My Rover Experience- #2 CQ WW VHF

<Posted in hopes of enouraging other to try Roving>

The plan was in place, but it really didn’t happen.  After an exhilarating June VHF contest 1st attempt as a rover, I was ready to try it again last weekend.

The CQ WW VHF Contest is a 2m and 6m contest over the weekend using CW, SSB and Digital.  As a Rover, I had planned to somewhat follow a route that John AB5SS had recommended– a nice path North-South route starting at San Marcos and North 250 miles up to Decatur.  This was strategically sound with the tactic of hitting coverage within the big VHF stations known to exist in San Antonio and Dallas.

For this event, I was filled with confidence especially since I had garnered new operating hints from a few of club members from the North Texas Microwave Society group.  Also, I *just* bought a 2m 300W TE Systems 1452g amp from the Texas City Hamfest which I successfully got integrated into the car just a day before the event.  This boosted up my 2m signal by 5 dB!

Sidenote:  I’ve researched many topics about ALC overshoot that happens on most radios.  This is an insidious phenomenon that injects spikes beyond the RF controlled levels from the exciter into an amplifier.  My TS-2000 needed to be dialed down to 20W output to prevent overloading the max input to the amp, but ALC overshoot was known to exceed 60W on initial keydown due to the ALC lag feedback loop.  Not wanting to risk damaging the “new” amp, I called the expert (owner?) at TE Systems who gave me great advice.  He suggested not turning down the power level at all, but use lossy coax as an in-line attenuator to drop most of the full 100W output power from the exciter to the amp.  The built-in GaAs FET preamp could compensate for the receive attenuation due to the coax attenuator. By running the full 100W, an ALC overshoot wouldn’t exist since a spike couldn’t exceed the 100W exciter’s power maximum.  So thru Amazon, I got 125′ of RG-58.  At 140MHz, RG-58 exhibits close to a terrible 6 dB loss per 100′.  So, this reduced the 100W to about 15W -well within the input max of the amp.  Much cheaper than buying an attenuator and I needed it within 3 days before the contest.  Brilliant exploitation of lousy and lossy RG-58 performance at VHF.  Since then, I’ve built an ALC voltage injector, but need to test this out.

After a late start, I finally got down to San Marcos beside a park that I had found via Googlemaps. 

Band conditions were terrible.  Nothing on 2m despite my 300W SSB aimed at San Antonio and Austin.  I then switched to 6m and only received another ham in my same grid on FT8.

I decided my location might have been flawed (a wire gate surrounding the park yard, and noise from the adjacent train tracks, so I regrouped to my next destination in New Braunfels.

This location was in another park with great clearance and parking.  When I fired up, 2m was again dead.  Then I noticed my rotor started to give me error messages of,  “RotorShorted”.  Then Murphy decided to cast its signature fait accompli  by corrupting my Dell Laptop.  The message I received on the Window 10 laptop, said “recovery may take as long as 1 hour…”.  Because of the poor conditions, the chance of 6m FT8 was my only hope, but without a laptop, it was futile.  Getting ready to leave for a long trip back home,  I did meet a ham at the park, who stopped by to say “hello”.  He knew I was roving for the CQ WW VHF contest.  He was tending to his kids in the nearby playground and told me he tried to be an active ham in the early days, but had kids.  I told him now to worry– he’ll be back on the air again… after 5-10 years!  Luckily, he nodded and laughed..

So, I headed back home, with subsequent no luck recovering my Dell laptop.  Previously, Mike KA5CVH had given me a nice nearby 4 grid rover route by Katy.  On Sunday, I considered a consolation attempt using Mike’s locations.  I feverishly tried to reroute a rover path out there as an abbreviated Sunday attempt, but with time running out and the searing heat dome, I decided to abort.

Overall, I’m so delighted that I my 2m amp worked great as a mobile.  Also, I’m getting more proficient at setting up the rooftop antennas and equipment in the car.  The next big VHF/UHF+ rover event is in September.  It’s known to be a bigger event that this CQ WW VHF contest.  I’m already starting to plan for that one, with using my ALC injector to replace the 125′ coax attenuator, and perhaps a better rotor/mast systems and maybe more power for 440… or 20cm?  AND I’m hopeful that weather will be cooler.

73

-dave

W5OC