K3 roofing filters: Important ordering information

[wayne burdick]

If you wish to transmit in wide-band modes (AM, ESSB, FM), you'll need
to have the corresponding wide filter bandwidths installed in the main
receiver. This is because the transmitter and main receiver share the
same circuitry. By "wide", I mean:

   AM or ESSB    KFL3A-6.0  (6 kHz)
   FM            KFL3B-FM   (approx. 13 kHz)

Of course you can also install wide filters on the subreceiver.

This information is being added to the order form. My apologies for any
inconvenience due to not explaining this sooner.

73,
Wayne
N6KR


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[Doug Faunt N6TQS [phone]]

Does that mean that if we substitute the 2.8kHz 8 pole filter for the
2.7kHz 5 pole then we'll get a slightly cleaner transmit signal, too?

73, doug

   From: wayne burdick <[hidden email]>
   Date: Tue, 1 May 2007 10:21:38 -0700

   If you wish to transmit in wide-band modes (AM, ESSB, FM), you'll need
   to have the corresponding wide filter bandwidths installed in the main
   receiver. This is because the transmitter and main receiver share the
   same circuitry. By "wide", I mean:

      AM or ESSB    KFL3A-6.0  (6 kHz)
      FM            KFL3B-FM   (approx. 13 kHz)

   Of course you can also install wide filters on the subreceiver.

   This information is being added to the order form. My apologies for any
   inconvenience due to not explaining this sooner.

   73,
   Wayne
   N6KR


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   http://www.elecraft.com

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[Brett gazdzinski-2]

 
And could you use the FM filter on AM or SSB?

Thanks,
Brett

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Doug
> Faunt N6TQS [phone]
> Sent: Tuesday, May 01, 2007 1:38 PM
> To: [hidden email]
> Cc: [hidden email]
> Subject: Re: [Elecraft] K3 roofing filters: Important
> ordering information
>
> Does that mean that if we substitute the 2.8kHz 8 pole filter for the
> 2.7kHz 5 pole then we'll get a slightly cleaner transmit signal, too?
>
> 73, doug
>
>    From: wayne burdick <[hidden email]>
>    Date: Tue, 1 May 2007 10:21:38 -0700
>
>    If you wish to transmit in wide-band modes (AM, ESSB, FM),
> you'll need
>    to have the corresponding wide filter bandwidths installed
> in the main
>    receiver. This is because the transmitter and main
> receiver share the
>    same circuitry. By "wide", I mean:
>
>       AM or ESSB    KFL3A-6.0  (6 kHz)
>       FM            KFL3B-FM   (approx. 13 kHz)
>
>    Of course you can also install wide filters on the subreceiver.
>
>    This information is being added to the order form. My
> apologies for any
>    inconvenience due to not explaining this sooner.
>
>    73,
>    Wayne
>    N6KR
>
>
>    ---
>
>    http://www.elecraft.com
>
>    _______________________________________________
>    Elecraft mailing list
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[wayne burdick]

On May 1, 2007, at 10:37 AM, Doug Faunt N6TQS wrote:

> Does that mean that if we substitute the 2.8kHz 8 pole filter for the
> 2.7kHz 5 pole then we'll get a slightly cleaner transmit signal, too?

If the 2.8 kHz filter had any advantage over 2.7 kHz in a given mode,
that advantage would be realized in both transmit and receive mode, if
the filter were installed in the main filter bank (rather than in the
subreceiver).

The 2.8 kHz filter will have sharper skirts, which may be an advantage.
Ultimate attenuation will be the same with either 5- or 8-pole filters
because of the I.F. DSP.

73,
Wayne
N6KR

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[wayne burdick]

AM, probably. I'm not sure there's a good reason to use the FM filter
in SSB mode. We'll provide more details in the FAQ.

73,
Wayne
N6KR


On May 1, 2007, at 10:45 AM, Brett gazdzinski wrote:

>
> And could you use the FM filter on AM or SSB?

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[Brett gazdzinski-2]

 I was thinking the FM filter could be used on
other modes as a wide filter. I think the K3 comes standard
with the 2.7 filter, plus just the FM filter would allow
wider bandwidths in the other modes with decreased performance.
I don't contest or DX hunt, and don't generally operate
(voice anyway) when the bands are crowded.

My hearing is gone and I don't need anything more than
6kc on AM, but others like it a bit wider.
Plus, if you get the FM filter, you could use the FM
mode, the AM mode, a wide ssb mode?, and only have
to pay for the one FM filter...

Am I right in thinking that with dsp, the roofing filter
is only real important if there are very close strong signals?

Am I right in thinking you could limit the bandwidth on TX
to say 3kc on ssb even though you have the FM filter in?
That would be 6kc with both sidebands on AM...

Best bet sounds like it would be one variable filter
that matched the bandwidth selected, from 15 KHz to 200 cycles!

Is that not possible?

Brett

> -----Original Message-----
> From: wayne burdick [mailto:[hidden email]]
> Sent: Tuesday, May 01, 2007 1:49 PM
> To: Brett gazdzinski
> Cc: [hidden email]
> Subject: Re: K3 roofing filters: Important ordering information
>
> AM, probably. I'm not sure there's a good reason to use the FM filter
> in SSB mode. We'll provide more details in the FAQ.
>
> 73,
> Wayne
> N6KR
>
>
> On May 1, 2007, at 10:45 AM, Brett gazdzinski wrote:
>
> >
> > And could you use the FM filter on AM or SSB?
>
> ---
>
> http://www.elecraft.com
>

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