Al,
The dynamic balance between the base and emitter of Q12 determine the
AGC Fast/Slow response. The dynamic characteristics of Q12 as well as
R2, C4, RP6 and C1 all come into play.
Remember when doing the analysis that the voltage at /SLOW AGC is at 5
volts for fast AGC. When you consider
I'm looking at the K2 schematic at the components on the Control Board that set
the AGC time constant, and I can't understand how the fast setting gets its
time constant... the parts involved, C4 and R2, appear to have a very long
time, much longer than necessary for the FST settting.
If you
Hi,
I had a few problems in the past (builder's mistakes hi!) with my K2.
Today, I suspect that these problem affect the AGC on my K2 when setting
up the CAL HI and LO, my actuel readings are CAL HI set at 013 and CAL LO
set at 184 when U2 PIN5 is set to 3.8V.
I also found she using the K2
Hi,
I had a few problems in the past (builder's mistakes hi!) with my K2.
Today, I suspect that these problem affect the AGC on my K2 when setting
up the CAL HI and LO, my actuel readings are CAL HI set at 013 and CAL LO
set at 184 when U2 PIN5 is set to 3.8V.
I also found she using the
J-F,
The AGC Threshold setting between 3.74 and 3.8 volts should work just
fine - do not exceed 3.8 volts. If set too low, the CAL S LO and CAL
S-HI settings get out of hand.
Your CAL S-LO setting of 182 is not unusual, but your CAL S-HI setting
is lower than usual - and that is the reason
Thanks for the tips !!!
I always use my XG1. I will try it again, but this time with the preamp on.
Regards,
JF VA2SS
--
View this message in context:
http://elecraft.365791.n2.nabble.com/K2-AGC-and-CAL-HI-LO-value-question-tp7583412p7583414.html
Sent from the Elecraft mailing list archive
In some time past, someone developed a mod for the K2 AGC which
allowed all parameters for the threshold and S-meter response to be varied.
The mod used 3 trimpots installed on the Control Board.
I need the documentation for this mod if possible. I thought I had most
all the K2 documentation
The information is now in my hands, thanks to Gary KI4GGX.
73,
Don W3FPR
On 1/27/2011 9:59 AM, Don Wilhelm wrote:
In some time past, someone developed a mod for the K2 AGC which
allowed all parameters for the threshold and S-meter response to be varied.
The mod used 3 trimpots installed
I don't recall seeing this mentioned. Perhaps overlooked amongst the hoopla
about the impending P3, and the latest K3 firmware and mods. Elecraft
released an application note for the K2 on August 10th. I don't remember
seeing this before, but it has a copyright date of 2008, and a rev A release
With my new K2 i have a strange AGC behavior. I cannot detect a difference
between AGC on and off. The voltage at pin 5 U2 is exactly 3.8v after changing
the 8V regulator to a better one. All my earlier k2's had a large increase in
AF when switching off AGC. I possibly made a short between pin
Michael,
Is this new K2 as sensitive (ability to receive weak signals) as the
prior ones? If not, you have have a fault somewhere in the receiver
section.
Do strong signals activate the S-meter bargraph? Try adjusting the
S-meter (CAL S-LO and CAL S-HI) as indicated in the manual, then if
Hi K2 builders,
I'm working on K2 #6318, and the voltage at pin 5 of of U2 is maxed out at
3.61v. The 8v regulator is only putting out 7.56v. I see some posts in the
archives recommend replacing the regulator, and a couple that say to leave it
alone, and all will be well. Is there a final
Mark,
The 8 volt regulator is a 10% tolerance part, and as of late, they have
been running on the low side of the nominal voltage. 7.56 volts is well
within the device specs. A replacement regulator from Elecraft may or
may not provide a higher voltage.
The maximum AGC Threshold voltage is
OK guys, now I need some guidance. I'm building K2 serial number 6625. I
am on page 48 on the manual, Setting the AGC Threshold. I have the RF GAIN
control fully clockwise. The highest voltage reading I can get on pin 5 of
U2 while adjusting R1 is 3.65V. The manual calls for 3.80V. All tests
Ken,
The problem is caused by the 8 volt regulator being on the low side of
its specification (the spec sheet says 7.5 to 8.5 volts is OK output for
the regulator - and the current batch of regulators at Aptos seem to be
on the low side (they were mostly on the high side a couple years ago -
Building K2 S/N 6430 and at page 48, AGC and S meter alignment. I can only
get a maximum of 3.60V from the pin 5 of U2 with R1 set at its ccw limit.
Additionally, for S meter alignment, both CAL S LO and S HI I am not seeing
the LEDs illuminate at all with either dot or bar settings. All other
.
Don Brown
KD5NDB
From: [EMAIL PROTECTED] To: Elecraft@mailman.qth.net Date: Thu, 13 Mar 2008
08:36:55 -0400 CC: Subject: [Elecraft] K2 AGC/S Meter Building K2 S/N
6430 and at page 48, AGC and S meter alignment. I can only get a maximum of
3.60V from the pin 5 of U2 with R1 set at its
Setting the AGC threshold on my K2.
Adjusting R1 for 3.8 volts. But turned full up I can only achieve 3.666
volts.
Is this a problem?
73
Jack VK2CJC / MM0AXL
FISTS #9666 - CW QRP Club #753 - Elecraft K2 #6404
Mid North Coast Amateur Radio Group www.mncarg.org
For MSN Messenger, use this
Setting the AGC threshold on my K2.
Adjusting R1 for 3.8 volts. But turned full up I can only achieve 3.666
volts.
Is this a problem?
73
Jack VK2CJC / MM0AXL
FISTS #9666 - CW QRP Club #753 - Elecraft K2 #6404
Mid North Coast Amateur Radio Group www.mncarg.org
For MSN Messenger, use this
, February 27, 2008 12:32:22 AM
Subject: [Elecraft] K2 AGC
Setting the AGC threshold on my K2.
Adjusting R1 for 3.8 volts. But turned full up I can only achieve 3.666
volts.
Is this a problem?
73
Jack VK2CJC / MM0AXL
FISTS #9666 - CW QRP Club #753 - Elecraft K2 #6404
Mid North Coast Amateur Radio
Jack,
The cause of the low AGC Threshold is a low output from the 8 volt
regulator (Control Board U4)
It will llikely not cause any problem at all if you simply set the
Threshold to max. You could consider replacing the regulator if it
causes you concern.
73,
Don W3FPR
Jack wrote:
Message -
From: Don Wilhelm [EMAIL PROTECTED]
To: Jack [EMAIL PROTECTED]
Cc: elecraft@mailman.qth.net
Sent: Thursday, February 28, 2008 3:16 AM
Subject: Re: [Elecraft] K2 AGC set
Jack,
The cause of the low AGC Threshold is a low output from the 8 volt
regulator (Control Board U4
Coast Amateur Radio Group www.mncarg.org
For MSN Messenger, use this emails return address
- Original Message - From: Don Wilhelm [EMAIL PROTECTED]
To: Jack [EMAIL PROTECTED]
Cc: elecraft@mailman.qth.net
Sent: Thursday, February 28, 2008 3:16 AM
Subject: Re: [Elecraft] K2 AGC set
Jack
My K2 s/n 1999 was completed in February 2002.
Last Sunday, during the EC Nets, I noticed that some strong stations were
actually getting audio signals into my ears that were close to the threshold
of pain. I also noticed they were not deflecting the S meter one bar.
After some experimenting,
Ed,
It certainly sounds like you have a bad solder connection there. It may
have worked just fine in the past and is just now developing enough
oxidation to be troublesome.
You may actually be looking in the wrong place if you are restricting
your search to U1. U1, U2, Q12 and their
Hmm, I went through that a couple weeks ago and I ended up needing to
replace the 8-volt regulator. Elecraft sent me a new one. Check the
output voltage on the 8-volt regulator (LM2930T-8) and see how close
it is to 8 volts.
I'll be interested to see what the more experienced builders have to
say
bill KE5KWE wrote:
This probably has been asked and answered before but I couldn't find it in
the archives. I Set the AGC Threshold and could only get 3.644 volts out of
R1 the potentiometer. Should I be concerned that I did not get 3.80 volts ?
I'd say it is a little on the low side, but
Hello All:
This probably has been asked and answered before but I couldn't find it in
the archives. I Set the AGC Threshold and could only get 3.644 volts out of
R1 the potentiometer. Should I be concerned that I did not get 3.80 volts ?
Thanks for the help.
Bill
KE5KWE
--
View this
On Nov 23, 2007, at 9:02 PM, Leigh L Klotz, Jr. wrote:
Circuit Specialists has meters and they throw in a free gift for
over $50. Or Fry's retail this weekend. BK is an OK economy
brand available at both places. The cheap analog meter might cause
you problems down the road with
Greetings Sarah, welcome to the hobby, and to a great radio. My AGC
measurement was down a bit, not quite as far as yours, but it has been
discussed here that there is some variation, and that it is not critical
at that point. I re-visited my a little later on in the build process,
and the
Sarah,
Congratulations on getting your license and venturing to build your K2.
The AGC Threshold high limit is directly proportional to the 8 volt
regulator actual output - if you follow the circuit you will discover
that that voltage is really the result of a 3 legged resistive voltage
On Nov 23, 2007, at 3:31 PM, Don Wilhelm wrote:
Sarah,
Congratulations on getting your license and venturing to build your
K2.
Thanks!
The AGC Threshold high limit is directly proportional to the 8 volt
regulator actual output - if you follow the circuit you will
discover that that
Well, I searched around a bit and found *another* cheap DMM, which
seels to be reading about 0.12 to 0.14 volts higher than the first
one. Now I don't know which one to believe! :-)
(Carry one watch, or three, but never two...)
Now I need to find my *other* other meter, the analog one I got when
Hi and welcome!
It doesn't happen too often, but have you checked the accuracy of your
cheap DMM? If you don't have anything to compare it with, you can get an
idea of its condition by measuring the voltage across a fresh alkaline
battery. It should read about 1.57 and 1.58 VDC.
Ron AC7AC
Thanks to everyone who replied! Wow, help sure comes in a hurry on
this list!
The general consensus appears to be that I'm ok for the time being
(yay!), so I'm going to go ahead and move on.
I did test with the internal voltmeter as well, and it reports 3.5V.
Special thanks to VE3TIX who
Hi,
I'm Sarah, AF6FH! I just got my license a couple weeks ago, and I'm
now assembling K2# 0622, which will be my first HF radio. I started
assembly on Wednesday night, and so far, everything's been going just
fine.
But...
I'm having a little issue with setting the AGC Threshold.
The
Welcome welcome Sarah!
Although you are starting at a time when signals are
low, stay on 40 meters at night and you cannot go
wrong. You have chosen the best possible place to
start your hobby, with the Elecraft group and there
are people here to help you with most anything outside
of typing your
On Nov 23, 2007 3:53 PM, Sarah K. [EMAIL PROTECTED] wrote:
I'm Sarah, AF6FH! I just got my license a couple weeks ago, and I'm
now assembling K2# 0622, which will be my first HF radio. I started
assembly on Wednesday night, and so far, everything's been going just
fine.
Congrats, and
Hi,
When I built my K2/100 the threshold adjustment didn't go right, I turn
trimmer R1 full CCW to get 3.74v on pin5 of U2 (full CW pin 5 goes to 2.6v).
This adjustment is supposed to swing U2 pin 5 fom from 4 to 8 v. I checked
diode polarity, resistor values, everything but never did find
by turning the
AGC on and off and adjusting for no change in the background noise.
Don Brown
KD5NDB
- Original Message -
From: Jim Stoneback [EMAIL PROTECTED]
To: elecraft@mailman.qth.net
Sent: Monday, October 08, 2007 1:53 PM
Subject: [Elecraft] K2 AGC Threshold Adjustment
Hi,
When
- Original Message -
From: Jim Stoneback [EMAIL PROTECTED]
To: elecraft@mailman.qth.net
Sent: Monday, October 08, 2007 11:53 AM
Subject: [Elecraft] K2 AGC Threshold Adjustment
Hi,
When I built my K2/100 the threshold adjustment didn't go right, I turn
trimmer R1 full CCW to get 3.74v on pin5
Yes, Paul the K2's AGC is definitely soft. Soft in that it has some
slope to it with quiet signals sounding quieter than loud.
And I love it that way. In fact that is one of a handful of factors
that make the K2 such a sweet sounding radio and such a pleasure to
listen to. I've had rigs (good
I completely agree about the K2's great sounding AGC. The fact that
there *is* some slope to the AGC to still allow the perception of
various signal levels while still maintaining control, is a testament to
the radio's excellent dynamic range. IMHO, it actually reduces listening
fatigue by
Paul,
You may find some information in the archives that could possibly help
your situation. Jack Smith K8ZOA has documented a good amount of info
on the AGC operation on his website and Dave White VE6DRW has created a
mod to give more control over the various AGC characteristics.
Look for
I am enjoying my recently completed K2-6148 very much, but I had a
couple of questions and thought others might have some constructive
thoughts.
While some folks like a slightly soft AGC in the receiver, I'm one of
those folks that finds that soft signals received softer than loud
There's something about the K2 that I haven't figured out yet. When I
listen to my 830s, 2B or the R4A, Omni V or other rigs I've owned, I
find their AGC to be very aggressive (Esp. the 2B). When a signal hits,
the AGC really drops the gain and when the signal is gone, the gain goes
way up.
Sjoerd,
Your AGC symptoms sound similar to some of what I found wrong with s/n 3641
when I bought it used. You can find a lot of details in the elecraft
archive - (search for low audio on K2 s/n 3641).
Among other problems, I had a leaky C10 cap in the AGC circuit, upsetting
the AGC control
Sjoerd,
When measuring millivolts some voltmeters are not very accurate. I've seen
them err as much as 40-50 percent. Compare two or three meters and see the
results. Also, some crystals don't put out a pure sine wave making RMS
measurements less acccurate. Look at it on an o'scope if one
Jim, AB0UK wrote:
When measuring millivolts some voltmeters are not very accurate. I've seen
them err as much as 40-50 percent. Compare two or three meters and see the
results. Also, some crystals don't put out a pure sine wave making RMS
measurements less acccurate. Look at it on an
Valc at some point and can tell me if these
values are way off?
Thanks again,
Sjoerd
PE2SVN
-Oorspronkelijk bericht-
Van: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Namens Sjoerd
Verzonden: dinsdag 29 augustus 2006 22:56
Aan: elecraft@mailman.qth.net
Onderwerp: [Elecraft] K2 AGC problem
Sjoerd,
If you look at the MC1350 data sheet, you will find the AGC characteristics
for operation wiht a 12 volt supply to the chip and that graph indicates
that the gain changes almost linearly from 0 dB to 20dB with an AGC voltage
change from 5 to 6 volts, or 10 dB for a 500 mV change, and the
Aan: Sjoerd; elecraft@mailman.qth.net
Onderwerp: RE: [Elecraft] K2 AGC problem
Sjoerd,
If you look at the MC1350 data sheet, you will find the AGC characteristics
for operation wiht a 12 volt supply to the chip and that graph indicates
that the gain changes almost linearly from 0 dB to 20dB
[mailto:[EMAIL PROTECTED]
Verzonden: woensdag 30 augustus 2006 14:02
Aan: Sjoerd; elecraft@mailman.qth.net
Onderwerp: RE: [Elecraft] K2 AGC problem
Sjoerd,
If you look at the MC1350 data sheet, you will find the AGC
characteristics
for operation wiht a 12 volt supply to the chip
Hello all,
While operating my K2 and switching between bands a lot i noticed my AGC is
a bit strange.
When trying to set the AGC treshold following Don FPR's instructions i find
that the noise level is not changing with the AGC treshold pot with both
preamp on and off. There is a difference in
Hi all,
i would lik evening I reconized a AGC problem on 40m band. My signal
meter shows
S8 to S9 and it sounds like RF-Gain is turned counter clockwise. If
i use ATT to reduce the signal level it does not help. The
signals will drop down but it still sounds like AGC
Thanks for the message.
A 10 pf at C8 did the trick. The receiver is now working properly in AGC off
mode.
Think that's at least 5 or 6 of us on the reflector have had this issue,
and this easy fix, so far. Does it deserve a builder alert on the
website yet?
For anyone else: If you are seeing
Waterman [EMAIL PROTECTED]
To: elecraft@mailman.qth.net; [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Sent: Sunday, May 21, 2006 9:36 AM
Subject: Re: [Elecraft] K2 AGC Off Problem
Thanks for the message.
A 10 pf at C8 did the trick. The receiver is now working properly in AGC
off
mode.
Think that's
Just finished alignment and test, part II of K2 #5093. All seems to be working
as it should, except for the AGC off function. This problems appears to be
the same as a few others have had, the cause of which was a bad 5.068 MHz
crystal (X1). Perhaps I have the same problem.
When the AGC is
@mailman.qth.net
Subject: [Elecraft] K2 AGC Off Problem
Just finished alignment and test, part II of K2 #5093. All seems to be
working as it should, except for the AGC off function. This problems appears
to be the same as a few others have had, the cause of which was a bad 5.068
MHz crystal (X1). Perhaps I
: [Elecraft] K2 AGC Off Problem
Just finished alignment and test, part II of K2 #5093. All seems to be
working as it should, except for the AGC off function. This problems
appears to be the same as a few others have had, the cause of which was a
bad 5.068 MHz crystal (X1). Perhaps I have the same
Bellerive
Sent: Saturday, May 20, 2006 5:50 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K2 AGC Off Problem
Ken,
Thanks for the message.
A 10 pf at C8 did the trick. The receiver is now working properly in AGC off
mode.
What are the implications of this substitution? Does changing
I have got the habit now on my K2 of turning off the AGC, cranking up the AF
gain and then using the RF gain to control the volume because the AGC has
too much effect on the receiver. I thumbed through the manual and didn't
find any obvious way of adjusting the it. How would I go about reducing
hi all,
I should have posted this before...
I found a related message when searching the archive. The reply was:
--
Sounds exactly like the problem I had with 5196. The problem was fixed by
replacing X1 on the Control Board. You will probably find that CtrlBd-U2-1
goes to about
Dr. Werner Furlan wrote:
I should have posted this before...
I found a related message when searching the archive. The reply was:
--
Sounds exactly like the problem I had with 5196. The problem was fixed by
replacing X1 on the Control Board. You will probably find that
hi Nick,
Nick Waterman schrieb am 23 Mar 2006 um 9:19:
Doing WHAT to the IF amp? Nice typo! :-)
well, I should have read the quote before pasting it - anyway, we are
probably having the same problem and it shouldn't be a great deal to
exchange a Quartz.
I wrote a message to support and
PROTECTED]; Elecraft support
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K2 AGC off problem
Dr. Werner Furlan wrote:
I should have posted this before...
I found a related message when searching the archive. The reply was:
--
Sounds exactly like the problem I had
hi elecrafters,
I received a new 5.068 Mhz Xtal and replaced the X1 on
the control board.
The Audio is not muted any more when I turn the AGC
off.
Thank you Ken K3IU, Bill WU0R, and Gary, Scott and
Brian at Elecraft service/parts.
73 de ON5AO K2#5237
joe
or did just replacing X1 the first time fix the problem?
Also, what value of RP6 is installed on your control board? My RP6 is a
4.7K network.
Thanks.
Jeff (K2#5210)
-Original Message-
From: jo benoit
Sent: 3/8/2006 8:27:20 AM
To: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] K2 AGC off
jeff (K2#5210),
I only changed the crystal X1, nothing else, and that
solved the problem . The value of RP6 is also 4.7 K.
73,
joe on5ao K2#5237
you wrote:
I have the same problem with my AGC and when I
replaced the 5.068MHz X1 the problem remained. I
wonder if both crystals are bad or if there
I seem to be having a problem with the AGC control on my K2. With no
signal input, when I turn off the AGC the s-meter reads +40 and stays
there regardless of rf gain setting whereas the K2 manual indicates that
the s-meter should increase when turning the rf gain ccw. Also, I can
hear the 1uV
Hi Elecrafters,
When I turn the AGC to off pushing pre/att and agc
together, the display reads off, but the audio mutes
and s-meter goes to maximum .
I reheated the solderings on U1 C10 and D2.
Voltage on U1 pin 2 is 1.44V when agc slow or fast
and 0.52V when agc is off
The other side of D2 , the
Subject: [Elecraft] K2 AGC off problem
Hi Elecrafters,
When I turn the AGC to off pushing pre/att and agc together, the display
reads off, but the audio mutes and s-meter goes to maximum .
I reheated the solderings on U1 C10 and D2.
Voltage on U1 pin 2 is 1.44V when agc slow or fast and 0.52V when
: Monday, February 27, 2006 1:40 PM
To: 'jo benoit'; 'elecraft mailman qth'
Subject: RE: [Elecraft] K2 AGC off problem
Hi Joe:
Sounds exactly like the problem I had with 5196. The problem was fixed by
replacing X1 on the Control Board. You will probably find that CtrlBd-U2-1
goes to about 6 volts when
I'd previously credited LA3ZA with the AGC image mod.
That should go to TF3MA.
Cheers to LA3ZA for gathering up the myriad of K2 mods together
in one well organized place, though!
73 HNY/HLNY, VR2BrettGraham
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Post to:
Elecraft team:
I am planning to use my K2 in CQWW with N1MM logger. When the radio is
polled by N1MM the radio behaves as if the RF gain was decreased. With no
antenna connected when the K2 is polled the S meter indicates an S6. I have
confirmed this effect when using DXBase as well, but since
Gregg,
My thought is that your computer running the N1MM logger or with DXB is
generating noise that is being picked up by the K2.
The reason I state that is because there is no change in the receive signal
path that would affect the S-meter reading because of any polling or other
microprocessor
Gregg W6IZT wrote:
I am planning to use my K2 in CQWW with N1MM logger. When the radio is
polled by N1MM the radio behaves as if the RF gain was decreased. With no
antenna connected when the K2 is polled the S meter indicates an S6. I have
confirmed this effect when using DXBase as well, but
Hello all,
I just noticed a strange thing in my K2.
When I turn off AGC the S meter goes to 9++ and the receiver is muted.
With ALC on (fast or slow) there is no problem.
When the trx is on for a few hours the problem is gone, and the next cold
start it is there again.
I have never seen
Sjoerd,
The only thing that I can think of to cause that behavior is a fault in
either D2 or U1 on the Control Board.
Check the voltage at U1 pin 2 - it should drop to almost zero with the AGC
off, if it does then D2 is likely OK and the problem lies in U1.
Before replacing U1 or D2, you may
hi
can anyone on the reflector advise with this agc problem
have instaled new control board
volts setting with r1 no problem sets to 3.8
fast and slow positions work fine with s meter acting normaly
when i go to agc off audio goes dead bar on s metre goes full
scale
volts checkes on controll
Someone, Don I think, posted a message this week suggesting that the
background noise with no antenna connected should be the same with AGC
either on or off. I checked mine out of curiosity and discovered that
mine was quieter with AGC on.
Before making adjustments to R1, I thought I'd run
Matt,
At this point, I don't think anything is wrong with your AGC circuit.
Re-check the TEST 3 readings with the RF Gain set to MAX and I believe you
will see readings a bit closer to the Expected values (I think a step is
missing here to tell you to set the RF Gain to max). The 'key' is that
Hi,
My K2 has been working well and I recently noticed that the AGC fast/slow has
little or no effect. I suspect it's been this way for quite some time. I made
some measurements and when performing the AGC tests on U2 (LM833), I get very
close to the expected values for the specified
Hi,
The problem is solved. After thinking about it for a while, and not having the
PIC's data sheet, I wondered if the AGC signal was an open collector / drain
type. It turns out that pin 1 of the resistor network had never been soldered
in by the builder...not me (the builder knows who he
I've read that the correct AGC voltage for _most_ K2s falls into the
3.65v to 3.8v range. When I adjust my AGC voltage such that I hear no
difference with AGC off and AGC on on a quiet 10m band, I find that my
AGC voltage is down around 3.5v. Other than this, my radio appears to
work fine. My
Michael,
You probably read that statement coming from me since I have posted it
frequently.
Even on a 'quiet' 10 meter band there is the liklyhood that there is still
some atmospheric noise. Try doing it with the antenna disconnected (so all
the noise is actual receiver internal noise). I
I'm trying to figure out why the AGC feed (IF OUT) is taken off before the 2nd
Xtal filter in the K2.
73
Stewart G3RXQ
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Marinos,
You may want to check the soldering of all associated components - look on
the K2 Control Board schematic lower left corner to identify the components
in question.
Actually the 3.78 volts may be close enough. The real test is when you
finish the K2 and if you do the advanced AGC
As others have pointed out, only a single I.F. amplifier chip is gain
controlled in the K2. The RF gain, the gain of post mixer I.F. amplifier
transistor, and the gain of the active product detector are not controlled
through AGC, yet they all contribute to the receiver's total gain.
Since the
Hi to all and season's greetings.
I am in the process of building my K2/100, and have almost finished the RF
board of the basic kit. Went through the alignment parts I and II with no
problem but have a question regarding 1 reading:
1) During the AGC threshold adjustment (control board) the
I've only seriously used two other HF rigs besides the K2, that is a
Kenwood TS-530S and a Kenwood TS-930S. So, when I make comparisons, its
between the K2 and the Kenwoods. When I have the AGC set to FAST on the
Kenwoods and am receiving a CW signal at say S-9, I can turn the RF gain
down to
Micheal,
The so called RF gain in the K2 is actually IF gain, which is the same as
used in the JRC NRD-515 RX. The difference is the K2 has fixed RF front end
gain before the RX mixer with a switchable preamp or attenuator in addition.
The
NRD-515 has no RF amplifier only a switchable RF
Michael,
Several factors come into play here:
For best sensitivity, you should adjust your K2 so that you discern no
change in the audio level when changing from AGC on to AGC off on a dead
band (caution - a high local noise level on the 'dead band' may cause an
erroneous conclusion).
The
Mike,
Just to let you know that I have received a very positive response from
Elecraft about the K2's AGC Threshold setting problem..
Your DMM appears to be fine, and I hope that the info I sent you solves your
problem. Would appreciate hearing when you have time.
73,
GeoffGM4ESD
I have been creating a back packable yagi for 20 meters and have needed
a means of measuring signal strength into the antenna under test. My
reference signal of choice is the nearby W6WX 20 meter beacon located
about 10 miles to the south. The beacon, part of the international
beacon
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