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Message |
    
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 222
Registered: 5-2002
| | Posted on Monday, June 13, 2005 - 10:34 am: | 
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look at this on e bay gpk that will get you 30 plus on tx and rx.haint figured out what the 30 plus is yet
the skilletlicker
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Hotwire
Intermediate Member
Username: Hotwire
Post Number: 404
Registered: 1-2005
| | Posted on Tuesday, June 14, 2005 - 11:29 am: |
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Speaking GPK on A 99s.......I was in Indianapolis the other day and looked up at a small tower with an A99 and noticed that the monkey who installed it put the GPK on upside down. Now I have been trying to find out who this is so I could maybe be enlightened as to why but have had no luck so far. I have never seen such a thing and to be honest it looks silly. When I get the info from the owner I will post again.
Skilletlicker....maybe they mean gain? Maybe 30 plus miles |
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 223
Registered: 5-2002
| | Posted on Tuesday, June 14, 2005 - 3:12 pm: |
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i am beginning to think tha lot of the sellers on ebay dont know split beans from coffee about electronics.if that antenna would give me a 30 db gain on transmit and recieve i sure would like to have it
the skilletlicker
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Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 659
Registered: 7-2004
| | Posted on Tuesday, June 14, 2005 - 3:52 pm: |
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GPK don't add much gain on tranmit or
recieve, but, seem to be helpful with
lowering the angle of radiation and from
spraying yourself or neighbors with
stray RF.Maybe they mean 30% more gain
or something to that effect. |
Dx431
Senior Member
Username: Dx431
Post Number: 1060
Registered: 2-2002
| | Posted on Wednesday, June 15, 2005 - 1:54 am: |
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Hotwire, I saw a GPK installed upside down on an Antron 99 when I was in Cheyenne WY. a yr ago, and it puzzled me also. I would think it would raise the angle of radiation and shoot your signal more straight up rather than out like most omni's do. Dunno, I'm just guessing here.
I would like to see what the signal pattern would look like.
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Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 664
Registered: 7-2004
| | Posted on Wednesday, June 15, 2005 - 12:21 pm: |
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A upside down mounted GPK...Hummmmmmm
I do see what that would do expect look
funny... |
Yankee
Advanced Member
Username: Yankee
Post Number: 669
Registered: 7-2003
| | Posted on Wednesday, June 15, 2005 - 1:27 pm: |
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 , Haven't seen or heard of a GPK down side up. I can only guess that after playing with different types of groundplanes and beams since 1963, that turning the GPK over does change the transmitted signal more skyward for working skip. Might even be worth a try on my IMAX-2000, If I could beg, borrow or get one dirt cheap, does sound interesting although. I can understand that strange things can work with antennas.
Carl CEF-357 |
Hollowpoint445
Intermediate Member
Username: Hollowpoint445
Post Number: 399
Registered: 6-2004
| | Posted on Wednesday, June 15, 2005 - 4:50 pm: |
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If the radials were even with any part of the radiator it would change the antenna's resonance - to what extent I'm not sure. Most GPKs aren't even 1/4 wavelength long, so it's effect - good or bad - might be minimal. |
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 224
Registered: 5-2002
| | Posted on Thursday, June 16, 2005 - 3:55 pm: |
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i took my gpk off of my 99 and raised it five more feet ,i am going to see if this will make any difference,asi feel the extra height might be better
the skilletlicker
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Hollowpoint445
Intermediate Member
Username: Hollowpoint445
Post Number: 408
Registered: 6-2004
| | Posted on Thursday, June 16, 2005 - 6:49 pm: |
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Higher is better - although if it's already in the clear another 5 feet won't make that much of a difference. The important thing is that it's clear of any local obstructions. |
Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 665
Registered: 7-2004
| | Posted on Thursday, June 16, 2005 - 10:18 pm: |
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How high is your antenna to the bottom
feedpoint Skilletlicker??? |
Shady
Junior Member
Username: Shady
Post Number: 30
Registered: 12-2004
| | Posted on Thursday, June 16, 2005 - 11:25 pm: |
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Im not sure about the GPK on A-99, but, I have a old Shakespear Pogostick I got for free, When I got it, the 3 wire radials of the GPK were upside down, first question in my mind was why they were pointing skyward, guy I got it from said it seemed to recieve better that way... While I was looking up info on it, I came across a page on Shakespears site with a FAQ, one of the questions was about the GPK for it and which way they went, Shakespear said it didnt matter which way radals were facing but didnt go any farhter into it, Im still curious on how it actually does affect it by turning them upside down.
William
CEF#463 Northwest Florida |
Crackerjack
Advanced Member
Username: Crackerjack
Post Number: 665
Registered: 7-2004
| | Posted on Thursday, June 16, 2005 - 11:51 pm: |
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An extra five feet could make a lot of difference.
It is not just the distance to the ground, it has a lot to do with lowering the "Take Off" angle, which jncreases the dustance effectiveness,
How much? That depends on a lot of other factors, but 5 feet is a BIG deal.
At 20' my Skylab was a useless, local only groundplane, And not very good at that.
At 30', it rocks and I turn down the power to 2W to use it within a 30 mile range. |
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 225
Registered: 5-2002
| | Posted on Friday, June 17, 2005 - 5:39 am: |
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from ground zero to feed point is 30 feet
the skilletlicker
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Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 666
Registered: 7-2004
| | Posted on Friday, June 17, 2005 - 3:39 pm: |
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Someday if possible, which you might
have streched how high it can go now,but,
try 36ft to feedpoint if possible. If not
30 ft is good. |
Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 667
Registered: 7-2004
| | Posted on Friday, June 17, 2005 - 3:52 pm: |
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I did have an Imax 2000, but, fell while
taking it down and it broke in half.
But, anyway the Imax was up 38ft to feedpoint.
I borrowed my uncles Top One antenna for
awhile until i get up my I-10k.
I was alittle surprised at the ears on the
Top One as it's up 31ft to bottom hoop.
At a lower height it outhears my Imax, but,
does not out talk it though.
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Hollowpoint445
Intermediate Member
Username: Hollowpoint445
Post Number: 409
Registered: 6-2004
| | Posted on Friday, June 17, 2005 - 5:31 pm: |
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Omnidirectional sticks aren't dependent on the distance above the ground for their angle of radiation because they're vertically polarized. The most important thing is that the antenna is in the clear and the coax isn't radiating. Horizontal dipoles and yagi-udas are much more dependent on their height for their angle of radiation.
The reason raising the antenna gets you better range is that you're increasing it's line of sight. When the antenna is low to begin with it makes a big difference, but as it gets higher and higher the added height makes less of a difference. |
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 226
Registered: 5-2002
| | Posted on Saturday, June 18, 2005 - 10:12 am: |
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thanks hollow point that gives me a lot to think about
the skilletlicker
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Bigbob
Senior Member
Username: Bigbob
Post Number: 1980
Registered: 12-2001
| | Posted on Saturday, June 18, 2005 - 6:21 pm: |
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Hmmmm.According to the arrl antenna book,height above ground does affect angle of radiation of vertical omni's especially vertical di-poles but excluding the 1/4 wave ground plane.Bigbob |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1981
Registered: 12-2001
| | Posted on Saturday, June 18, 2005 - 6:26 pm: |
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One more thing,ask this in the antenna section and specifically ask for tech 833's opinion,he is the antenna man bar none,if there is one man that practically knows everything about antennas,he's the one.Bigbob |
Hollowpoint445
Intermediate Member
Username: Hollowpoint445
Post Number: 412
Registered: 6-2004
| | Posted on Saturday, June 18, 2005 - 7:56 pm: |
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Of course antennas react with their environment. Ground plane antennas react with earth ground too - why do you think they are an exception? Because they have a "ground plane?" It's not really a "ground plane," it's a counterpoise and needed to make the antenna resonant.
THE MOST IMPORTANT CONCERN for a vertical omnidirectional antenna's radiation pattern are local obstructions. When the antenna is high and in the clear the pattern will be more regular AND as you get higher above earth ground the radiation angle drops. Like I said earlier - HIGHER IS BETTER! The effect becomes less and less critical as you get several wavelengths above earth ground. For VHF HI and above you can basically ignore it because height becomes far more critical.
When I made that post I originally was going to use different verbage, but for simplicity's sake I worded it like I did to emphasize the importance of height. I assumed those that knew better would understand why I made the post that way. |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1987
Registered: 12-2001
| | Posted on Sunday, June 19, 2005 - 6:32 am: |
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I hate to type,I use one finger and it's frustrating.But WORDS MEAN THINGS,we may all consider each other freinds,but I don't really know anybody on here or their education,so I try not to take anything for granted when explaining my point,simplicity is nice,but I'd rather be boring to 99 people if just one achieved enlightenment on the subject.Bigbob |
