[Elecraft] Noise from KAT500?

[Jack Brindle]

I remember those days. I still have my Heath SB-303 and SB-401 pair, both of which run from 117VAC. I didn’t have to get a 12V supply until I started upgrading back around 2000.
You might want to invest in a small Astron linear supply (or similar). You will slowly start acquiring equipment that runs on 12 - 13.8VDC, so getting one now would be a good thing.
What kind of things? I love my Heath HM102, but modern SWR/Power bridge meters provide so much better info. This is just one example…

73!
Jack, W6FB


> On Dec 3, 2023, at 1:16 PM, W2HX <w2hx at w2hx.com> wrote:
> 
> ?  I don't have any 12v transceivers. This is the only 12 device I have in the shack.
> Thanks
> Eugene W2HX
> Sent from Nine<http://www.9folders.com/>
> 
> ________________________________
> From: Bob McGraw <rmcgraw at benlomand.net <mailto:rmcgraw at benlomand.net>>
> Sent: Sunday, December 3, 2023 12:11 PM
> To: elecraft at mailman.qth.net <mailto:elecraft at mailman.qth.net>
> Subject: [Elecraft] Noise from KAT500?
> 
> Just power it from the transceiver power supply and all will be
> resolved.   There is no point in making life complex.
> 
> 73
> 
> Bob, K4TAX
> 
> 
> On 12/3/2023 9:52 AM, elecraft-request at mailman.qth.net wrote:
>> Message: 8
>> Date: Sun, 3 Dec 2023 01:48:45 +0000
>> From: W2HX<w2hx at w2hx.com>
>> To: Michael Carter<Mike.Carter at unh.edu>, Elecraft Reflector Reflector
>>       <Elecraft at mailman.qth.net>
>> Subject: Re: [Elecraft] Noise from KAT500?
>> Message-ID:
>>       <BL1PR12MB52692D0596AADD969A286E4EB587A at BL1PR12MB5269.namprd12.prod.outlook.com>
>> 
>> Content-Type: text/plain; charset="utf-8"
>> 
>> Mike, K8CN wins the cigar!
>> 
>> 
>> 
>> The issue is the power supply ? I took some spectrum analyzer plots to 7
>>  MHz and you can see what I saw. The set up is spectrum analyzer ->
>> KAT500 -> Dummy Load. First picture are two "max hold" traces
>> superimposed where the problem can be seen.
>> 
>> https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-AC-Power.png
>> 
>> The "lower" trace is what I saw with the kat500 in bypass. The "top"
>> trace is with the kat500 inline (auto or manual).
>> 
>> 
>> 
>> I then replaced the wall-wart power supply with a 12V battery. And this
>> is what I saw for BOTH bypass and inline. Clearly the problem.
>> 
>> https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-battery.png
>> 
>> using a battery, the noise is about -80 dBm. Using the wall-wart, in some cases the noise is as high as -60 dBm
>> 
>> 
>> 
>> My task now is to either leave it on battery or preferably, find a low noise PS.
>> 
>> 
>> 
>> Thanks everyone for the ideas.
>> 
>> 
>> 
>> 73 Eugene W2HX
>> 
>> Subscribe to my Youtube Channel:https://www.youtube.com/@w2hx/videos
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