[Elecraft] K2 Problem in NAQP

Mon Jul 18 12:44:20 EDT 2011

Mike,

Looks like Don was right.  I haven't done an on air test with another station yet but comparing my K2 & K3 they now are the same after I changed the sidebands.  Hopefully, I can get an on air test in a day or so with a friend to confirm all is well.  In spite of my best effort I guess I goofed it up the first time.  I've been unable to find clear instructions in the assembly manual nor other instructions available on the internet on what values are correct for the BFO and DAC values.  Those values are in the assembly manual for LSB/USB and CW and it's reverse but not for RTTY.  I guess I had a one in two chance of getting it right and didn't do well on the odds.

Looks like I have plenty of range on my radio so that doesn't seem to be an issue here.  I still don't understand why the upper bands were correct and the lower were not.  Hopefully both are now correct.  Live and learn.

Thank you for your input.

Take pride in the USA. 73

Jim, W0EM

>________________________________
>From: Mike Murray <w0agmike at gmail.com>
>To: Jim Harris <jim.w0em at yahoo.com>
>Sent: Sunday, July 17, 2011 6:52 PM
>Subject: Re: [Elecraft] K2 Problem in NAQP
>
>
>Jim,
>
>
>Don was right on with his response - I had exactly the same problem with my K2 even though I thought I had carefully setup the filters.  Turned out I didn't have enough VFO low end range to get them set correctly.  Searched the archives and found Don's suggestion to pad U11 to change it.  Seems to have worked correctly since the VFO values now correspond to LSB/USB values but haven't had a chance to try on the air.
>
>
>Thanks again Don!!!
>
>
>73,
>Mike - W0AG
>
>
>On Sun, Jul 17, 2011 at 6:29 PM, Jim Harris <jim.w0em at yahoo.com> wrote:
>
>Don,
>>
>>That was the leading suspect in my mind.  But I tried very hard to assure they were correct when I set them up.  I still don't grasp why the upper band was correct and the lower were opposite.  I realize there is an inversion of side bands up there but I thought it was a simple inversion which to me means they should have behaved as did the lower but maybe opposite from the lower on receive and transmit.
>>
>>I will follow your instructions and see how they work out.  As always,  thank you for your assistance.
>>
>>
>> 
>>Take pride in the USA. 73
>>
>>
>>Jim, W0EM
>>
>>
>>>________________________________
>>>From: Don Wilhelm <w3fpr at embarqmail.com>
>>>To: Jim Harris <jim.w0em at yahoo.com>
>>>Cc: Elecraft Email <elecraft at mailman.qth.net>
>>>Sent: Sunday, July 17, 2011 10:52 AM
>>>Subject: Re: [Elecraft] K2 Problem in NAQP
>>
>>>
>>>Jim,
>>>
>>>I suspect you have the sidebands inverted in your RTTY filter set.
>>>
>>>Do the following with the K2 set to a band lower than 15 meters,
>>>
>>>First set the FL1 filter to use the OP1 filter on the KSB2 board, and that filter along with its BFO settings will be used for transmit.  Set RTTY the same as your SSB FL1 settings - the BFO setting for RTTY should be the same as LSB, and the RTTYr BFO should be the same as USB.
>>>
>>>The other filters are created from the variable bandwidth filter.  I usually set FL2 to 1.00, FL3 to 0.70, FL4 to 0.40, and center these 3 filters at 1000 Hz. - use Spectrogram
>>>MMTTY mark frequency is set at 915 Hz to be compatible.
>>>
>>>Check the BFO frequencies for RTTY and RTTYr - normally the RTTY BFO frequency will be in the vicinity of 4914.xx and the RTTYr BFO will be near 4912.xx if you are using 1000 Hz as the center frequency.
>>>
>>>Higher center frequencies may be possible, but you may run into difficulty with limits of the BFO range for RTTYr.
>>>
>>>The K2 reverses its mixing scheme on 15 meters and above - below 15 meters the VFO and BFO subtract while on 15 and above the VFO and BFO add.  The K2 automatically swaps sidebands for you, but it will not come out right on all bands if the sidebands have been inverted in the filter settings.
>>>
>>>73,
>>>Don W3FPR
>>>
>>>
>>>
>>>On 7/17/2011 11:14 AM, Jim Harris wrote:
>>>> Hi Folks,
>>>>
>>>> I ran into a problem during the just completed NAQP RTTY contest with my Elecraft K2.  To make a very long and frustrating story short, on at least 20 and 40 meters it receives on the lower side band but transmits on the upper sideband.   On 15 meters it receives and transmits on the same sideband which appears to be the lower sideband.  The only way I was able to get it to transmit on the same sideband on the two bands mentioned was to put the radio into RTTY reverse (with CW REV) and then operate MMTTY in REV.  As a result of the problem I lost about three hours in the contest while troubleshooting the problem.  If someone can shed (and I'm sure they can) some light on this perplexity, I would very much appreciate it.
>>>>
>>>> This was my first serious attempt to do SO2R.  I used my K3 for the right radio and the K2 for the left.  I had aligned the RTTY filters in the K2 using the procedures found on the internet and used Spectogram.  I tried to be careful to set them on the correct sideband.  I can accept that maybe I didn't get that done right and will recheck them.  But, I don't understand why the upper band is correct and the lower bands are not.
>>>>
>>>>
>>>
>>>
>>>
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