This ought to be worth discussion.

[pro151]

http://www.youtube.com/watch?v=7POViM1007U

 

[BOOTY MONSTER]

i wonder what the tube on the side is . it looks like a very short and beefy gamma match but its not tapped from the 239 .... and its got the bent rod thats tapped off the off the , 239 . and it looks like symmetry was of no concern .
but it looks like it should be extremely durable !!

 

[BOOTY MONSTER]

$400 bucks

ZeroFive-Antennas | Got questions or want to order? Call Tom at 773-704-9006

21 feet tall , a few inches taller than a maco and 2 ft short of the magical .64 .

"THE NEW COLOSSAL 10K

We are now accepting orders on this vertical. Delivery time is around 5 to 10 days.

THIS IS A TRUE 5/8 WAVE
FREQ RANGE --- 26 TO 30 MHZ TUNABLE
POWER 5KW CARRIER 10KW SSB
BANDWIDTH --- 900KHZ
WEIGHT --- 20LBS
HEIGHT --- 21 FEET
WIND RATING --- 100MPH
MAST SIZE --- UP TO 1 7/8 INCH OD
RADIALS --- 4 AT 108 INCHES
MATCHING --- PARALLEL TUNED NETWORK
FEED CONNECTOR --- SO-239 10KW --- 7/16 DIN 15KW
$399.00"

 

[bob85]

booty,
the tube on the side is a capacitor in parallel with the coil doing the same job as the aluminum slugs inside the sigma2 and saturn,
his old model looked more like the maco v5/8 with an external cap

 

[BOOTY MONSTER]

thanks bob
so it is a gamma .... kinda sorta ? why would it need both a tuning coil and a capacitor ?
sorry that every time you answer a question for me it causes 10 more !! hahahaha

 

[RatsoW8]

I built a dummy load in 1989 that would handle a lot more than 10kw.

 

[Shockwave]

thanks bob
so it is a gamma .... kinda sorta ? why would it need both a tuning coil and a capacitor ?
sorry that every time you answer a question for me it causes 10 more !! hahahaha

The truth is you don't need the capacitor. The tapped coil is all you need to perfectly match the 5/8 wave to 50 ohms. Without the shunt cap, the radiator would also tune longer. I question the use of Teflon in the cap on the side but not on the radiator insulator. Both insulators have the same RF voltage across them so they should be similar in size and material. The large non symmetrical matching inductor could skew the pattern slightly from being truly omni directional but it's no worse then the trombone. The helical loop or coil provides the most omni directional pattern. I'd like to see the coax connector bracket with a little bead of weld around it too. That's easy to do today with the special aluminum solder they make and it would insure that RF connection does not get loose.

 

[Marconi]

Looks like maybe the sleeve on the gamma moves up and down to fine tune the radiator to the proper length to get reactance = or close to zero.

 

[Shockwave]

Looks like maybe the sleeve on the gamma moves up and down to fine tune the radiator to the proper length to get reactance = or close to zero.

Indeed is does but you can also tune the reactance out of a 5/8 wave by adjusting the radiator length, matching inductor length and tap point. Adding the gamma match here was a gimmick since the base inductor was already variable. The only advantage I can see is to give the user a wider range of adjustment from the base of the antenna without having to adjust the radiator length perfectly. The small problem here is that the length of the radiator can now be farther from optimal in terms of gain and the capacitor will hide it by showing a good impedance match.

 

[BOOTY MONSTER]

i wonder why the builder didn't just make the vertical the optimal length so no adjusting/gamma thingy is necessary ??
so the two matching devise work in tandem kinda like jays i10k trombone ?

 

[Shockwave]

i wonder why the builder didn't just make the vertical the optimal length so no adjusting/gamma thingy is necessary ??
so the two matching devise work in tandem kinda like jays i10k trombone ?

I'm thinking the big gamma on the side is at least an extra $100 worth of eye candy to many operators.

 

[MrSuburban]

Not very effeicient, only BANDWIDTH --- 900KHZ

Bandwidth isn't a measure of efficiency of the antenna.

 

[Marconi]

Bandwidth isn't a measure of efficiency of the antenna.

In my opinion bandwidth is a characteristic measure of antenna effectiveness over a range or frequencies. So, I disagree with Mac again that a 900 khz bandwidth can't be effective, even if the range of frequency deviation is somewhat limited. A lot of beam type and vertical antennas operate very well at this spec while trying to attain maximum gain.

 

[Marconi]

Indeed is does but you can also tune the reactance out of a 5/8 wave by adjusting the radiator length, matching inductor length and tap point. Adding the gamma match here was a gimmick since the base inductor was already variable. The only advantage I can see is to give the user a wider range of adjustment from the base of the antenna without having to adjust the radiator length perfectly. The small problem here is that the length of the radiator can now be farther from optimal in terms of gain and the capacitor will hide it by showing a good impedance match.

I believe that is true SW, and many antenna makers try such tricks to allow their antenna to be easily tunable or fixed tuned...with no tune at all.

 

[MrSuburban]

Hmmm! then what is? that big old useless gamma match?

Antenna efficiency can be defined in a couple of ways:

(1) Radiation Efficiency

Rad Eff = (Power_Radiated)/(Power delivered to antenna )

(2) Total Efficiency

Total Eff = (Power_Radiated)/(Power The Transmitting Radio Outputs)

The difference has to do with mismatch loss. The first, radiation efficiency, ignores antenna mismatch loss, and only looks at the power delivered to the antenna.

The second, total efficiency, is technically a function of the impedance of the radio and transmission line (typically 50 Ohms). Then the mismatch loss is calculated (see gamma, the reflection coefficient or
<a href="http://www.antenna-theory.com/definitions/vswr.php">VSWR</a>. The total efficiency can be increased with an impedance matching network, the radiation efficiency cannot.

If the antenna is exactly matched to the transmission line/radio, then
the two efficiencies are the same.