K3 H-Mode Mixer Main & Sub RX plus other mods

[I7SWX]

Hi All,

I like to inform you that following the K3 1st mixer replacement with a 2T H-Mode Mixer, as previously announced,  a 2T H-Mode Mixer is now available for the Sub RX.

Following K3 owners request, a mod relative to a diplexer termination fot the xtal filters bank is available. This is made to reduce filters IMD due to change of impedance of the HAGC Q1 amplifier.

Also, to reduce possible am/phase modulation of VCO a  PSU filter  is made available.

For any additional information please e-mail

73

Gian
I7SWX
______________________________________________________________
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

[Geoffrey Mackenzie-Kennedy-3]

Hi Gian,

Did you find that your diplexer termination for the filters also prevented
the changing input impedance of HAGC controlled amp Q1 from changing the
Group Delay Variations of the filters, especially the narrower filters?

My apology for not replying to your last email, will explain off-list.

73,
Geoff
LX2AO



On May 14, 2012 at 21:57 +0200, Giancarlo Moda wrote:

<snip>


> Following K3 owners request, a mod relative to a diplexer termination fot
> the xtal filters bank is available. This is made to reduce filters IMD due
> to change of impedance of the
> HAGC Q1 amplifier.


______________________________________________________________
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

[I7SWX]

Hi Geoff,

thanks for your question. The diplexer that includes an attenuator, does some stabilization for the filters. The Amplifier still changes impedance as Idss current is changing due to HAGC action.

No apology, thanks

Best 73

Gian
I7SWX

>________________________________
> Da: Geoffrey Mackenzie-Kennedy <[hidden email]>
>A: Giancarlo Moda <[hidden email]>
>Cc: Elecraft Discussion List <[hidden email]>
>Inviato: Lunedì 14 Maggio 2012 22:56
>Oggetto: Re: [Elecraft] K3 H-Mode Mixer Main & Sub RX plus other mods
>
>Hi Gian,
>
>Did you find that your diplexer termination for the filters also prevented the changing input impedance of HAGC controlled amp Q1 from changing the Group Delay Variations of the filters, especially the narrower filters?
>
>My apology for not replying to your last email, will explain off-list.
>
>73,
>Geoff
>LX2AO
>
>
>
>On May 14, 2012 at 21:57 +0200, Giancarlo Moda wrote:
>
><snip>
>
>
>> Following K3 owners request, a mod relative to a diplexer termination fot the xtal filters bank is available. This is made to reduce filters IMD due to change of impedance of the
>> HAGC Q1 amplifier.
>
>
>
>
>

______________________________________________________________
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