[Elecraft] KX3 - UHF emissions

[Phil Genera]

If you have an early KX3, you probably need KX3BNCMDKT, a new BNC connector
assembly with some inline filtering.

See: http://www.elecraft.com/order_form_parts.htm

-- 
Phil


On Tue, Jun 24, 2014 at 3:00 PM, Darren Long <darren.long at mac.com> wrote:

> Hi,
>
> I've noticed that my pair of scanners often receive strong spurii from my
> KX3's
> receiver, in the UHF mil air band.  Whilst the spurii can be detected
> faintly
> with no cables attached to the KX3, when I attach certain cables, the
> strength
> of the spurii increase, most notably the I/Q cable, which causes (what
> passes
> for) the S-meter on the scanner to fully deflect. Connecting an antenna to
> the
> KX3 doesn't seem to have any effect.
>
> The other day I noticed that my scanner had stopped on a locally used UHF
> channel that was exactly 100 times the frequency in the 80m band that I was
> listening to.  Today I have noticed that listening on 7.08Mhz SSB, my
> scanners
> stop on 389.4Mhz, which seems to be the 55th harmonic of the KX3's dial
> frequency.
>
> This is affecting my AOR-8600mk2 and IC-R20. Unfortunately, I've also been
> developing a hybrid spectrum sensing scanner (called Onsense), that uses a
> HackRF to sample the mil air band and tune in my AOR-8600mk2 to the
> strongest
> signal detected.  I find that I am constantly having to add frequencies to
> Onsense's blacklist as I tune my KX3.  This isn't a good situation to be
> in.
>
> I already have a ferrite on the I/Q cable, but that doesn't help.  When I
> enable
> the 8kHz shift on the KX3, the previously detected spurii goes away.
>  Whether it
> goes entirely or not, I don't know, it may just shift to another frequency
> that
> isn't being scanned.  The RX Isolation filter is enabled.
>
> Is anyone else having similar problems? Is this normal for a KX3?  Is there
> anything I might try to mitigate this?
>
> Cheers,
>
> Darren, G0HWW
>
>
>
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