New Sirio 1/2 wave Gain Master

[gamegetter]

it's likely because sirio is targeting a niche market in the cb and 10-12 meters, where they feel they can capture sales without retooling and spending too much on materials.

that is just my guess, a cost vs profit thingy based on anticipated sales from past experience in the market.

 

[Needle Bender]

Accidental double post, please delete.

 

[Needle Bender]

So their 1/2 wave, at close to twice the price of the ever-popular Antron99 "1/2 wave" is a viable, profitable "Niche"?
Sorry, I just don't see it.

...not to mention I toasted a Sirio Gain Master 5/8 last night @ 500w PEP SSB

- Just gonna throw a piece of RG213 in there and see if
it resurrects it, as per Shockwave's specs.

 

[The DB]

Accidental double post, please delete.

Deleting Needle Bender... I apparently don't have those privileges... Sorry man...


The DB

 

[bob85]

sirio over estimate the power handling on most of their antennas,
I have seen two fault modes for the gainmaster related to power input,

the well known coax cap arcing on early examples and another where vswr creeps up on long winded overs when using well below the claimed power rating on FM,

gainmasters use rg58 size coax made by Bieffe, it looks similar to the 50ohm coax on their website,
bear in mind that the stub only corrects vswr from the stub back towards the transmitter,
vswr on the coax above the stub could be very high with high voltage and/or current on the stub and coax above the stub reducing the power rating of the coax,

maybe somebody could model the 5/8 gainmaster and tell us what magnitude of vswr voltage and current we have on the coax above the stub with a 500w carrier.

 

[Needle Bender]

...(my edit)...maybe somebody could model the 5/8 gainmaster and tell us what magnitude of vswr voltage and current we have on the coax above the stub with a 500w carrier.

I 2nd that excellent suggestion. Would be very informative regarding what power handling to expect after coaxial capacitor repair.

 

[Marconi]

I would be interested to read someone's report using the New Half Wave Gain Master. Has it ever been available for sale in the U.S.?

 

[gamegetter]

the antenna appears to be on sale from DNJ radio on both amazon and it's own website, but i found it lower priced on amazon.

 

[Marconi]

GG, I checked on YouTube if anybody reported on the New HW Gainmaster and found nothing here or from Europe.

sirio over estimate the power handling on most of their antennas,
I have seen two fault modes for the gainmaster related to power input,

That maybe Bob, but I ran my about 15 watts into my 2 x 500z Swan Mark 2 that produced a bit less than 500 watts into my GainMaster for period of time...and I never had any problems.

I don't recommend this much power however. A year or more later a spike of lightning struck my GM, and it fried it at the center section and the top fell in the neighbors tree next door. After that I only ran a CB into it using my New Top One.

maybe somebody could model the 5/8 gainmaster and tell us what magnitude of vswr voltage and current we have on the coax above the stub with a 500w carrier.

I believe the only man around here that I know might do a model with matching for the GM...would be The DB.

Have you asked him?

 

[Needle Bender]

GG, I checked on YouTube if anybody reported on the New HW Gainmaster and found nothing here or from Europe.



That maybe Bob, but I ran my about 15 watts into my 2 x 500z Swan Mark 2 that produced a bit less than 500 watts into my GainMaster for period of time...and I never had any problems.

I don't recommend this much power however. A year or more later a spike of lightning struck my GM, and it fried it at the center section and the top fell in the neighbors tree next door. After that I only ran a CB into it using my New Top One.



I believe the only man around here that I know might do a model with matching for the GM...would be The DB.

Have you asked him?

Hey Eddie, sorry to hear about your GM, it's never fun to invest good ca$h only to have nature destroy it.

On the upper part of the older 5/8 GM above the phasing stub, Bob, I'd presume that since it's designed & performing as a 5/8, I'd expect the high voltage node to be at the top & the current peak a 1/4 wave down.

...and on a similar but side note;
I'm curious Eddie, have you ever overlaid eznec patterns of a full .625 5/8 vs a .55 19' 8" Maco V58 type?

 

[vkrules]

 

[vkrules]

Bit hard to tell from this video but the joint seems to be just a piece of circuit board with no matching or cap. So it's just a T2LT/Coax Dipole in fancy packaging.Dont get me wrong nothing wrong with that. And it should handle what ever power the coax is rated at

 

[vkrules]

Original Gainmaster is a center fed 5/8th dipole . impedance is about 200 ohms.
The shorted matching stub is carrying enough current to get warm to the touch with 200w . On my homebrew copies I use RG213 for the stub and cap .They can handle a lot more power.

 

[bob85]

it does look like a piece of pcb and no cap on the feedpoint, a coax dipole with a built in choke,
the vswr curve doesn't look like they used a top coupling cap or if they did its not been used to increase the bandwidth like it is in the x-pole and probably 5/8 gainmaster,

i ran 600w+ fm through low quality rg58 for years, it gets warm when long winded but works ok if vswr is very low it stays low,
gainmasters will not take that power on fm, they struggle with 300w for long overs,

if the stub gets warm @200w and the rg58 above the stub has high vswr, upgrading the cap is not all that needs doing to increase power handling,

sirio could have left the 1/2wave as a 4 section with shorter sections for a faster taper stiffer stronger antenna but they missed the boat again.

 

[Marconi]

...and on a similar but side note;
I'm curious Eddie, have you ever overlaid eznec patterns of a full .625 5/8 vs a .55 19' 8" Maco V58 type?

NB, here is the overlay you requested.