I'm pretty sure that there is no such data set in existence and I don't know of a good way to collect one. I expect there is sufficient data available from the WSPR folks (WSPRnet) for WSPR or from
Here's some references that are interesting... https://www.isode.com/whitepapers/skywave.html talks about variations over 10 seconds to a few minutes. http://tracebase.nmsu.edu/hf/reports/walnut.pdf
Here's the ITU-Recommendation F.1487, which provides a definition of standard ionospheric propagation path properties. They've been validated by field measurements, so it's a good place to start. ht
On 5/18/22 11:02 AM, Jim Brown wrote: On 5/18/2022 10:33 AM, Lee Hiers wrote: K1DG has a presentation he's done for Contest University. Per his study over time, he estimates that a 1dB improvement i
Or as I would put it, DXing RIP. well, more that there's nowhere left to DX to that's actually accessible. The whole DX entity thing is kind of political/philosophical - How big a rock sticking up c
On 5/18/22 12:51 PM, Jim Brown wrote: . What George has invented here is REAL ham radio. George has done at least a half dozen activations of remote islands with old friend from HA, several times sai
http://ham-radio.com/k6sti/pileup.htm As noted in the analysis limitations section, I'm not sure how much it really adds. But I do think a probabilistic approach is needed to tease out the effect of
From December 1983 to April 1989 I operated 160 through 6 meters from Kwajalein, Marshall Islands. The pileups were big and were there every time I pressed a key or opened a mic. I made 83,000 QSOs,
This is exactly what the models predict. It turns out that if you model two paths, separated by 2 milliseconds, with random phase, you get Rayleigh fading with 10-20 dB fades. I forget what speed th
On 5/19/22 6:35 AM, Charles Gallo (KG2V) wrote: On 2022-05-19 09:23, Lux, Jim wrote: <snip> I'm not so sure that it's out of reach. yes, trying to implement it with gear from 1980 would be challengin
On 5/19/22 11:38 AM, Jim Brown wrote: On 5/19/2022 6:23 AM, Lux, Jim wrote: I'm not so sure that it's out of reach. yes, trying to implement it with gear from 1980 would be challenging. But with more
Another thing, the antenna I saw seemed to be part of one of the (multi-band) hex-beam antennas. It didn't have an obvious feed-point; it just formed one of the hex sides of the (single band) hex-bea
73 John N5CQ HFTA should never be used to try to optimize stacking distance. It simply does not actually calculate the stacking gain as a function of stacking distance like EZNEC would. 73, Dave AB7E
On 6/22/22 12:18 AM, Jim Brown wrote: On 6/21/2022 7:37 PM, Billy Cox wrote: So outside of the cautions Dean shared, and used with other methods (EZNEC/etc.) why would one not use HFTA as a useful so
On 6/22/22 7:06 AM, Lux, Jim wrote: On 6/22/22 12:18 AM, Jim Brown wrote: On 6/21/2022 7:37 PM, Billy Cox wrote: So outside of the cautions Dean shared, and used w We could do a simple experiment abo
Great suggestion. Jim. I ran HFTA for four conditions at 14 MHz over flat ground. 1. two dipoles at 50 feet and 70 feet 2. one dipole at 50 feet 3. one dipole at 70 feet 4. one dipole at 60 feet
Below is from pages 12 and 13 of Dean's document, perhaps this might help to explain what you have observed there? ACCURACY AND TESTING THE RESULTS What would I estimate as the accuracy of HFTA eleva
With new, inexpensive VNAs, I think it would be interesting to start looking at redesigns of the typical 4 square control box. At a simple level, keep the same phase shift network (Collins hybrid), b
You might want 5/8" double braided polyester if your grip is bad, but 1/2" will lift anything a human can pull up. I'd also suggest, that if the "pull up" is difficult, you might want to modify your
Or, some form of low voltage relays and a hardwire connection. Or a WiFi connected relay controlled by a dedicated app, but I'd be a bit nervous about trusting a "safety sensitive" function to Alexa,