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IMAX2000 no GPK vs 1/2 wave Silver Rod
- Thread starter RadioDaze2.0
- Start date
Here is a wider view of where this hot spot is on Galveston. The map should be active and you can make it zoom. If you zoom out to include Houston my station is right inside the Loop 610 at 290 and you can see how I am positioned relative to the Island and the sky line of downtown Houston.
https://www.google.com/maps/place/G...2!3m1!1s0x863f59c8c4059259:0xe58b03c9b9eaecc1
https://www.google.com/maps/place/G...2!3m1!1s0x863f59c8c4059259:0xe58b03c9b9eaecc1
I even learnt something about Texan geography there ; )
One day when skip seems ok and the wind is low I must go out with the set up to some coastal location.
One day when skip seems ok and the wind is low I must go out with the set up to some coastal location.
Well I guess I'll add my $.00002 worth...
I bought a Proton99 just for this type of installation and was a little disappointed by it's seriously 'light-duty' construction, however, it almost kept up with my Imax 60' in a tree when mounted on a 1/2 wave high portable mast. It also stomped my A99 in several different distance tests and made me a believer.
The Good:
1) Near Imax 2000 level performance, a true 1/2 wave, 18' long above the 1' bottom mounting tube.
2) Breaks down into four 4.75' sections, 19' total versus the 17.5' A99.
3) Light and easy to quickly assemble.
4) Rated at 10 million watts - wait, ...oh yeah, 2000 watts.
5) Crazy inexpensive; $68 to my door.
The Bad:
1) Rather flimsy construction, requiring a fiberglass 'touch-up' to make it as stout as I like.
2) uhmmm...
The Ugly:
1) When assembled it's typically a little snake-ish, not straight as an arrow.
2) Needs (NON-metallic!) paint, bright white & stands out like a horse peni...
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That is actually a plus point. The more rigid it is the more stress it puts on the base when its windy. By "beefing it up" you may unintentionally be hastening its demise due to the additional lateral stress being placed on the base. There are times where being rigid is good and there are times where having a bit of flex is better. The reason the top section of the Imax 2000 is so bendy is it seriously reduces lateral loading on the base section when its really windy.
Well, actually the base is what I had to glass up, the glue used to secure the fiberglass to the metal wasn't holding & preventing from spinning, though it stayed together I felt it should have a better secured bottom section.
I also modded the top by using a Wilson whip & a 3/8 x 24 tip from a Whiskey Still type mobile antenna to cut down on the wind loading for portable application.
I set the rings to near X=0 with the original top then swap out and re-tune by trimming the whip length.
So Bob85, sorry, a little off-topic but I'm wondering if you've ever tried your I-10K at .64WL? I know it's only 6.5" longer but Marconi's EZNEC plots show considerable improvement at a mid angle TOA and what a mess that so-called 'small difference' makes of the SWR if the match remains adjusted for .625.
Just wondering, since I did see an improvement when tried with my I-10K several years ago and thought it might be interesting to hear your report.
No NB,
My 10k is set very close to jay's settings from the paperwork for the frequency i use,
at those settings it has a small edge on the gainmaster but its behind any of my sigma/vector antennas on the same pole,
mainly due to their extra length and height of current maxima.
My 10k is set very close to jay's settings from the paperwork for the frequency i use,
at those settings it has a small edge on the gainmaster but its behind any of my sigma/vector antennas on the same pole,
mainly due to their extra length and height of current maxima.
I have owned the Imax 2000 and the Ham International Silver Rod 1/2 wave antenna for over 20 years now. I have both antennas here broken down looking at me in the corner. I remember when I had the silver rod up (at 20ft) for a quick setup, a distant signal was giving me around a S7, when I swapped out to the imax (no gpk) the signal went up to around a S9. I got out much better with the imax in my field comparisons. When I swapped out my imax 2000 (with GPK) to a Mr coily enforcer with 7/16" din the signals went up another 1 1/2 sunits or so (on a galaxy 55/66/99 style of 60db meter), very noticeable with reduced background noise. it was like i had a amp turned on all the time when I was only running barefoot. Short 75 foot run of heliax 7/8", nothing less...
Yepperz, that's right about what I've seen. a basic .625 = about 1 solid S-unit over an Imax2k and the .64 about .5-1 S-unit above that.
Then there's the NV4K... Still awaiting that perfect weather/energy day to replace the P500.
I have done so many back and forth comparisons with all these antennas and which analyzers over the past 10-20 years, its nuts. I have spent so much time and money and effort. After I put up the coily ground plane, I change out the lmr400 to heliax 7/8 and that was also another noticeable jump in rx/tx improvement as the total losses was significantly lower. That setup outperformed a vertical 4 element maco 104 and a gizmotchy 4 element mounted at the same height by a wide margin, the only thing the beams give me was rejection, however I should note it was not a fair comparison because the beams where using lmr400 and not heliax, which is a great difference between the two, and the coily uses a superior connector (7/16" din versus so-239 on other antennas). I would have to say you would need about a 6 element maco 106 or a 5 element optimized longer boom beam to outperform that very low loss .64 groundplane heliax setup. If I ever run another coily groundplane setup in the future I am going to run the newer excalibur .64 with heliax Direct Feed connect with LDF7-50A 1 5/8" heliax.
6dB per S-unit is more myth than real world. I usually figure about 1.5 to 3dB on most CBs, 3-5dB from most Amateur radios.
- Here's a good read about measured dB per S-unit: http://www.ac6v.com/sunit.htm
- Here's a good read about measured dB per S-unit: http://www.ac6v.com/sunit.htm
NB I agree on the S-unit myth especially in CB's.
I do a lot of testing and experimental building on 11 meters mainly due to the fact it is not such a big antenna, cost effective, and there is always someone to get a signal report, ( helps if you know who is doing the signal report and since I align most of the radios in this area I know how many s-units per db their meter displays)
Usually about 3 db per S unit on most rigs until you get to S9 then it is anyone's guess.
Crazy D. with all due respect, I have 35 years in communications and I have never seen any transmission line, be it ladder line, coax, hard line, or even fiber optic than can INCREASE SIGNAL strength of an RF signal.
The claims of your heliax greatly improving tx and rx over lmr400 at HF frequency would need to have some very expensive, sensitive test equipment to see any difference in receive or transmit.
A simple S meter on a CB would not even show a needle width of difference.
Post a video or something to substantiate your claim.
Not saying you are not telling the truth, just looking at specifications of cable loss at HF freq for the two transmission cables you are using.
Now if it was UHF MAYBE there could be that big a difference.
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