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avanti sigma 4 ...broadbanded ?

Nov 2, 2013
45
6
18
just wondering if any you guy ever tuned your sigma 4 for any bands lower than 11mtrs ..without adding ant length to it ? ..thanks
 

Marconi

Usually if I can hear em' I can talk to em'.
Oct 23, 2005
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60, sorry I don't know the answer to your question here, but..............

There are folks out there that claim the gamma match will, more or less, tune anywhere you want and maybe even into other bands without changing the length...like you suggest. I'm not sure about that however.

I have a Antenna Specialists model of the S4, and it is a great antenna. I have never tried to tune it anywhere except in the 11 meter band...where IMO the kit was designed to work.

Some suggest that you can make the antenna 30' feet and longer and then re-tune the gamma match correctly and the antenna will preform notably better. I have tried making it longer and shorter in overall length than specs call for, and it did change the frequency as one would expect, but I never tried to re-tune it to another band in the process.

You will note that Sirio once modified their old Vector antenna by making the radials longer, but they also made the overall length shorter...so I figure those guys probably know best with all their experience and their seeming top level testing capabilities.

So on the subject of best performance of the S4/NV4K, I tend to go with the basic ideas Sirio publishes for this antenna, and I note the specs show a tune-able range from 27.185 to 28.500 mhz for their NV4K and it looks to get shorter as you go up in frequency.

Sirio also shows a <2.00:1 SWR bandwidth for the NV4K at 1.40 mhz.

So, if you do try going lower...keep and eye on the bandwidth too.

Good luck and keep us posted.
 
  • Like
Reactions: knight patrol 60
Nov 2, 2013
45
6
18
60, sorry I don't know the answer to your question here, but..............

There are folks out there that claim the gamma match will, more or less, tune anywhere you want and maybe even into other bands without changing the length...like you suggest. I'm not sure about that however.

I have a Antenna Specialists model of the S4, and it is a great antenna. I have never tried to tune it anywhere except in the 11 meter band...where IMO the kit was designed to work.

Some suggest that you can make the antenna 30' feet and longer and then re-tune the gamma match correctly and the antenna will preform notably better. I have tried making it longer and shorter in overall length than specs call for, and it did change the frequency as one would expect, but I never tried to re-tune it to another band in the process.

You will note that Sirio once modified their old Vector antenna by making the radials longer, but they also made the overall length shorter...so I figure those guys probably know best with all their experience and their seeming top level testing capabilities.

So on the subject of best performance of the S4/NV4K, I tend to go with the basic ideas Sirio publishes for this antenna, and I note the specs show a tune-able range from 27.185 to 28.500 mhz for their NV4K and it looks to get shorter as you go up in frequency.

Sirio also shows a <2.00:1 SWR bandwidth for the NV4K at 1.40 mhz.

So, if you do try going lower...keep and eye on the bandwidth too.

Good luck and keep us posted.
thanks Marconi ..was just a general question really ..it does ok with atu within radio and good on 28.400ish ..I did read that some guys had messed about with the salute 27 version ...the Avanti and Antenna Specialist S4s are fine doin what they where made for ...always nice to see guy pushing boundaries with their stuff ...this ones in really good condition so would like to keep it as so ...
73 sir ..
 

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