New antenna from Sirio Gain-Master

[dxswe]

Dxswe, does this happen the same on a flat bridge as it does on a bridge that has significant elevation? If so, then you may be right.

I don't work mobile anymore, but when I did I use to notice some areas driving around that seemed to either cause the signals to improve or get worse. Often the areas were quite small, so when I could I tested to see if it was just conditions making the difference. I called the good spots "Hot Spots" and I don't think it was metal in the ground that made the difference.

I also have a buddy that use to work on Galveston Island, south of me over 60 miles. Typically we could not talk after about 30-40 miles. We could not copy his signal even as he drove over the connecting causeway bridge to the Island. The bridge is over Gulf water and you may know how transmitting a signal over Sea water can benefit radio signals. In such case however, I think you have to be within a few feet of the water for that to happen. On the island he had located two different spots where he could easily hear traffic in the Houston area, and then we could talk with very strong signals. However, as soon as he drove out of these small areas, his signal was gone again. We thought that was really "cool."

I don't know the cause, but there are areas I can drive to in my city where I consider radio signals basically dead. It is difficult to talk over a couple of miles from such areas...even to nearby channel 19 traffic. There are other areas where signals are always "Hot."

Try these ideas out and let us know more.

I have drive over many bridges most flated bridge, and see the same results..
The longer the bridge is there stronger is the signal.

 

[Oggy]

I would be intresting to test SGM with a non conductive pole with same
feedline and same height.It will worth a try and see whats happening.

I think the antron 99 will work better with higher pole because the
radiation angle will be lower.What do you think

I think the issue here is the Sirio Gain Master does NOT use the pole as part of the antenna.The pole is just a mounting point and is not connected at all.
The RF Choke as we will call it decouples the antenna fron the feedline also.
So I think a metal,alloy Fibreglass or a pole made of bamboo painted lilac won't make any difference.

 

[Marconi]

I would be interesting to test SGM with a non conductive pole with same
feedline and same height.It will worth a try and see whats happening.

I think the antron 99 will work better with higher pole because the
radiation angle will be lower.What do you think

Dxswe, I have a digital Field Strength meter with a shorted 14' foot coax for the antenna. It is set up horizontal in my shack so as to be very sensitive to RF in the area around the radio.

I have my GM on an all metal 40' pushup pole out back about 40' away from my shack. I get no signal even when I put 100 watts into the antenna. When I had my TopOne on the same pole, with 100 watts...it always showed over 100 on the FS meter. I figure this AstroPlane type antenna probably makes a bit of very low angled signal below the antenna. I have place the FS meter right below the TopOne's mount and the meter did not reflect any RF, so I figure it does not radiate much on the feedline.

I also have an A99 with 3 x 72" radials horizontal mounted on a similar pushup pole. It is right outside my shack. When I put 100 watts into it...the FS meter reads maybe 15 on the scale. When I had my GM on this same mount...again it did not show a signal on the FS meter. That might be telling me the feed line on the A99 is radiating a little RF on the feedline...while the GM shows none. Because of this experience I think the GM is not radiating very much RF below or on the feedline...just as the design suggest it should.

IMO, when you place the GM on an insulated mast...it probably will not result in much if any noticeable difference in any measurement you might do. What kind of response will you be looking for in such a test?

I have drive over many bridges most flated bridge, and see the same results..
The longer the bridge is there stronger is the signal.

I've noticed the signal increasing on going over elevated high bridges as I approach the top, but can't recall the same going over a flat bridge. Maybe I just wasn't paying attention though. That is interesting and something I would like to test.

Keep us posted.

 

[dxswe]

I think the issue here is the Sirio Gain Master does NOT use the pole as part of the antenna.The pole is just a mounting point and is not connected at all.
The RF Choke as we will call it decouples the antenna fron the feedline also.
So I think a metal,alloy Fibreglass or a pole made of bamboo painted lilac won't make any difference.

I took my ohm meter and check it.
The antenna connector is coupled to the mounting clambs.
So pole is not decoupled from the antenna

 

[CDX-007]

Well, I'll be back in a while... I haven't had an email alert to this thread in 2 days so I've got quite a bit of catch-up reading to do!

First, more coffee!

 

[dxswe]

Well, I'll be back in a while... I haven't had an email alert to this thread in 2 days so I've got quite a bit of catch-up reading to do!

First, more coffee!

Same here more coffe:

 

[dxswe]

When running with a directional beam antennas with elevation, so you know that to some degree may affect
distance considerably.
So it is with vertical antennas.
With different heights, you see different results on the signals.
There are so many different designs of antennas so that makes it difficult to find a good position.You must have to test different heights to find the optimum performance.:mellow:

 

[Shockwave]

The GM is completely RF isolated from the mast and coax. Yes the outside of the coax is connected to the mast but what is being forgotten is that the RF choke has already isolated the RF before it connects to the mast or the shield of the coax connector. Meaning it has eliminated all common mode currents before making this connection.

 

[CDX-007]

Well, having finally digested both breakfast and more coffee, plus the new posts here, all I can conclude in my finite wisdom is it's either a function of your meter AGC showing much less increase per dB, or your ground conductivity being high, thus hurting the pattern of the balanced SGM especially in comparison to other designs not so critical of unbalancing ground effects, since it's not a full wave above ground as is mine and most others who are seeing great increases in performance on the SGM, or it's doing what it's supposed to and offering you a more flatish take off angle, and more so than the other antenna designs and possibly other operators with poorer ground conductivity, thus causing your signal to hit the atmosphere at a downward reflective point further away than the others, giving you possibly more of an over-their-heads type of performance (from the first bounce) at a relatively shorter distance.

Ie: where the SGM might offer noticeably better performance at 75miles, the higher TOA antennas might hit & bounce off the atmospheric ceiling and come down with more reflected signal at a point maybe only 40-50 miles away.

Now if that isn't a conjectured inspired guess, I don't know what is!@!

I'll have to go with door number...

 

[CDX-007]

The GM is completely RF isolated from the mast and coax. Yes the outside of the coax is connected to the mast but what is being forgotten is that the RF choke has already isolated the RF before it connects to the mast or the shield of the coax connector. Meaning it has eliminated all common mode currents before making this connection.

Damn, you said it better than I could!

 

[Oggy]

Damn, you said it better than I could!

I said the same early but not as well......and mentioned Lilac Bamboo masts also Scott

 

[CDX-007]

I said the same early but not as well......and mentioned Lilac Bamboo masts also Scott

Are you harassing me about my home-built quad? I happen to like Lilac

 

[Marconi]

Thus far I have compared my GM to my Top One, and my A99 with 3-72" horizontal radials. I've seen a variety of differences, but the gain was minimally better compared to the TO and is just about on par with the A99.

To this point however, I've not set the GM and the A99 to the same height to the mount. I thought I was closer than I was, because this morning I raised my GM about 5' today and I'm still about 2'-3' short of both being at the same base height as best I can see. See attached pictures.



I'll try and fix that tomorrow and get the base closer to 36' feet to make CDX007 happy. BTW, some of the problem in the picture is the angle perspective.

I have to say I was disappointed in raising the GM the 5' feet higher today and I don't know why. I've not done much comparison testing today, but what I did seemed disappointing. The A99 showed a little better signals as I switched antennas back and forth and the audio was noticeably down for some reason on the GM. Earlier with the GM even lower I was seeing about the same small difference, but the GM being better. If I didn't know better, I would swear that I had the antennas hooked to my switch box backward.

I'll be doing my testing with my regular group of contacts in the AM, so I'm not recording these observations today which were solid but random.

I also got my Wolf .64 out and attempted to rebuild it, but got disgusted with the manual, not clear on where the bottom of the antenna really is measured from. Reminded me of our discussion on the Maco V58, which is still a mystery...even considering the new owner has developed a brand new and much better manual for the V58. I also found the gamma connection to the SO239, which is supposed to be solid brass, was severely rusted. It showed good continuity, but knowing the SWR was hay-wire when I took it down in 2008, prior to Hurricane Ike, I got disgusted with the manual and took the junk apart again. I didn't want to spend the time to fix, experiment, and tune.

So, I rebuilt my I-10K and that will be my next project for comparison to my GM. I'm going to take my GM down and remount it where the A99 is and retest and record results. Hopefully I will get the same results for the GM that I got earlier. That will be what I'm expecting anyway. Then I will replace it with my I-10K and test and record it too.

I think and thank you guys that complained about my using two locations to mount for comparisons work. You were right to question.

With my recent experiences, I'm seeing issues that are unpredictable and unexpected, plus the audio from that location is not up to par with my new mount next to the shack. But, do you think I could tell about the audio if I didn't have the antennas on a switch box side by side?

It could be the GM's extra sensitivity that is at issue. However, I've never noticed this before with other antennas on that mount. From now on it will be one antenna at a time on the same mount. The only thing I've not done thus far on the recommendation of others is mount the Top One on the new mount. I'll do that after the I-10K if I still have any energy. The I-10K results should tell me if my experience with the A99 vs. GM was a fluke or not.

I'm not getting any younger, even if I'm well ahead of most that have promised to do some antenna testing. Homer, it's me and you showing these young whipper-snappers a thing or two...to GET'ER DONE.

Great work on your AstroPlane project. You guys take a look and maybe Homer will give us some comparison results with some of his other antennas.

 

[CDX-007]

"I'll try and fix that tomorrow and get the base closer to 36' feet to make CDX007 happy. "

 

[HomerBB]

If I didn't know better, I would swear that I had the antennas hooked to my switch box backward.

Ooo, boy. I've done that . . .

I think and thank you guys that complained about my using two locations to mount for comparisons work. You were right to question.

I was convinced a while back that this is the way to do it. But what do I know?? Now that you're gonna do it, I know I'm right.

I'm not getting any younger, even if I'm well ahead of most that have promised to do some antenna testing. Homer, it's me and you showing the whipper-snappers a thing or two to GET'ER DONE. Great work on your AstroPlane project. You guys take a look and maybe Homer will give us some comparison results with some of his other antennas.

Thanks. We'll see what the local work makes of it. DX is working out great on it.