Made In the USA - SigmaIV ;)

[HomerBB]

I decided to use the materials I had at hand to make another antenna to replace the Qv4k I had traded away for a radio I wanted. I knew I could always make another antenna, and lacked the skills to build a radio.

So I did. Here is the Made in the USA SigmaIV
This antenna is built virtually identically to the SigmaIV discussed in at least two prominent threads on this forum.

The only significant difference is the ring is slightly smaller in diameter because it is preformed and served to get the project kicked off.

It's very windy today!

More later. Time to go to the Home Depot and earn a living.

More adjusting to do later, But here is SWR bandwidth with MFJ-209 at the shack end of the coax.

2.1:1 ---------------------- 28.155
1.5:1 ---------------------- 27.840
1.0:1 ---------------------- 27.565
1.0:1 ---------------------- 27.555
1.0:1 ---------------------- 27.445
1.5:1 ---------------------- 27.085
2.1:1 ---------------------- 26.600

Initially, it appears to be less widebanded than the Qv4k, but I will have to look that up and do some more adjusting. It is 4 feet above the roof ridge for now - 23' from the ground.

 

[bob85]

looking good homer,
makes me smile when i see somebody build a proper vertical

 

[wavrider]

Great lookin antenna.

 

[212Dan]

i use to have one the tubing was all fluted it worked 101% better than the sirio vector 4000 knock off

anyone know where i can get a original one?

 

[gamegetter]

It's 10-8 and straight!

 

[BOOTY MONSTER]

looks good homer

i see you went with three basket elements this time . was there a reason other than just trying something different than before or just using materials on hand ? i think i recall a comment somewhere about the making the ring larger than stock making the antenna more broad-banded . i,ll see if i can find it in a bit tosee if i'm wrong again ... if i'm not the smaller ring may have something to do with the smaller bandwidth you're seeing on this one . what diameter is it ? also what length did you make the basket elements and vertical ?

can we get some closer pics ?

 

[bob85]

i found the 4 radial setup more broadbanded than the three radial so i put the vector basket on the avanti vertical and extended it,


the ribbed tube version was a cte clone.

 

[sp5it]

SWR is nothing. On what frequency is resonance located?
Mike

 

[HomerBB]

looking good homer,
makes me smile when i see somebody build a proper vertical

Thnx, Bob.

Great lookin antenna.

And, you too, wav

It's 10-8 and straight!

thnx!

 

[HomerBB]

looks good homer

i see you went with three basket elements this time . was there a reason other than just trying something different than before or just using materials on hand ? i think i recall a comment somewhere about the making the ring larger than stock making the antenna more broad-banded . i,ll see if i can find it in a bit to see if I'm wrong again ... if I'm not the smaller ring may have something to do with the smaller bandwidth you're seeing on this one . what diameter is it ? also what length did you make the basket elements and vertical ?

can we get some closer pics ?

You're correct, Booty,
I used what I had. The loop is 27.5" diameter. It has three pre-attached ears on it at exact spacing so I just put three basket radials on it.

As Bob said, it likely is more broadbanded with four, so I'll likely upgrade to four radials.

As for dimensions otherwise, look back into the "... an alternative view" thread and you find the assembly dimensions I used. They are stock SigmaIV.

 

[HomerBB]

SWR is nothing. On what frequency is resonance located?
Mike

I do not have an MFJ-259, but I do have a MFJ-209.
It reads only SWR across a tremendous spectrum of frequencies. What it does not read out on an LED screen, it points out on a analog meter. 1.0:1 SWR (no needle movement) was between 27.565 and 27.445 putting T5 right in the middle.

 

[Marconi]

I do not have an MFJ-259, but I do have a MFJ-209.
It reads only SWR across a tremendous spectrum of frequencies. What it does not read out on an LED screen, it points out on a analog meter. 1.0:1 SWR (no needle movement) was between 27.565 and 27.445 putting T5 right in the middle.

Hey Homer, how does your 209 compare to an inline meter at the same location in the feed line? Does different jumper lengths, used with your inline meter, make any difference in the readings?

 

[HomerBB]

Hey Homer, how does your 209 compare to an inline meter at the same location in the feed line? Does different jumper lengths, used with your inline meter, make any difference in the readings?

I'm not sure, but suspect that it would should there be any issues with the feedline. I may be able to take the 209 to the antenna on a short coax to test if there's a difference.

As for the inline SWR meter, the bandwidth reads a little different, but generally the same as the 209.

********** 209 ********** SWR meter

2.1:1 ------ 28.155 --------------- 27.935
1.5:1 ------ 27.840 --------------- 27.735
1.0:1 ------ 27.565 (1.2:1)-------- 27.555
1.0:1 ------ 27.555 --------------- 27.335
1.0:1 ------ 27.445 --------------- 27.115
1.5:1 ------ 27.085 --------------- 26.675
2.1:1 ------ 26.600 --------------- 26.415

 

[HomerBB]

More Photos:

 

[curlyjo]

Thanks for showing off your pics! I just restored a CTE LW150 with stronger tubing at the top. it works great too.