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Operating in cold weather

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Joe Ford

Operating in cold weather

Hello Elecrafters, I have a little problem and would appreciate some
advice.

My ham shack is in a room which is separated from the main house.
Consequently, it does not receive heat from the main house and during
this cold weather is only heated when I am in the room and even then I
don't get it very warm. I normally only have an hour or so in the
evenings for operating. I dress warm, and, fortunately I'm in Alabama
where winters are relatively mild.

Well I have almost completed construction of the KPA100 and planned to
power it with an Alinco switching supply. I was using this supply with
my K2 on a cold morning recently and almost as soon as I powered up it
notified me my battery was low (not on battery). I looked at the
Alinco's meter and the voltage was showing just over 10V when it should
have been 13.8.

First question: Am I correct in attributing this drop in voltage to the
cold? I think it was about 45 degrees in the room at that time. I also
have an Astron RS-20 which did not show a similar voltage drop, leading
me to this conclusion. I can use the Astron to power the KPA100 but will
need another supply for the K2. Second question: Can someone suggest a
smaller supply to use with the K2 which will not suffer in the cold
(most of the small ones seem to be switchers)? Or, final question, Is it
really necessary to use separate supplies for the K2 and KPA or
could/would the Astron power both.

Thanks in advance for any assistance.

Joe
K4NVJ
K2#4155
K1#764

"LONG LIVE ELECRAFT'

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Bob Nielsen

Re: Operating in cold weather

On Fri, Jan 14, 2005 at 08:57:08PM -0600, Joe Ford wrote:

> Hello Elecrafters, I have a little problem and would appreciate some
> advice.
>
> My ham shack is in a room which is separated from the main house.
> Consequently, it does not receive heat from the main house and during
> this cold weather is only heated when I am in the room and even then I
> don't get it very warm. I normally only have an hour or so in the
> evenings for operating. I dress warm, and, fortunately I'm in Alabama
> where winters are relatively mild.
>
> Well I have almost completed construction of the KPA100 and planned to
> power it with an Alinco switching supply. I was using this supply with
> my K2 on a cold morning recently and almost as soon as I powered up it
> notified me my battery was low (not on battery). I looked at the
> Alinco's meter and the voltage was showing just over 10V when it should
> have been 13.8.
>
> First question: Am I correct in attributing this drop in voltage to the
> cold? I think it was about 45 degrees in the room at that time. I also
> have an Astron RS-20 which did not show a similar voltage drop, leading
> me to this conclusion. I can use the Astron to power the KPA100 but will
> need another supply for the K2. Second question: Can someone suggest a
> smaller supply to use with the K2 which will not suffer in the cold
> (most of the small ones seem to be switchers)? Or, final question, Is it
> really necessary to use separate supplies for the K2 and KPA or
> could/would the Astron power both.
>
> Thanks in advance for any assistance.

My shack is in my unheated garage, which often gets to <50F this time of
year. I use an Alinco supply for my K2, TS-570 (not at the same time)
and packet station and have never had any problems with the voltage
being temperature sensitive. I keep the voltage control on the detent.

Bob, N7XY
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Don Wilhelm-3

Re: Operating in cold weather

In reply to this post by Joe Ford

Joe,

Use the Astron since you said it does not sag voltage with the cold - it
will supply both the base K2 and the KPA100. Connect it only to the APP
connector on the KPA100 and all will be well (you do not need seaprate
supplies for the K2 and the KPA100 unless you have the KPA100 mounted in an
external enclosure without the DC connection to the K2 RF board).

73,
Don W3FPR

----- Original Message -----
From: "Joe Ford" <[hidden email]>
To: <[hidden email]>
Sent: Friday, January 14, 2005 9:57 PM
Subject: [Elecraft] Operating in cold weather

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Brian Mury-3

Re: Operating in cold weather

In reply to this post by Joe Ford

On Fri, 2005-14-01 at 20:57 -0600, Joe Ford wrote:
> First question: Am I correct in attributing this drop in voltage to the
> cold? I think it was about 45 degrees in the room at that time.

45 degrees is not particularly cold; I wouldn't expect any power supply
to have problems at this temperature. It's easy enough to test: warm it
up, check the voltage, cool it down, check the voltage - repeat a few
times to be sure that the temperature is the cause. Your fridge can do
double duty as a test chamber.

> need another supply for the K2. Second question: Can someone suggest a
> smaller supply to use with the K2 which will not suffer in the cold
> (most of the small ones seem to be switchers)? Or, final question, Is it
> really necessary to use separate supplies for the K2 and KPA or
> could/would the Astron power both.

As Don already said, you don't need a power supply hooked up to the K2's
power connector, only to the KPA100's. If the exception that Don
mentioned applies to you (KPA100 in separate enclosure without a DC
connection to the K2) then you could connect the same supply to both.

--
73, Brian
VE7NGR

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Bill Coleman-2

Re: Operating in cold weather

In reply to this post by Joe Ford

On Jan 14, 2005, at 9:57 PM, Joe Ford wrote:

> My ham shack is in a room which is separated from the main house.
> Consequently, it does not receive heat from the main house and during
> this cold weather is only heated when I am in the room and even then I
> don't get it very warm. I normally only have an hour or so in the
> evenings for operating. I dress warm, and, fortunately I'm in Alabama
> where winters are relatively mild.

Don't walk, but RUN down to your local home improvement store and buy a
small electric space heater. These will make the operating position
much more comfortable.

Barring that, tie the room into the heating system for the house.

I can think of nothing worse than an uncomfortable operating position,
especially indoors.

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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