[Elecraft] KX3 - UHF emissions

[Dave]

Hi Darren,

I have a later KX3, number 5111, with similar options to you, built in ASTU 
and KX3 hardware, but I don't have the battery charger or additional 
heatsink options.

I built mine from the kit.  It was very straight forward but I did buy an 
anti-static mat first.

BTW - I made a mistake in labelling those pictures! The 1st is KX3 off and 
the second KX3 on.  I'll issue an ammendment just in case it causes 
confusion later.

Good luck in tracking it down, I would be interested to see your screen 
grabs showing the effects that you are seeing between on and off, so that I 
can compare them to my own results.  I'm downloading updated software for 
the RF Explorer, which may improve the resolution of the pictures.

Cheers - Dave (G0DJA)

----- Original Message ----- 
From: "Darren Long" <darren.long at mac.com>
To: <elecraft at mailman.qth.net>; <dave at g0dja.co.uk>
Sent: Friday, June 27, 2014 2:58 PM
Subject: Re: [Elecraft] KX3 - UHF emissions


> Hi Dave,
>
> Thanks for performing this comparison test.  I admit that I found it 
> difficult
> to perform repeatable measurements, as levels varied by as much as 10 to 
> 15dB
> due to position and orientation of the rig and cables  and my position 
> with
> respect to the equipment.  That is why I chose to provide considered
> representative figures derived from multiple observations as opposed to 
> precise
> measurements or screen-shots, but I could provide screen-shots by way of
> examples if anyone feels that would be really useful.
>
> My KX3 is #01685, purchased complete (not kit) with the roofing filter and 
> ATU
> options, from Waters & Stanton in the UK. I fitted the battery charger 
> when it
> shipped, and have also recently fitted the SideKX end-plates and a VE7FMN
> CoolerKX heatsink (although as noted before, the issue described pre-dates 
> these
> retrofits).
>
> Your results lead me to hope that my KX3 might be defective and that the 
> problem
> could be resolved by repair or exchange. I suppose I should order a 
> KX3-PCKT
> cable set to try in case the official I/Q cable mitigates this issue, but 
> I have
> tried the 2.5mm to 3.5mm stereo cable that came with my Sennheiser 
> headphones
> and that didn't seem any better.
>
> I look forward to hearing confirmation from Elecraft of whether or not 
> these
> emissions are considered typical for this build standard of KX3.
>
> Cheers, 73
>
> Darren, G0HWW
>
>
>
> On 27/06/14 11:39, Dave wrote:
>> Here are two more screen grabs for KX3 on and off, but just looking at 
>> the
>> frequency range 100MHz to 500MHz.  Everything else is the same between 
>> the test
>> done earlier.
>>
>> KX3 on
>> https://dl.dropboxusercontent.com/u/65397105/KX3%20Test%2027-06-2014%201122.jpg
>>
>> KX3 off
>> https://dl.dropboxusercontent.com/u/65397105/KX3%20Test%2027-06-2014%201123.jpg
>>
>> I can't see any additional frequency peaks and moving the VFO on the KX3, 
>> or
>> changing the band, doesn't appear to make any difference to the display 
>> on the
>> analyser.
>>
>> So, I can say that I'm not seeing seeing any distinct frequency spikes, 
>> which
>> vary as I tune the KX3 VFO up and down, as Darren is seeing from his KX3.
>>
>> Dave (G0DJA)
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