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Bullseye
| | Posted on Sunday, June 22, 2003 - 12:16 am: | 
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Been using the Maco V-58 for years but the neighbors tree slapped this last one,and it lost the fight.(the ant.not the tree) Wondering what everybody thought of these two or comparison of all three. Figured maybe it's time to try something different. |
Tech833
| | Posted on Sunday, June 22, 2003 - 1:59 am: |
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How high will you be mounting the antenna above ground? How much wind do you get? |
mikefromms
| | Posted on Sunday, June 22, 2003 - 6:23 pm: |
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The AP is 5/8 wave while the SD is 1/2. AP should have lower radiation pattern and therefore higher gain. The AP will handle the wind better and is easy to install. According to the antenna test done here at Copper the AP wins every time in the under 30' height comparisons. I'm not convinced it would do so badly up over 30'. It sure mounts great to a pole, actually around the top of the pole. Only 4' sticks up above the pole!
Mikefromms
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Bullseye
| | Posted on Sunday, June 22, 2003 - 9:53 pm: |
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The feedpoint of my Alpha is about 33ft. and it is tower mounted. I live about 30 miles from the east coast of Florida so we get some serious wind occasionally hence the antenna slapping tree but thanks to the handy-dandy McCullough that won't be a problem anymore. |
Tech833
| | Posted on Monday, June 23, 2003 - 11:16 am: |
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If you have the ability, put up a Maco V-5/8 and live hapily ever after. |
CM 3885
| | Posted on Monday, June 23, 2003 - 11:38 am: |
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If this tells you anything about the AP I hope it helps.. I used to talk to an old timer a few years ago that swore by the AP. He bought his new in 1974 and had it up on 2 diff houses and he had it up about 35' in the air on his second house. He talked all the time off of it and never had any problems getting out on it at 35'. AT one time he put it up 70'on a tower and he said it worked great up until he bought his beams that replaced the AP then it went on the roof of his house and was used as a standby.. |
Kc0gxz
| | Posted on Monday, June 23, 2003 - 4:19 pm: |
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Bullseye
Like Tech-833 suggested, the Maco V-5/8 is a good choice. You also might want to consider the I-Max 2000.
Both the Maco and the I-Max are 5/8 wave and both perform equally well. About the only difference between the two is the fact that the I-Max is 24 feet long and will by far out-broadband the Maco V-5/8 and there are no radials to worry about. If broadbanding is not a factor, then go with the Maco V-5/8.
If ever hit by lightning, the Maco is more than likely to survive a strong hit where the I-Max won't. "Capacitance grounding for the I-Max". (Bummer)
I personally prefer the I-Max ONLY because of it's length and it's 3Mhz bandpass. I have one on a 60 foot tower and 20 feet of masting under it. That puts the tip a little over 100 feet in the air so I can clear a few trees around here.
I lost one due to a lightning strike. Actually, the Max didn't take the hit but the mast did. And it was still enough to blow the Max to pieces. The trouble is, there is no REAL way to ground a I-Max. Or a A-99 for that matter.
I'll leave you with this. Whatever you decide to put on your tower next, just remember that there is NOT a 11 or 10 meter omnidirectional antenna on the market that will ever out-perform any 5/8 wave antenna.
Ah hell. Just go with what Tech-833 suggested. Don't pay any attention to me. I ramble.
73s my friend.
Jeff, kc0gxz. |
mikefromms
| | Posted on Tuesday, June 24, 2003 - 12:08 am: |
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Also, keep in mind the Astroplane is a 5/8 wave and is very broadbanded. It was tested by techs here at Copper and at 30 feet and below outperformed I-max 2000 and all. That does say something about it. Also, it works wonderfully as a shortwave receiving antenna on just about every band. The I-max and Maco are great antennas too.
Mikefromms |
Tech833
| | Posted on Tuesday, June 24, 2003 - 10:51 am: |
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Hey Mike,
Here's a test for you.
In your opinion, why does the Top One recieve better on SW than the Maco V-5/8 or the Imax 2000?
Go ahead and think out loud. I'll provide the answer in a couple days. |
mikefromms
| | Posted on Tuesday, June 24, 2003 - 11:35 am: |
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Tech833,
I figure it's because this is one continuous antenna. It runs almost a full circle and is one of the few ground planes (if not only one) to operate effectively in the vertical and horizonal mode at the same time. Also, The ground effect does not affect this antenna, which is why it operates so good close to the ground. It's a strange looking bird, not ugly, that certainly makes you wonder why you would need another antenna for shortwave. I've yet to try it on my scanner to see how high I can receive well on the VHF and UHF.
So, am I close to the right answer?
Mikefromms--getting back into the hobby and giving Copper my business....
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mikefromms
| | Posted on Tuesday, June 24, 2003 - 11:49 am: |
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I need to add that I have never tried receiving shortwave signals on a Maco V-5/8 nor the I-max 2000. I can't say which is "better." If it is a fact that the AP out receives these two on shortwave then my conjectured answer above is my opinion on why this is true.
I've spent a lot of time lately restudying antennas. There's a lot of good antennas out there. The I-max gets too many good reports to be a fluke. What turns me away from the I-max is the total length of the antenna. I've read reports where it just can't take the windy areas. The Maco V 5/8 would be my antenna of choice if I were going to place one really high followed by the Astroplane, old starduster or Attron 305.
The Attron 305 gets high scores from every one who has reported on it. Some report it to outperform the Maco 5/8, starduster and A-99. Maybe when the Anttron 305 is back in production, Copper techs can test it out in the above 30' and below 30' catagories and see how it pans out in their test. I believe their tests to be honest. Afterall, it would be convenient to have the highest dollar antenna win every catagory just for profits sake. I mean, I would assume antenna salespeople would make more profit on the sale of I-max 2000 or Maco V 5/8 than on a Top One Astroplane, which is cheaper but won the under 30' catagory. I appreciate honesty. Thanks techs! Oh, please do test the Anntron 305 for us.
Mikefromms |
mikefromms
| | Posted on Tuesday, June 24, 2003 - 2:14 pm: |
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Might I add to my answer about the AP being a better shortwave receiver than Maco 5/8 and I-Max 2000--the others are end fed and have coils which don't mix well with the earth or ground.
This is my final answer.
Mikefromms |
Scrapiron63
| | Posted on Tuesday, June 24, 2003 - 3:54 pm: |
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I would guess the astroplane receiving SW would have something to do with the grounding, if its an open or shunt antenna, its been so long since i've had one, don't remember much about them. I know lots of the CB antennas will receive SW very well if you back the shell of the connector off, just use the center conductor, that works best at 80 meter or below. I use one of my tower guy wires as an antenna for my old hallicrafters 99 tube type receiver, man does that thing pickup those far off AM stations at night time.
Mike, don't sell that I-Max 2000 short on taking wind and ice, when I first saw one, I thought the same thing, but after having one up on this mountain top in Arkansas for a few years, I changed my mind. It'll take the ice and wind, i've saw it almost bent double with ice. Its not my main antenna, but is very good for a ground plane. I've always thought that higher is better, thats why I bought this mountain top years ago. If your total height is limited to 30 feet or less, the AP is better I suppose, but if you just have say a 30 mount, pole or tower, with the AP, your total height want be over 34 feet or so. Put that old I-max 2000 on that same mount and the tip will be near 54 feet, I think it's gotta be better, especially if you have any trees, buildings or anything blocking your signals.
scrapiron |
Kc0gxz
| | Posted on Tuesday, June 24, 2003 - 7:01 pm: |
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Scrapiron63-
Excellent point.
The Astroplane IS the one to have if you are limited to height. But when height is not a factor, the I-Max or the Maco 5/8 will out-perform the rest. I personally like the I-Max only because of its length and it's near 3Mhz bandpass. The longer the 5/8 wave + the higher the 5/8 wave, the farther the 5/8 wave is going talk.
It's scary looking at the Max in a wind storm but it's a lot tougher that it looks. I've only lost one due to a lightning strike but it sure can take a lot of Nebraska Plains heavy wind with the tip at a little over 100 feet.
mikefromms-
I have a little test for you. The next time you have your Astroplane pluged into your SW receiver, back the PL-259 out a little bit so the collar and ground are not touching the SO-239. Watch the receive come up even more down there on 80 and 40.
Jeff, kc0gxz. |
Tech833
| | Posted on Tuesday, June 24, 2003 - 11:01 pm: |
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Jeff,
You're right, the Imax 2000 and the Maco V-5/8 will work better than the Top One (Astro Plane) when mounted higher above ground. In fact, I would take an Imax 2000 over an A99 anyday, except in really windy areas.
The Imax 2000 performance and bandwidth make me like it even a little better than the Maco V-5/8. I have one on top of the tower on my office with the Imax GPK. It is fed with about 110 feet of 1/2 inch Andrew Heliax. I only use it for listening, but might key up some day. I chose the Imax 2000 w/GPK because I knew it would be the best performer in my installation. The tip of the antenna is 106 feet above ground. |
Bullseye
| | Posted on Thursday, June 26, 2003 - 10:17 pm: |
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I appreciate all the input guys. This is why I love this forum. I have looked at all the antennas mentioned plus. The main thing I am looking for is wind and lightning durability. Here in Central Florida (Hurricane Central) we get a lot of both and for that reason,short of a 10k, the Alpha is going back up on the tower. It will probably be a couple of weeks cause I gotta get new coax and all but thats all part and parcel of this hobby. Once again thanks and hope to hear y'all again soon.. |
mikefromms
| | Posted on Friday, June 27, 2003 - 6:52 pm: |
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Tech 833, what was the answer to the question?
Mikefromms |
Tech833
| | Posted on Friday, June 27, 2003 - 9:09 pm: |
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Not enough guessing yet. I'm waiting to see if someone knows. |
mikefromms
| | Posted on Friday, June 27, 2003 - 11:16 pm: |
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Now I'm wanting to know how to get my swr right on 27 mhz. It's fine on 28 mhz.
AP tuned to 28 mhz.
Mikefromms |
Kc0gxz
| | Posted on Tuesday, July 15, 2003 - 3:49 pm: |
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Tech833
In reference to your (Tuesday, June 24, 2003 - 10:51 am) post, I am curious to know why you think the Top One receives better on SW than the Maco V-5/8 or the Imax 2000. It's possible that you may have posted the answer elsewhere and I may have missed it.
I have used my Max for receiving SW with good results by unscrewing the collar of the PL-259 from the back of my receiver. Without the shield being intact or touching the radio in anyway, the coax becomes part of the antenna. Or actually, it makes for a very long antenna. However, it still doesn't compare to my 135 foot Van Gordon All Bander.
Those of you with SW receivers should give it a try. Plug your "CB antenna" into the back of your receiver and tune to a weak signal. 40 meters or below would be a good testing point. Once you are there, unscrew the coax, then back the PL-259 out a bit so only the center conductor is touching and the shielding is not touching the radio at all. When you do this, the receive will jump up dramatically.
Looking forward to your thoughts, Tech833, because I know they will (as usual) be interesting.
73's my friend.
Jeff, kc0gxz. |
Tech833
| | Posted on Tuesday, July 15, 2003 - 8:49 pm: |
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No guesses? |
Kirk
| | Posted on Tuesday, July 15, 2003 - 10:12 pm: |
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elevated feedpoint reduces ground loss and results in a more true 50 ohm impedence match to feedline? |
Kc0gxz
| | Posted on Wednesday, July 16, 2003 - 1:49 am: |
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Tech833
Come on already. Will you cut it out and tell us?
Personally, I haven't got a clue to your question.
Jeff, kc0gxz. |
mikefromms
| | Posted on Wednesday, July 16, 2003 - 11:37 am: |
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is it off center fed, is that the answer?
mikefromms |
Tech833
| | Posted on Wednesday, July 16, 2003 - 5:32 pm: |
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Here it is...
The Imax and V-5/8 are end fed 5/8 wave designs for 27 MHz. The base of these antennas have an impedance of a couple thousand ohms (at 27 MHz.). To achieve a 50 ohm feedpoint at the base, they are 'tapped'. If you examine the schematics for the Imax, you will see that the coax center conductor and shield are seperated by only a few turns of wire. On the V-5/8, it is a few inches of the matching ring seperating the two conductors. As frequencies go lower than 27 MHz. that 50 ohm tap goes lower and lower in impedance and is more and more of a 'short'. By the time you get down to 5 or 10 MHz., that tap is like 1 ohm or less. That's the same as shorting out your coax right when it gets to the antenna!
However, the Top One seperates the center conductor and shield by 15 feet of aluminum wire. That raises the tap impedance on shortwave frequencies quite a bit. The rest of the mast, guy wires, etc. act like antenna, and the tap point impedance is low enough that much of the induced signal makes it down the coax and does not get 'shorted' to ground.
Trivial, but fun to contemplate.
Keep in mind, the Top One does not make an ideal SW antenna, that is not at all what I am saying. A long wire works much better! This was just answering Mike's pondering about why the Top One would make a better SW antenna than an Imax or V-5/8.
Actually, the Firestik type mobile antennas make pretty good SW antennas too. |
Tech833
| | Posted on Thursday, July 17, 2003 - 10:11 am: |
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Tech833,
Taken care of for you.
Lon
Tech808
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