Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire.

The place to talk about specific radios, equipment and accessories. Do you prefer the latest generation of rigs and antennas or do you like the classics? Discuss it here!
User avatar
George EI7KO
Moderator
Moderator
Posts: 4476
Joined: 23 Jan 2011, 12:34
Call Sign: EI7KO
Location: Central Ireland

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by George EI7KO »

Just a question Si... Have you or any of the other posters threw a load of watts into one of these? Say two or three hundred whiskeys and what was the result
User avatar
Kaos
Radio Addict
Radio Addict
Posts: 964
Joined: 14 Nov 2007, 06:53

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by Kaos »

400w no bother.
User avatar
George EI7KO
Moderator
Moderator
Posts: 4476
Joined: 23 Jan 2011, 12:34
Call Sign: EI7KO
Location: Central Ireland

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by George EI7KO »

rms or Italian watts??? Lol
User avatar
Kaos
Radio Addict
Radio Addict
Posts: 964
Joined: 14 Nov 2007, 06:53

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by Kaos »

Texas Star American muscle watts.
User avatar
George EI7KO
Moderator
Moderator
Posts: 4476
Joined: 23 Jan 2011, 12:34
Call Sign: EI7KO
Location: Central Ireland

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by George EI7KO »

Ah. Cool. Was just curious about it.
vkrules
Regular
Regular
Posts: 38
Joined: 28 Sep 2013, 00:10
Call Sign: vk4aap

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by vkrules »

400 watts no problem, but that was with the rg213 stub.An rg58 stub might be a different ball game.
User avatar
Kaos
Radio Addict
Radio Addict
Posts: 964
Joined: 14 Nov 2007, 06:53

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by Kaos »

RG213 used here, though I agree with RG58.......mmmm
kamikazeandi
Regular
Regular
Posts: 9
Joined: 13 Jun 2013, 10:48

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by kamikazeandi »

Hi Psi,
sorry, I have sent the wrong picture. Now here is the right image for the antenna with vf = 0.66:
GainMaster 15.png
And with your answer, I have created a new version with a slightly larger capacity C = 8.6pF (as the original version):
GainMaster 18.png
Ultimately, I want to build the new optimized for 10-12m antenna with the low-loss coaxial cable HF5000:
http://www.k-po.com/data/shop/download/7463/HF-5000.pdf
This coaxial cable seems to be a cheap-china-version of H2000Flex or Ecoflex10. Just at this moment, I see that the HF5000 has vf = 0.84, so I have to remodel again. This version should be completely build with this HF5000, and to the TRX not contain connectors, so I hope to reduce the loss.

Is it correct that I need to change the value to 0.84 in the "Trans-line Nr1" in point "Len" in the "Source / Load" menu, for the usage of this coax?

Until today I use the original version witch a longer vertical radiator (3.607m) and a stub length of 0.583m, completely build with RG213 (see image):
Vertikal-Strahler & Stub-Länge_kl.jpg
The position of the stubs should be at 1.265m, but I do not have this captured on film.
In this configuration, the antenna operates on both 10m and 11m band very well, and in the 12m band with an SWR of 2.5. Digital connections from West-Germany to Australia, Argentina and Japan, on the 10m and 12m HAM bands are very nice results. I was even heard in New Zealand, but unfortunately could not even receive the ZL-OMs (reports from the PSK Reporter).

My next antenna project should be an 10m or 11m-SKYPPER antenna. For 11m I have finished the modeling for vertical- and horizontal-configuration, in the program MMANAGAL_BASIC.
But, what do you think? Can we extend this GainMaster to a broadband vertical SKYPPER for the 10m to 12m band? Too crazy? At least it is a dipol-antenna!

Regards Andi
You do not have the required permissions to view the files attached to this post.
User avatar
PsiDOC
Super Member
Super Member
Posts: 446
Joined: 16 Aug 2011, 18:39
Call Sign: 163FKU
Location: Moonbase Alpha
Contact:

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by PsiDOC »

Andi,
The numbers you have are what I'd expect to see. Curve looks good and you have the 12m band in reasonably at the bottom end. 1 thing though, I do not recommend using Rg58 for the stub. It's way too lossy and a significant amount of you TX power is lost as heat in the stub. Although that HF-5000 coax will do very nicely. The specs look good - almost as good as W-103 / Ecoflex so that will work very well.
I see from your pictures that you have used RG213 throughout. How did you get on with such thick coax for the choke coil for the bottom? Did you re engineer it to a larger diameter?
You are correct on how to change the VF for the lower radiator / feed line. I left it non editable as I assumed most would be using RG58 for the lower radiator, but you know what you are doing so please adjust accordingly. :)
I am happy to see it's working very well for you and you have adjusted the lengths to suit your needs.
RE: The skypper no that's not crazy. It'll be interesting to see if we can model it out to a 5/8 wave broadband antenna, although putting the Gainmaster on it's side does give you about 8 dbi in 2 directions on it's own. ;)

Si
*Proud owner of a Cornflake Packet Amateur License and registered instructor in the art of gaining said license*
Icom IC-756 Pro III
Yaesu FT100D.
President Washington
President Adams
Tait T2020 70mhz
Baofeng UV-5R 2m / 70cm
kamikazeandi
Regular
Regular
Posts: 9
Joined: 13 Jun 2013, 10:48

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by kamikazeandi »

Hi Psi,
the choke I've created also in original size (with 66mm inside diameter) with the RG213. It was not easy with this rigid coaxial cable. In the first step, I have this fixed with 4 cable ties. In the review I have this fixed with fiberglass mat and epoxy (see picture):
Choke-Balun_kl.jpg
This looks stable and it is, but was not such a good decision because the cured epoxy has cut the insulation of the coaxial cable in the bends by moving the cable. I suspect that the choke properly now contains water in the shield. This will not just improve performance. ;)
A much more secure solution is a suitable sewer pipe and an attachment with cable ties to it. A suitable tube I had at the time but not at hand. In the optimized version, I'll use a sewer pipe.

Now I have modeled a variant for the HF5000 coaxial cable and then all that remains is the implementation of the data obtained. In this version I have also adjusted the radii of the cable, because that has a non-negligible influence on the result (see picture):
GainMaster HF5000-1.png
Thank you for publishing your work in the form of the file. That was what I was missing. I can now use this file and customize. But an understanding of the stub length and the form in the program has not yet set on me.
However, I have not played with this length. This certainly has something to do with impedance matching. Do you have a tip to understand for me?

Best regards,
Andi
You do not have the required permissions to view the files attached to this post.
User avatar
Kaos
Radio Addict
Radio Addict
Posts: 964
Joined: 14 Nov 2007, 06:53

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by Kaos »

Its a hard job with the RG213 on the choke with 66mm.

Took me a few attempts until it was tight and I was happy with it.
JGR
Registered New User
Registered New User
Posts: 985
Joined: 19 Mar 2013, 15:20

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by JGR »

Try warming the stuff up in the sun before winding the RG213 might help.
Do not believe everything that is in black and white.
Oh and prestigious Winner of "In Before The Lock June 2014"
Flex 5000A, Trio TS-830S, Icom IC-E2820, IC-E92D and a DVB-T SDR Dongle
User avatar
PsiDOC
Super Member
Super Member
Posts: 446
Joined: 16 Aug 2011, 18:39
Call Sign: 163FKU
Location: Moonbase Alpha
Contact:

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by PsiDOC »

Hi again Guys.
You do realise you are below the minimum bend radius winding RG213 at 66mm diameter don't you? The minimum radius is 50mm so minimum diameter is 100mm and you're winding it a 66mm. Just remember that with a bit of power there is the possibility of the centre core migrating outwards through the dielectric and shorting out on the screen. Something to watch out for. ;)
Andi,
The HF5000 version stretched to 6 mhz is looking good. get building :)
I will be honest the stub I have only partially worked out mathematically. I roughly calculate it by taking 1/4 wavelength the centre frequency of the antenna then use 71% of the 1/4 wavelength x by the VF for the attach point and 29% of the 1/4 wavelength x by the VF for the stub.
It's nowhere near exact but it puts you close enough to play with on the model. Also the attach point is dependent on the capacitor size as well.
Sorry I cannnot be any more specific than that.
IrishHam, With the RG58 version I recommend no more than 125 watts. The weak point with regards to power is the coax capacitor and it can flashover if you push it too far. If you were to substitute coax used for the capacitor for something more exotic and are careful with the construction techniques, as people have with the original they will cope with some serious power.
Si
*Proud owner of a Cornflake Packet Amateur License and registered instructor in the art of gaining said license*
Icom IC-756 Pro III
Yaesu FT100D.
President Washington
President Adams
Tait T2020 70mhz
Baofeng UV-5R 2m / 70cm
kamikazeandi
Regular
Regular
Posts: 9
Joined: 13 Jun 2013, 10:48

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by kamikazeandi »

Hello again!
Yes, PsiDOc, of course you're right! We use the RG213 outside the specs. But what the hell, my antenna still works very well. :-D
The cable used by me, more than 30 years old, would be hiked in the trash.
In the new version I will wind the coil with the new cable to a 100mm sewer pipe. How many turns I'll probably need? With a coil calculator I have calculated 9-10 turns in the same inductance. Confirmation?
Next Friday I will go to "Ham-Radio" to Friedrichshafen. Then I hope to catch new, low-cost coax cable. And then the new version is constructed.
Andi
User avatar
PsiDOC
Super Member
Super Member
Posts: 446
Joined: 16 Aug 2011, 18:39
Call Sign: 163FKU
Location: Moonbase Alpha
Contact:

Re: Homebrewing a Sirio Gainmaster using RG58 and 2.5mm wire

Post by PsiDOC »

Andi, Apologies for the late reply. It's been a hell of a week here between my day job and rebuilding the grandson's racing quad bike ready for an event on the weekend time has been at a premium.
Ok to business.. I'd go with 11 turns at 100mm, if the swr starts acting strange - Shooting up quicker than you'd expect - at either end then unwrap half a turn and try again... Then unwrap andother half turn etc. You know the drill. But with 11 I think you'll be very close if not there.

Si
*Proud owner of a Cornflake Packet Amateur License and registered instructor in the art of gaining said license*
Icom IC-756 Pro III
Yaesu FT100D.
President Washington
President Adams
Tait T2020 70mhz
Baofeng UV-5R 2m / 70cm
Post Reply