Tuesday, October 15, 2013

Sometimes it Pays to Check the Power Output!

The QRPARCI Fall QSO Party took place second weekend in October. I took an oppurtunity to participate in it albeit in a limited fashion. Mainly I wanted to test deploy my End Fed Half Wave antenna, and have some fun slingin' some dits and dahs.
20m Portable Operation, QRPARCI Fall QSO Party
Saturdays I work a monster 12 hour shift beginning at noon. After I got done doing some UI testing, and before the next batch of jobs I have to monitor began, I decided to take a half hour lunch break to feed my brain using ham radio, specifically the QSO Party. I sprinted out to "El Toro" (our red Mazda Tribute) after clocking out for lunch, and got to my station. This is the third time I've deployed in the parking lot using a wire antenna like this, and it was the first time I've used the EFHW to make a QSO from the parking lot. I made exactly one QSO, with NM4T on 20m. The EFHW did well over all, lots of signals, some were VERY loud, especially the SKCC WES stations near the QRP watering hole. I did make a couple of mistakes though.
1. I assumed I had everything I needed in my box. when I got out there, I realized I didn't have the connector for my 7AH gel cell battery. I did have the end that plugged into the radio, but not the end that plugged into the battery.
2. I could have used a second roll of fishing line. The EFHW works well on 20m with 33' or 66' of line deployed. I used 33' because I didn't have a way of stretching the second 33' section out, and time was too short to attempt a redeploy of the antenna. I didn't want to cut the line because I felt that would have been a waste of string.
3. I intentionally left my NoGAwatt at home, and I missed it. I like having the reassurance that my forward power is good to go. I would have checked, and then removed it from the line. I've discovered that it does add some non-trivial at QRP levels loss in the line, so I left it home.
Sunday I try to limit my "on the air" time in favor for some "play with the kids time" but I did take a little time to play radio at my in-laws from their driveway. We went over there to eat hamburgers, and the kids were playing as the sun was setting. This time I deployed on 40m, and confirmed my issue number 2: when setting up an EFHW on 40m as an inverted vee (It kinda looks more like a caret (^)to me) It helps to have two separate lines, one to support the middle, and one to support the far end. I keep a piece of paracord handy in the box to tie down the end where the RF goes.
Best Pic I have of my Sunday Night Setup
This time instead of using 20m I decided to go with 40, using "The Killer Watt Radio." It's supposed to be calibrated to transmit at one watt with the little 8 cell AA battery pack I use. That's with a fresh battery pack. I did take a better picture of my setup, but right when I snapped the pictured, my phone's battery died and it was lost :(. I did managed to get two QSO's on 40 before the skeeters got bad, and about carried me off. The first QSO was with WB4MNK, he was so loud, I had to turn the gain down to be able to hear anyone but him when tuning to people calling on nearby frequencies.
The second QSO was with N0WL. I had hoped that I could stay around and work him during the 4SQRP SS after the ARCI Party, but I could not stand the skeeters.

Monday morning I decided to check out my power levels and I discovered something interesting. The open circuit voltage on the battery pack was down to about 11.7 volts, and I was transmitting about .689 watts on both radios! This makes my Fall QSO party power multiplier a 10. Heh! that's one way to boost your score.

Here's what I learned:
66' of wire can be tough to quickly deploy without two support lines. I could have gone for a single support on the far end as High as I can get it, but I think I get some benefit from having the high current portion of the antenna (on 40m at least) at the apex. Might be worth modeling, if I can ever get a computer that will successfully run software.
  • Check and double check your kit, and make sure you have power redundancy. That saved my bacon both days, because I forgot the part that hooks up to my battery the first night, and then I forgot the part that hooks up to the radio the second night!
  • If you think you'll use it, bring it. I didn't technically "Need" my NoGAWatt, but I missed having it.
  • Bugspray is your friend, but having a layered strategy is better. Wish I had long sleeves, bugspray, and some sort of "area skeeter control" gadget with me instead of just bugspray. Them things are meaner now than when I was a kid!

GB Hoyt

1 comment:

Unknown said...

I love reading posts like this. Makes me so look forward to operating portable again. Nice story with some good lessons.