Monday, July 7, 2008

Stars Fell on Alabama...


Of course this phrase refers to the classic 1934 jazz tune, and earlier than that, a book by Carl Carmer, describing the spectacular Leonid meteor shower of 1833. But in my case, it is a fitting description for the July 4th weekend this year.

My operating time was very limited. I awoke at 6AM, and rushed out to the shack, attempting to hear some of the stations checking into the East Tennessee 432mhz net. Scatter was poor, with no enhancement noted. So instead, I called up the boys on PingJockey, and decided to give WSJT another try.

Within three hours of sitting down at my desk, using this amazing software, I'd managed to work four new grids, and thanks to VA3WLD, my 2nd country on 2 Meters!

Learned a lot in the experience...including that my recently acquired ARR 144mhz GaSFet pre-amp was DOA. That's a shame, because it's clear that I'm near deaf on 2 Meters using the Icom pre-amps.

Today, I'm shipping all three ARR pre-amps back for service, just to verify that they're working correctly before I install them. One of the hazards of used equipment.

Everything I can read on the net tells me that my Icom mast mounted pre-amps are on the noisy side with noise figures of over 1db...but even if I can improve that with the ARR's it may not translate into real world success. Why? Super low noise pre-amps at best suited for EME work, where antennas are pointed at "cold" sky...for both meteor scatter and tropo work, most of the action is at the horizon.
Pointed down there, the noise floor comes up sharply, and 1db may already be below the noise. Having antennas in the attic can't be helping either.

One station that I worked on Saturday reported hearing me well on nearly every sequence, while I could only copy his station during audible "pings" (bigger rocks and louder signals)

So still a lot of work to do here. I'm installing slightly larger antennas for both 2M and 222 soon. Improvements should be on the order of 1.5-2db. Not huge, but every db counts, right? That will max out the room for hardware, though.

Another "trick" that someone on the WSJT group suggested is to "tilt" the 2M beam up towards the sky more. Perhaps as much as 15 degrees. I may try this too...pointing up would allow better pre-amps to help out for sure.

Still all in all...quite a thrill, and a huge aid to the VUCC hunt! Now I want to see if my puny station can manage WSJT on 222, or even 432.

If you haven't tried MS yet...download WSJT and give it a try!

Hopefully a lot more stars will be falling on Alabama soon!

73 DE N1LF


1 comment:

sar said...

Hi Les,

Thanks for the blog. I appreciate your ideas and situation, living in an antenna restricted area.

I'm in a similar situation, and I am always looking for better methods for operating. Keep up the good work, and let us know how you've solved your latest problem!

73,

Dave
AF6KD