[Elecraft] Backward CW?

[Don Wilhelm]

Tom,

Since I don't know about the dial calibration accuracy on your TS-820S 
even though it may have been factory calibrated, and I haven't 
investigated the high side/low side injection scheme for its mixer and 
product detector, I cannot comment on the dial reading comparison.  I do 
ask one question for you to investigate for a possible answer - does the 
820 display the frequency the receiver is actually tuned to or does it 
compensate for a CW offset in the dial reading.  The K2 will always 
indicate the carrier frequency, and in CW the dial will read correctly 
when a carrier is received at the same pitch as the sidetone.

The pitch change vs. dial frequency change - if you switch the K2 to 
CWr, you will find the pitch of the note will decrease as the frequency 
increases, just like your TS-820.  It is just a matter of which side of 
the IF signal the BFO is positioned (and also a result of the VCO 
injection, high vs. low).

If you want a valid check on the K2 dial accuracy, tune a WWV carrier so 
that the pitch (during silent periods) is the same as your sidetone 
pitch - the K2 dial should then read 10000.00 MHz (or 15000.00) or very 
close to that value (within 30 Hz).  If it does not, you can do the dial 
calibration procedure indicated on my website http://w3fpr.qrpradio.com 
- remember you must complete ALL the steps before you can evaluate the 
correctness of the result.

73,
Don W3FPR

KJ3D wrote:
> Hi Don, Mike, et al.
> 
> Thanks for the advice.
> 
> Using spectrogram I checked filter alignment for all filters and then
> reworked them all.  Now, the DAC for each of the filters in CW is BELOW the
> center frequency and the DAC for each of the filters in CWR is ABOVE the
> center frequency.
> 
> However, when I tune identical signals on my TS-820S (factory calibrated a
> couple of years ago) all the signals are about 1 KHz higher on the 820.
> 
> Before I crack the case and see if I put the board in backwards, or
> something, would you please comment on the following:
> 
> As I tune up the band (to higher frequencies) on 40, the pitch of the
> received signal goes up.  On the 820, the pitch goes DOWN as I tune up the
> band.
> 
> Frustrated in VA (but it IS Miller-time)
> 
> Tom, kj3d
> 
> 
> -----Original Message-----
> From: Don Wilhelm [mailto:w3fpr at earthlink.net] 
> Sent: Wednesday, April 11, 2007 11:01 AM
> To: KJ3D
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Backward CW?
> 
> Tom,
> 
> I believe you asked the right question.
> 
> Assuming that your filters are set so you do hear a signal at the sidetone
> pitch on both CW and CWr, do the following - (if not, you should do the
> whole filter setting task - see the 3rd paragraph below).
> 
> To see if your filters are set to the correct side of the carrier, you
> should enter the menu for CAL FIL, then tap the BAND- button. You can see
> the DAC values for both CW and CWr - for each of the 4 filters, the DAC
> value for CW should be lower than the one for CWr.  If that is true, then
> you have the BFOs set to the correct sideband.  If you have the counter
> probe installed in TP2, you can read the actual BFO frequency by tapping the
> DISPLAY button.
> 
> If you find the BFOs on the wrong sideband, you must open the K2 and connect
> the K2 frequency counter probe to TP2 to change the settings. 
> The K2 manual contains information for entering the menu and the related
> 'button-tap/hold' sequences to get to the CAL FIL menu - if you are not
> familiar with that part of the task, please review that portion of the
> manual first (if you built your K2 you already know how to do it).
> 
> Should your filters/BFOs need changed, I recommend you use Spectrogram to
> give a visual display of your filter passbands.  Spectrogram version
> 5 (the last freeware version) and how to use it info is available at Tom
> Hammond's website www.n0ss.net and if you want to accomplish a full K2 dial
> calibration job while you are in the process, check out my website
> http://w3fpr.qrpradio.com article on K2 Dial Calibration.  If you do not
> wish to do the full task, you can simply set the filters to the settings
> indicated in the KSB2 manual (if you have that option installed) or in the
> K2 manual if the KSB2 is absent.
> 
> It is not difficult, I am just trying to be complete here with some
> consideration for brevity.
> 
> 73,
> Don W3FPR
> 
> 
> KJ3D wrote:
>>  Well here comes the probably-stupid-question-of-the-day:
>>
>> After nearly 90 minutes on the NAQCC sprint last night - sending and 
>> answering dozens of calls, some from pretty strong signals - without a 
>> single contact, I gotta wonder if the problem is on my end.
>>
>> How can I tell if my carrier is on the correct side of zero-beat?  
>>
>> Then how do I fix it?  
>>
>> Have I even asked the right question?
>>
>> Thanks es 73,
>>
>> Tom, kj3d at comcast.net
> 
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