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My Sirio 3000 is on a 7" magmount i know it would perform better if i drilled the roof and mounted that way. The thing is i don't want to damage the van roof as it's a fairly new van. The Sirio 3000 is the best mobile antenna i've ever used, i swear by them. The bandwidth is good too at 26-28mhz. I use a RM KL 200 linear with mine too and i drive all over London with no problems getting out through the concrete jungle to friends in the suburbs.

its magnet mount.using a wilson magnet.screws right onto wilson magnet
makes it really nice.swrs were perfect upon setup just bottomed out
the whip and was perfect took me 5 minutes to install and check swrs

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magnum delta force
magnum omega force
uniden grant
cobra 2000gtl
sirio z180
skythumper65dx

Is this antenna DC grounded(shunt fed)?

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I U 212

I'm not sure but i think maybe dc grounded. The mounting is an SO239 type.

To my knowledge, I have never seen a 'DC grounded' mag-mount antenna of any kind. Name one, please.
- 'Doc

I was reading on another forum where a fellow said his performer 5000 was dc grounded and not finding any info at the sirio site on that antenna I just wondered if the 3000 and 4000 series had the same claim?

I've seen cut aways of these antennas and they do not show any matching circuits that are visible.

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I U 212

Just what did this testing involve.....and what unit of measure did you use to base your results on. Did you keep these stastics and are they viewable? Or is this just your opinion?

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Ignorance can be cured by learning, there is no cure for stupid......

Is the dc shunting in the mounting base of the antenna, hidden from view? and it would still need to be fed through the coax on a magnet mount which I can't see it matching well through that length of wire.

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I U 212

I never even seen a Sirio mobile antenna to this day.
Sounds pretty decent - though.
Screws right on to a Wilson mag-mount you say - eh?
Better still!

Now, a single S-unit is equivalent to 6db's; and two S-units would make a 12db change.
And every 3db change upward would double the percieved volume/loudness to the ear.
That is a lot!
If it was only a couple of db's - I wouldn't consider it.
But if it is a couple of S-units; well - that's a horse of a different color!

So - is it 'S-units' or 'db's'?

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What gear do I use?
BASE: Icom IC-718 & GAP Titan DX, Yaesu FT-8800R & Diamond X50A, Magnum OmegaForce S45 & IMAX 2000 w/Astatic D104/TUP9.
MOBILE: Galaxy DX99V & Wilson 1000 w/Astatic D104-M2, Yaesu FT-8800R & Diamond NR-770.
"...The 444 in San Jose CA; the Central Gold Coast..."

That DC ground thingy. If it were DC grounded it would mean there had to be a ground at the base of the antenna. If you're going to do that, why not just drill the hole and do it right? Mag-mounts work through capacitive coupling through that magnet. Actually the magetism has nothing to do with anything except holding the thing on. But the magnet acts as one plate of a capacitor and the metal body of the vehicle as the other plate. It works and that just great. But it does have limits which relate to frequency of use, and surface area. Oh well. Not telling you anything new with that.


Shunts.
Actually they are inductive links with ground for most base loaded antennas. They help, or do the impedance matching which is always required with antennas. Just wish they were adjustable!
- 'Doc