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View Full Version : Optimum 6 Meter yagi height for Sporadic E



WS4B
05-05-2012, 09:56 PM
E-season will be here in just a few short weeks and I have made a decision to get on six this summer and try my hand at this band. I am thinking of getting a five element yagi and spending most of my time at or near 50.400. Since my intention is for e-skip, is 15 feet above ground the best height for a yagi of this size? I am looking at a boom length around 20 feet. Since I live in an HOA development with antenna restrictions, the weight of the antenna I can just put on a telescoping pole w/o a rotator at 12 pounds. Any suggestions on the best height of the antenna would be appreciated, knowing that on six meters the signal may be there one moment and gone the next! (No old buzzard transmissions I guess)

KM1H
05-05-2012, 10:28 PM
Low for close in E and high for long and double hop. Aurora is mostly high angle.

At one time and mainly for contesting I had antennas at 20, 60, 100 and 190'. All had their good moments. Currently just have one at 60' but a quad of LFA 5 el at 190' is in the works.

Carl

KO6WB
05-05-2012, 11:34 PM
Having the antenna that low is okay for sporadic E. Having it higher wouldn't hurt and for any terrestrial type of work it's an absolute necessity. You will still be able to make contacts though just not very far or very strong. That is if you are not living on the top of a hill.
As Carl has already pointed out the incoming signals can vary widely on the angle of propagation. Contest operators know this and usually have antennas at different heights. The higher antenna isn't always the one with the best signal.
The best thing to do is to put the antenna up and use it.
73
Gary

WB2WIK
05-05-2012, 11:34 PM
I'd say often "really high" for 2x and 3x hop Es.

Best demonstration I ever saw of that was in 1987 during the June VHF QSO Party, when as a multiop group we ran WB2WIK/4 from FM27 off the coast of VA. The 6m antennas were on a crank-up tower on a tower trailer, so could go from about 25' above ground to about 75' above ground in just a minute or two

The close-in single hop was all pretty easy with the tower nested. But when the band opened for double-hop, and then later triple-hop (we worked from VA to Alaska and Hawaii, both, via 3x Es), we could hear absolutely nothing of those stations -- not even 1 dB over the noise -- with the antennas nested. Cranking them up all the way, those signals became S9. Cranking it back down, they completely disappeared. What a graphic demonstration of height vs. angle.

We had absolutely no obstructions in any directions, operating from an island at the beach. Nearest "hill" was probably 50 miles away.

KM1H
05-06-2012, 12:41 AM
More likely double hop E linked to F2 which is rather common for those paths at the bottom of the cycle.

I remember during the sun peak year of 1991 I had a 6 el at 60' and another on a different tower at 170' (that tower was later extended 20'). During a F2 opening I could hear loud West Coast stations calling HI but couldnt hear them on the 60'. Switched to the 170' and the HI was loud and the West Coast was down around S2 and there was a KL7 in there also calling. Sort of created a mini uproar when the KH6 answered me on one call and the KL7 broke in to ask if I could have the KH6 listen for him. All 3 of us than chatted for a bit commenting on the strangeness of this 3 way which gave me my last 2 states and 2 new countries and I was the first NH for both. Nobody else in the area was hearing either one including other hilltoppers with 50-80' high antennas. After that I worked 3 more HI and the locals were listening and giving me a ribbing so I put the receive audio on the 2M repeater that we used for DX alerts.

Carl

WB2WIK
05-06-2012, 12:50 AM
I know what that's like. I've operated from Mt. Pinos (el. 8831' asl and about 3000' above average terrain) working long strings of JAs on six when all the locals came on nearby repeaters to talk about me making it all up. I had to play the audio back to convince them, nobody else was hearing anything.

In 1979 from Mt. Pinos, using N6NB's mobile station (a kW and 5L beam on a 30' crank-up on the back of his van) I made AJD (workd All Japan Districts) in two hours, and got an award from them saying I was the first U.S. station to make 50 MHz AJD.

KM1H
05-06-2012, 01:17 AM
My hilltop property is at 650' ASL but it drops to the 150-250' area in under a mile in most directions which results in lots of ground gain. The new array will give me a chance to try some EME aimed at the negative horizon which will give me several more degrees of moon time.

WB2WIK
05-06-2012, 01:31 AM
My hilltop property is at 650' ASL but it drops to the 150-250' area in under a mile in most directions which results in lots of ground gain. The new array will give me a chance to try some EME aimed at the negative horizon which will give me several more degrees of moon time.

That should be fun. Differences in terrain are really something. 650' asl here would be 200' below my patio.:o

And I'm in the city!

Of course unfortunately there are also hills 'round here that go to 11,499' asl. All in southern CA, before even heading north where they get a lot higher.

WS4B
05-06-2012, 01:33 AM
Thank you everyone for the replies. I guess height depends on type of propagation. With single hop e-Skip being the most "common", I guess I will go with a 15-20' antenna height. Again I cannot erect an actual tower due to my HOA antenna restrictions. I am hopeful that a 5 element at that height will produce good single hop results. Since I will be spending most of my time looking for AM QSOs on 50.400, I would rather have the single hop opportunities that may have a longer proprogation duration than those of multi-hop which have a smaller condx window. Thanks again everyone.

WB2WIK
05-06-2012, 02:01 AM
My hilltop property is at 650' ASL but it drops to the 150-250' area in under a mile in most directions which results in lots of ground gain. The new array will give me a chance to try some EME aimed at the negative horizon which will give me several more degrees of moon time.

That should be fun. Differences in terrain are really something. 650' asl here would be 200' below my patio.:o

And I'm in the city!

Of course unfortunately there are also hills 'round here that go to 11,499' asl. All in southern CA, before even heading north where they get a lot higher.

WB2WIK
05-06-2012, 02:08 AM
Thank you everyone for the replies. I guess height depends on type of propagation. With single hop e-Skip being the most "common", I guess I will go with a 15-20' antenna height. Again I cannot erect an actual tower due to my HOA antenna restrictions. I am hopeful that a 5 element at that height will produce good single hop results. Since I will be spending most of my time looking for AM QSOs on 50.400, I would rather have the single hop opportunities that may have a longer proprogation duration than those of multi-hop which have a smaller condx window. Thanks again everyone.

The band has to be really open for Es on AM. The S/N difference between AM and SSB is about 12 dB. So when the SSB ops are working stuff that's S2 or so, on AM you probably wouldn't hear that.

Also there's a LOT more SSB/CW activity on six than there is AM activity. However, it all happens and go for it!

I worked a lot in Cycle 20 (which peaked in '69-70) on six meter AM. I had both SSB and AM at the time, but there was still quite a lot of AM and it was great fun.

My AM rig at that time was a Clegg Zeus (120W carrier power, plate modulated AM) and NC-303 receiver with a Tecraft nuvistor converter, and a 6L beam on my parents' roof at about 35 feet. Worked a lot of stuff.

Most of the "DX" on six is around 50.110 on SSB, or below 50.100 on CW.

WS4B
05-06-2012, 02:31 AM
Also there's a LOT more SSB/CW activity on six than there is AM activity. However, it all happens and go for it!


I totally understand that Steve, but being a die-hard AMer I want to give it a try this summer. This is one of the many wonderful things about our hobby in that we can try something totally different and see how it goes.

My expectations are realistic in anticipating a handful of contacts on a weekly basis between mid June and the early part of August. I'll be using an American made rice box (so to speak) in an Omni VII with the yagi. Nothing ventured nothing gained and I'll use the AMfone web site in an additional effort to generate some e-layer AM activity here in the SE US this summer on six.

K8JD
05-06-2012, 03:31 AM
I just returned to 6M after a 20+ year absence. I was in a hurry to get my new 4 el HyGain Yagi up and stuck it on a mast below my 10M Yagi at about 25 ft.
With QRP on SSB & CW, I Have only heard some local and Aurora DX signals so far.
I worked some of the locals (up to 40 miles away) and tried to work some AU answering several CQs but no luck there.
The only station I worked outside the metro area was 90 miles away and he HAD A 125 FT TOWER.
Higher is always better for good results on VHF !


height will produce good single hop results. Since I will be spending most of my time looking for AM QSOs on 50.400, I would rather have the single hop opportunities that may have a longer proprogation duration than those of multi-hop which have a smaller condx window. Thanks again everyone.[/QUOTE]

WS4B
05-06-2012, 04:24 AM
I just returned to 6M after a 20+ year absence. I was in a hurry to get my new 4 el HyGain Yagi up and stuck it on a mast below my 10M Yagi at about 25 ft.
With QRP on SSB & CW, I Have only heard some local and Aurora DX signals so far.
I worked some of the locals (up to 40 miles away) and tried to work some AU answering several CQs but no luck there.
The only station I worked outside the metro area was 90 miles away and he HAD A 125 FT

I am just curious if your return to six meters has been since last summer? I ask because it is my understanding that six meters experiences two e-skip seasons. There is a minor one around Christmas/New Year's, but a much stronger/longer season during the summer months. Thus you may have not been back during a long E-layer season. I subscribe to DX Sherlock with the e-mail alerts. I am already seeing condx on six becoming frequent with e-layer propagation clouds. My upcoming six meter venture is mostly centered on the oncoming summer e-Skip season(s) ending in August. I say that because I am sadly fearful that Cycle 24 just won't produce the solar numbers to provide F-layer propagation on six, and we may have to wait for Cycle 25 for that.

WB2WIK
05-06-2012, 04:27 PM
I've been on six since 1966 and my observation is the peak Es season is generally mid-to-late May through about early-to-mid July. It's actually a pretty short "season" typically lasting about six weeks.

Es can happen any day at any hour, though. The "peak season" is only that, when it occurs most often with most intensity.

I'm only on CW/SSB and don't even have AM capabilities on 6m anymore, but I might build or pick up something for that. My amps work on any mode, I really just need an exciter. Good luck this season, it will be starting very soon, probably within 1-2 weeks.

ND6M
05-06-2012, 09:51 PM
well, I am only about 150 miles south of you,...... salt water on 3 sides DOES make difference!!

my neighbor abt 5 mies away has an m squared antenna, don't get me wrong, they are good antennas on six, but,.... he just can't understand how my home made 6 element quad hears better than his yagi.

I don't tell him that I can raise or lower my quad on the tower by just pushing a button.

WB2WIK
05-06-2012, 10:20 PM
Much of what can be heard/worked depends more on location specifics than on the antenna, for sure.

I could have ten stacked 6L quads on six, at 4500' above sea level in Gorman, CA and would be able to work very little from there, since that's in a depression surrounded by much higher hills in almost all directions.

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