[Elecraft] KPA-1500 Fan Noise

Sat Jun 2 18:53:32 EDT 2018

It is NOT JUST a matter of of getting an HD15 M-->F extension cable 
(which can be had in lengths up to 100 feet.

A VGA signal is analog and can be extended to up to 100 feet TOTAL 
according to the spec, all things being optimum.

But one MUST look at the signals being sent between the KPA-1500 power 
supply and RF deck...  Are they analog, digital, a mix?
What are the timing spec requirements?  Voltage levels? State 
difference, et al...  Are there capacitance limitations, et al.

73,

______________________
Clay Autery, KY5G
(318) 518-1389

On 06/02/18 12:56, Don Wilhelm wrote:
> Les,
>
> A VGA extension will NOT do the job.  Get a cable with all 15 pins 
> connected straight through.
>
> 73,
> Don W3FPR
>
> On 6/2/2018 12:07 PM, Les Peters wrote:
>> Jim I agree with your personal observations.  I run some high duty 
>> cycle modes so I notice the fans kicking into speed 3 a lot when the 
>> PA temp gets to 68-70 degrees.  That setting does a good job of 
>> reducing the temp and keeping it from climbing past 73 degrees.  I've 
>> changed my min fan speed threshold from 0 to 1 to also help.  As you 
>> have pointed out 1 is barely perceptible and this helps to reduce the 
>> amount of time that fan speeds are on 2+.
>>
>>
>> I'd like to have more separation between the K3S and the KPA1500 RF 
>> deck to further distance any noise but the KPAK3AUX cable is only 
>> about five feet long, it would be great if that were more like ten 
>> feet.  Since the cable pin out is straight thru I would imagine a 
>> DB15 VGA M-F extension cable would suffice?  That would put the 
>> potential fan noise even further away but have the RF deck still 
>> plenty close enough to view.
>>
>>
>> Les, N1SV
>>
>> #113
>>
>>> Date: Fri, 1 Jun 2018 23:07:20 -0400
>>>      From: "James F. Boehner MD"
>>>      To: "'Elecraft Reflector'"
>>>      Subject: [Elecraft] KPA-1500 Fan Noise
>>>      Message-ID: <[email protected] 
>>> mailto:[email protected] >
>>>      Content-Type: text/plain; charset="utf-8"
>>>
>>>      Just thought I would add a few thoughts as far as the fan noise.
>>>
>>>      I'm not certain a YouTube piece would help, but perhaps 
>>> personal observations might.
>>>
>>>      First, via the menu, you can select the minimum fan speed, 0-5. 
>>> Of course, the fan speed will go up with the Amp temperature.
>>>
>>>      These are my personal observations:
>>>
>>>      0-Nothing
>>>      1-Barely perceptible
>>>      2-Acceptable fan noise, even for SSB operating. Low pitched whine
>>>      3-The noise and the pitch of the whine is past the acceptable 
>>> point. Even a very directional mic will probably pick up the noise. 
>>> This is where Noise Cancelling headphones would start to help.
>>>      4-Louder and higher pitched whine
>>>      5-Very loud and higher pitched whine
>>>
>>>      So, the fan noise becomes particularly bothersome on level 3 
>>> and above. If you are doing CW and/or Digital, the noise will only 
>>> be a factor with the operator. On SSB, the noise will probably be 
>>> noticeable on the air. However, the SSB duty cycle may not require 
>>> higher fan speeds. Those who have been active in contests will 
>>> probably know that answer.
>>>
>>>      Rich, if fan noise is going to be that strong a factor, perhaps 
>>> you should be looking at tube amps instead. Personally, if I found 
>>> the KPA-1500 fan noise excessive in the future, I would plan on 
>>> moving it off my desk or remoting it rather than replacing it. It's 
>>> integration with the K3 would be very hard to give up.
>>>
>>>
>>>      ?73 de JIM N2ZZ
>>>      #106
>>>      **************************
>>>
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