Is it possible to work meteor scatter on twenty meters? Let's take a look at some observations of radio contacts, correlate that with astronomical data, and see if meteor scatter on the HF bands is truly possible.
This observation comes as a result of operating in the field during the 2008 Hawaii QSO Party, KH6J, Camp Mokuleia, the morning of Saturday, August 23, 12:27-12:45z, 2:27-2:45 am HST.
Martin, KH6MB and I were working the KH6J station for the Hawaii QSO Party early on the morning of Saturday, August 23, 2008. We had just completed working the 40 meter CW band, and tuned up on 20 meter phone at 14.241 MHz. Martin programmed the voice keyer on the Icom IC-756 PRO III, and we started making contacts with the USA on 20 meters phone around 2:30 am in the morning, during the absolute bottom of the sunspot cycle.
The voice keyer would complete the call (after perhaps one, two or three times), and a US station would reply with their callsign. We'd reply with a 59 Honolulu County exchange, and they'd give us their 59 signal report and state. We'd give them a thank you, then press the voice keyer button. The phone contacts were occurring about one every 1 to 2 minutes.
We picked up Ohio stations and one Indiana station. As the Ohio QSO Party was on the same weekend, we began to recognize that there was some consistency with this path to Ohio. Both of us turned to each other with the same thought...this is a very odd time to work the Midwest, as 20 meter phone should not be open at that time.
It was highly unusual for contacts with the mainland on 20 meters at this time of the night and sunspot cycle. Normally, we would expect the sun to warm up the upper reaches of the ionosphere, make it refractive and provide the refractive hops for a 20 meter signal. Since Ohio was about four hours ahead of us, one of the two hops would be in the visible sunlight portion of the ionosphere and be possible for part of the contact. But, the second hop would be in darkness over the Pacific Ocean, with a MUF (Maximum Usable Frequency) way below 14 MHz, perhaps around 8-9 MHz or less. That's what usually makes that part of the early morning unusable for Hawaii-mainland contacts for 20 meter contacts for this time of the sunspot cycle. We would normally expect to be making 20 meter contacts closer to our twilight. Yet, the 20 meter phone contacts were occurring with some regularity every 1 to 2 minutes at 2:30 am in the morning.
I told Martin I thought we were experiencing meteor scatter on 20 meters. Martin was initially skeptical at the thought, although both of us recognized that meteor scatter is often reported on 50 MHz and above. It is difficult to work VHF meteor scatter in Hawaii, as the range for us would not be enough to make contact with the West Coast of the US. I asked Martin to ask the next contact for the amount of power he was using.
After the exchange of the 59 exchange, Martin asked the station how much power he was using. He replied that it was "The station setup here is a *pfft* .....". In mid-sentence, his signal went from a very strong and clear voice and rapidly fizzled out into nothing as he was speaking. That gave us strong evidence that we had just worked a meteor scatter over the Northeast Pacific that lasted perhaps 10 - 12 seconds on 20 meter phone.
We worked a couple more stations, then tuned up on 40 meter CW.
The Signals and Exchanges
These contacts were captured in the station log that morning.
|Time (UTC)||Frequency (MHz)||Station||Location||Report Received|
The station was an Icom IC-756 PRO III, powered by a Honda 1 KW generator, transmitting 100 watts. Located about 100 feet away, the antenna was a two element vertical wire beam positioned about 15 feet from the Pacific Ocean, on the shore of Mokuleia, facing approximately in the Northeast direction. The antenna was a 20 meter end-fed half-wave, supported by a DK9SQ pole embedded into the sand beach, and a reflector wire supported on a second DK9SQ pole about twelve feet behind the driven element. The driven element was tuned by Martin's home-brew tuner which transforms the very high, 4200 Ohm, impedance of the driven element to that of the coaxial transmission line.
The HF Conditions
The visible disk of the sun was spotless. The Kp index at that time was about 0. The GOES X-ray flux was below 10 -8 Watts, below the A class level.
A look around the Internet reveals little in the way of research and tangible observations for meteor scatter in the HF bands.
The Meteor Conditions
Click on this link to see a log of meteor activity recorded at the University of Ghent, Belgium for the month of August 2008. This is an image of the meteor conditions from that page. The meteor conditions at that moment were relatively quiet, having had a slightly higher amount of activity the day before.
2008 Hawaii QSO Party Overall Summary
This is a summary of the overall 2008 Hawaii QSO Party operation as provided by Bev Yuen, AH6NF.
Using only 100 watts and vertical wire antennas at the bottom of the sunspot cycle, it could have been a quiet weekend on the radio. However, there was plenty of activity. Here's some stats for the weekend:
Bands worked: 20, 40 and 80 meters
- 1270 total QSOs
- 875 of these were SSB
- 395 of these were CW (thanks Martin!)
- 48 US States. (We only missed N. Dakota and Maine).
- 5 Canadian provinces (as far east as Nova Scotia).
- 49 different countries (DXCC entities).
- 31 of these were European countries (with amazing pile ups on Friday and Saturday evenings!).
Martin Barr, KH6MB and Ron Hashiro, AH6RH, believe that we observed meteor scatter on the 20 meter phone band on the morning of August 23, 2008 at 12:30 UTC. The first hop was via meteor scatter; the second hop was the usual F2 layer refraction. The amount of meteor activity during the observed period was minimal, as opposed to a peak associated with a meteor shower.
Occurring at the bottom of the sunspot cycle, with no sunspots visible on the sun, and minimal meteor activity, it gives added encouragement for contesting on the HF bands above the Maximum Usable Frequency during early morning hours, especially towards the eastern direction as HF meteor scatter can skip the radio signals outside of the nighttime darkness and into the daylight, thereby expanding the hours of usable operations for HF contesting.
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