[Elecraft] An ode to K3 #2545--no useful info here

[eric norris via Elecraft]

Due to my mobility issues, I have two stations set up in my house--one with a 
newer K3S, and one with my old buddy K3 #2545.  Number 2545 has been upgraded 
over the years several times, and about a year ago I sent her back to the 
mothership to get the full set of upgrades that became available with the K3S.  
However, for whatever reason--maybe 10 years of fiddling with every single 
setting, or maybe just that the K3S is in an electrically noisier part of the 
house--I can still pull signals out of the noise more easily with the old girl. 
It sounds silly, but I'm really attached to her.  Maybe it's just because she 
was the first radio I ever owned in nearly a half-century of hamming that was 
state-of-the art.  Maybe it's because she and her brick-wall roofing filters 
allowed me to get back on 2m EME when a new, very loud local station completely 
wiped me off the air with my old radio.  For whatever reason, K3 #2545 will 
always be my favorite radio.  
I hope we're together for many years to come--even if she gets a K4 sibling 
eventually.  Thanks, Elecraft.  My apologies for the bandwidth.  
73 Eric WD6DBM

Sent from Yahoo Mail on Android
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Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

[K9MA]

Based on my experience, the KPA1500 is very sensitive to small changes 
in load impedance (SWR) with respect to power gain and current. The ATU 
software is much better than it started out, but still sometimes doesn't 
get below 1.2:1. That could result in the kind of power gain variation 
Pete is seeing.


73,
Scott K9MA


On 10/23/2019 12:24, Jim Rhodes wrote:

Actually the fact that you were using the internal tuner doesn't change the
chance that with the settings on the auto tuner don't tell you which
direction the tuning of a certain antenna approach unity from. So there
could be twice the variation allowed between the 2 antennas. So if one is
coming from high impedance and stops at say 1.2:1 and the other is coming
from low and stops at 1.2:1 then there is still a considerable difference
between them. Putting an analyser on them to see the starting point the
tuner is working on could explain a lot.

Jim Rhodes
K0XU

On Wed, Oct 23, 2019, 11:17 N4ZR  wrote:


Thanks to everyone who replied, either directly or on the list.  I'm
sorry, but I forgot to mention one key fact - I was running the amp's
ATU with both of these antennas.  Assuming that the amp's power output
measurement is done at the input of the ATU and not the output, and that
the ATU settings for the two antennas ( ATU rRetune SWR and ATU Stop Tun
SWR ) are identical, this really does look to me like a difference in
amplifier gain rather than measurement error.

The antennas are clearly a lot different - in fact the Windom will often
throw a Reflected Power fault when I first switch to it - but it seems
to me that after the ATU they should look the same.

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 10/23/2019 9:55 AM, Bob McGraw K4TAX wrote:

Pete:

The fact it requires more drive with one antenna as opposed to another
says the two antennas do not have the same impedance. This is not at
all unusual.  Power measurements, with the methods used in ham radio
applications, are based on voltage measurements with the impedance
presumed to be 50 ohms.   Ohms law says P = E²/R thus any change in R
{impedance} will cause a change in Power indicated or measured at a
given point.

A second factor is SWR which is an indication of the relative
impedance between the source {amp} and the load {antenna}.  In this
case, as example, a 1.5:1 SWR can be 75 ohms or it can be 33 ohms.
SWR and Power meters are calibrated for 50 ohms and are based on
voltage on the feed line.  Again we see that the impedance or the R
part being different will affect the Power. In order to deliver the
same power into a 33 ohm load, the amp is required to deliver more
current and thus more drive is required.

 From an RF measurement at a given point with different impedance's we
find:

1500 watts into 75 ohms is 335 volts with a current of 4.47 amps

1500 watts into 50 ohms is 273 volts with a current of 5.47 amps

1500 watts into 33 ohms is 222 volts with a current of 6.74 amps

 From the above one can see the amp is required to deliver more current
into a lower impedance and to do so will require more drive power. And
from the above, one can see the voltage on the feed line is different
with different loads.  In this regard, in as much as we measure power
as a voltage with a known resistance the power measurements can be in
error.   Our power indicating devices are calibrated for 50 ohms.
Any deviation from 50 ohms will thus cause an error in power indication.

A third component of SWR and Power measurements would be Common Mode
Current on the feed line. This is usually current induced on the
outside of the feed line from the power radiated from the antenna.
This common mode current is not measured by our power indicating
instruments.   As a side note, Windom antennas are noted to exhibit
high Common Mode Current conditions.  The solution for CMC is to have
a good Common Mode Choke at the feed point of the antenna, where the
feed line connects, and also at the station end.

Jim, K9YC, has and excellent paper on the topic:
http://audiosystemsgroup.com/2018Cookbook.pdf

Also, Rick, DJ0IP has a lot of valid information on his site:

http://www.dj0ip.de/balun-stuff/

http://www.dj0ip.de/rf-cmc-chokes/

Now after all of this is said and done, I'd say your results with your
KPA1500 are normal.   Hence the reason for the variation in drive is
due to the load impedance presented to the amp and the power
measurement method.

73

Bob, K4TAX



On 10/23/2019 6:59 AM, N4ZR wrote:

I have two 40M antennas, a Carolina Windom and a full-wave parasitic
sloper.  I have just noticed that on any given frequency, my K3 must
deliver considerably more power on one than the other, in order for
the amp to produce 1500 watts.  The difference is 27 watts on one vs
42 watts on the other.  Is this normal?





__

Re: [Elecraft] OT - Hot Air Soldering Guns for SMDs

[Byron Servies]

Years ago QST had an article on calibrating and using a toaster oven
and a multi-meter with a k-type probe for reflow soldering.  I have
been using that successfully for years, for about $35.

73, Byron N6NUL

On Sun, Oct 20, 2019 at 5:16 PM Gwen Patton  wrote:
>
> I was a backer for the ReflowR computer controlled SMD hot plate a few
> years ago. I had to cough up a little extra for shipping because the
> creator munged up his figures and didn't leave enough for shipping, and was
> selling the things on Tindie to build up cash to send units to his backers
> -- which caused people to get really cheesed off at him. I did get my
> ReflowR, however, one with built in Wi-Fi for control with an app, or it
> has a bunch of preconfigured profiles in it for most reflow jobs. This was
> before ovens like the one you got were available so cheap, so there's only
> a LITTLE buyer's remorse.
>
> It DOES work pretty well, though. Combined with my I-Extruder pen for
> applying solder paste, it makes SMD work much easier. The I-Extruder can be
> used as a vacuum pick-and-place tool as well, or for applying flux in
> controlled amounts. Since I don't work a lot with SMD yet, I use it for
> applying Amtech Tacky Flux (Thank you, Louis Rossmann!) to my thru-hole
> components for good soldering with much less flux application mess.
>
> I also have one of those cheap Chinese WEP hot air reflow stations. Cost me
> $60 on Amazon, and it works like a champ. I use it primarily for
> heat-shrink, though. Used with that marine-grade heat shrink that's lined
> with hot glue, it's a total wizard's tool.
>
> 73,
> Gwen, NG3P
>
> On Sun, Oct 20, 2019 at 7:01 PM Mark Goldberg 
> wrote:
>
> > I have a well used hot air gun (OK Industries SMT-1160) but I use my Metcal
> > iron and hot tweezers a lot more. They have an infinite selection of tips
> > for almost anything. They are expensive though, even used.
> >
> > For us old farts with unsteady hands and bad eyes, a vacuum pickup, lots of
> > tweezers and a binocular microscope are a huge help. A flux bottle with a
> > dispensing needle tip and a bottle of Isopropyl  Alcohol are musts too. I
> > have some tiny solder, solder wick and solder paste for my reflow oven. The
> > reflow oven is the bees knees if you are building a lot.
> >
> > Youth and delicate hands also helps, I have neither but I get by.
> >
> > Look at my qrz.com page for my setup and links to more info.
> >
> > 73,
> >
> > Mark
> > W7MLG
> >
> >
> > On Sun, Oct 20, 2019 at 12:33 PM Dauer, Edward  wrote:
> >
> > > I am thinking about trying my hand at building a kit with a bunch of
> > > SMDs.  I don’t yet know the gauge.  Any suggestions about the brand or
> > type
> > > of hot air soldering gun I should buy?  Any other tools I’ll need, like
> > > narrow-gauge solder, wicks, whatever?
> > >
> > > Thanks,
> > >
> > > Ted, KN1CBR
> > >
> > > __
> > > Elecraft mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > > Help: http://mailman.qth.net/mmfaq.htm
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> > >
> > > This list hosted by: http://www.qsl.net
> > > Please help support this email list: http://www.qsl.net/donate.html
> > > Message delivered to marklgoldb...@gmail.com
> > __
> > Elecraft mailing list
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> >
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> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to ard...@gmail.com
>
>
>
> --
>
> -+-+-+-+-
> Jenny Everywhere's Infinite: Quark Time
> http://quarktime.net
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-- 
- Northern California Contest Club
- CU in the Cal QSO Party 3-4 Oct 2020
- www.cqp.org
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[Elecraft] KX3 For Sale

[Ken Nicely]

I am selling my KX3 transceiver.

KX3  KX3-K 160-6 M Transceiver
KXAT3  Internal automatic antenna tuner
KXBC3  Internal NiMH Charger/Clock
KXFL3   KXFL3 Dual-Passband Roofing Filter
KXPD3  KXPD3 Precision Keyer Paddle
MH3  MH3 Hand Microphone
KX3-PCKT  Cable Kit
KXUSBa USB Cable
Power Cable
Soft Case

I am the original owner.

Asking $1100.00 shipped CONUS.

https://photos.app.goo.gl/oG7jeYb3YsuKAz1EA

Please respond directly to k...@nicelyweb.com if interested.

Ken Nicely KE3C
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Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

[Jim Rhodes]

Actually the fact that you were using the internal tuner doesn't change the
chance that with the settings on the auto tuner don't tell you which
direction the tuning of a certain antenna approach unity from. So there
could be twice the variation allowed between the 2 antennas. So if one is
coming from high impedance and stops at say 1.2:1 and the other is coming
from low and stops at 1.2:1 then there is still a considerable difference
between them. Putting an analyser on them to see the starting point the
tuner is working on could explain a lot.

Jim Rhodes
K0XU

On Wed, Oct 23, 2019, 11:17 N4ZR  wrote:

> Thanks to everyone who replied, either directly or on the list.  I'm
> sorry, but I forgot to mention one key fact - I was running the amp's
> ATU with both of these antennas.  Assuming that the amp's power output
> measurement is done at the input of the ATU and not the output, and that
> the ATU settings for the two antennas ( ATU rRetune SWR and ATU Stop Tun
> SWR ) are identical, this really does look to me like a difference in
> amplifier gain rather than measurement error.
>
> The antennas are clearly a lot different - in fact the Windom will often
> throw a Reflected Power fault when I first switch to it - but it seems
> to me that after the ATU they should look the same.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at , now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> On 10/23/2019 9:55 AM, Bob McGraw K4TAX wrote:
> > Pete:
> >
> > The fact it requires more drive with one antenna as opposed to another
> > says the two antennas do not have the same impedance. This is not at
> > all unusual.  Power measurements, with the methods used in ham radio
> > applications, are based on voltage measurements with the impedance
> > presumed to be 50 ohms.   Ohms law says P = E²/R thus any change in R
> > {impedance} will cause a change in Power indicated or measured at a
> > given point.
> >
> > A second factor is SWR which is an indication of the relative
> > impedance between the source {amp} and the load {antenna}.  In this
> > case, as example, a 1.5:1 SWR can be 75 ohms or it can be 33 ohms.
> > SWR and Power meters are calibrated for 50 ohms and are based on
> > voltage on the feed line.  Again we see that the impedance or the R
> > part being different will affect the Power. In order to deliver the
> > same power into a 33 ohm load, the amp is required to deliver more
> > current and thus more drive is required.
> >
> > From an RF measurement at a given point with different impedance's we
> > find:
> >
> > 1500 watts into 75 ohms is 335 volts with a current of 4.47 amps
> >
> > 1500 watts into 50 ohms is 273 volts with a current of 5.47 amps
> >
> > 1500 watts into 33 ohms is 222 volts with a current of 6.74 amps
> >
> > From the above one can see the amp is required to deliver more current
> > into a lower impedance and to do so will require more drive power. And
> > from the above, one can see the voltage on the feed line is different
> > with different loads.  In this regard, in as much as we measure power
> > as a voltage with a known resistance the power measurements can be in
> > error.   Our power indicating devices are calibrated for 50 ohms.
> > Any deviation from 50 ohms will thus cause an error in power indication.
> >
> > A third component of SWR and Power measurements would be Common Mode
> > Current on the feed line. This is usually current induced on the
> > outside of the feed line from the power radiated from the antenna.
> > This common mode current is not measured by our power indicating
> > instruments.   As a side note, Windom antennas are noted to exhibit
> > high Common Mode Current conditions.  The solution for CMC is to have
> > a good Common Mode Choke at the feed point of the antenna, where the
> > feed line connects, and also at the station end.
> >
> > Jim, K9YC, has and excellent paper on the topic:
> > http://audiosystemsgroup.com/2018Cookbook.pdf
> >
> > Also, Rick, DJ0IP has a lot of valid information on his site:
> >
> > http://www.dj0ip.de/balun-stuff/
> >
> > http://www.dj0ip.de/rf-cmc-chokes/
> >
> > Now after all of this is said and done, I'd say your results with your
> > KPA1500 are normal.   Hence the reason for the variation in drive is
> > due to the load impedance presented to the amp and the power
> > measurement method.
> >
> > 73
> >
> > Bob, K4TAX
> >
> >
> >
> > On 10/23/2019 6:59 AM, N4ZR wrote:
> >> I have two 40M antennas, a Carolina Windom and a full-wave parasitic
> >> sloper.  I have just noticed that on any given frequency, my K3 must
> >> deliver considerably more power on one than the other, in order for
> >> the amp to produce 1500 watts.  The difference is 27 watts on one vs
> >> 42 watts on the other.  Is this normal?
> >>
> >
> >
> >
> __
> Elecraft mailing list
> Home: 

Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

[N4ZR]

Thanks to everyone who replied, either directly or on the list.  I'm 
sorry, but I forgot to mention one key fact - I was running the amp's 
ATU with both of these antennas.  Assuming that the amp's power output 
measurement is done at the input of the ATU and not the output, and that 
the ATU settings for the two antennas ( ATU rRetune SWR and ATU Stop Tun 
SWR ) are identical, this really does look to me like a difference in 
amplifier gain rather than measurement error.


The antennas are clearly a lot different - in fact the Windom will often 
throw a Reflected Power fault when I first switch to it - but it seems 
to me that after the ATU they should look the same.


73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 10/23/2019 9:55 AM, Bob McGraw K4TAX wrote:

Pete:

The fact it requires more drive with one antenna as opposed to another 
says the two antennas do not have the same impedance. This is not at 
all unusual.  Power measurements, with the methods used in ham radio 
applications, are based on voltage measurements with the impedance 
presumed to be 50 ohms.   Ohms law says P = E²/R thus any change in R 
{impedance} will cause a change in Power indicated or measured at a 
given point.


A second factor is SWR which is an indication of the relative 
impedance between the source {amp} and the load {antenna}.  In this 
case, as example, a 1.5:1 SWR can be 75 ohms or it can be 33 ohms.  
SWR and Power meters are calibrated for 50 ohms and are based on 
voltage on the feed line.  Again we see that the impedance or the R 
part being different will affect the Power. In order to deliver the 
same power into a 33 ohm load, the amp is required to deliver more 
current and thus more drive is required.


From an RF measurement at a given point with different impedance's we 
find:


1500 watts into 75 ohms is 335 volts with a current of 4.47 amps

1500 watts into 50 ohms is 273 volts with a current of 5.47 amps

1500 watts into 33 ohms is 222 volts with a current of 6.74 amps

From the above one can see the amp is required to deliver more current 
into a lower impedance and to do so will require more drive power. And 
from the above, one can see the voltage on the feed line is different 
with different loads.  In this regard, in as much as we measure power 
as a voltage with a known resistance the power measurements can be in 
error.   Our power indicating devices are calibrated for 50 ohms.   
Any deviation from 50 ohms will thus cause an error in power indication.


A third component of SWR and Power measurements would be Common Mode 
Current on the feed line. This is usually current induced on the 
outside of the feed line from the power radiated from the antenna.  
This common mode current is not measured by our power indicating 
instruments.   As a side note, Windom antennas are noted to exhibit 
high Common Mode Current conditions.  The solution for CMC is to have 
a good Common Mode Choke at the feed point of the antenna, where the 
feed line connects, and also at the station end.


Jim, K9YC, has and excellent paper on the topic: 
http://audiosystemsgroup.com/2018Cookbook.pdf


Also, Rick, DJ0IP has a lot of valid information on his site:

http://www.dj0ip.de/balun-stuff/

http://www.dj0ip.de/rf-cmc-chokes/

Now after all of this is said and done, I'd say your results with your 
KPA1500 are normal.   Hence the reason for the variation in drive is 
due to the load impedance presented to the amp and the power 
measurement method.


73

Bob, K4TAX



On 10/23/2019 6:59 AM, N4ZR wrote:
I have two 40M antennas, a Carolina Windom and a full-wave parasitic 
sloper.  I have just noticed that on any given frequency, my K3 must 
deliver considerably more power on one than the other, in order for 
the amp to produce 1500 watts.  The difference is 27 watts on one vs 
42 watts on the other.  Is this normal?







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[Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

[N4ZR]

I have two 40M antennas, a Carolina Windom and a full-wave parasitic 
sloper.  I have just noticed that on any given frequency, my K3 must 
deliver considerably more power on one than the other, in order for the 
amp to produce 1500 watts.  The difference is 27 watts on one vs 42 
watts on the other.  Is this normal?


--

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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