K3 birdies - question?

[John Lemay]

Hello all

I think it may be useful to tackle this problem from the other direction,
and try ferrite rings or chokes on all the connections to your router.

Regards

John G4ZTR

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Geoffrey
Mackenzie-Kennedy
Sent: 05 March 2009 10:08
To: Elecraft Discussion List
Subject: Re: [Elecraft] K3 birdies - question?

David,

Double shielded coax would certainly reduce leakage from the coax, and is a
good investment in my opinion. However its use might not have too much
impact on the receiver's birdie problem, because many of the "rogue" signals

involved are probably flowing on the outside of the coax's braid, certainly
if the coax emerges from some enclosure through a hole.

The usual cause of a receiver birdie is that some response of the receiver
is "hearing" some oscillator or a harmonic, or some mixing product of two or

more oscillators, contained within the receiver. In a down conversion HF
receiver, the great majority of the receiver's responses, therefore the
"rogue signals", that cause birdie problems are at HF and up to low/ mid
VHF, which means that choking off coax runs within a receiver becomes
cumbersome.

73,

Geoff
GM4ESD

David Cutter wrote on Wednesday, March 04, 2009, at 10:32 AM:

>I also wonder if it would be worthwhile buying higher spec coax.  Don't
>know what is used in the K3, but for the lengths involved it would be worth

>the investment to get short cables made in say LMR100 or RG142 etc if it's
>not already
>
> David
> G3UNA


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[Geoffrey Mackenzie-Kennedy]

Hello John,

That could reduce any trash from a router is , but it would not remove any
of the receiver's self inflicted birdies.

73,
Geoff
GM4ESD


John Lemay wrote on Thursday, March 05, 2009 10:28 AM

> Hello all
>
> I think it may be useful to tackle this problem from the other direction,
> and try ferrite rings or chokes on all the connections to your router.
>
> Regards
>
> John G4ZTR



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[Geoffrey Mackenzie-Kennedy]

It might help, but it might not, because until such time as the source of a
particular birdie is contained or removed, it will remain to be a source of
a birdie. If you block one route, these birds have a habit of finding
another, especially if the layout is open plan.

73,

Geoff
GM4ESD


David G3UNA wrote:


> So, could we use the good old methods of wrapping the coax around a
> suitable toroid.  That would mean a longer cable at which point I would
> invest in a better quality cable if I were doing it and I'm tempted to do
> so to get the best chance of cracking the main issues we are addressing.
>
> David
> G3UNA

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[Merv Schweigert]

Heres one I really dont want to bring up as I have seen so many
reports of how effective the NB is on the K3.
In fact one of the key factors that tilted me over the edge to buy
the K3 was reports that it had the best NB people had used.

This morning the long silent (at least on 40 meters) Chinese or
whom ever buzz saw was on again.  Not the one that was called
the dragon but one that sounds like power line noise buzz.  
The NB on the K3 was not only totally inefective, but actually
increased the noise by several S units.   There is no setting of
either blanker that even touches the noise, and if using the IF
blanker as you increase the setting the noise increased also to
the point of at a setting of 7 it was 2 s units stronger.
I have also had almost zero effect on power line noise which is
very similar type buzz sound.
I turned on the other brand X radio which has two blankers,
a standard NB and a wide NB,  on either setting the buzz was
completely eliminated at a low setting of the blanker control.

Perhaps there is a way for Aptos to hear that type of noise and
twiddle software to make it work on the K3.
Sure need some major help on this one,  makes the 40 meter
band unusable when its on and the blanker does not work.
Merv KH7C

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