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Input vs. output power question

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Bekir Kemal Ataman

Input vs. output power question

I intend to join the IARU HF contest in the QRP category (i.e. 5 watts output).

I have got a RG58 going to my inverted V antenna. The coax is about 45
meters in length (roughly 135 feet).

How much power should I request from my K2 to get 5 watts output from the
antenna?

73!
de TA2RX

----------------------------------
Bekir Kemal Ataman
ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>

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Bob Nielsen

Re: Input vs. output power question

On Jul 6, 2006, at 1:37 AM, Bekir Kemal Ataman wrote:

The 5 watt power level for QRP refers to the output of the
transmitter, not the antenna.

73 - Bob, N7XY

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Stephen W. Kercel

Re: Input vs. output power question

In reply to this post by Bekir Kemal Ataman

Bekir:

The technical answer to your question is as follows. The loss of your
coax depends on the SWR and frequency. 45 meters of CQ125 (a high
quality version of RG-58) at 14 MHz with an SWR of 2:1 has an
idealized loss of 2.7 dB. If you request 9.5 Watts on your K2, you
would get close to 5 Watts at the antenna.

There is an excellent coax loss calculator at:

http://www.ocarc.ca/coax.htm

HOWEVER, please note N7XY's post. As with virtually all contests, the
IARU contest counts QRP as 5 Watts at the transmitter output rather
than the antenna input.

K2s tends to heat up a bit (with a consequent rise in power out)
after the first few seconds of operation. I find that I need to set
my requested power at 4.5 Watts to assure 5 watts after the first few
characters on CW. Other list members tell me that this is typical
behavior of normally functioning K2s.

Good luck in IARU. Perhaps I'll see you there.

73,

Steve Kercel
AA4AK

At 04:37 AM 7/6/2006, Bekir Kemal Ataman wrote:

>I intend to join the IARU HF contest in the QRP category (i.e. 5
>watts output).
>
>I have got a RG58 going to my inverted V antenna. The coax is about 45
>meters in length (roughly 135 feet).
>
>How much power should I request from my K2 to get 5 watts output from the
>antenna?
>
>73!
>de TA2RX
>
>----------------------------------
>Bekir Kemal Ataman
>ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>
>
>
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com

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n6wg

Re: Input vs. output power question

In reply to this post by Bekir Kemal Ataman

You should request 5w, as the rules call for 5w from the transmitter, not
the antenna.
Good luck. Hope to hear you and work you.
73, Bob N6WG/qrp

----- Original Message -----
From: "Bekir Kemal Ataman" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, July 06, 2006 1:37 AM
Subject: [Elecraft] Input vs. output power question

> I intend to join the IARU HF contest in the QRP category (i.e. 5 watts
output).

>
> I have got a RG58 going to my inverted V antenna. The coax is about 45
> meters in length (roughly 135 feet).
>
> How much power should I request from my K2 to get 5 watts output from the
> antenna?
>
> 73!
> de TA2RX
>
> ----------------------------------
> Bekir Kemal Ataman
> ArchiMac BBS Sysop & Webmaster <http://www.archimac.org/>
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

Stephen W. Kercel

K2 Audio Output

In reply to this post by Stephen W. Kercel

Does the K2 produce sufficient audio power to drive a set of Bose
Quiet Comfort 2 noise cancelling headphones?

Has anyone on the list tried Bose Quiet Comfort 2 noise cancelling
headphones with a K2?

73

Steve Kercel
AA4AK

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Chuck Gehring

RE: K2 Audio Output

Steve Kercel
AA4AK wrote:
"Does the K2 produce sufficient audio power to drive a set of Bose
Quiet Comfort 2 noise cancelling headphones?

Has anyone on the list tried Bose Quiet Comfort 2 noise cancelling
headphones with a K2?"

Steve,
I use the Bose QuietComfort 2 noise cancelling headphones all the time with
my K2. They work great.

73 K2CG
Chuck Gehring
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