Imax 2000 swr problems

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Astro fantom
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Imax 2000 swr problems

Post by Astro fantom » 01 Oct 2019, 22:25

For some odd reason the swr on my imax seems to have a mind of its own..
I can use it one day and all is fine swr at 1.1/1.4 :twisted: from 26 to the low end of 28mhz no problems then go on again the next day and its 3 plus across the bands..
No ideas why it does this as it can be caml weather and dry and still be high but then sorts its self out the next minute..
I have took it down cleaned the s0239 made sure the drain hole was clear and put it back up but no change so now wondering if this antenna is ready for the bin or does anyone have any ideas why i seem to be struggling with high swr as its become damned annoying now

108EH002
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Re: Imax 2000 swr problems

Post by 108EH002 » 02 Oct 2019, 11:58

I wouldn't say its ready for the bin,cleaning a pl259 isn't the same as cutting the coax and re-doing the pl259's again.

1) I would start with doing all of the pl259's first.
2) If still the same I would then change the coax.
3) Still the same then I would consider changing the antenna.

Is there any chance a bird has maybe hit your coax ?
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The Collector
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Re: Imax 2000 swr problems

Post by The Collector » 02 Oct 2019, 18:42

Did you clean the threads on the joints when it was down with a wire brush before tightening them again and waterproofing them with self-amalgamating tape etc?

If say the top section isn't making a good permanent contact, it might be swaying and connecting/not connecting/connecting.. ditto..

Just a thought if it's not co-ax related.

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Re: Imax 2000 swr problems

Post by 108EH002 » 02 Oct 2019, 19:38

Had similar results with my 6 year old Imax a few month ago,I re-done the plugs and still the same,but after renewing the coax it worked ok again like before,hopefully it's a plug or coax problem.

Maybe the pl259 at the Imax,as one of the locals had the same with a 1 year old Imax,it was doing the same with the swr readings it was showing,and it was the old coax (4 year old) from his silver rod that he was using,after he done the plugs again it was fine,the last plug to be re-done before the swr dropped,was the one at the Imax ;)
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Astro fantom
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Re: Imax 2000 swr problems

Post by Astro fantom » 11 Oct 2019, 20:41

Thanks for all the replies and suggestions yes i have taped all the sections at each join with self amalgamating tape i do this as a matter of course when doing antenna installs as i have had past experience with water ingress resulting in high swr readings and with regards coax i am currently using rg8 mini although not sure if this is good or bad coax to use and it came with one plug already fitted and i soldered the other end when it was cut to size..
To be honest it was fine when it was first set up just seems to have gone bad over a period of time..
I was thinking of buying rg213 coax and seeing if that was any different with regards swr readings as i dont know if there’s any damage in the cable run at any point as it tucks under the roof tiles to feed into the loft and could possibly be nipped under there..
Im currently thinking new coax and see if the problem exists and if so new antenna although what to get as a replacement is tricky as i have heard all the arguments for and against fibreglass antennas and alloy versus fibreglass so if i do decide on a new antenna it will be a difficult decision..
Id like to get it done before the weather gets too bad as i live in a top floor flat three up and have to climb out the bathroom window to get on the neighbours roof to access the thing so helps when its not chucking down with rain🤣

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Re: Imax 2000 swr problems

Post by prettypolly » 12 Oct 2019, 00:24

I use bike inner tubes to seal a joints with mastic

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Re: Imax 2000 swr problems

Post by The Collector » 12 Oct 2019, 13:13

It won't hurt to get some nice, shiny new 213 - the best you can afford. It should hopefully last you 20 years then.

Buy 2 metres more than you need so you have plenty of extra co-ax to redo the PL plugs in the future in case of any water ingression at the end, or say accidental damage at the radio end. Don't coil up.any excess co-ax though.

Wrap over the PL plug when attached to the aerial too with amalgamating tape or similar. It'll not only seal it, but should stop the plug from vibrating or working itself loose. Ensure you wind the tape on the right way too, from 4 inches from the end of the co-ax UPWARDS to and around the PL plug, getting it as snug as you can to the aerial base ;)

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