6meter and 2meter yagi

[kg7td]

I want to build a VHF station for meteor scatter and 6 meter openings. What would be the best antenna for this mode? #I have a 48ft tower and #the ICOM 706 transceiver.
Any help would be appreciated.
Gerry Pennington KG7TD
<a href="www.citlink.net/~kg7td" </a>

This should probably go in the "Q & A" section, but just very briefly, for 6 meter openings, a good beam with perhaps 4 or 5 elements should be sufficient. If the band is open, that's all you need, and more elements tends to make the darn thing rather "peaky" (too narrow a beamwidth).

I don't know much about meteor scatter, so I'll leave that for someone else to tackle, except to say that it doesn't sound to me like a very practical method of getting signals around !

Jean

[kg7td]

Thanks Jean-
This is my first post and your reply is helpful.
thanks
Gerry Pennington KG7TD

[WB2WIK]

To work meteor scatter any time other than during a major shower or storm (which only happen a few times each year, and many of those are fizzles) takes more hardware than that.

A typical, successful 6m m.s. station would include a long-boom Yagi (or more) with low-loss transmission line and usually a large power amplifier. By "long boom," I mean 20 feet or longer (quantity of elements doesn't mean as much as boom length), and the majority of active m.s. stations are using 24'+ booms, often more than one. And a kilowatt.

m.s. is a tricky mode that requires some skill and experience to navigate. Typically, you're trying to make contact with another station you can only hear maybe 1% of the time, so your mind must fill in the 99% that's missing -- takes some doing. Not unusual for an entire m.s. transmission to be copied as just a few individual letters and nothing more than that -- and that's when large antennas and high power are employed. But if you already know the callsign of the station you're trying to contact, hearing a couple of letters is more than enough to let you know he's really there, and to encourage you to keep on going at it, to capture more copy.

On c.w., most m.s. contacts are made at rather high speed (typically 30 wpm or more, since going slower is extremely inefficient when the other station only copies one second of each 30 seconds' worth of transmission) and indeed many m.s. contacts are made on HSCW (high speed CW, usually computer-generated and several hundred words per minute) or WSJT modes.

On SSB, successful m.s. operators learn to speak very quickly and very distinctly, using excellent diction, no accents, while actually speaking 200 words per minute or faster. I can say my callsign, "WB2WIK" about thirty times within 30 seconds, clearly and distinctly, so that if the other station hears one second worth of my transmission, there's a good chance he'll get the whole call.

If you use casual conversational operating technique for m.s., you won't complete a single contact.

Obviously, since m.s. contacts are usually just above the noise level, running high power provides a far better chance of completing two-way contacts.

When I was very active on 6m m.s. back in the 1970's and 1980's (and made m.s. contacts pretty much every single day, with or without any shower activity), I ran a pair of stacked 5L beams at sixty feet, 1/2" hardline, and 1500W PEP from a homebrew 4-1000 amplifier (which I still have). Contacting anyone similarly equipped -- and there are many who are similarly equipped -- made for pretty reliable m.s. work at least weekly, if not daily.

Running lesser equipment can result in contacts, but they can be few and far between, or possibly only during the major showers (like the Perseids).

Still, although a lot is "in the hardware," a whole lot is "in the operator," and sharp operating skills go a long way when working m.s.

WB2WIK/6

[K3UD]

While not in the same league with Steve, I did work quite a bit of m.s. in the mid to late 60s using a Swan 250 and a pair of HyGain 4 element beams up about 35 feet. It was mostly high speed CW but there were times when SSB skeds got through. The Swan ran about 90 watts out.

I upgraded to a Clegg Venus and Apollo Amp which gave me about 350+ watts out and I noticed that m.s. became a bit easier to do. While the receivers were pretty good for their day, they probably would not compare with what is available today in the way of low noise front ends. With my setup, random nightly contacts were almost impossible. Running schedules with other m.s. enthusiasts was the way to go back then as you knew someone was listening and transmitting.

I had very good luck during meteor shower periods and during VHF contests. M.s. allowed me to snag contacts in sections that I otherwise would not have gotten in the contests.

I would think that with 100 watts out of the 706 and a single 5 or 6 element long boom beam at 30+ feet, you would have a fighting chance of making contacts, especially during high periods of meteoric activity. However, you will most likely not be able to emulate the kind of performance Steve describes.

M.s. was always a thrill for me everytime I accomplished it.
Good luck, and let us know how you make out if you do try it.

73
George
K3UD

[WB2WIK]

Hi George K3UD...since you were on 6m SSB working a bit of scatter back in those days, I wonder if we ever worked? Probably did.

The guys I used to contact via m.s. on pretty much a daily basis from my home in NJ included K9HMB (IL), K8MMM (OH), WA9SDC (WI), WB2OTK/4 (SC), lots of others, nearly all running 1kW or more and large antennas. My first reasonably successful m.s. setup was a Venus and Johnson Thunderbolt 6n2 at about 1kW PEP output, with a 6L Hy-Gain (24' boom) at 45 feet. From there, I only went "up" in power and antenna gain, for many years. Worked FP0CA via 6m m.s. when almost nobody as far south as NJ made the contact.

I don't think "today's rigs" are any better than "yesterday's rigs" when it comes to receiver performance on six meters. A noise figure better than about 2.5 dB on 50 MHz is pretty much a waste of time, if you have an antenna connected to your receiver, because sun noise runs higher than that almost always.

What has improved, obviously, is frequency accuracy and stability. Today's rigs are just about perfect, the old ones weren't.

I doubt the IC-706MK2G is a very meteor-worthy receiver on six, although I'm not certain of that. The reason I doubt it's as good as, say, an old Venus is that the 706MK2G has no receiver front-end bandpass filtering, at all. What it has is selectable low-pass filters which are used to meet FCC purity requirements as you switch bands, and those filters are also used in the RX signal path. But the front end is very wide open and subject to fairly easy overload, from what I've been able to tell. If I connect a 706MK2G to my 20 meter beam at home, and then tune across 20 meters, it hears lots of signals that simply aren't there: They are images resulting from intermodulation, and they're not present on my "big rigs" at all. I think that makes it a fine mobile/portable rig and not so fine a base station, at least not if you use large antennas.

WB2WIK/6

[kg7td]

Thanks to everyone who responded to my antenna question. The replies were very helpful.
I've decided on the 2M5WL and 6M5X from M2 and an upgrade to the 706 may also be in the works.
thanks again!
Gerry Pennington KG7TD

[WB2WIK]

KG7TD, good luck and success!

BTW, I think you'll find that the 2M5WL is very sharp, having such a narrow beamwidth that it's a bit difficult to steer...this thing is sharp as a razor and although it does have a lot of gain, if you have any play in your rotor at all, you can literally miss stations because you go past them with the beam. I stopped using such long-boom and "sharp" yagis many years ago, in favor of shorter-boom stacked yagis having equivalent gain but much broader horizontal beamwidth.

The 6M5X, on the other hand, is fairly "short" for 50 MHz (18'http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif and not very sharp at all. I have one, and I think you'll like it. If I get serious about 6m again, I'll get another 6M5X and stack it with the one I already have -- that would be a "scatter worthy" setup.

73,

Steve, WB2WIK/6

[K3UD]

Steve,

I know we probably worked everytime we were both in a VHF contest. My first one was the January 65 VHF sweepstakes as a Novice at the K3ZSG's station on two meters. I was pretty active in VHF contests up until 1976 either operating with my WA3DNC call or with the the Packrats and some other contest groups.

As I recall your signal into the Philadelphia area was pretty good... to say the least. You may be right about the old receivers. I used a converter with 417A on two meters which was very good for weak signal work. The Swan and the Venus IMO had decent receivers although there was not a narrow filter option other than outboard audio filtering which would have helped.

Yes, I remember K8EEE and K9HMB, there was also a WA9 from Northern Illinois, and several around Nashville and Memphis.

Meteor Scatter is about as different experience as you will have with any propogation as everything comes in very short bursts. I think my best m.s. contact was with CO2CN. All of a sudden he was there for about 10 - 15 seconds and we worked, then he was gone. Right when I finished up my brother came into the shack and told me about a large fireball crossing in the southeast sky withing the time frame. The ionization lasted much longer than is typical. Another interesting effect was working someone via extended tropo and also hearing m.s. bursts on the signal.

I know of at least two hams in the Philadelphia area, Pres, W3MFY and AL, K3CZI who claimed to have worked m.s. while mobile. I think they are both SKs now.

73
George
K3UD

[WB2WIK]

Hi George,

I sure remember Pres, W3MFY, very well. He owned Trevose Hamtronics and I purchased several items there over the years, mostly in the 1970's. He lived around the corner from the store and that enormous, self-supporting 140' (or so) tower which occupied almost his entire backyard was hard to miss.

M.s. while mobile should be possible for a very experienced operator who knows how to complete a contact in about five seconds. I've never done it, myself, but I have had "complete contacts" in 5 seconds or less, so I imagine if I had been mobile during one of those, it could have happened.

2m m.s. is a whole different story! I'd never recommend that anyone start out life trying to work 2m meteor scatter -- just too difficult. I recommend anyone interested in this interesting mode start out on 6m, figure out how it's done, and then try 2m after at least a few dozen m.s. contacts' worth of experience.

I've also worked 220 MHz m.s. a couple of times! Talk about incredibly difficult -- it's painful. As WB2WIK/4 in FM27 (Chincoteague Island, VA) in 1987, we had about every kind of propagation imaginable during the June VHF QSO Party, including tons of Es, 2xEs, 3xEs, m.s., Au -- and tropo ducting. It was an amazing weekend, complete with thunderstorms directly on top of us that forced us to shut down a few times. We made an m.s. contact on 220 MHz SSB with W5LUA (he was WB5LUA back then), distance about 1000 miles. Don't know what Al was running, but my station was 1kW output from an 8877 to four stacked yagis up 50' on a trailer-mounted tower. I know almost nobody who's made successful 220 MHz m.s. contacts, then or now.

73!

Steve, WB2WIK/6