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K3 going expeditionary

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Ted Edwards W3TB

K3 going expeditionary

I am planning to put my K3 in the car for the upcoming Tennessee QSO Party
so that I can go rover/expeditionary.

With that comes a question: Powering from that accessory socket which
appears limited to 15 amps instead of the 20 amps that the K3 wants at full
power, do I understand right that reducing to 50 watts output and taking
the -3dB will work out in terms of power draw?

In the past, I have done QRP and would like to be a bit louder this time.
Thanks to all who might respond.

--
73 de Ted Edwards, W3TB and GØPWW

and thinking about operating CW:
"Do today what others won't,
so you can do tomorrow what others can't."
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Ed K1EP

Re: K3 going expeditionary

You could do that. I wouldn't advise it for other reasons. Why don't you
measure the current at different power levels when on a power supply? There
is a current display on the radio. The cigarette plug is not directly
connected to the battery. There is likely to be poor connections resulting
in IR losses and other problems.

On Sun, Aug 23, 2020, 14:22 Ted Edwards W3TB <[hidden email]> wrote:

> I am planning to put my K3 in the car for the upcoming Tennessee QSO Party
> so that I can go rover/expeditionary.
>
> With that comes a question: Powering from that accessory socket which
> appears limited to 15 amps instead of the 20 amps that the K3 wants at full
> power, do I understand right that reducing to 50 watts output and taking
> the -3dB will work out in terms of power draw?
>
> In the past, I have done QRP and would like to be a bit louder this time.
> Thanks to all who might respond.
>
> --
> 73 de Ted Edwards, W3TB and GØPWW
>
> and thinking about operating CW:
> "Do today what others won't,
> so you can do tomorrow what others can't."
> ______________________________________________________________
> 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]

George Thornton

Re: K3 going expeditionary

Concur.

The K3 can in my experience be vulnerable to voltage drop which can happen with a questionable power source.

For a rig like the K3 you should draw straight from the battery. You can add some additional protection in a mobile setup by incorporating a voltage regulator In the circuit just before the K3.

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Ed K1EP
Sent: Sunday, August 23, 2020 11:32 AM
To: Ted Edwards W3TB <[hidden email]>
Cc: Elecraft Reflector <[hidden email]>
Subject: Re: [Elecraft] K3 going expeditionary

You could do that. I wouldn't advise it for other reasons. Why don't you measure the current at different power levels when on a power supply? There is a current display on the radio. The cigarette plug is not directly connected to the battery. There is likely to be poor connections resulting in IR losses and other problems.

On Sun, Aug 23, 2020, 14:22 Ted Edwards W3TB <[hidden email]> wrote:

> I am planning to put my K3 in the car for the upcoming Tennessee QSO
> Party so that I can go rover/expeditionary.
>
> With that comes a question: Powering from that accessory socket which
> appears limited to 15 amps instead of the 20 amps that the K3 wants at
> full power, do I understand right that reducing to 50 watts output and
> taking the -3dB will work out in terms of power draw?
>
> In the past, I have done QRP and would like to be a bit louder this time.
> Thanks to all who might respond.
>
> --
> 73 de Ted Edwards, W3TB and GØPWW
>
> and thinking about operating CW:
> "Do today what others won't,
> so you can do tomorrow what others can't."
> ______________________________________________________________
> 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]

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Rick Bates, NK7I

Re: K3 going expeditionary

In reply to this post by Ed K1EP

Not only is the accessory circuit shared with others, it is often loaded
with noises from the electronics in the vehicle. They can harm both
your RX and TX signals.

It takes a little time to run #12 ROMEX (with 40 or 50 A mobile,
self-resetting circuit breakers at the battery to protect the wire,
fuses for radios AT the radios; both positive and negative) but the
returns are worth it. You'll have to remember to turn the K3 OFF each
time you start the engine; the wandering voltage could cause harm or
scramble the settings. Also bond to chassis AT the K3 to keep some RFI
down...

*IF* you have a newer vehicle that measures current draw and charging
rate at the battery (sometimes via the negative pole), you'll want to
use that sensor point for negative connection; not at the battery.

That's the super quick description, to start a foundation of proper set up.

73,
Rick NK7I

On 8/23/2020 11:32 AM, Ed K1EP wrote:

> You could do that. I wouldn't advise it for other reasons. Why don't you
> measure the current at different power levels when on a power supply? There
> is a current display on the radio. The cigarette plug is not directly
> connected to the battery. There is likely to be poor connections resulting
> in IR losses and other problems.
>
> On Sun, Aug 23, 2020, 14:22 Ted Edwards W3TB <[hidden email]> wrote:
>
>> I am planning to put my K3 in the car for the upcoming Tennessee QSO Party
>> so that I can go rover/expeditionary.
>>
>> With that comes a question: Powering from that accessory socket which
>> appears limited to 15 amps instead of the 20 amps that the K3 wants at full
>> power, do I understand right that reducing to 50 watts output and taking
>> the -3dB will work out in terms of power draw?
>>
>> In the past, I have done QRP and would like to be a bit louder this time.
>> Thanks to all who might respond.
>>
>> --
>> 73 de Ted Edwards, W3TB and GØPWW
>>
>> and thinking about operating CW:
>> "Do today what others won't,
>> so you can do tomorrow what others can't."
>> ______________________________________________________________
>> 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]
> ______________________________________________________________
> 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]

AI4NS

Re: K3 going expeditionary

Go to K0BG.com and read everything. His site is probably the best resource
on the internet for mobile operations.

Mike

On Sun, Aug 23, 2020 at 3:17 PM Rick NK7I <[hidden email]> wrote:

> Not only is the accessory circuit shared with others, it is often loaded
> with noises from the electronics in the vehicle. They can harm both
> your RX and TX signals.
>
> It takes a little time to run #12 ROMEX (with 40 or 50 A mobile,
> self-resetting circuit breakers at the battery to protect the wire,
> fuses for radios AT the radios; both positive and negative) but the
> returns are worth it. You'll have to remember to turn the K3 OFF each
> time you start the engine; the wandering voltage could cause harm or
> scramble the settings. Also bond to chassis AT the K3 to keep some RFI
> down...
>
> *IF* you have a newer vehicle that measures current draw and charging
> rate at the battery (sometimes via the negative pole), you'll want to
> use that sensor point for negative connection; not at the battery.
>
> That's the super quick description, to start a foundation of proper set up.
>
> 73,
> Rick NK7I
>
>
> >
> >> I am planning to put my K3 in the car for the upcoming Tennessee QSO
> Party
> >> so that I can go rover/expeditionary.
> >>
> >> With that comes a question: Powering from that accessory socket which
> >> appears limited to 15 amps instead of the 20 amps that the K3 wants at
> full
> >> power, do I understand right that reducing to 50 watts output and taking
> >> the -3dB will work out in terms of power draw?
> >>
> >> In the past, I have done QRP and would like to be a bit louder this
> time.
> >> Thanks to all who might respond.
> >>
> >> --
> >> 73 de Ted Edwards, W3TB and GØPWW
>
>

Clay Autery-2

Re: K3 going expeditionary

In reply to this post by Ed K1EP

IF it were me, I would run two NEW, 10GA or better high strand count
wires (twisted by hand or drill) from the battery to the cabin with
appropriate fuses in BOTH POS and NEG lines, and the Anderson PP
connector on the end.
Ideally, I would also put a SPST switch in the POS (my pref), or a DPST
switch across both leads so that I could turn the power off there for
connection purposes (optional).

This gives you the ability to 1) power the K3 with Key off, engine off
if desired, and 2) gives you a big, shortest run dedicated to the radio.
Additionally, it gives you a twisted pair, AND the ability to put chokes
wherever you might need them to quiet down the power source from
possible noise from the vehicle.

73,

______________________
Clay Autery, KY5G
(318) 518-1389

On 08/23/20 13:32, Ed K1EP wrote:

AI4NS

Re: K3 going expeditionary

Twisting the wires doesn’t do anything.

On Mon, Aug 24, 2020 at 09:28 Clay Autery <[hidden email]> wrote:

> IF it were me, I would run two NEW, 10GA or better high strand count
>
> wires (twisted by hand or drill) from the battery to the cabin with
>
> appropriate fuses in BOTH POS and NEG lines, and the Anderson PP
>
> connector on the end.
>
> Ideally, I would also put a SPST switch in the POS (my pref), or a DPST
>
> switch across both leads so that I could turn the power off there for
>
> connection purposes (optional).
>
>
>
> This gives you the ability to 1) power the K3 with Key off, engine off
>
> if desired, and 2) gives you a big, shortest run dedicated to the radio.
>
> Additionally, it gives you a twisted pair, AND the ability to put chokes
>
> wherever you might need them to quiet down the power source from
>
> possible noise from the vehicle.
>
>
>
> 73,
>
>
>
> ______________________
>
> Clay Autery, KY5G
>
> (318) 518-1389
>
>
>
> On 08/23/20 13:32, Ed K1EP wrote:
>
> > You could do that. I wouldn't advise it for other reasons. Why don't you
>
> > measure the current at different power levels when on a power supply?
> There
>
> > is a current display on the radio. The cigarette plug is not directly
>
> > connected to the battery. There is likely to be poor connections
> resulting
>
> > in IR losses and other problems.
>
> >
>
> > On Sun, Aug 23, 2020, 14:22 Ted Edwards W3TB <[hidden email]> wrote:
>
> >
>
> >> I am planning to put my K3 in the car for the upcoming Tennessee QSO
> Party
>
> >> so that I can go rover/expeditionary.
>
> >>
>
> >> With that comes a question: Powering from that accessory socket which
>
> >> appears limited to 15 amps instead of the 20 amps that the K3 wants at
> full
>
> >> power, do I understand right that reducing to 50 watts output and taking
>
> >> the -3dB will work out in terms of power draw?
>
> >>
>
> >> In the past, I have done QRP and would like to be a bit louder this
> time.
>
> >> Thanks to all who might respond.
>
> >>
>
> >> --
>
> >> 73 de Ted Edwards, W3TB and GØPWW
>
> >>
>
> >> and thinking about operating CW:
>
> >> "Do today what others won't,
>
> >> so you can do tomorrow what others can't."
>
> >> ______________________________________________________________
>
> >> 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]
>
> > ______________________________________________________________
>
> > 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]
>
> ______________________________________________________________
>
> 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]

Jim Brown-10

Re: K3 going expeditionary

On 8/24/2020 8:11 AM, Mike Short wrote:
> Twisting the wires doesn’t do anything.

Au contraire! Twisting provides an excellent rejection of of crosstalk,
including RFI. Have you not noticed that CAT5/6/7 cables are four
tightly twisted pairs, each with a slightly different twist ratio, all
very well engineered to minimize crosstalk between them? Twisted pair
has been widely used in pro audio for a century. Beginning with the
earliest days of telephony, their cables were run on the same poles as
AC, with a crossover every other pole to provide the twist (the only
rejection needed was at 60 Hz, 50 Hz in EU).

Those who make and sell zip cord, glorified or otherwise, as speaker
cable are ignorant of this. When I lived in Chicago, I solved a lot of
RFI to home stereo systems by replacing such with twisted pair.

73, Jim K9YC

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AI4NS

Re: K3 going expeditionary

RFI on audio, agreed. Noise on DC, not so much. Routing is the most
important factor for DC power. It is hard to get enough turns on the proper
size wire to make a difference.

On Mon, Aug 24, 2020 at 10:24 AM Jim Brown <[hidden email]>
wrote:

> On 8/24/2020 8:11 AM, Mike Short wrote:
> > Twisting the wires doesn’t do anything.
>
> Au contraire! Twisting provides an excellent rejection of of crosstalk,
> including RFI. Have you not noticed that CAT5/6/7 cables are four
> tightly twisted pairs, each with a slightly different twist ratio, all
> very well engineered to minimize crosstalk between them? Twisted pair
> has been widely used in pro audio for a century. Beginning with the
> earliest days of telephony, their cables were run on the same poles as
> AC, with a crossover every other pole to provide the twist (the only
> rejection needed was at 60 Hz, 50 Hz in EU).
>
> Those who make and sell zip cord, glorified or otherwise, as speaker
> cable are ignorant of this. When I lived in Chicago, I solved a lot of
> RFI to home stereo systems by replacing such with twisted pair.
>
> 73, Jim K9YC
>
>
> ______________________________________________________________
> 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]

Jim Brown-10

Re: K3 going expeditionary

In reply to this post by Jim Brown-10

Of course it applies. Mother nature does not pay attention to what we
CALL things. It is quite common for DC and mains power to carry AF and
RF currents. That's how most noise is radiated -- as a common mode
signal on cables connected to equipment that includes noise sources.

BTW -- as Vice-Chair of AES Standards Committee for 20 years, I HAVE
studied this stuff extensively, along with colleagues around the world
with excellent engineering chops.

73, Jim K9YC

On 8/24/2020 8:47 AM, Rich NE1EE wrote:
> Well...this reply covers a lot of ground. We are addressing power lines running DC, not signal lines with high freq signals? Even audio moves the question from DC to audio frequencies. I have seen coupling of AC to very long DC signal wires (current loop or voltage sensors, such as RTD), but I am addressing hundreds of meters. I have not looked at the effect for shorter wires running essentially DC, in an environment where there are high freq signals to couple. But then, I included the inline filter from the start, so I don't know if it did any good or not. For $30 (I think?), it was not worth thinking about. I'm familiar with twisting, crosstalk, etc, for signals, but not sure that it translates to DC power supplies of short length.

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Ted Edwards W3TB

Re: K3 going expeditionary

My thanks to everybody.
It is rather overwhelming for just a Sunday afternoon of portable operation
in remote counties powered by the car.
I will really want to keep simple in those terms.

Reading through all this several times. Thanks to all who contributed.

On Mon, Aug 24, 2020 at 11:26 AM Jim Brown <[hidden email]>
wrote:

> Of course it applies. Mother nature does not pay attention to what we
> CALL things. It is quite common for DC and mains power to carry AF and
> RF currents. That's how most noise is radiated -- as a common mode
> signal on cables connected to equipment that includes noise sources.
>
> BTW -- as Vice-Chair of AES Standards Committee for 20 years, I HAVE
> studied this stuff extensively, along with colleagues around the world
> with excellent engineering chops.
>
> 73, Jim K9YC
>
> On 8/24/2020 8:47 AM, Rich NE1EE wrote:
> > Well...this reply covers a lot of ground. We are addressing power lines
> running DC, not signal lines with high freq signals? Even audio moves the
> question from DC to audio frequencies. I have seen coupling of AC to very
> long DC signal wires (current loop or voltage sensors, such as RTD), but I
> am addressing hundreds of meters. I have not looked at the effect for
> shorter wires running essentially DC, in an environment where there are
> high freq signals to couple. But then, I included the inline filter from
> the start, so I don't know if it did any good or not. For $30 (I think?),
> it was not worth thinking about. I'm familiar with twisting, crosstalk,
> etc, for signals, but not sure that it translates to DC power supplies of
> short length.
>
> ______________________________________________________________
> 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]
>

--
73 de Ted Edwards, W3TB and GØPWW

and thinking about operating CW:
"Do today what others won't,
so you can do tomorrow what others can't."
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Jim Brown-10

Re: K3 going expeditionary

On 8/24/2020 11:56 AM, Ted Edwards W3TB wrote:
> My thanks to everybody.
> It is rather overwhelming for just a Sunday afternoon of portable
> operation in remote counties powered by the car.
> I will really want to keep simple in those terms.

In that contest, I'd simply use smaller gauge twisted pair.

73, Jim K9YC
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Jim Brown-10

Re: K3 going expeditionary

In reply to this post by AI4NS

On 8/24/2020 9:03 AM, Mike Short wrote:
> RFI on audio, agreed. Noise on DC, not so much. Routing is the most
> important factor for DC power. It is hard to get enough turns on the
> proper size wire to make a difference.

Yes, routing is important. But what you're missing is that a major issue
is RF getting into the vehicle's computers, and the RF noise from those
computers getting into our DC wiring. I learned this the hard way with
my 2006 big Toyota SUV. Calling CQ barefoot on 20M SSB put the car's
computer into "limp-home" mode in the NV high desert. Had to disconnect
main battery terminals to reboot the computer to get home.

73, Jim K9YC

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k6dgw

Re: K3 going expeditionary

"Had to disconnect main battery terminals to reboot the computer to get
home." 440 in my old Ford Ranger just cancelled the cruise control if
it was engaged. Just like Windoze Jim!

Glad your house has survived ... really hoping for Bob's.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/24/2020 3:45 PM, Jim Brown wrote:

> On 8/24/2020 9:03 AM, Mike Short wrote:
>> RFI on audio, agreed. Noise on DC, not so much. Routing is the most
>> important factor for DC power. It is hard to get enough turns on the
>> proper size wire to make a difference.
>
> Yes, routing is important. But what you're missing is that a major
> issue is RF getting into the vehicle's computers, and the RF noise
> from those computers getting into our DC wiring. I learned this the
> hard way with my 2006 big Toyota SUV. Calling CQ barefoot on 20M SSB
> put the car's computer into "limp-home" mode in the NV high desert.
> Had to disconnect main battery terminals to reboot the computer to get
> home.
>
> 73, Jim K9YC

K8TE

Re: K3 going expeditionary

In reply to this post by George Thornton

As is often the case, connecting directly to the battery for the negative
lead is misunderstood. In today's world, it depends. The Battery
Monitoring System (BMS) is a big deal in most of today's vehicles. To
function properly, we should NOT CONNECT to the battery's negative terminal.
That used to be good advice and may be bad today. See:
http://www.k0bg.com/wiring.html.

As Alan, K0BG, states, "It WORKs." often means "WithOut Real Knowledge. Not
all advice on this reflector is current or correct. Caveat emptor.

BTW, using vehicle wiring for a 100 Watt radio can lead to losing the
vehicle due to fire! I have seen the pictures.

I worked in the Gulf of Mexico oil fields. I swatted down with gusto the
idea of "It's only temporary." and "I can do it quickly." Do it right, even
if it's for an hour or a weekend.

73, Bill, K8TE

--
Sent from: http://elecraft.365791.n2.nabble.com/
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