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Author Topic: New Antenna for DX-ing!  (Read 4685 times)
N4RSS
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Posts: 258




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« Reply #15 on: October 27, 2012, 10:30:02 AM »

I guess today is the day for stacked antenna stories.

I was on 10 meters this morning and I saw a huge signal on the Panadapter.  It turned out the ham was in Northern Ireland and his signal was 40 over S9 with the K3's preamp off.  That's just a huge signal because the meter on the K3 is very stingy and very few DX signals go that high on the meter.  I asked him what he was running and he said 7 over 7 over 7 over 7 on a 210 foot tower! He said K3LR designed the system and went to his QTH in Northern Ireland. He told me he had it built to his personal specs by M2. I told him I'd hate to have received the bill for that and he assured me it was indeed a big bill. His bill for all the 7/8th inch hardline was more than most guys spend on their antenna systems. It was an









incredible amount. He also had stacks for 15 and 20.  I mentioned Ian, VK3MO, who has that




big stack on 20 meters and he told me Ian supplied the prop pitch motor

I got the feeling the guys with massive antenna farms have a small fraternity and most know one another. He rattled off a bunch of calls with big antenna farms and I had heard of most.

He then told me about being at Dayton with some multimillionaire one year and the guy dropped one million in one day on equipment at Dayton. He actually had a staff who did the paperwork so he could spend his time going from booth to booth.

We had about a half hour QSO and I was told that was very unusual since most of his contacts were simply reports.  A very modest man. He said he usually does not talk about his station.
Needless to say it was one of my most unusual and interesting QSOs.  Thank God for the P3 panadapter!

73,

Chris/NU1O



That sounds like Ivor. I believe he builds race car engines
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NU1O
Member

Posts: 2662




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« Reply #16 on: October 27, 2012, 11:13:01 AM »


That sounds like Ivor. I believe he builds race car engines

Since he was not a braggart and said he rarely discussed his antenna systems I did not mention his call, but, yes, it was Ivor, GI0AIJ.  He has a website which has some photos of him racing his motorcycles back in the 70's.  He does build engines and was headed to his shop when he signed with me.

Here is the link to his webpage:

http://www.gi0aij.com/default.htm

73,

Chris/NU1O
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WA2VUY
Member

Posts: 136




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« Reply #17 on: October 28, 2012, 11:24:02 AM »

Back a couple of cycles ago there was an Italian station that had 8x8 yagis....those 64 el were loud.
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NU1O
Member

Posts: 2662




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« Reply #18 on: October 28, 2012, 07:26:33 PM »

Back a couple of cycles ago there was an Italian station that had 8x8 yagis....those 64 el were loud.

Ivor told me no matter how big an array you put up somebody comes along and beats it.  In that respect I guess it is like car engines or any competitive sport.

I'm not greedy.  One day I'd just like some stacked Yagis and a beam, it doesn't matter how big, for 40 meters.  I heard the station on from the Mariana Islands Sunday morning at 20 over S9 on 40, but my inverted V was not good enough versus beams.

73,

Chris/NU1O
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KY6R
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Posts: 3173


WWW

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« Reply #19 on: October 31, 2012, 03:31:03 AM »

The antenna system that I actually have ended up with is a design by Tom, N6BT of Force-12, and now N6BT fame, and one where we collaborated with Dean, N6BV to validate the idea and my implementation of it. It is 100% home brewed because I wanted to control all parameters (I wanted maximum gain at the expense of some F/B). I will significantly lower the TOA - so I will start hearing the DX that others hear in NCAL - but that I don't.

Its a stack of two 17/12M interlaced 2 element yagis. They are spaced a half wave apart on 17M on my AB-952 rotating tower. I will rotate it from the bottom.

I will have 7 dBd on 17M and 8 dBd on 12M. Tom says it is the equivalent of a 6 element long boom yagi on each band. The boom of these antennas is only 7.5 feet - and fit on my rotating tower with a very low wind load.

On "Tower 2", I will have the Force-12 C3S that I just picked up for $150. I will run A-B tests.

You can see the plots on my QRZ.COM page, and this will form my next years Pacificon Antenna Forum presentation.
« Last Edit: October 31, 2012, 03:59:18 AM by KY6R » Logged
NU1O
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Posts: 2662




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« Reply #20 on: October 31, 2012, 10:44:19 AM »

Rich, or anybody else that has the information I'm looking for,

I want to learn how to use EZNEC as well as to learn how to physically build a robust Yagi.  I have the ARRL Antenna Handbook but I know there must be some specialty books on both antenna modeling, and actually building a Yagi so I don't have to reinvent the wheel.

Some recommendations on very good books relating to these topics would be very helpful.

73,

Chris/NU1O

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KY6R
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Posts: 3173


WWW

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« Reply #21 on: October 31, 2012, 06:22:34 PM »


Some recommendations on very good books relating to these topics would be very helpful.


You should look at YW - Yagi for Windows, which is free and comes with the ARRL Antenna Handbook. Its written by Dean, N6BV, and I used it instead of EZNec to build my 3 element 17M yagi. In fact, it comes with many files that you can just load into YW and instantly get the "taper schedule".

What I did - because the taper schedule that it suggested did not match the actual aluminum that I had on hand (I bought several old yagis that were in AI6V's "antenna graveyard"), and so all I had to do was tweak the taper schedule to match my aluminum, and VOILA!

I did use EZnec just to validate that YW was correct.

YW is a lot easier to use than EZNec.

I've never used a book or read a manual - but I have had worked with three West Coast antenna designers and basically emailed EZNec files back and forth and chatted on the air about what I was trying to do.

I made a ton of silly mistakes at first. The best hint I can give you is to add one thing at a time and keep going back and looking at the "SRC DAT" button. You have to make sure that - if you are trying to build a 50 ohm direct feed yagi - that SRC DAT _ALWAYS_ shows 50 ohms - with as little reactance as possible.

The other thing to do is make sure you run the geometry and segment check - and I always use "Conservative".

That's about it. The best way to learn EZNec is to keep opening files that are from the ARRL Antenna Book CD and seeing what is going on. Its pretty intuitive.
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NU1O
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Posts: 2662




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« Reply #22 on: November 02, 2012, 06:22:32 AM »

I received a bad disk with my 2010 or 2011 ARRL Antenna Book. I would've called and asked for another book (and disk) but it was months after I had bought the book so I have a nice book but my programs do not work.

Rich, do you know if those programs, like YW, are in the public domain?  I'd love to be able to go to a site and download a copy that works.

I do not buy an ARRL Antenna Handbook every year since so little changes.  I have 3 different copies and have been licensed for 24 years and even those 3 copies have much repetition but it's not as if there is radical change in antenna theory every year.

73,

Chris/NU1O
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N4OGW
Member

Posts: 302




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« Reply #23 on: November 02, 2012, 10:04:47 AM »

One program I have found very helpful when building HF yagis is YagiStress (http://k7nv.com/yagistress/). It will estimate the wind survival of your antenna.

It also does useful things like figure out the weight of the antenna, whether it is torque balanced, where the balance point is, the resonant frequency of each element, etc.

Tor
N4OGW
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NU1O
Member

Posts: 2662




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« Reply #24 on: November 02, 2012, 12:02:26 PM »

One program I have found very helpful when building HF yagis is YagiStress (http://k7nv.com/yagistress/). It will estimate the wind survival of your antenna.

It also does useful things like figure out the weight of the antenna, whether it is torque balanced, where the balance point is, the resonant frequency of each element, etc.

Tor
N4OGW


Thanks for the info.  That looks like more than I need at present but I have it bookmarked for the future.

73,

Chris/NU1O


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KY6R
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Posts: 3173


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« Reply #25 on: November 02, 2012, 08:32:03 PM »

The two yagi's are now built and tested. One is on the tower - for a picture - check out my QRZ.COM page.

Both will be tuned and ready to DX by Sunday - maybe even Saturday (tomorrow).

73,

Rich
KY6R
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K5GS
Member

Posts: 91




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« Reply #26 on: November 05, 2012, 02:02:54 PM »

So, the big question is (drum roll):

Will it all be ready by ZL9HR  ??

73,
Gene K5GS
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KF6ABU
Member

Posts: 351




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« Reply #27 on: November 05, 2012, 02:13:49 PM »

So, the big question is (drum roll):

Will it all be ready by ZL9HR  ??

73,
Gene K5GS

ZL9 is a picnic from W6. 10-20m no problem.
« Last Edit: November 05, 2012, 02:17:16 PM by KF6ABU » Logged
KY6R
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Posts: 3173


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« Reply #28 on: November 05, 2012, 06:18:07 PM »

So, the big question is (drum roll):

Will it all be ready by ZL9HR  ??

73,
Gene K5GS

Yes. The first yagi is up at the top and I have been testing it on the air. ZL9A pounding in here S9 +20 on 17M right now.

The second one goes up in the next couple of days - so I will have everything done by this weekend.

It was a lot of work, but well worth it.

I learned a ton - and had a lot of fun too. The weather here has been perfect for working on antennas - upper 70's.
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KY6R
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« Reply #29 on: November 08, 2012, 02:03:02 PM »

FINALLY got the stack up and running 100%. It took 3 weeks and 2 weekends, but it sure was worth it. The Array Solutions Stackmatch II box is killer - really does some cool things, and not sure why yet - the circuit is just a switch with and UNUN.

I have never had an antenna like this before. It has a measurable 6 dBd gain and with only 100 watts I am busting pileups like I have never done before - even when I tried 1.5 KW.

I am busy testing, measuring and recording my results (I have a reference dipole and am taking measurements in the same directions), but first impressions are that on my AB-952 rotatable mast  - that replacing the A3S with this antenna system was a great idea.

This took more than 200 rivets and a drill press and lots of tuning . . . using a hack saw . . .

« Last Edit: November 08, 2012, 02:26:30 PM by KY6R » Logged
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