Hi - How do you decide what length to adjust the ground planes please? Is there a calculation?here it is if you don't want to read to 5 pages or so from my imax died thread:
so I had the maco 5/8 up for about 3 weeks, when I did the initial tuning of it before it went up on the tower it was misting rain out, swr was set very good, put it on the tower and started talking on it, results were good, but I noticed my swr had changed the next couple days when it dried out, so I climbed the tower and got the swr re-set, had to shorten it even more, the antenna was still working fine, but I noticed large swr changes when it was raining/damp out compared to other antenna's
I also didn't like the fact that after the final tuning the radiator was at less than 19' long, so I had some vaction time the last couple weeks, and had a sirio tornado 5/8 that I had ordered also.
so I set up the tornado and placed it on the tower that the maco was on, it tuned in very nice with the exact length given in the instructions and 22' long radiator with 4 6' ground planes, also this antenna is not dc shorted to ground/radials, it uses a nice open thick coil at the base. and rain does not seem to be changing the swr much at all
after using this antenna for the last week and a half I can say it works way better than the maco / imax / and (gainmaster that is tree mounted at 42')
and the proof:
my buddy that is around 30 miles from me has a grandson down the road from him that has a small radio set up, old un touched realistic ssb radio with a A99 about 10' off the ground only, on my imax and maco 5/8 I could here his grandson but with only 1 light lit up on my 2950dx, now with the sirio tornado I have him at 3 lights on my 2950 dx
and the guys that I have made contact with that are 100 miles south from me I have made several contact with and they are coming in with 1 more light than they used too, also with the maco / imax I could always here them talking to another guy on the iowa/Wisconsin border that I could not make out,, now with the sirio tornado I have the guy in iowa that is 130+ miles from me at 3 lights on my 2950dx and made contact with him no problem the last week several times in the evening.
What are you replacing it with?yup my sirio tornado is packed away in the shed, it took out one radio ,,, during a snow storm the static build up from the snow/wind was enough for me to sit and watch the pl259 on the end on my coax arc and spark like crazy
you can add a shorted tuning stub to bleed of the charge, but I just took it down, other wise it did work very well
The ground plane radials are pre drilled on that antenna if memory serves me correctly. Just pull the inside length out and when it gets tight, or where it's supposed to be, you'll know. Then spin it to find the holes for the outer length of the radials and use the self tapping screws to put them together. Pretty sure that is how they go together. They are pre drilled on both outer and inner part of aluminum. The total length should be around 6ft. They aren't full 1/4 wave ones.
They are an Easy antenna to tune. Just takes some fine tuning to get it right. Start with the 1120mm measurement in the book and raise or lower tip for best match at desired frequency.
That and get it off the ground at least 30ft. or more and away from obstructions. JMHO's.
Also remeber that this is a very lightweight antenna and you will need to have a good plan in place for putting it up. Add a good 1:1 isolating balun and use good coax. Also a Low Pass Filter at the radio is a good idea. Again, just my experience with the Sirio Tornado. Good luck and be safe placing it up.
RG58 Military with sealed plugs - Its only 5m to rig so i guessed it would be fine - Only running standard 4w at momentWhat kind of coax you got there? Rg58, looks pretty thin