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Discussion Starter #1
This is a pretty wild looking new antenna. (Wildwillie, you didnt have anything to do with it, did you ? Heh.)

http://www.fracarro.com/international/download/prodottitvsat/Aerials/SIGMA_COMBO.pdf


They say (from their marketing dept I assume of course) :
For the first time a combined aerial has been made as an autonomous project, not as a result of adapting a UHF aerial.
I totally disagree, thats bull crap. By the looks of it, they took a basic corner reflector design, with similar to 91XG driven element, and adapted and optimized vhf-hi elements to it. I think I could very well make it a uhf only antenna by removing the reflectors from behind the corner reflector, removing the 2 big hoop directors, and removing the wires sticking off of the driven element, heh.

They say:
H or V polarisation
Nah, not without some gain penalty.

They say:
Impedance 75 Ohm
It doesnt mention that a 1:1 balun is included or not.

I would love to get some accurate detailed dimensions from it.

The wisdom of using round directors on a driven element that is shaped like it is, is something Ill have to model. Channel Master used round disks as directors on some of their old uhf LPDA antennas. (they were blue anodized, and one is still up locally near an eye doctors place, so Ill try to get a photo)

And I forgit, is Europe still going up to 862 Mhz ?

From what Ive read, Fracarro makes a quality antenna, and their specs always do seem to be in line. Why dont they increase their warranty even longer ?

Heh, they can always pull a disappearing receipt trick like my local Compusa. Back story, I bought my 25" LCD monitor last black Friday at Compusa. It started going flaky, so it was RMA time. They wanted an emailed copy of the receipt, fine. I got it out, it was kept in a folder with NO exposure to the sun. It was so so faint, it looked like it had completely disappeared into a blank piece of paper. Luckily, the Compusa manager issued me a new receipt. In another 6 months, I would have had nothing to show, heh.

So, they could offer a lifetime warranty on everything, with a receipt that completely disappears in 3 years, and be way ahead of the game. Or am I being too unscrupulous, heh ?
 

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Unreadable Receipt

They wanted an emailed copy of the receipt, fine. I got it out, it was kept in a folder with NO exposure to the sun. It was so so faint, it looked like it had completely disappeared into a blank piece of paper. Luckily, the Compusa manager issued me a new receipt. In another 6 months, I would have had nothing to show, heh.

So, they could offer a lifetime warranty on everything, with a receipt that completely disappears in 3 years, and be way ahead of the game. Or am I being too unscrupulous, heh ?
Although I will be going off subject with this post, I'd like to point out that there is a solution to your fading receipt. I had that problem a long time ago with a receipt I couldn't read at all. Then I put it on a scanner connected to a PC and played with contrast and brightness (and maybe a few other setting) and I could extract a very clear image of the receipt. Those machines can discern shades of white our eyes can't...

jf
 

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Now thats wild i would love for them to post a NEC of that puppy .

They need to get the HI VHF reflectors futher apart to bring up the gain and make them a little longer looks like 25 inch reflectors or smaller by the looks of the HI VHF gain is down past the 216 mhz 6 to 7.? dbi from 174 to 213

after i get done with my project looks like a go on this puppy :cool:
 

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Good gain stats....
I'd try one out to see what it does.
 

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Discussion Starter #5
Good gain stats....
Over our new TV channel ranges, 11 - 12 dbi uhf, 6 - 8 dbi vhf-hi.

A SBGH with NARODs or an mclapp M4 with the wide reflector does better for uhf. But, for a compact corner reflector model, its presently better than any other compact corner reflector for vhf-hi. :)
There are plenty of larger vhf-hi antennas with a corner reflector uhf front end.


Those machines can discern shades of white our eyes can't...
Yep, but they always have trouble with a true blue, heh.
 

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stampeder with my young eyes i see to steering wheels
now look at the UHF element just below it is the VHF Hi element i believe
see it 300ohms and stampeder

So reflectors and element needs ajustment in lenght
thn the reflectors need to be placed further apart the furthes ones out top and bottom this should help with the gain ajustment. and front to back
 

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Discussion Starter #9
Isn't this a corner reflector with NARODs?
Hard to tell from the picture if the vhf-hi rods below the uhf driven element are electrically connected or not.
 

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I think it's a double reflector---the obvious one for UHF and four long rods for Hi-VHF.
What I don't know is whether the directors are simple Loops (with insulated cross pieces).....
or whether they are Shorted-Bowtie-Loops (SBL).
 

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i was wondering why i could not get the Hi VHF down in the swr below 32 . i knew i seen a dipole coming out of the bottom

thanks FranKllr for the pic now i can rezoom my regualer 4NEC2 programing lmao

I even had the 470mhz up to 12.3 dbi
and the Hi VHF at 174mhz at 8dbi

now to play again.
 

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I suggest you to look at the instructions. All image are in vectors, you can zoom as you want. With side view, image #5, you can replicate exactly (minus the dipole), if it is on scale... Length is 102 cm, matter of Cross-multiplication.
 
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