Sunday, 22 June 2014

Propagation is fickle

This past week, I set up an HT in my kitchen so that I could monitor a few of the local repeaters as I get ready to go to work in the morning. The radio is the dual-band PuXing PX-888K that used to be my mobile rig (before I got a tri-band Kenwood F6A for the car), so it has several out-state repeaters programmed in for potential use on road trips. The antenna is the laughable Nagoya UT-108 dual-band mag-mount with the really thin, lossy cable. I bought it about a year ago for a camping trip for (non-ham) communications between two campsites at Beaver Creek State Park, and considered it disposable. It was slapped on top of a camp stove and hooked up to a BaoFeng tuned to (unlicensed) MURS frequencies, and it served this (non-challenging) purpose well enough. On UHF, however, it's not much of an improvement over a stock "duck", and so it wasn't very useful to me beyond that camping trip. But I put it on top of the refrigerator and ran the cable to the PuXing on the kitchen counter. I even attached a speaker mic, and clipped it to a cloth on top of the refrigerator so that the radio's speaker didn't need to be facing me.

I had no delusions about this arrangement. It's a low-power HT with a marginal antenna inside of the building. But it worked okay for listening to the drive-time activity on the 146.850-, the 145.370-, the HandiHam 145.450-, and the 444.425+ repeaters. I was happy that I could get in to the .450 and the 147.000+ machines with this makeshift station. And, since the strong majority of my time is spent on UHF and 1.25M, it was an easy way to expose myself to two metres on a more frequent basis.

Yesterday (6/20), as I was getting ready to go to work on a Saturday, I put the PuXing on scan and set about the usual routine kitchen tasks, making breakfast, and packing a light lunch. I heard a CW ID come from the speaker mic, and I glanced over at the display because it sounded unfamiliar.

I was really quite surprised to find that I was picking up the 147.030+ repeater in Willmar -- over 75 miles away! I stabbed at the radio to stop the scan, and I was once again amazed to find that my feeble kitchen rig was "ker-chunking" the Willmar repeater.

Over the course of the next few minutes, I also "ker-chunked" the Baldwin 145.250- (53 miles), the Foley 147.050+ (50 miles), and the Avon 147.105+ (63 miles) repeaters! This is the same rig that utterly failed to bring up the Carver 147.165+ (20 miles) and the Minneapolis 145.370- (10 miles) repeaters the day before.

Obviously, there was a tropospheric opening on the the two-metre band.

If I didn't have people expecting me to show up at my job in the immediate future, I would have loved to experiment with that kind of propagation.

This morning, APRS is showing excellent propagation:

VHF propagation Sunday 6-22-14
 With a map like that, I should be able to reach hundreds of miles. However, I had no luck reaching distant two-metre repeaters with my FT-897D, my best VHF antenna and 50 watts.


4 comments:

Unknown said...

I agree with your band opening assessment. I've been able to get into the Giese repeater with my FT-60 the last three mornings. The antenna is nothing more than a small roll up j-pole stuck on my living room window at ground level. It comes back S5 and sounds very clear. It fades away by 11am to noon. I believe that is around 90 air miles to that repeater from here.

Todd Dugdale said...

The problems come in when new hams experience 50+ mile range on FM, and come to think that that's *normal*. I got a response from a new ham in Indiana last month berating me for my (putative) enthusiasm for PuXing. On one day he reached a repeater sixty miles away with a stock duck on a PX-777. A week later, he couldn't bring it up again, so the PuXing was "junk" and was "broken" -- and I was a "fraud" that he brilliantly exposed.

There are simple, low-tech ways of getting on the air, as you know -- particularly with FM. They are all compromises, however, and expectations need to be adjusted accordingly.

To me, the propagation effects are are an exciting and mysterious aspect of the hobby. I take what I can get, and I don't want to "look behind the curtain". It only spoils the fun. And it's *supposed * to be fun.

Unknown said...

propagation for me is sort of like when you go to the ice cream shop, and see that your favorite unusual flavor is flavor of the month. Enjoy it while it lasts, but it won't always be there!

Unknown said...

I did a little Google-Fu work, it's a little over 70 miles to the Giese repeater.

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