[Elecraft] K2 RF Output

[Frank Krozel]

Just power the radio, not the PA
-73-  Frank    KG9H
kg9hfrank at gmail.com




> On Aug 8, 2021, at 12:16 PM, jerry <jerry at tr2.com> wrote:
> 
> All,
> 
>   Can I just remove the KPA100 and test the K2 "bare" for current draw?
> 
>                 - Jerry KF6VB
> 
> 
> On 2021-08-08 09:49, Don Wilhelm wrote:
>> Jerry,
>> Replace diodes D16 and D17 in the KPA100 wattmeter, and things should
>> settle down.
>> If you attempted to adjust KPA100 C1 while this condition was present,
>> balance the wattmeter again, it will change with good diodes
>> installed.
>> The diodes are 1N5711 type.
>> That wattmeter is still used as long as the KPA100 is installed on the
>> base K2 - reducing the power to less than 12 watts does not take it
>> out of line.
>> CAL CUR should be set at 3.5 amperes with the KPA100 installed. That
>> (and the current display) is the current drawn by only the base K2,
>> and not to the KPA100.
>> 73,
>> Don W3FPR
>> On 8/8/2021 12:24 PM, jerry wrote:
>>> All,
>>>   My new QRO K2 behaves a little strangely...
>>> On Tune - it makes 108W on 40M, very nice.
>>> But on 20M it behaves strangely.  It won't make more than 20W or so, complains about high SWR. Even though my Heathkit HM-102 SWR/Wattmeter says the SWR is zilch.
>>> So I moved it to a dummy load.  As I turn the power up, it makes up to about 80W, and then says "Hi CURR".  And it claims that the dummy load ( an 800W "Florida RF" resistor bolted to a large heatsink ) is 1.6 to 1, which is totally bogus.
>>> OK, there's a null trimmer for the SWR bridge.  I got it down to 1-to-1 SWR on 20M.  It degrades on higher bands though - up to 1.5 to 1 on 10M.
>>> Now, 20M gives me a max of 45W - above that it complains "HI CUR".  It's doing that on all bands.  With the PA off via menu, I get a maximum of about 8.5W before getting the "HI CUR" message. I tried setting the current up a little bit on the CAL CUR menu, but no real difference.
>>>   With a clamp-on DC ammeter ( which I don't trust THAT much ) I see 340mA on receive,
>>> and just about 3.6A when the display goes "HI CUR".  This is with the PA turned off.  The
>>> display shows 7W just before this happens.  Hmm, 13.8V times 3.5A means 48.3W DC input.  Seems a little excessive.
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