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Base An idea for strengthening iMax 2000 top section

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My IMax came down in a Delrecho back in 2014. When it did the top section snapped in half. Not having any funds available at the time I had a 102" whip mounted in a 12" whip extension in the garage I used to run on my truck. I screwed that on top and adjusted the swr by the whip since the rings didn't get moved. The top of an Imax is 96.5 inches. 96.5 inches didnt work on the whip setup. Eventually got it tuned in at 103.25". I set my center frequency at 27.505 as I talk on 27.485 most of the time. Swr at 505 was 1.0. 27.205 was 1.1 and 26.905 was 1.2. At 29.100 the Swr was 1.5. I was able to stay below 2.0 12 thru 10 meters. It would also tune decent on 20 meters and 6 meters without a tuner. I have ran this set-up since June 2014. I just recently pulled antenna down to add the gpk and run it up another 10ft. The bottom is still solid although it did have green moss on the north side of antenna. I coated the bottom and middle section after a light sanding with first a white marine epoxy paint and then a clear coat of marine epoxy. We re-raised the antenna back up the next day and swrs across the bands are still the same. The whip and extension still looked like new after 6 years of weather. Anyhow with this configuration the top still sways in the wind but not as wildly as the original but has not had any affect on the lower sections. At winds of 30 mph it hardly moves. I have had several more delrecho's since 2014 and numerous high wind warnings with no effect. I will also say with this configuration it did lower the noise level 1 s-unit. Only until recently did the antenna become noisey again and thus is why we took it down. Reworking it did not help the noise level and neither did the gpk. The coax still looked good but did put a new run of lmr-400 on it anyway. Then on a reccomendation of a long time antenna builder added a MFJ-915 at the transmitter. That dropped the noise level 2 s-units and seemed to increase the radiated power of the antenna. Guys 30 miles away I went from a S-5 to and S-7. I think the rest of my noise issues are from wall-warts and led lighting I recently switched to. Im in process of fixing those issues with torroids. So my point anyway is yes a 102"whip will replace the top section but for the one poster if you ever try that dont cut it down first. The 12" whip extenson is very light and really adds no extra strain to the top. I use the hollow aluminum one. If anything it balances the whole lower unit even better and still lets the whip dance and move when needed. I even think it may broadband the antenna a little further than original spec. My whip does have a corona ball on it about twice the size of a normal one. I made it from a ss ball bearing. I do think the little extra length needed by the whip is due to velocity factors of different materials. Either that or the wire is wrapped in the original top section just enough to shorten length the 96.5 in. FYI the whip and extenson is 20 plus years old and has been used time and time again for different projects prior to going on top of the IMax. Its even had several thousand watts run thru it on more the one occasion. 2000 on the IMax a few times. I don't normally run more than 150watts however 98% of the time. I know this post is old but with Covid and such been reading a lot of different stuff and ran across this post.

73's

Buzz
 
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