[Elecraft] KX3 - UHF emissions

[Darren Long]

Hi Dave,

Well, the only time that I've specifically investigated one of these spurs, was
with my KX3 tuned to 7.080Mhz.  The only reason why I've followed up on this one
is that I've cleared the backlog of other things to do and figured that I'd try
and nail this problem now. I've had the scanners stop on UHF channels whilst
operating on most HF bands with the KX3.

I noticed the spur (from 7.08MHz) on 389.4MHz, which is a frequency used at RAF
Marham.  A related spur can be found at 141.6Mhz too.  It would be interested to
see if you can find anything.  I've used my USRP with a whip in the near field
to monitor a wider swath of spectrum and can see the spur from 7.08MHz drop down
by 160KHz to 141.440Mhz and down by 440kHz to 388.96kHz when I enable the 8kHz
shift in the KX3.

I watched 8MHz of spectrum and knobulated (there's another one for the
dictionary) the KX3's VFO and followed the sprog as it traversed the plot.  I
slewed the KX3's VFO down to 60m and at some points could see a pair of spurs
tracking the VFO.

Anyway, I've ordered about £30 of type 61 ferrite which should arrive tomorrow,
so I'll see if that gets results.

Cheers,

Darren, G0HWW



On 25/06/14 15:07, Dave wrote:
> I can back Darren up on this, sprogs and sproggies are common slang words used
> in Amateur Radio and the Radio/TV industries in the UK to mean spurrious emissions.
> 
> So, at a typical Microwave Roundtable you might hear someone say "Look at the
> sproggies on that!" when connecting the output of an oscillator or amplifier to
> a spectrum analyser.
> 
> It can also mean a small child or baby, as in "I see she has brought her sprogs
> with her" it was also used in the RAF as a description of a new recruit,
> possibly putting 'frog spawn' into one word, as the recruit was often said to be
> 'as green as a frog' as they didn't know much.
> 
> What frequencies are these emissions on specifically?  As I'll get out my
> portable spectrum analyser and go and look for them on my KX3 if I know where to
> look.
> 
> Dave (G0DJA)
> 
> 
> ----- Original Message ----- From: "Darren Long" <darren.long at mac.com>
> To: "K8JHR" <jrichards at k8jhr.com>; <Elecraft at mailman.qth.net>
> Sent: Wednesday, June 25, 2014 12:44 AM
> Subject: Re: [Elecraft] KX3 - UHF emissions
> 
> 
>> Well, I've always thought of sproggies as spurious emissions, i.e. external to
>> the source, whereas I've thought of birdies as internal interference, perhaps
>> like tinitus.
> 
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