Hi,
Now traffic on the new K3 Macro functions has somewhat died down,
I would like to raise again the issue of the K3's SWR measurement
accuracy.
I did some tests using dummy loads and a LP-100 meter as follows.
The dummy load is a precision 100W one which I measured with a VNA
and has a VSWR
Mike,
Other than the wiring paths for ENC A and ENC B signals through the
connectors and to CB U6 pins 8 and 16,
there is nothing else for these two signals. However, for the encoder
to be read, the /ENC RD signal must be at a low level and that signal is
generated from FP U3 pin 14. Look
Just curious how you know that the LP100 is accurate?
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Stewart
Sent: Wednesday, November 04, 2009 2:45 AM
To: Elecraft Reflector
Subject: [Elecraft] K3 SWR Accuracy - reprise
LP100 is calibrated with NIST traceable reference.
I have no question about the accuracy with LP100. I caliberate my W1 by
using LP100.
73
Johnny Siu VR2XMC
寄件人﹕ Robert Naumann w...@w5ov.com
收件人﹕ Stewart stew...@baker.nildram.co.uk; Elecraft Reflector
Hi Don,
OK, on that line which is pin 14 on U3, there is only a couple mv but no
pulses. The state of that line never changes. The other strange thing is
the ENC-A data level only being 2v p-p verses ENC-B which is a full 5v
p-p signal. Shouldn't both ENC data lines be a full 5v p-p TTL
After reading your table and comments again, I'm also curious why you are
using the antenna tuner in these measurements?
Shouldn't the internal ATU be OFF in order to evaluate the SWR meter?
With the tuner on, the K3's SWR meter is showing the results of the tuner
doing it's job - no? I would
Just a snippet from November RadCom, in the article about NFD and on
page 43 in the section 'Equipment and Antennas' ...
... it appears that the long supremacy of the FT1000 series as an NFD
rig has finally passed. The most commonly appearing transceiver in
2009 was the Elecraft K2/3
Mike,
Do you have the 'scope vertical amp set to DC? This is logic level
switching and the DC levels are significant, not the peak to peak
variation. Yes, the levels must be above or below the switching thresholds.
On the /ENC RD line, compare it to the levels at FP U3 pins 6 and/or 16
- it
Of course Robert, the ATU was OFF. My typing error.
Any measurements made with it ON would be meaningless.
73
Stewart G3RXQ
On Wed, 4 Nov 2009 07:14:43 -0600, Robert Naumann wrote:
After reading your table and comments again, I'm also curious
why you are
using the antenna tuner in these
I suggest a reading of Larry's original paper on the design of the LP-100 to
understand the heroic efforts needed to make these measurements with any
accuracy.
see: http://www.telepostinc.com/Files/phipps-1.pdf
It should come as no surprise that the K3's built-in directional coupler lacks
the
David Ferrington, M0XDF wrote:
Just a snippet from November RadCom, in the article about NFD and on
page 43 in the section 'Equipment and Antennas' ...
... it appears that the long supremacy of the FT1000 series as an NFD
rig has finally passed. The most commonly appearing transceiver in
2009 was
Hi Don,
OK, I can see those signals on pin 6 16 easily. Pin 14 is dead. It
stays low. I am using DC coupling. ENC-A is only going to 2v and ENC-B
goes to 5v. Both those data lines show data when the encoder is spun in
either direction. Both lines will either rest at zero or a high state.
Mike,
Yes, it sounds like you have it adequately analyzed and I do agree with
your conclusions. FP U3 has a bad pin 14 output and the MCU input for
ENC A also has a problem and is dragging the signal down.
73,
Don W3FPR
Mike-WE0H wrote:
Hi Don,
OK, I can see those signals on pin 6 16
Wes and all,
It is not unreasonable to expect some frequency dependency in the
detection diodes as well.
The tuner will function properly in any case - it tunes for the lowest
SWR no matter what the exact value of that SWR may be.
Now, if the SWR = 1.0 point was not correct, that would say
Don:
I sent the txt below a while back but it must have gotten lost in
cyberspace. In addition to the measurements below, when I turn on the K2
now I get the full Elecraft in the LCD, a few clicks from relays and the
speaker as well as a steady medium frequency tone. Nothing works on the
Hi all,
I might be having a blonde moment but I am looking at the W2 and it seems to
me that with 2 sensors, it can act as an antenna switch too. Is this the
case or am I missing something?
73 Ian
--
Ian J Maude, G0VGS
SysOp GB7MBC HB9DRV-9 DX Clusters
Member RSGB, GQRP 9838, FISTS 14077 | K3
Hi Stewart,
The KAT3, like all wide-range ATUs, has significant stray reactance,
especially on the higher bands. When you tuned it into 50 ohms, you
created an L-network on each band that tunes out this reactance--at
that one impedance.
In your test, the KAT3 is between the K3's SWR bridge
OK, I will contact the Elecraft Parts department and see how to order
these two components. Thank you again and lets hope this is the final
answer to this damaged K2. I will post when and what all was required to
repair this radio on this reflector so it may help others if they run
into this
You know, I realised as soon as I pressed send! :)
73 Ian
2009/11/4 Dick Dievendorff die...@comcast.net
You're missing something.
The sensors each have an RF input, an RF output, and a CAT-5 cable to the
W2
main unit. You put the sensors where it makes sense to put RF cables.
If you get
Chris,
The email may have arrived while I was on vacation a week ago - yes, I
missed it..
Are you certain you measured the gate of Q3 and Q4? Those voltages are
normal at the drains of Q3 and Q4 for a K2 in transmit. You can check
U6 pin 27 (5 volts during transmit, 0 during receive) and
The KAT3 cannot be completely removed from the circuit. When it is in
BYPASS it uses very small L/C values to attempt to compensate for
its own strays. There is not an actual bypass relay.
73,
Wayne
N6KR
On Nov 4, 2009, at 6:10 AM, Stewart wrote:
Of course Robert, the ATU was OFF. My
I don't have the KAT3, i use an external homemade tuner and a cheap
swr-meter between it and the K3. Don't know how accurate the swr-meter
is, but i notice that the K3 shows 1.1:1 while the external meter still
reads worse. Fiddling with the controls of the tuner settles the needle
on the external
What power level were you using? And what type of external bridge?
The K3's SWR bridge has two sensitivity ranges. If you have power set
to 12 W or lower, the higher-sensitivity range is used. If you have
power set above 12 W, the lower-sensitivity range is used. This is
necessary to
Hi Wayne,
Thank you for your prompt and informative replies.
When I first ran my experiment the results I got rather surprised me.
Now you have explained the fact that the KAT3 is never really out of
circuit even in BYPASS mode, and is seeing strays which the LP-100
does not, clarifies the
Slight clarification. I said:
The K3's SWR bridge has two sensitivity ranges. If you have power set
to 12 W or lower, the higher-sensitivity range is used. If you have
power set above 12 W, the lower-sensitivity range is used. This is
necessary to prevent heating of the transformers in the
There were a couple of posts about this a few days ago but they didn't seem
to provoke much comment. Yesterday I switched on and tried to call someone
and there was no output. The TX sound level from the speaker (MON was set to
about 4) was barely audible. After examining various software
How long is the coax between the LP100 sensor and the K3? This can have
a significant impedance transformation impact as you go to higher
frequencies, leading to a different indicated SWR at each end.
73, Eric
Stewart wrote:
Hi,
Now traffic on the new K3 Macro functions has somewhat died
'bout 2 feet.
73
Stewart
On Wed, 04 Nov 2009 09:53:25 -0800, Eric Swartz - WA6HHQ, Elecraft wrote:
How long is the coax between the LP100 sensor and the K3? This can have
a significant impedance transformation impact as you go to higher
frequencies, leading to a different indicated SWR at
I've noticed that too, but never though much of it since the external meter
and the K3 agree at 1:1.
Above 1:1, the K3's SWR indication reads lower than the external meter at
100 watts on the lower frequency bands (80, 160) but agrees well with the
external meter on the higher frequency bands.
Try using a double male connector to put the two SWR sensors right next
to each other and repeat the measurement.
At the higher freq's, even 2 ft of coax can change the indicated SWR,
especially when the actual SWR is 1.9:1 like yours. I regularly see this
when driving an amplifier with a non
But if you:
1. Connect the antenna directly to the K3, ANT1 say, with KAT3 in bypass and
note the SWR reading on the K3,
2. Then disconnect the antenna from ANT 1 and instead connect the external
SWR indicator to ANT 1 with a length of coax,
3. Then connect the antenna to the external SWR
Hi Brian,
The TopBand query that you reference had a situation that may or may not
apply to your setup. He only had 15' of feedline between the Tx and the
antenna. Weird things can happen.
Phil's situation was somewhat remedied by adding a longer run of coax.
I've had my share of issues on 160
Ken,
Congrats and we sure appreciate you putting on the tough ND multiplier!
See ya in da 160 piles!
73,
Julius
n2wn
Kenneth A. Christiansen-2 wrote:
I was in 1st place single operator low power cw North Dakota and #7 10th
Area.
I got into the wrong log the other day and thought I did
--- On Wed, 11/4/09, Stewart stew...@baker.nildram.co.uk wrote:
Of course, as others have pointed out the value of SWR measured is
immaterial, as the KAT3 will try and adjust to 1:1 when it is selected.
I don't think I would go so far as to say SWR is immaterial.
I've been noticing some apparently anomalies in this area too, for example...
I have two dummy loads - one is a 2kW rated PalStar, which doesn't
appear to be exactly 50ohms (but close enough for usual purposes), and
a Bird Termaline, which is mil-spec 50ohms (and shows as such on a
sweep
On Nov 4, 2009, at 12:31 PM, Ron D'Eau Claire wrote:
I
It's a non-issue to me since all I care about is knowing I have the
antenna
system well matched to the K3.
I have to parrot the non issue part of this. I have several SWR
bridges/meters. They rarely agree about anything.
Accuracy
Why do you still have both? The K2 is my main station rig. I recently
considered buying a K3 and even went to the Elecraft web site to order it.
Each time I backed off so that I could think more about it. In the end, I
decided to add a couple of options to my K2. I could still order a K3
Gary D Krause wrote:
Why do you still have both?
A lot of reasons, not the least of which is that I built my K2. I only
assembled my K3. It isn't the same. There's a bond with a radio that you
built yourself that doesn't exist if you only bought it.
Then the K3 does modes like AM, FM and
I don't have a KAT3. I often use an external remote matching unit. I
cannot directly control the lowest SWR found. My linear is somewhat
sensitive to SWR.
At times I have observed a more than satisfactory apparent SWR indication on
my K3 and found my amplifier was less than satisfied.
Ouch, this slipped by me in my
move to the K3 IF for the VHF-Microwave station. I use FM frequently on
10Ghz rainscatter when signals are strong. So I am looking for a K3 FM
filter (KFL3B-FM 13 kHz FM filter ), anyone have one surplus to your needs
that would be for sale?
Thanks Bill
K3: Better performance, more features. Good base-station radio.
K2: Smaller. lighter, built-in battery. Good QRP portable radio.
Al N1AL
On Wed, 2009-11-04 at 12:39 -0700, Gary D Krause wrote:
Why do you still have both? The K2 is my main station rig. I recently
considered buying a K3
Wow, that's the first time I've done that to my own call sign. Thanks for the
input Jack. A K3 just may be in my future yet.
Gary, N7HTS
On Wed, 4 Nov 2009 12:05:00 -0800
Jack Brindle jackbrin...@earthlink.net wrote:
Gary;
I have both. The K2 now serves as a backup to the K3, but I
The K3 sucks because, it creates such a dilemma for me. Should I buy one,
should I not and so on. Those guys at Elecraft are pretty good at dangling
the carrot. ;-)
Gary, N7HTS
__
Elecraft mailing list
Home:
Gary,
I have both also and pretty much agree with what has been said. The
only thing I can add is that the K2 has been capped and you can't expect
much if anything in the way of new features from Elecraft while the K3
is under active development and there seems to be something new every
On Wed, 04 Nov 2009 12:39:51 -0700
Gary D Krause n7...@bresnan.net wrote:
Why do you still have both? The K2 is my main station rig. I
recently considered buying a K3 and even went to the Elecraft web
site to order it. Each time I backed off so that I could think more
about it.
snip
Hi
Ted;
I don't think that the K2 has been capped is all that accurate. The
developer for the radio is awfully busy doing other things, but he has
assured us the dream is still very much alive and the ideas are there!
Jack Brindle, W6FB
On Nov 4, 2009, at 12:46 PM, Ted Roycraft wrote:
Gary,
Jack,
On 10/15/2009, Wayne Burdick had this exchange on this reflector under
the subject line: has the k2 a future. It sounds capped to me.
Ted, W2ZK
=
Michael van Hauten wrote:
Dear elecraft -team,
during the last 2
The issue(s) that I'm facing are being dealt with fully in the other
thread re: K3 SWR accuracy. I would like to abandon this thread.
73 -- Brian -- K1LI
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
I have both K2 and K3. Although the K3 is my main station i am not
considering to sell my K2 at all. Like Julian said, it is a home build rig
and I am proud to have it. I once had a HW8 and sold it. Now feel sorry for
doing so. I think when i should sell my K2 i will regret it in the near
Did we ever ever get anything final on the subtle bug that may have
created a problem with RF Gain calibration in the Mac version of K3
Utility?
I used the new test version sent out a few days ago, calibrated to an
XG2 on 20M. Didn't have to adjust S-Meter cal on the Main receiver,
but
Grant,
Re-do the S-meter Cal on the main receiver. There seems to be some
confusion on this topic, but there is only *one* set of S-meter
calibration settings (at least that is the way it is right now). So
when you thought you were calibrating the subRX S-meter, you likely
messed up the
I'm fault finding a K2 that is deaf and has low TX output and have a basic
question regarding the sig gen I'm using. My generator will only produce
145mV pk to pk and I want to know if this should be enough to drive the AGC
into saturation. I'm only measuring 4.9V on pin 1 of U2 which seems way
Hi all,
This thread is getting rather long but I want to put my 2 cents worth in.
The huge discrepancy between the K3 indicated SWR and the LP-100 shown in
Stewarts original post is *not* normal or expected. Either there is
something wrong with the data or the K3. I am finding that the K3
Ted Roycraft wrote:
Gary,
I have both also and pretty much agree with what has been said. The
only thing I can add is that the K2 has been capped and you can't expect
much if anything in the way of new features from Elecraft while the K3
is under active development and there seems to be
I built a K2/100 with every option except DSP and loved it. I planned to
keep next to my K3 forever but I found that I was using the K2 less and less
and favoring the K3 so I finally sold it. Wasn't easy as I had put so much
into building it and the K2 is a great rig but it just didn't make
Much the same experience here. As much as I loved the K2 it hardly got
used. Tough decision but I sold it and it's enjoying a new life in VK land
(I'm rather envious in fact!).
73 Stephen G4SJP
K3, KX-1
On 04/11/2009 22:27, NZ0T n...@cox.net wrote:
I built a K2/100 with every option except
How long is the coax between the LP100 sensor and the K3? This can have
a significant impedance transformation impact as you go to higher
frequencies, leading to a different indicated SWR at each end.
The impedance changes, but not the SWR. Looking at this on a Smith Chart,
you can see that you
Thanks to everyone that responded to my post. It's a hard choice to make and
I agree with everything that has been mentioned so far. I've written similar
posts in the past just to get as much information as possible and to look at
it from as many different perspectives as possible. As my
Hi all,
Why CW is allways in REV mode each time I change band ?
73, Michel -- FM5CD
K3 #02727
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post:
Don ..
I realized that as I was redoing the adjustments one more time -- no
separate S-meter adjustments for the Sub.I'll start from scratch.
But the results do seem a bit odd. As it now sits on the Main (and
this is after mistakenly tweaking S_meter cal on the Sub), a 50uV
signal
Paul,
That is not enough signal to saturate the AGC for certain - but then if
you have the Extremely Strong Signal Handling diodes in place you will
likely find a similar condition because the diodes clip on those very
large signals.
All is not lost, you can still do the signal tracing with a
Grant,
The compensation between 'nor' and 'abs' is done in software, so it may
be that something you did in the calibrations has thrown it off a bit -
it is not hard to re-do both the RF gain and S-meter calibrations, so I
would do them both (in that order).
73,
Don W3FPR
Grant Youngman
That assumes there is no RF on the exterior of the coax and the SWR
sensors are ideal. Neither is the case and from personal experience I
can tell you that the swr meters will change readings based on coax length.
73, Eric
Phil Debbie Salas wrote:
How long is the coax between the LP100
Don Wilhelm-4 wrote:
Did you really mean 4.9V signal?
No - 4.9V AGC voltage which should be over 6V at saturation hence the
question about the generator and it's output.
Thanks for the pointers - I was looking for relative loss to the input
signal anyway so will carry on tomorrow in more
Phil Debbie Salas wrote:
How long is the coax between the LP100 sensor and the K3? This can have
a significant impedance transformation impact as you go to higher
frequencies, leading to a different indicated SWR at each end.
The impedance changes, but not the SWR. Looking at this on a
That assumes there is no RF on the exterior of the coax and the SWR
sensors are ideal. Neither is the case and from personal experience I
can tell you that the swr meters will change readings based on coax
length.
The SWR *reading* may change as a function of coax length when current is
I can vouch for Eric's statement. I routinely calibrate KPA100
wattmeters for SWR using a precision 100 ohm dummy load (which should
produce a 2.0 SWR). At 40 meters, I get 2.0 if I use a direct
connection with a male to male adapter, with a 1 foot coax, it shows
SWR=2.1 and with a 2 foot
I was using 4 Watts, the external bridge is a taiwan-made AV-20, I
forgot the brand name. There is a sticker, it says accuracy 10%.
Today I tested again using 10 Watts, the K3's and the external meters
readout match a lot closer.
With 10 W i can bring the K3s readout to 1.0:1 , with 4 W it was
The first statement is correct. Length of coax will transform impedance and
cause SWR meters to read differently.
I've seen this Smith Chart reference before and it makes no sense. You can
certainly use your feeder to match your antenna. Of course, if SWR meters
didn't care what the impedance
The SWR definitely does not change with line length.
However the SWR _READING_ often does because of the inaccuracy of
inexpensive SWR meters. The SWR reading should depend only on the
relative magnitudes of the forward and reflected power and not on the
phase angle between them. But with
Transmission line theory (and therefore the Smith Chart info) IS correct.
Transmission line length DOES transform the impedance, but not SWR. So you
may be changing the impedance to something that your tuner can tune when you
add coax length, but you are not changing the SWR by adding coax -
Steve,
Just one clarification - a mismatched length of coax will transform the
impedance, but a perfectly matched line will not.
Since we calibrate things at 50 ohms, if the coax is exactly 50 ohms and
the SWR is 1.0:1, no impedance transformation will exist. But real coax
lines are nominally
Hello,
Please, please, does anybody remember the original poster's problem anymore?
Quote:
The results I got for 2:1 VSWR are as follows:-
LP-100 K3
160 1.991.8
80 1.991.8
60 1.991.8
40
You have something terribly wrong. Two feet of coax at 7 MHz is negligible (~8
electrical degrees for solid dielectrics), even if its impedance is wildly
different from 50 ohm.
Furthermore, any loss in the cable should reduce the SWR, not increase it.
--- On Wed, 11/4/09, Don Wilhelm
After implementing Elecraft's VFO tuning hash modification, there was still
hash to be heard on my K3, most notably in the bottom 40kHz of 10 metres.
The problem was finally eased by replacement of the two silicon diodes used in
the modification. Although no fault could be found with the
So here is the bottom line:
1. SWR is the same anywhere along the transmission line per Mr. Smith and
his Chart.
2. When the transmission line doesn't match the antenna we have an SWR other
than 1:1.
3. The SWR meter will often read differently at the antenna vs. at
transmitter.
4. Example: A
--- On Wed, 11/4/09, Steve Ellington n...@carolina.rr.com wrote:
The first statement is correct. Length of coax will transform impedance and
cause SWR meters to read differently.
Absent loss, if the cable Zo matches the SWR bridge design impedance (or vice
versa), then the SWR reading should
On Nov 4, 2009, at 4:41 PM, Steve Ellington wrote:
4. Example: A full wave dipole center fed with 50 ohm coax. SWR reads
infinite at the antenna but with 1/4 wavelenth of coax, SWR reads low!
Nope -- the *impedance* at the end of a 1/4 wave transmission line
when it is looking at a very
I give up. Please somebody end this thread. There is no useful information in
this thread to the OP. I can't really help him because I don't experience
his problems. I have decent agreement between all instruments in my feed
line about the antenna SWR.
Knut - AB2TC
Wes Stewart wrote:
I agree with you, Dick.
The K2 and K3 are very different radios and I LOVE THEM BOTH. The K3 is a
Ferrari Enzo, and the K2 is a Porsche 911 GT2.. Why not drive them both?
My biggest regret as a ham is selling the Heathkit HW-16 and HW-101 I built in
my youth--to buy a used TS-520. It
The KAT3 is between the two bridges. The two will see different
impedences on some bands as a result of stray L and C. This probably
accounts for some or most of the reading error.
73,
Wayne
N6KR
http://www.elecraft.com
On Nov 4, 2009, at 4:23 PM, ab2tc ab...@arrl.net wrote:
Hello,
Nope:
The 1/4 wave line transforms the high impedance to a low one and the SWR
meter reads low. It's called a transmission line transformer and is very
common. It's the reason everyone is having trouble understanding why SWR
meters read differently. The ONLY way to compare them is to swap them
I have a K2/100 and 2 K3s. They each have their place. I think it's a mistake
to compare the two different radios because they were obviously intended for
very different purposes. If I wanted a very portable CW rig which still offers
me up to 100 W when needed and which also has some SSB
Julian, G4ILO wrote:
I think a bug has crept in during one of the recent updates. I'm running
3.47/2.41 at the moment.
Julian - I have had the same experience recently - I go to another band,
transmit there, then come back and it generally fixes it. Unfortunately I
can't replicate the
On Nov 4, 2009, at 5:05 PM, Steve Ellington wrote:
It's called a transmission line transformer and is very common.
Yes, we all know about them. Just walk 180 degrees on a constant SWR
circle on the Smith Chart, with the transmission line impedance at the
center of the Smith Chart (or use
But you cannot transform anything other than a 50 ohm feed point into
a 50 ohm termination by using a 50 ohm transmission line. (Unless the
line is infinitely lossy.)
Don't worryIt will be!
Steve
N4LQ
n...@carolina.rr.com
- Original Message -
From: Kok Chen c...@mac.com
To: Steve
My two cents to this endless topic.
I am one of the many owners of both the K3 and the K2 and when I got recently
my K2 which is fully loaded with every single board Elecraft designed and
built,I had them both side by side for a month testing them day and night using
always same antennas
On Wed, 2009-11-04 at 16:56 -0800, eric norris wrote:
My biggest regret as a ham is selling the Heathkit HW-16 and HW-101 I built
in my youth--to buy a used TS-520. It makes me sick thinking about it.
My biggest regret is that I no longer have my first homebrew project, a
one-tube (6U8A)
I believe Steve is onto something critical to this discussion - here is
my 'take' on the differences -- Remember that we *are* talking about
the resultant SWR indications on a mis-matched line.
The way most wattmeters indicate SWR is to detect the forward power
and the reflected power - then
Al,
I have similar regrets about my first transmitter - the 5763/6146
transmitter that was in the ARRL Hnadbook for 1955 and 1956. It too was
cannibalized for parts at a later time, and I have often considered
building another from scratch, but now cannot find all the required
parts at a
Everyone that homebrews has these stories. Each one is a
heart-breaker. Mine was a Heathkit DX-20 with my own custom screen
modulator for AM, built in 1971 and mod'ed in 1973. I reused the
tubes in another TX and tossed everything else. Argh.
Ah... history. Still have the DX-60 that came
I did the same thing and got rid of the HW-101 and some other stuff to buy a
TS-520 then on to the TS-820. I never looked back. I never had anymore
Heathkit Green in the shack (except for the Sb-220 which I did dump too) I did
not miss the Hw-101. The darn thing had paper coil slugs and the
92 matches
Mail list logo
