From: Tom Hammond (N0SS)
Dated: June 16, 2003
Update: August 5, 2003 with new price ($45) for latest version of Spectrogram.
Subject: Re: [Elecraft] CAL FIL / BFO setup with sound card?
With regard to the software which seems to be best for K2
filter alignment, you may download the Spectrogram Software from:
NOTE that there is a FREE version of Spectrogram which is FULLY
operational, BUT which limits the user to 10 minutes per activation.
While 10 minutes seems like a very short time, it should only take
a few re-starts of the program to complete your filter alignment.
Additionally, once you become a bit 'familiar' with Spectrogram,
you will find that it may not take even 10 minutes to complete a
realignment of your filters.
Of course, you can also buy a no-time-limit version of the software
for $45 (US).
Version 5.0 of Spectrogram is available as FREEware from:
To find the Spectrogram (CW & SSB) Filter Alignment Articles, go to:
Once there, if the file you wish to access is a PDF (Acrobat Reader)
file, RIGHT-CLICK on the link and when prompted to do so, SAVE the
file to wherever on your HD you want it to go. If the link is NOT a
a PDF, then LEFT-CLICK on the link and proceed.
A while back, someone asked about setting differences between Spectrogram
v6.x and Spectrogram v7.x.
I've just downloaded and installed (into a SEPARATE subdirectory)
Spectrogram v7.0.6 and find it to be virtually (in normal usage) identical to v6.x.
Version 7.x is about 3X the size of v6.x, and, for most of us, will
probably not provide a significant improvement in those features we will
want to use most of the time. It will however, probably provide a 'cleaner'
plot if you are attempting to 'characterize' the bandpass of your filters.
Though this is not something most of us will require and is NOT required to
permit you to correctly adjust your K2/K1 filter settings.
The main differences, with regard to how most of US would use it, seem to
be in the Scan Input (parameter settings) screen.
Here are the setting I (personally) am using, of course your mileage will
vary, and you are the final judge of how YOU wish to configure this program
for your particular tastes.
Sample Rate (Hz) 11kHz (others work well, too)
Resolution 8 bit (16 bit's OK, too)
Plot Type Signal
Averaging msec 500 (others work well, too, the higher
the value, the longer it'll take
the plot to stabilize. Though, the
higher the value, the 'smoother'
the plot will be)
Time Scale N/A
Amplitude Scale 60dB
Scroll Mem N/A
Freq Scale Linear
FFT Size (Points) 2048 (1024 works fine here, too)
Freq resolution (Hz) (Use lowest value available for
FFT value you have selected)
Low Band Limit (Hz) 0
High Band Limit (Hz) 3000 (use what floats your boat. Other
values may work better for you)
Pitch Detector OFF
Cursor Freq Offset 0
Recording Enable OFF (If you ENABLE this function, note
that a higher value for Sample Rate
will REALLY increase the size of the
Trigger Level (dB) N/A