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IMAX 2000 GROUND PLAIN?

Marconi in your test did you get the antenna mount isolated from a metal mast on to a non condutive pole. if not then your mast was still part of the groundplane and radiating. this is what freecell and others have been saying is very important.
also the balun at the feedpoint to keep the coax from radiating.

after doing those 2 things is when i noticed the difference in RX and TX.

locals say not only did my TX go up on there RX but also said my audio was clearer. oh and i havent heard from the nieghbors all week.

i had one older tv that i would comeover in the audio section of it. that is no longer there.
8)
 
FL Native said:
Marconi in your test did you get the antenna mount isolated from a metal mast on to a non condutive pole. if not then your mast was still part of the groundplane and radiating.
Click to expand...
How would I go about isolating my Imax from the pushup pole that it's mounted to? Also I have a grounding cable run from the base of the Imax to a ground rod sunk 8'. Am I understanding this thread correctly that I do not need that extra ground?
 
I never could understand why these antennas have so many 'unusual' characteristics. You know: wide frequency use, low SWR across the entire bandwidth between 10-12 meters, too much TVI, and always needing a choke/balun. When the ground plane kit is used, it is almost never setup the factory recommended way and works better. Isn't it just a dipole with a tuning coil in the base?!?
Is it ultimately fantastic or horribly pathetic?
I'm afarid of buying one and trying it. I've even read that one guy (on 'eHam') claimed that he can uses it from 10 meters all the way up to 20 meters.
?????????????

Also, there are constant arguments that the db output is inflated, while some people say that they aren't rated high enough. The is one of the most puzzling antennas that I've ever heard of, one that doesn't seem to work the same way in any two places. I had a 'Big Stick' years ago, and thought it was OK for talking locally, but couldn't get it to talk skip at all - and certainly wasn't even close to the performance of my old-and-long-gone Archer 5/8 wave.
Does it run on snake oil? I'll give it a "7" - because it's easy to dance to.
Go figure...
:confused:
 
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this method works a treat cajun
http://www.worldwidedx.com/cb-antennas/32337-modified-silver-rod-spiderplane.html
i can confirm a substantial improvement in tx/rx performance with the endfed silver rod and a99's,
the s5 -s8 report came from a local ham using a yaesu ft840 with larger increases shown on the stupidly over happy ft847 meter,
if your worried about grounding i would ground the coax where it reaches the floor, you can buy ground clamps for coax from decent suppliers.
 
Switch Kit said:
I knew a guy that used the ground plain kit upside down on his Antron 99 ....he swore up and down that it helped reduce a lot of his TVI .....He always sounding great !! ......I wasn't going to argue with him or doubt his theroy , but boy did that antenna look silly up ther in the sky like that !! ......but I always though those sigma 4s looked kind of strange as well but boy did those antenna's kick some a$$ out there on the airwaves !!
Click to expand...

Like a Sirio Vector 4000
reMARKable - YouTube
http://youtu.be/7dH16PyV0Lo
 
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Just for grins here are some facts you can believe, they are very common in the industry.
An 'A99' is an end fed 1/2wave antenna. A 1/2 wave antenna no matter if it's end fed or center fed is used as the standard antenna other antennas are compared to for gain. A 1/2 wave antenna has no gain at all it is 'unity'. A typical 1/4 wave antenna has a slight negative gain when compared to a 1/2 wave. A typical 5/8 wave antenna has a very slight gain when compared to a 1/2 wave. That's a fact no matter what any manufacturer says, it's physics and not changeable. The typical advertised gain figures for almost all antennas are more advertising than anything factual.
The 'A99' doesn't require a 'groundplane', or the 'other half' of the antenna, because it uses the feed line as that 'other half', or something like 9 feet or so of it. So does the Imaxx, it uses the feed line too. Adding a groundplane to either antenna is changing it's design and will either have no effect or probably only a -perceived- effect. That -perceived- effect is more imagination than anything factual unless something other than the commonly sold 'groundplane' kit is used, that thing is too short.
Really wanna understand all this stuff? Then I would suggest you find some published texts by reputable authors. What you hear on forums is mostly incomplete at best (that includes me too).
have fun.
- 'Doc
 
I've been reading and studying but also because of another thread in which the member has swr problems with his newly installed A99. I tend to agree with Booty Monster about his comments on the subject. I too had thought about running a RF choke 1/4 wavelength down the coax from the antenna feed point or at least put a stub on it.
What authors would you suggest?

By the way,I've been using my SS 1/4 wave R/S whip for a base antenna with my tv antenna's booms for a ground plane. Every time I key up my tv picture freezes.
 
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Lil'Yeshua said:
I've been reading and studying but also because of another thread in which the member has swr problems with his newly installed A99. I tend to agree with Booty Monster about his comments on the subject. I too had thought about running a RF choke 1/4 wavelength down the coax from the antenna feed point or at least put a stub on it.
What authors would you suggest?

By the way,I've been using my SS 1/4 wave R/S whip for a base antenna with my tv antenna's booms for a ground plane. Every time I key up my tv picture freezes.
Click to expand...
ROFL!
And you are surprised by this?
 
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Robb said:
ROFL!
And you are surprised by this?
Click to expand...

ROFL? Don't know that one.
I'm wanting to get my A99 up this week and I want to get the install nailed down. My brother has dibs for at least one of my tv antennas so that will put more space between the remaining tv antenna and the A99.
Hey!, the SS whip works!

I could use the two of these I have along with four 101.5" SS R/S whips for a ground plane.
http://www.mfjenterprises.com/Product.php?productid=MFJ-347



P.S. Those of us who are learning the hobby are in a way,children of those who have gained knowledge,wisdom, and experience. A springboard to propel those learning farther.
 
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I still think in order to have a fully function able A99 that it needs it's other half,namely,the GPK-1 ground plane kit. Plus I'd like to see how it performs myself even if it has marginal gains instead of using the mast,coax,etc.... For the other half.
This is a learning experience for me and I'll get it right. In the future it Might be possible to enhance it and lengthened to a 5/8 wave along with extra tuning on the bottom end. Also, I have my MFJ-971 QRP tuner to tweak it but I want to get it right at the antenna end first.

P.S. Yes,I've read to where you need a 5/8 wave antenna before you start seeing any appreciatable gain.
 
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No; you cannot simply change the length of the antenna to make it a 5/8 wave unless the tuning coil inside was also changed out. Not worth hacking it up to do that either.

You can always make a 5/8 wave antenna from scratch, lotsa guys have done that and there are lots of threads on this forum that can help you do it.
 
Robb said:
No; you cannot simply change the length of the antenna to make it a 5/8 wave unless the tuning coil inside was also changed out. Not worth hacking it up to do that either.

You can always make a 5/8 wave antenna from scratch, lotsa guys have done that and there are lots of threads on this forum that can help you do it.
Click to expand...

Yeah. I was thinking about making one from scratch. I'm wanting to get this A99 up and running this week while I'm on vacation and don't want any unexpecteds. That's why I've been studying. I have enough material to make one sans the matching section. Thanks.
 

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