Update from Charleston
tfox at knology.net
Fri Sep 8 21:14:35 CDT 2006
Well, I've been busy on various fronts. My Soft Rock V5.0 is working on 40
and 20 meters. I did a lot of playing with sound cards, the results are as
1. Don't use mic inputs on any computer. The mic input is typically mono,
so you won't get the image rejection benefits. This is especially true on
laptops, but on desktops too from what I have found. Both the Audigy 2 ZS
notebook card and the Audigy 4 PCI card can do 96kHz sampling, which extends
the Rocky spectrum to 96kHz. My SoftRock V5 (with 40 meter xtal @ 7.037)
displays 6.989 to 7.085MHz.
2. I found the SounBlaster Audigy 2 ZS notebook PCMCIA card will work with
laptops, but only if you download the latest drivers from Creative. The old
drivers that come with the card on CD are bad. They do not provide a stereo
audio signal to external software, the new driver does. I found the Audigy
2 ZS card at Circuit City a couple weeks ago for $40 after rebate.
3. Do NOT use the SoundBlaster Audigy VE or SE card. It is cheap, but the
bandwidth is poor. For a few bucks more, the Audigy 4 card works much
better. I just bought an Audigy 4 at Office Depot today for 59 after 20
4. Get updated drivers for all Creative cards. They had problems with the
drivers sent with cards, usually dated late 2005.
5. Rocky software works OK. You may want to play with the sample timing,
either delay or advance until you see image rejection.
6. You can tell if image rejection is working or not by looking at the
whole spectrum with either a signal generator or an antenna. If you see
both sides of the spectrum (from the center frequency) look like mirror
images, then there is not any image rejection. If some signals are only
showing up on either the upper or lower half of the spectrum, you probably
have things working OK. Try adjusting the bit-delay (View/settings/audio
tab) on Rocky, and see if the imaging gets better. I see up to 40 db
isolation between the true signal and its image. Some times this is much
better, other times it is worse.
I am copying a W1AW CW practice session right now.
Tony Parks, who sells the Soft Rock receiver kits, just announced an exciter
kit that complements the Soft Rock V6 receiver. The kit is two boards, and
exciter, and a 1watt amp, for $35. He will be sending prototypes out in
September, production units in October.
I hooked up one of my DDS modules to my Soft Rock on 40 meters, and was able
to listen to 40 meters SSB. The 10-bit DDS sure generates spurs, but since
the Rocky software allows you to receive over 90kHz at one DDS setting, a
freq can be put into the DDS that minimizes the spurs.
I put a ground rod in place, and put a pulley in a tree to prepare for a
60ft random wire antenna to use with my MFJ auto-tuner. Hopefully, the
antenna goes up next week.
I will be in the DC area one week from this coming Monday, for about a week.
I plan to be at tacos Saturday, September 23.
Paul and others: Has anyone had any experience with the SteppIR vertical
antenna? I might be able to hide one in the yard, but it is expensive. I
don't want to spend over $700 on a vertical antenna if the performance is
mediocre. I have heard a couple people like it.
Hal: do you wnat to set up a sked on 40, 20, or ??
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