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Powering a K3s from a battery?

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Juliean Galak

Powering a K3s from a battery?

I'm contemplating using a battery rather than a power supply to run a K3s and am wondering how well it does on 12V (as opposed to the 13.8V most supplies deliver). Comments appreciated"

Juliean
KD2JPF
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MarcV

Re: Powering a K3s from a battery?

My K3/P3/VGA monitor are happy with power from http://bioennodepot.com/lithium-iron-phosphate-lifepo4-batteries/bioenno-power-12v-40ah-lfp-battery-pvc-blf-1240w.html

It's small enough to lie flat on a shelf with 3.5" clearance with a footprint smaller than my iPad.

My KX3/PX3/KXPA100 run on another identical battery. These have plenty of capacity to power 100 watts CW for longer than I can stay active. They start out at 13.2 volts and stay there for hours. I do use #10 AWG wire, though, to minimize resistive loss.
--
Marc W8SDG

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kk4oyj

Re: Powering a K3s from a battery?

I run /P on a 35aH lead acid battery. Whilst there is a noticeable voltage
drop, I have worked dx till the battery voltage falls well below 11v
without any noticeable effects on signal quality (I asked)!
I have also run from a battery in the shack with a charger connected. No
problem.

Clearly the larger the battery, the less problems you will have.

GL and 73
John, C6ATS

On Tue, 29 Dec 2015 15:43 Marc Veeneman <[hidden email]> wrote:

> My K3/P3/VGA monitor are happy with power from
> http://bioennodepot.com/lithium-iron-phosphate-lifepo4-batteries/bioenno-power-12v-40ah-lfp-battery-pvc-blf-1240w.html
>
> It's small enough to lie flat on a shelf with 3.5" clearance with a
> footprint smaller than my iPad.
>
> My KX3/PX3/KXPA100 run on another identical battery. These have plenty of
> capacity to power 100 watts CW for longer than I can stay active. They
> start out at 13.2 volts and stay there for hours. I do use #10 AWG wire,
> though, to minimize resistive loss.
> --
> Marc W8SDG
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Jim Brown-10

Re: Powering a K3s from a battery?

On Tue,12/29/2015 7:57 AM, John Macrae wrote:
> I run /P on a 35aH lead acid battery. Whilst there is a noticeable voltage
> drop, I have worked dx till the battery voltage falls well below 11v
> without any noticeable effects on signal quality (I asked)!

It is well known that IMD (splatter, clicks) with a K3 is least with
higher DC supply voltage, and increases as the supply voltage is lower.
By 11V, it's increased a lot.

IMD is also reduced when the K3 operates at lower power. This is helpful
when you're driving a power amp. The KPA500 needs about 25-30W for full
power, my big 1.5kW tube amps need about 50W.

There is a menu setting for the DC voltage below which the K3 will not
transmit. Check the manual.
> I have also run from a battery in the shack with a charger connected. No
> problem.

I currently run from two big 6V golf cart batteries that are
float-charged by a regulated DC supply. With the charger connected, I
get about 13.4V on TX. Without the charger, the voltage falls below 11.5
V when the batteries are getting low. Because I'm usually driving an
amp, I have my K3s set to cut off at 11V.

> Clearly the larger the battery, the less problems you will have.

Yes, but the battery chemistry also matters. The "normal" operating
voltage of LiFePO4 batteries is at least a volt higher than lead-acid,
and the discharge curve is flatter. The problem is that LiFePO4 is
currently a lot more expensive, and the chemistry requires a special
charger. Prices are gradually dropping, and eventually that's likely
where I'll end up.

73, Jim K9YC
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Mike Maloney

Re: Powering a K3s from a battery?

In reply to this post by Juliean Galak

I've been running my K3 on a 55Ah Optima Yellow Top 34/78-OY almost daily for 7 years now with no issues. A small 3A float charger keeps it topped off.I operate primarily CW at 60W barefoot and reduce power further if using amp. Have found most remote ops cant detect difference between 60 and 100W.
Mike AC5P

On Tuesday, December 29, 2015 8:58 AM, Juliean Galak <[hidden email]> wrote:

I'm contemplating using a battery rather than a power supply to run a K3s and am wondering how well it does on 12V (as opposed to the 13.8V most supplies deliver). Comments appreciated"

Juliean
KD2JPF
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K8TE

Re: Powering a K3s from a battery?

In reply to this post by Juliean Galak

Actually, IMD in the PA increases significantly as battery voltage drops!
For example, during Field Day a few years ago someone kicked off the
generator power to our SSB station which kept operating on the back-up
battery. Sometime later the CW captain stopped by asking if we had changed
anything. He could hear "splatter" from our 20m signal on his 20m rig.
This was not the case earlier in the day.

I checked everything and discovered the AC power issue. I turned the outlet
switch back to On and checked with the 20m CW operator. His reception had
immediately cleaned up! He no longer heard anything from 20 SSB the rest of
the (non-contest) event. BTW, we went on to take 4th place overall with
just six transmitters (2012).

When driving a KPA500, this is much less of an issue since the K3 runs
typically under 30 Watts for 500 Watts from the KPA500. NC0B has spoken
frequently, in less than glowing terms, about IMD issues in 12 VDC (nominal)
PA's.

I've seen a number of comments recently that some folks don't care if their
radios' TX IMD is high. That attitude is exemplified in many DX pileups. I
have raised my power supply's voltage in an effort to keep my TX IMD as low
as possible based on my reading and empirical evidence related above.

73, Bill, K8TE
Albuquerque DX Assn

Message: 23
Date: Tue, 29 Dec 2015 15:57:18 +0000
From: John Macrae <[hidden email]>
To: Marc Veeneman <[hidden email]>, Juliean Galak <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Subject: Re: [Elecraft] Powering a K3s from a battery?
Message-ID:
<CAGfPUrh=[hidden email]>
Content-Type: text/plain; charset=UTF-8

I run /P on a 35aH lead acid battery. Whilst there is a noticeable voltage
drop, I have worked dx till the battery voltage falls well below 11v
without any noticeable effects on signal quality (I asked)!
I have also run from a battery in the shack with a charger connected. No
problem.

Clearly the larger the battery, the less problems you will have.

GL and 73
John, C6ATS

On Tue, 29 Dec 2015 15:43 Marc Veeneman <[hidden email]> wrote:

> My K3/P3/VGA monitor are happy with power from
>
http://bioennodepot.com/lithium-iron-phosphate-lifepo4-batteries/bioenno-pow
er-12v-40ah-lfp-battery-pvc-blf-1240w.html

>
> It's small enough to lie flat on a shelf with 3.5" clearance with a
> footprint smaller than my iPad.
>
> My KX3/PX3/KXPA100 run on another identical battery. These have plenty of
> capacity to power 100 watts CW for longer than I can stay active. They
> start out at 13.2 volts and stay there for hours. I do use #10 AWG wire,
> though, to minimize resistive loss.
> --
> Marc W8SDG
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Lynn W. Taylor, WB6UUT

Re: Powering a K3s from a battery?

In reply to this post by Jim Brown-10

Once upon a time, car battery manufacturers made 8 volt batteries.
These were for cars with 6v systems that were aging, and a couple of
extra volts made up for a lot of problems.

Might take a bit to figure out how to charge them, but a 6v plus an 8v
battery would give you a really clean supply just over 14 volts.

73 -- Lynn

On 12/29/2015 9:55 AM, Jim Brown wrote:
> Yes, but the battery chemistry also matters. The "normal" operating
> voltage of LiFePO4 batteries is at least a volt higher than lead-acid,
> and the discharge curve is flatter. The problem is that LiFePO4 is
> currently a lot more expensive, and the chemistry requires a special
> charger. Prices are gradually dropping, and eventually that's likely
> where I'll end up.
>
> 73, Jim K9YC

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Don Wilhelm-4

Re: Powering a K3s from a battery?

In reply to this post by K8TE

Read Bill's post carefully. Notice that he had no indication of the
effects of poor IMD due to low power supply voltage. You will *not*
hear bad reports from the stations you contact.
However, your signal will "splatter" over the band at frequencies away
from where you are transmitting.
Be kind to your ham 'neighbors' (and they do not have to be in close
proximity) and keep that power supply voltage up to reduce the transmit
IMD. Most Elecraft products will be happy with a power supply voltage
up to 15 volts. I recommend a power supply voltage of 13.8 volts (the
voltage of a fully and recently charged "12 volt" lead acid battery).

73,
Don W3FPR

On 12/29/2015 7:00 PM, Bill Mader wrote:

Wes (N7WS)

Re: Powering a K3s from a battery?

In reply to this post by K8TE

Good points all.

Something else to note, even at 14V, running a K3 at 11-12 watts is a disaster.
Just because you're using "low power" doesn't mean that the amplifier isn't
distorting. IMD is also frequency sensitive. One frequency measurements tell you
nothing about IMD performance. At 30 watts output on 3.8 MHz my K3 IMD was 17dB
lower than at 14 MHz.

At 24 MHz the IMD at 10W was 29 dB worse than 30W! In all cases of frequency
or output power the IMD was worse at 10W output.

On 12/29/2015 5:00 PM, Bill Mader wrote:

> Actually, IMD in the PA increases significantly as battery voltage drops!
> For example, during Field Day a few years ago someone kicked off the
> generator power to our SSB station which kept operating on the back-up
> battery. Sometime later the CW captain stopped by asking if we had changed
> anything. He could hear "splatter" from our 20m signal on his 20m rig.
> This was not the case earlier in the day.
>
> I checked everything and discovered the AC power issue. I turned the outlet
> switch back to On and checked with the 20m CW operator. His reception had
> immediately cleaned up! He no longer heard anything from 20 SSB the rest of
> the (non-contest) event. BTW, we went on to take 4th place overall with
> just six transmitters (2012).
>
> When driving a KPA500, this is much less of an issue since the K3 runs
> typically under 30 Watts for 500 Watts from the KPA500. NC0B has spoken
> frequently, in less than glowing terms, about IMD issues in 12 VDC (nominal)
> PA's.
>
> I've seen a number of comments recently that some folks don't care if their
> radios' TX IMD is high. That attitude is exemplified in many DX pileups. I
> have raised my power supply's voltage in an effort to keep my TX IMD as low
> as possible based on my reading and empirical evidence related above.
>
> 73, Bill, K8TE
> Albuquerque DX Assn
>

Jim Brown-10

Re: Powering a K3s from a battery?

Something you're missing, Wes. The 100W amp doesn't kick in until you
ask for more than about 14W. So at 11-12W, you're seeing the IMD of the
QRP exciter stage running near it's maximum power.

I'm wondering if it might be practical to modify the control software so
that the 100W amp kicks in at lower power levels. Are there other
consequences? Wayne?

73, Jim K9YC

On Tue,12/29/2015 8:19 PM, Wes (N7WS) wrote:
> Something else to note, even at 14V, running a K3 at 11-12 watts is a
> disaster.

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Wes (N7WS)

Re: Powering a K3s from a battery?

I'm not missing a thing.

All I'm saying is that if you run the LPA at 10-12 watts, according to my
measurements*, the IMD is pretty bad. If you have an HPA, then after it's
kicked in, (13W in my K3S) the LPA is running at greatly reduced power. I don't
believe Elecraft has to change anything. Guys with a KPA3(A) just need to avoid
the grey area of 10-15W.

Wes N7WS

*Remarkably, IMD measurements I made on my K3S using modest equipment correlated
within 1dB or less to measurements made by Elecraft, on the same radio.

On 12/30/2015 12:08 AM, Jim Brown wrote:

> Something you're missing, Wes. The 100W amp doesn't kick in until you ask for
> more than about 14W. So at 11-12W, you're seeing the IMD of the QRP exciter
> stage running near it's maximum power.
>
> I'm wondering if it might be practical to modify the control software so that
> the 100W amp kicks in at lower power levels. Are there other consequences?
> Wayne?
>
> 73, Jim K9YC
>
> On Tue,12/29/2015 8:19 PM, Wes (N7WS) wrote:
>> Something else to note, even at 14V, running a K3 at 11-12 watts is a disaster.
>

Christian Gondard

KXPA100 connection to PC via RS232

Hello

I have my new KXPA100 connected to the KX3 as described in the manual ,
via the adapter cable (page 13 of the manual) ; all is working fine and
the KX3 communicates with the KXPA100. I have made already some qso's at
100 watts.

but ..

when I was using the KX3 barefoot, it was connected to my PC via the
KXUSB cable at ACC1, which provides an RS232 to USB conversion ; and
logger32, which is my logbook software, was reading the KX3 frequency on
the simulated COM6 port.
I was expecting that the same will occur when I use the same hardware
connected this time to the RS232 exit on the KXPA100 ; but now logger32
doesn't receive the frequency info from the KXPA100 when the PA mode is
selected. When the PA mode is OFF , logger32 reads the correct frequency

If I come back to the KX3 barefoot configuration, logger32 receives the
frequency data as before.

What did I missed ? I suppose something is not behaving as I was
expecting on the RS232 exit from the KXPA100 when he is ON ?

Thanks for any help !

Best season's greetings to everybody on the list

73 de Chris / F6FTB

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Edward R Cole

Re: Powering a K3s from a battery?

In reply to this post by Juliean Galak

Wes,

So you are saying all of us with K3/10 should never run at 10w+
because the LPA is a terrible producer of IMD? Does that also apply
to the KX3 which is also a 10-12w radio (160-24m)?

I'm finding that hard to swallow considering the QRP background of
the Elecraft owners.

I note the topic started about using a battery but you cite this is
still true at 14v regulated supply.

Or are you saying this only about running the HPA at 10w? (which I do
not have). I thought the HPA switched off below a set power level
(again, not something I need to know since I do not have a HPA).

Wayne you want to respond on this?

I'd like to think I did blow a whole lot a money on a defective
design (I bought both the K3/10 and KX3).

Oh HNY!
73, Ed - KL7UW
considering the KXPA100 a after Christmas purchase

Date: Wed, 30 Dec 2015 09:19:41 -0700
From: "Wes (N7WS)" <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] Powering a K3s from a battery?
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=utf-8; format=flowed

I'm not missing a thing.

All I'm saying is that if you run the LPA at 10-12 watts, according to my
measurements*, the IMD is pretty bad. If you have an HPA, then after it's
kicked in, (13W in my K3S) the LPA is running at greatly reduced
power. I don't
believe Elecraft has to change anything. Guys with a KPA3(A) just
need to avoid
the grey area of 10-15W.

Wes N7WS

*Remarkably, IMD measurements I made on my K3S using modest equipment
correlated
within 1dB or less to measurements made by Elecraft, on the same radio.

On 12/30/2015 12:08 AM, Jim Brown wrote:
> Something you're missing, Wes. The 100W amp doesn't kick in until
you ask for
> more than about 14W. So at 11-12W, you're seeing the IMD of the QRP exciter
> stage running near it's maximum power.
>
> I'm wondering if it might be practical to modify the control
software so that
> the 100W amp kicks in at lower power levels. Are there other consequences?
> Wayne?
>
> 73, Jim K9YC
>
> On Tue,12/29/2015 8:19 PM, Wes (N7WS) wrote:
>> Something else to note, even at 14V, running a K3 at 11-12 watts
is a disaster.
>

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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Wes (N7WS)

Re: Powering a K3s from a battery?

Ed,

Gosh, I didn't mean to get the faithful all riled up. Drop me an email address.

Wes

On 12/30/2015 3:13 PM, Edward R Cole wrote:

> Wes,
>
> So you are saying all of us with K3/10 should never run at 10w+ because the
> LPA is a terrible producer of IMD? Does that also apply to the KX3 which is
> also a 10-12w radio (160-24m)?
>
> I'm finding that hard to swallow considering the QRP background of the
> Elecraft owners.
>
> I note the topic started about using a battery but you cite this is still true
> at 14v regulated supply.
>
> Or are you saying this only about running the HPA at 10w? (which I do not
> have). I thought the HPA switched off below a set power level (again, not
> something I need to know since I do not have a HPA).
>
> Wayne you want to respond on this?
>
> I'd like to think I did blow a whole lot a money on a defective design (I
> bought both the K3/10 and KX3).
>
> Oh HNY!
> 73, Ed - KL7UW
> considering the KXPA100 a after Christmas purchase
>
>
> Date: Wed, 30 Dec 2015 09:19:41 -0700
> From: "Wes (N7WS)" <[hidden email]>
> To: [hidden email]
> Subject: Re: [Elecraft] Powering a K3s from a battery?
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> I'm not missing a thing.
>
> All I'm saying is that if you run the LPA at 10-12 watts, according to my
> measurements*, the IMD is pretty bad. If you have an HPA, then after it's
> kicked in, (13W in my K3S) the LPA is running at greatly reduced power. I don't
> believe Elecraft has to change anything. Guys with a KPA3(A) just need to avoid
> the grey area of 10-15W.
>
> Wes N7WS
>
> *Remarkably, IMD measurements I made on my K3S using modest equipment correlated
> within 1dB or less to measurements made by Elecraft, on the same radio.
>
> On 12/30/2015 12:08 AM, Jim Brown wrote:
> > Something you're missing, Wes. The 100W amp doesn't kick in until you ask for
> > more than about 14W. So at 11-12W, you're seeing the IMD of the QRP exciter
> > stage running near it's maximum power.
> >
> > I'm wondering if it might be practical to modify the control software so that
> > the 100W amp kicks in at lower power levels. Are there other consequences?
> > Wayne?
> >
> > 73, Jim K9YC
> >
> > On Tue,12/29/2015 8:19 PM, Wes (N7WS) wrote:
> >> Something else to note, even at 14V, running a K3 at 11-12 watts is a
> disaster.
> >
>
>
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

k6dgw

Re: Powering a K3s from a battery?

In reply to this post by Edward R Cole

Ummm ... I don't think that was what was suggested at all. I read the
post to be an observation of a *relative* condition. All amplifiers [at
least that I've ever encountered] exhibit increasing distortion near
their rated power limits. I've always assumed that's why distortion
numbers are almost always accompanied by the power when the measurements
were taken.

My K3/100 is a K3/10 below about 15 watts ... the 100 W amplifier
switches out of the circuit. I think all that the post was trying to
point out is that, from 100 W downward, the distortion will decrease
*until* the KPA3 cuts out. At that point, the LP amplifier/exciter is
near it's max power, and it's distortion will probably be higher than
the values from the KPA3 operating just above that power. In any case,
absolute distortion from a K3/<anything> is still among the lowest in
the marketplace.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 12/30/2015 2:13 PM, Edward R Cole wrote:
> Wes,
>
> So you are saying all of us with K3/10 should never run at 10w+ because
> the LPA is a terrible producer of IMD? Does that also apply to the KX3
> which is also a 10-12w radio (160-24m)?
>
> I'm finding that hard to swallow considering the QRP background of the
> Elecraft owners.

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Don Wilhelm-4

Re: Elecraft gear relative IMD

I think it is time to change the subject line (and I did). The original
question was about increased IMD with lower power supply voltages.
It has now morphed into the relative IMD at different power levels with
higher (normal) power supply voltages.

Whatever the actual IMD of the K3/K3S at any power level, the
information I have heard from contesters and DXers is that the Elecraft
gear is has lower IMD than most other transceivers. We have heard
testimony to that repeatedly from Field Day setups and DXpeditions where
there are multiple transceivers operating in close proximity to other
stations. When station A cannot hear anything interfering when station
B transmits, that is a good thing. Elecraft gear can do that while many
other manufacturer's transceivers cannot say the same thing.

What we do know is that higher power supply voltages provide better IMD
figures, and since the Elecraft gear is rated for up to 15 volts, we
will achieve better IMD performance if the power supply is cranked up to
provide a voltage just a bit below 15 volts.

73,
Don W3FPR

On 12/30/2015 6:52 PM, Fred Jensen wrote:

> Ummm ... I don't think that was what was suggested at all. I read the
> post to be an observation of a *relative* condition. All amplifiers
> [at least that I've ever encountered] exhibit increasing distortion
> near their rated power limits. I've always assumed that's why
> distortion numbers are almost always accompanied by the power when the
> measurements were taken.
>
> My K3/100 is a K3/10 below about 15 watts ... the 100 W amplifier
> switches out of the circuit. I think all that the post was trying to
> point out is that, from 100 W downward, the distortion will decrease
> *until* the KPA3 cuts out. At that point, the LP amplifier/exciter is
> near it's max power, and it's distortion will probably be higher than
> the values from the KPA3 operating just above that power. In any
> case, absolute distortion from a K3/<anything> is still among the
> lowest in the marketplace.
>

Mike Maloney

Re: Elecraft gear relative IMD

Who has some measured 2 tone IMD test figures for an actual K3/K3S at full and reduced power levels and at supply voltage levels between 12-15 volts?Must assume the Harmonic and Spurious Outputs exceed 50dB below carrier @ 100W within ham bands as per Elecraft manual specs. HOW much better than 50dB with above variables is the question? Can someone share these figures?
73,Mike AC5P

On Wednesday, December 30, 2015 6:39 PM, Don Wilhelm <[hidden email]> wrote:

I think it is time to change the subject line (and I did). The original
question was about increased IMD with lower power supply voltages.
It has now morphed into the relative IMD at different power levels with
higher (normal) power supply voltages.

Whatever the actual IMD of the K3/K3S at any power level, the
information I have heard from contesters and DXers is that the Elecraft
gear is has lower IMD than most other transceivers. We have heard
testimony to that repeatedly from Field Day setups and DXpeditions where
there are multiple transceivers operating in close proximity to other
stations. When station A cannot hear anything interfering when station
B transmits, that is a good thing. Elecraft gear can do that while many
other manufacturer's transceivers cannot say the same thing.

What we do know is that higher power supply voltages provide better IMD
figures, and since the Elecraft gear is rated for up to 15 volts, we
will achieve better IMD performance if the power supply is cranked up to
provide a voltage just a bit below 15 volts.

73,
Don W3FPR

On 12/30/2015 6:52 PM, Fred Jensen wrote:

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Wes (N7WS)

Re: Elecraft gear relative IMD

I have some of those data, but not all. This conversation had already given me
the idea that I should remeasure the two radios' IMD at different voltages, as
well as vs power vs. frequency.

But you are asking for two different things, IMD and spurious signals. With a
nominal "12 V" radio, absent some fancy feedback, IMD products will never be
down 50 dB in this lifetime, even when using the "cheating" (IMHO)
dB-relative-to-PEP method.

Looking for and measuring spurs, other than harmonics, is a job for a spectrum
analyzer, something I lack.

On 12/30/2015 8:09 PM, [hidden email] wrote:

> Who has some measured 2 tone IMD test figures for an actual K3/K3S at full and reduced power levels and at supply voltage levels between 12-15 volts?Must assume the Harmonic and Spurious Outputs exceed 50dB below carrier @ 100W within ham bands as per Elecraft manual specs. HOW much better than 50dB with above variables is the question? Can someone share these figures?
> 73,Mike AC5P
>
>
> On Wednesday, December 30, 2015 6:39 PM, Don Wilhelm<[hidden email]> wrote:
>
>
> I think it is time to change the subject line (and I did). The original
> question was about increased IMD with lower power supply voltages.
> It has now morphed into the relative IMD at different power levels with
> higher (normal) power supply voltages.
>
> Whatever the actual IMD of the K3/K3S at any power level, the
> information I have heard from contesters and DXers is that the Elecraft
> gear is has lower IMD than most other transceivers. We have heard
> testimony to that repeatedly from Field Day setups and DXpeditions where
> there are multiple transceivers operating in close proximity to other
> stations. When station A cannot hear anything interfering when station
> B transmits, that is a good thing. Elecraft gear can do that while many
> other manufacturer's transceivers cannot say the same thing.
>
> What we do know is that higher power supply voltages provide better IMD
> figures, and since the Elecraft gear is rated for up to 15 volts, we
> will achieve better IMD performance if the power supply is cranked up to
> provide a voltage just a bit below 15 volts.
>
> 73,
> Don W3FPR
>
> On 12/30/2015 6:52 PM, Fred Jensen wrote:
>> Ummm ... I don't think that was what was suggested at all. I read the
>> post to be an observation of a *relative* condition. All amplifiers
>> [at least that I've ever encountered] exhibit increasing distortion
>> near their rated power limits. I've always assumed that's why
>> distortion numbers are almost always accompanied by the power when the
>> measurements were taken.
>>
>> My K3/100 is a K3/10 below about 15 watts ... the 100 W amplifier
>> switches out of the circuit. I think all that the post was trying to
>> point out is that, from 100 W downward, the distortion will decrease
>> *until* the KPA3 cuts out. At that point, the LP amplifier/exciter is
>> near it's max power, and it's distortion will probably be higher than
>> the values from the KPA3 operating just above that power. In any
>> case, absolute distortion from a K3/<anything> is still among the
>> lowest in the marketplace.
>>
> ______________________________________________________________
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>
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>
>
>
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Kevin Stover

Re: Elecraft gear relative IMD

In reply to this post by Mike Maloney

Two different animals.
Harmonics and spurs are regulated by the FCC to be at least -43dB down
on HF and -60dB down on 6 meters.
The K3(s) meets those specs easily as evidenced by a couple of QST reviews.
IMD is not regulated I think because most hams don't have the test
equipment to pull it off accurately.

All of this IMD hullabaloo would quickly go away if the manufacturers
would switch from 12V finals to 50V finals or used pre-distortion of
some sort. How much will Ham's pay to clean up the IMD problem when the
FCC doesn't regulate it?

On 12/30/2015 9:09 PM, [hidden email] wrote:
> Who has some measured 2 tone IMD test figures for an actual K3/K3S at full and reduced power levels and at supply voltage levels between 12-15 volts?Must assume the Harmonic and Spurious Outputs exceed 50dB below carrier @ 100W within ham bands as per Elecraft manual specs. HOW much better than 50dB with above variables is the question? Can someone share these figures?
> 73,Mike AC5P
>

--
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441

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N1EU

Re: Elecraft gear relative IMD

Pre-distortion dsp processing on the tx signal makes a DRAMATIC
improvement. Check out the tx spectrum and waterfall outside the filter
passband on this video before and after W1AEX switches in pre-distortion at
34 seconds in: https://www.youtube.com/watch?v=MCm3mKHyuAo

73/HNY,
Barry N1EU

On Thu, Dec 31, 2015 at 7:34 AM, Kevin Stover <[hidden email]>
wrote:

> Two different animals.
> Harmonics and spurs are regulated by the FCC to be at least -43dB down on
> HF and -60dB down on 6 meters.
> The K3(s) meets those specs easily as evidenced by a couple of QST reviews.
> IMD is not regulated I think because most hams don't have the test
> equipment to pull it off accurately.
>
> All of this IMD hullabaloo would quickly go away if the manufacturers
> would switch from 12V finals to 50V finals or used pre-distortion of some
> sort. How much will Ham's pay to clean up the IMD problem when the FCC
> doesn't regulate it?
>
>
> On 12/30/2015 9:09 PM, [hidden email] wrote:
>
>> Who has some measured 2 tone IMD test figures for an actual K3/K3S at
>> full and reduced power levels and at supply voltage levels between 12-15
>> volts?Must assume the Harmonic and Spurious Outputs exceed 50dB below
>> carrier @ 100W within ham bands as per Elecraft manual specs. HOW much
>> better than 50dB with above variables is the question? Can someone share
>> these figures?
>> 73,Mike AC5P
>>
>>
>
> --
> R. Kevin Stover
> AC0H
> ARRL
> FISTS #11993
> SKCC #215
> NAQCC #3441
>
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
> ______________________________________________________________
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>