Gainmaster 5/8

Hi guys just a quick one Siri gainmaster 5/8 is it pre tuned and cannot be tuned 
And what the swr like across the band atu and not 20m up to 6m please

There is a brass bit at the top of the antenna witch the wire goes to.
You can tune it with that pulling the wire through it a bit.

Hi Kevin,


All the information is available from the manufacturer and the manuals they provide :-

https://www.sirioantenne.it/en/products/hf/gain-master


I wouldn't start pulling the 'wire' up through the top ferrule for fear of over tightening the antenna cabling/connections and the manual states as such to prevent damage. I think Alan may have been referring to the Gainmaster HW (half wave) which can be tuned by such methods and although you probably could adjust it with some jiggery-pokery it probably isn't recommended. (A look at the manual will show you this is a more complicated antenna than a simple wire with a capacitive connection as well as matching stub.)

As ever there are the typical complications surrounding operator installation. Much depends on how high it is installed, whether near metallic objects, quality of coax cable used by you for connection, how long the coax is with losses incurred, etc. etc.

Also it will depend on what you find is an 'acceptable' SWR.

The manufacturer states a SWR range of 2:1 (25.5MHz - 30MHz) which most radios can easily handle and is actually a 90% or better efficiency.

As you make mention you could probably load it almost anywhere with an appropriate ATU/Matcher but gaining an acceptable SWR doesn't necessarily make it a good antenna.


Hope that helps.

All the best,
Victor

oop's yes it was the halfwave i had.
Still have it but lost the inner wire when the old greenhouse was taken down to make way for the new shack.

No worries Alan mate, doesn't help that Sirio called them both 'Gainmasters'.

Just thought I'd clear that up a bit in case you get the old "but you said".......

ive had the 5/8 wave gainmaster since they came out. Its been mounted on a 6 meter pole that whole time with no issues at all. It covers from 24.65 upto 30.3 mhz all below 1:5:1. without any ATU or other form of matching. 

And for some reason it also tunes on 4m without an ATU although i cant say performance is any good.

Hi guys,
Has anyone perhaps tried to make a Gainmaster 5/8 antenna themselves from a spare part that can be ordered separately?

I decided on something like that because that part is cheap here, and I wouldn't want to miss the specifications if I made the entire antenna myself.
So I wanted to ask if anyone has tried something similar and what experiences were like...?
That would be an excellent solution for my balcony, and it could also be useful for a trip in nature.

That is the part that got binned when the old greenhouse was taken away.

Alan Pilot wrote:

That is the part that got binned when the old greenhouse was taken away.

That part can be ordered here in Germany for 35e.
Here is the DIY plan (unfortunately in German, but the dimensions don't need translation).

Don't know if this is what you seek, but i'm also a member on the facebook T2LT group, where we've had a thread about the gainmasters.

Will have to dig it out well what i have left lol.
Not this week i don't think full of a cold well that was what i thought until Linda got a Covid test kit out and yes we are both positive not good when you have COPD but it's a first so we did well i think.

I have finished my Gain Master 5/8

factory specification:


My antenna:



I mounted the antenna on a Spiderbeam 12m fiberglass pole.

Altogether, it cost less than a factory-made Gain-Master antenna.
Now I have an antenna that I can quickly disassemble in case of strong winds or bad weather. 
I can also take it with me on trips into nature.