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:[EMAIL PROTECTED]
Sent: Wednesday, April 11, 2007 11:01 AM
To: KJ3D
Cc: [email protected]
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, [EMAIL PROTECTED]
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