need to get up to about 10.125  mhz so
will need about  130 khz due to some overlap at the low end.  Thanks, I
hadn't thought ahead enough.  Maybe I will just leave it at 178 khz for
awhile and check out some new territory.  Even 7120 khz is new for me.
Prior to SKCC being started up in Janurary, I never went far from 7040 khz.
73 - Rick - K7MW

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Re: K1 VFO frequency range change

Sandy W5TVW
In reply to this post by Rick Dettinger-2
Irecently changed my K1's VFO range.  Now I can reach 7150 on 40 meters.
On 80 (with my 2 band 160/80 meter RF board) I get up to around 3673.
I also tried the 1 mf cap in AGC circuit with no results.

73,
Sandy W5TVW
----- Original Message -----
From: "Rick Dettinger" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, April 05, 2006 2:53 PM
Subject: [Elecraft] K1 VFO frequency range change


| I changed the VFO frequency range capacitor to 120 pf and now have a 178 khz
| tuning range.  Since I only need 125 khz to reach the SKCC frequency  of
| 7120 khz, I may try a 100 pf capacitor.  I would like to know what types of
| capacitors will work will here.  The 68 pf  capacitor is a disc ceramic and
| the 120 pf  capacitor is a polystyrene type.  To make this change, I not
| only needed to change the VFO capacitor, but also the 30m xtal and futz
| around with the turn spacing on the VFO coil to get the proper VFO range.  I
| do not find the 18 khz per revolution tuning rate to be difficult but it is
| my nature to keep fussing.      73 - Rick - K7MW
| ----- Original Message -----
| From: "Rick Dettinger" <[hidden email]>
| To: <[hidden email]>
| Sent: Monday, April 03, 2006 10:12 PM
| Subject: [Elecraft] K1 AGC time constant
|
|
| > 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: K1 VFO frequency range change

Sandy W5TVW
In reply to this post by Mike Morrow-3
This is the MAIN reason I changed the VFO span, to get up to 7100
to 7150 coverage.  At the same time, I pulled the 30 meter crystal and
installed the 10-10.15 crystal originally supplied if the "150 Khz span" was
desired.  I also replaced the original plastic shaft 10 turn tuning pot
with a metal shaft/busing replacement, as my old pot was getting a bit
sloppy mechanically.
Really like this little rig.  Now I wish I could have 160-10 meter coverage
without changing RF boards!  Wayne:  THAT would be a feat in the space
allotted for the RF board!  A 9 band board?

73,
Sandy W5TVW
----- Original Message -----
From: "Mike Morrow" <[hidden email]>
To: "Rick Dettinger" <[hidden email]>; <[hidden email]>
Sent: Wednesday, April 05, 2006 5:32 PM
Subject: Re: [Elecraft] K1 VFO frequency range change


| >I changed the VFO frequency range capacitor to 120 pf and now have
| >a 178 khz tuning range.
|
| That's why I've always termed this option as the "180 kHz" option rather than Elecraft's "150 kHz"
characterization.
|
| >Since I only need 125 khz to reach the SKCC frequency of
| >7120 khz, I may try a 100 pf capacitor.
|
| There's a lot more Morse activity above 7120 kHz.  To me, that's more than worth the additional
VFO span.
|
| You mentioned having changed out the 30m hetrodyne crystal, which I assume means that your 30m
band tuning now starts near 10 MHz.  Reducing VFO span to, say, 125 kHz will mean that you'll only
be able to cover about the first 20 kHz of the 30m band.
|
| 73,
| Mike / KK5F
| _______________________________________________
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|
|
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| Checked by AVG Free Edition.
| Version: 7.1.385 / Virus Database: 268.3.5/301 - Release Date: 4/4/2006
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|

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Re: K1 AGC time constant

Rick Dettinger-2
In reply to this post by Rick Dettinger-2
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: K1 AGC time constant

wayne burdick
Administrator

On Apr 5, 2006, at 9:59 PM, Rick Dettinger wrote:

> It wouldn't be to difficult to put a panel mount RF Gain pot in place
> of the
> AF Gain control.

I agree that this would be possible, but I'm not sure how many K1
owners would want to make this tradeoff. I use the AF GAIN control
constantly.

Let me know if you try this (and/or my suggested AGC implementation).

73,
Wayne
N6KR


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