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Homemade Sigma 4 11 meter base antenna

My thoughts are since I have a Sirio Vector 4000(still in it's shipping box)I could see about ways to strengthen this antenna but first take measurements for future reference points in case I decide to make a heavy duty .82 wave version of it. Interesting.
Maybe modify the one I gave for .82 wave or make one from scratch.
 
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An excerpt:All in all the worst version of the lot is the Sirio vector 4000 and only really down to the built quality , the weak parts are the base section and the 3rd section from the top , the Gama match is also pretty bad on the 4000 as the insulator is just plastic , better to make a new one and use teflon (plumbers PTFE tape) to insulate the 2 sections , my last modified 4000 had a slightly lengthened and widened bottom cage as per sigma 4 , and the radiator when properly metered in was 29 3/4 ft , 50 ohm and 1.3 to1 on .555 ,antenna base @35 ft , In my personal experience THE No1 11/10m antenna both local and DX .
 
Lil'Yeshua said:
Using the MFJ-207,would you use an ohm meter to fine tune the gamma match on the Sirio Vector 4000?
I haven't read this link yet but I will.
http://www.worldwidedx.com/cb-antennas/17498-what-does-gamma-match-do.html
Hevener.Com© - The Sirio Vector 4000 Review
Click to expand...


fwiu a ohm meter can't measure the impedance of a antenna . a ohm meter doesn't know what frequency you're trying to tune to and can't generate a signal on that frequency to tune with . if i'm wrong and there is a way to do it please describe how to do it . :)


Lil'Yeshua said:
An excerpt:All in all the worst version of the lot is the Sirio vector 4000 and only really down to the built quality , the weak parts are the base section and the 3rd section from the top , the Gama match is also pretty bad on the 4000 as the insulator is just plastic , better to make a new one and use teflon (plumbers PTFE tape) to insulate the 2 sections , my last modified 4000 had a slightly lengthened and widened bottom cage as per sigma 4 , and the radiator when properly metered in was 29 3/4 ft , 50 ohm and 1.3 to1 on .555 ,antenna base @35 ft , In my personal experience THE No1 11/10m antenna both local and DX .
Click to expand...

i've never seen a sirio vector 4000 in person but there are many comments about it's physical construction not being very substantial . i've seen videos of them and didn't care for how ...... flexable ... they are . that'a why i suggested a penetrator 500 or a gainmaster for your use in south carolina .

i'll suggest not using plumbers tape for modifying the insulator on the gamma . i tried it and didn't like it . i think moisture got in mine and caused some VSWR fluctuating . i used Homerbb's pex idea and it worked fine . i let it hang about 1/2 a inch below the bottom of the gamma rod and sealed that little 1/2 inch bottom section with silicone , i also put some on the rod itself befor i permantly put on the pex insulator so water doesn't get in it and to keep the rod from moving in the insulator . the bottom of my gamma tube is open .

http://www.worldwidedx.com/home-brew/145761-pex-insulation-material.html
 
BOOTY MONSTER said:
fwiu a ohm meter can't measure the impedance of a antenna . a ohm meter doesn't know what frequency you're trying to tune to and can't generate a signal on that frequency to tune with . if i'm wrong and there is a way to do it please describe how to do it . :)




i've never seen a sirio vector 4000 in person but there are many comments about it's physical construction not being very substantial . i've seen videos of them and didn't care for how ...... flexable ... they are . that'a why i suggested a penetrator 500 or a gainmaster for your use in south carolina .

i'll suggest not using plumbers tape for modifying the insulator on the gamma . i tried it and didn't like it . i think moisture got in mine and caused some VSWR fluctuating . i used Homerbb's pex idea and it worked fine . i let it hang about 1/2 a inch below the bottom of the gamma rod and sealed that little 1/2 inch bottom section with silicone , i also put some on the rod itself befor i permantly put on the pex insulator so water doesn't get in it and to keep the rod from moving in the insulator . the bottom of my gamma tube is open .

http://www.worldwidedx.com/home-brew/145761-pex-insulation-material.html
Click to expand...

Thanks. Here's the PDF downloads page for the MFJ-207. I'm wanting to know how to fine tune a gamma match using the 207. I'll be off from work in a hour. I can attend to this post without distractions.
MFJ Enterprises Inc.
 
By the book!

This sounds good.
K1TTT Technical Reference
:pop:
Also I've been thinking about getting an antenna tuner to use in conjunction with the Sirio Vector 4000. Plus I would use a A/B switch and run the MFJ-207 on 'B'. It would be used to keep the SWR low for a frequency spread from 25.615-30 MHz.
 
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Lil'Yeshua,
If you do use that '207 to tune a tuner then I think I'd do what MFJ suggests, take it completely out of line when finished with that tuning! Other wise you are taking an unnecessary chance on harming it.
Something else to consider is that the reviewers were very careful in saying the '207 is an "SWR analyzer" not an antenna analyzer, they aren't the same things at all. The '207 is a 'portable'/'stand-alone' SWR meter, all it does is measure SWR at the point you are using it. It can't tell you anything about resonance, SWR has nothing to do with resonance, they are completely different things.
I can certainly see where they may come in handy in particular instances. But are sort of redundant at the transmitter/tuner end of a feed line where a 'regular' SWR meter could be used.
- 'Doc
 
W5LZ said:
Lil'Yeshua,
If you do use that '207 to tune a tuner then I think I'd do what MFJ suggests, take it completely out of line when finished with that tuning! Other wise you are taking an unnecessary chance on harming it.
Something else to consider is that the reviewers were very careful in saying the '207 is an "SWR analyzer" not an antenna analyzer, they aren't the same things at all. The '207 is a 'portable'/'stand-alone' SWR meter, all it does is measure SWR at the point you are using it. It can't tell you anything about resonance, SWR has nothing to do with resonance, they are completely different things.
I can certainly see where they may come in handy in particular instances. But are sort of redundant at the transmitter/tuner end of a feed line where a 'regular' SWR meter could be used.
- 'Doc
Click to expand...


Well, this guy made some sense and cleared things up a bit as far as tuning the antenna. I emailed MFJ to get their input on what other inline devices to buy. I looked their A/B switch,antenna tuner.matcher. I know what a matcher does more or less. The tuner,they make different types.
http://www.k1ttt.net/technote/gamma.html
 
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Well, from their instructions it doesn't seem like they think it's necessary. Try it, see what happens. Then try it the other way and see what happens. If it made their antenna significantly better, I would think they would recommend insulating it, wouldn't you?
- 'Doc
 

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