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K3s IF bandwidth?

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Jim Miller

K3s IF bandwidth?

The P3 displays a maximum of 200khz. Is that the maximum useful K3 IF bandwidth or is it wider?

73

Jim ab3cv
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Don Wilhelm

Re: K3s IF bandwidth?

Jim,

The IF takeoff point in the K3 is right after the 8.215mHz mixer, so at
that point, it has a very wide bandwidth.
The K3 filtering is after that IF takeoff point, so any filtering in the
K3 will not affect that bandwidth.

I don't know how much wider than 200kHz the IF takeoff might be.
200kHz is a substantial portion of any band.

73,
Don W3FPR

On 12/25/2017 12:17 PM, Jim Miller wrote:

> The P3 displays a maximum of 200khz. Is that the maximum useful K3 IF bandwidth or is it wider?
>
> 73
>
> Jim ab3cv
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tomb18

Re: K3s IF bandwidth?

In reply to this post by Jim Miller

HiIf you connect an sdrplay to the if output you can see over 2mhz bandwidth. 73 Tom

Sent from my Samsung Galaxy smartphone.
-------- Original message --------From: Don Wilhelm <[hidden email]> Date: 2017-12-25 12:31 PM (GMT-05:00) To: Jim Miller <[hidden email]>, [hidden email] Subject: Re: [Elecraft] K3s IF bandwidth?
Jim,

The IF takeoff point in the K3 is right after the 8.215mHz mixer, so at
that point, it has a very wide bandwidth.
The K3 filtering is after that IF takeoff point, so any filtering in the
K3 will not affect that bandwidth.

I don't know how much wider than 200kHz the IF takeoff might be.
200kHz is a substantial portion of any band.

73,
Don W3FPR

On 12/25/2017 12:17 PM, Jim Miller wrote:

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Jim Miller

Re: K3s IF bandwidth?

Thanks all!

Jim ab3cv

On Dec 25, 2017, at 12:37 PM, tomb18 <[hidden email]> wrote:

Hi
If you connect an sdrplay to the if output you can see over 2mhz bandwidth.
73 Tom

Sent from my Samsung Galaxy smartphone.

-------- Original message --------
From: Don Wilhelm <[hidden email]>
Date: 2017-12-25 12:31 PM (GMT-05:00)
To: Jim Miller <[hidden email]>, [hidden email]
Subject: Re: [Elecraft] K3s IF bandwidth?

Jim,

The IF takeoff point in the K3 is right after the 8.215mHz mixer, so at
that point, it has a very wide bandwidth.
The K3 filtering is after that IF takeoff point, so any filtering in the
K3 will not affect that bandwidth.

I don't know how much wider than 200kHz the IF takeoff might be.
200kHz is a substantial portion of any band.

73,
Don W3FPR

On 12/25/2017 12:17 PM, Jim Miller wrote:

ab2tc

Re: K3s IF bandwidth?

In reply to this post by tomb18

Hi all and Merry Christmas,

Well, the ham band specific HF filters are probably significantly narrower
than 2MHz, tailored to the actual width of the band in question. I don't
know if there is a way to tell the K3(S) to use a general coverage filter,
if installed, even if inside a ham band. That would circumvent the problem.

AB2TC - Knut

tomb18 wrote
> HiIf you connect an sdrplay to the if output you can see over 2mhz
> bandwidth. 73 Tom
> <snip>

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David Gilbert

Re: K3s IF bandwidth?

I could be wrong, but I thought they were low pass filters, not band
pass. I think each filter even covers more than one band if they are
within an octave or something like that.

Somebody please correct me if I'm wrong.

Dave AB7E

On 12/25/2017 11:10 AM, ab2tc wrote:

> Hi all and Merry Christmas,
>
> Well, the ham band specific HF filters are probably significantly narrower
> than 2MHz, tailored to the actual width of the band in question. I don't
> know if there is a way to tell the K3(S) to use a general coverage filter,
> if installed, even if inside a ham band. That would circumvent the problem.
>
> AB2TC - Knut
>
>
> tomb18 wrote
>> HiIf you connect an sdrplay to the if output you can see over 2mhz
>> bandwidth. 73 Tom
>> <snip>
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> Elecraft mailing list
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ab2tc

Re: K3s IF bandwidth?

Hi again,

Heavens no, they are definitely bandpass filters, tailored to each ham band.
I think I have seen a plot of their responses somewhere, but can't remember
where. Each filter covers 2 bands with a relay to choose which one of the
two.

AB2TC - Knut

David Gilbert wrote
> I could be wrong, but I thought they were low pass filters, not band
> pass. I think each filter even covers more than one band if they are
> within an octave or something like that.
>
> Somebody please correct me if I'm wrong.
>
> Dave AB7E

--
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K9MA

Re: K3s IF bandwidth?

Yes, they are bandpass filters, to reject the image 16 MHz from the
desired frequency, among other things. There are, of course, also low
pass filters, to reduce transmitted harmonics.

73,
Scott K9MA

On 12/25/2017 16:27, ab2tc wrote:

> Hi again,
>
> Heavens no, they are definitely bandpass filters, tailored to each ham band.
> I think I have seen a plot of their responses somewhere, but can't remember
> where. Each filter covers 2 bands with a relay to choose which one of the
> two.
>
> AB2TC - Knut
>
>
> David Gilbert wrote
>> I could be wrong, but I thought they were low pass filters, not band
>> pass. I think each filter even covers more than one band if they are
>> within an octave or something like that.
>>
>> Somebody please correct me if I'm wrong.
>>
>> Dave AB7E

--
Scott K9MA

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k6dgw

Re: K3s IF bandwidth?

In reply to this post by Jim Miller

It's as wide as the bandwidth of the BPF ahead of the 1st mixer. There
are several BPF's for the various bands and their BW no doubt varies,
but is likely much larger than 200 KHz.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 12/25/2017 9:17 AM, Jim Miller wrote: