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TX Power

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G3XVR

TX Power

I have a K3S/100 and I can get full power when the mode is set to CW, but if I change it to CW REV I only get a small amount of RF output. Have I set something wrong?

Danny, G3XVR

G3XVR

Re: TX Power

The problem is different on 80M and 6M. On 80M I can get full power on Normal CW, but not much on CW Rev. The opposite is true on 6M. However, if I reduce the bandwidth so that FL4 is selected instead on FL2 I can get full power on both bands and on both CW modes. If I select Split and use the sub-RX, I can get full power on both bands, using both filters on both CW modes. I sounds like a filter offset problem. I've reset it to what the sticker inside the K3S says (-97 for main RX and -79 for sub RX). I assume these figures are in Hz. Is there any way of confirming that there is an offset problem?

Danny, G3XVR

G3XVR

Re: TX Power

In reply to this post by G3XVR

Guy Olinger K2AV

Re: TX Power

Sounds like your roofing filter configuration is not done correctly
(especially check offsets), or your filter placement does not match
your definitions. Something of that sort. This stuff is usually set in
the K3 utility.

73, Guy K2AV

On Sun, Sep 13, 2015 at 4:16 PM, G3XVR <[hidden email]> wrote:

> The problem is different on 80M and 6M. On 80M I can get full power on
> Normal CW, but not much on CW Rev. The opposite is true on 6M. However, if
> I reduce the bandwidth so that FL4 is selected instead on FL2 I can get full
> power on both bands and on both CW modes. If I select Split and use the
> sub-RX, I can get full power on both bands, using both filters on both CW
> modes. I sounds like a filter offset problem. I've reset it to what the
> sticker inside the K3S says (-97 for main RX and -79 for sub RX). I assume
> these figures are in Hz. Is there any way of confirming that there is an
> offset problem?
>
> Danny, G3XVR
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/TX-Power-tp7607570p7607580.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Message delivered to [hidden email]

Joe Subich, W4TV-4

Re: TX Power

In reply to this post by G3XVR

On 9/13/2015 4:16 PM, G3XVR wrote:
> The problem is different on 80M and 6M. On 80M I can get full power
> on Normal CW, but not much on CW Rev. The opposite is true on 6M.
> However, if I reduce the bandwidth so that FL4 is selected instead
> on FL2 I can get full power on both bands and on both CW modes.

CW TX and SSB TX should use the 2.7 or 2.8 KHz filter. Only AM TX and
FM TX should use other (wider) filters. What is the bandwidth of your
FL2 and FL4?

73,

... Joe, W4TV

On 9/13/2015 4:16 PM, G3XVR wrote:

G3XVR

Re: TX Power

FL2 is 2.7kHz and FL4 is 400Hz on both receivers. The CONFIG is set to
transmit CW using the 2.7kHz filter, but the power output seems to vary on
the main RX when I narrow the receive bandwidth down to 400Hz where FL4
kicks in. I first discovered this yesterday when trying to set up SSB.
After following all the setting instructions I didn't get much RF out when I
went to normal TX and full power. I didn't try this with the opposite
sideband, but I now suspect that one sideband will be good and the other
will be poor.

When I get back tonight I will check the filter responses using band noise
and a program called Visual Analyser from Sillanum Software which allows me
to plot both the main and sub-RX frequency responses at the same time.

Danny, G3XVR

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Joe
Subich, W4TV
Sent: 13 September 2015 23:37
To: [hidden email]
Subject: Re: [Elecraft] TX Power

On 9/13/2015 4:16 PM, G3XVR wrote:
> The problem is different on 80M and 6M. On 80M I can get full power on
> Normal CW, but not much on CW Rev. The opposite is true on 6M.
> However, if I reduce the bandwidth so that FL4 is selected instead on
> FL2 I can get full power on both bands and on both CW modes.

CW TX and SSB TX should use the 2.7 or 2.8 KHz filter. Only AM TX and FM TX
should use other (wider) filters. What is the bandwidth of your
FL2 and FL4?

73,

... Joe, W4TV

On 9/13/2015 4:16 PM, G3XVR wrote:

> The problem is different on 80M and 6M. On 80M I can get full power
> on Normal CW, but not much on CW Rev. The opposite is true on 6M.
> However, if I reduce the bandwidth so that FL4 is selected instead on
> FL2 I can get full power on both bands and on both CW modes. If I
> select Split and use the sub-RX, I can get full power on both bands,
> using both filters on both CW modes. I sounds like a filter offset
> problem. I've reset it to what the sticker inside the K3S says (-97
> for main RX and -79 for sub RX). I assume these figures are in Hz.
> Is there any way of confirming that there is an offset problem?
>
> Danny, G3XVR
>
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/TX-Power-tp7607570p7607580.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> 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]

G3XVR

Re: TX Power

In reply to this post by G3XVR

I think I've got it sorted now. The filter offsets were marked as -79 and -97. I took this to be Hz, but by looking at the noise spectrum on an analyser I needed to set the offsets to -0.97 and -0.79.

I've still got an odd effect on SSB. After setting it up according to the handbook, things appear OK when I press the PTT and start talking, but if I adjust the Mic or CMP up or down by "1" the monitor level jumps up, but settles back down again next time I press the PTT. Does anyone else notice this?

Danny, G3XVR