[Elecraft] SSB Confirmed

[jerry]

All,

    So the K2 yielded up its first sideband QSO this evening.  10M 
roundtable of the local ham club.  People gave me good reports.

    The next step is to organize up some power.  The KPA100 is a mighty 
elegant package, but I'm having trouble getting my head around the price 
tag.

    An alternative might be one of those Chinese amp
kits off Ebay.  I actually have one in hand.  It requires a bit of 
redesign to work well.  Mostly,
going to a bifilar-transformer power feed and verifying/optimizing the 
input and output turns ratios.  And providing a proper switched LPF.

                    - Jerry KF6VB







On 2021-06-30 19:54, Bill Coleman wrote:
> The K2SB was absolutely the hardest kit to build out of the entire K2.
> There are a lot of parts, and it is a very small board.
> 
>> On Jun 30, 2021, at 10:06 PM, jerry <jerry at tr2.com> wrote:
>> 
>> So I got up at 5:30 this morning and continued stuffing the SSB 
>> adapter card.  Finished it up this afternoon.
>> 
>> Trying it out, the CPU came up... CW still worked... But no SSB 
>> transmit, and the SSB receive was very very soft.  Had to turn the AF 
>> gain up all the way to hear
>> anything at all.
>> 
>> My untutored diagnosis - something was wrong with that 7-crystal SSB 
>> filter.
>> 
>> So I pulled the card out, scrubbed it again with IPA, stuck it under 
>> the microscope to look - again - for solder splashes and  cold joints. 
>>  Scraped off a little something here & there.  Also, I had doubts 
>> about the connections to the input & output transformers.  So I hit 
>> those again with the soldering iron.
>> 
>> Put the card back in the K2 - and ...Wow!  Lively SSB receive!  RF out 
>> on transmit!
>> 
>> Still need to align the rig.  Piping the output into another ham rig 
>> through a big attenuator - it sounds pretty good.  One niggle - 
>> carrier suppression.  If it's nulled out for LSB, it's not for USB.  
>> The nulls are in different places on the pot.  I guess you set a 
>> compromise position, and make sure the carrier is off the skirts of 
>> the filter, so that can help.
>> 
>>                   - Jerry KF6VB
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> 
> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
>            -- Wilbur Wright, 1901