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  #41  
Old 01-14-2011, 01:46 PM
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Quote:
Originally Posted by Marconi View Post
Homer, again a good report. I have found much the same type results over the years with my AP's. In 2006, I published this link: The Radio Operators Roundtable: AstroPlane . You may have seen it before, but just in case...you might be interested.
Thanks. I'll take a look at the reference.
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I've changed my mind a little on the AP being a 5/8 wave however, and that is because I could never account for the bottom loop in the antenna. I just assumed it was a 90* bent bottom 1/8 section of a 5/8 wave. I now feel certain that it's a 1/2 wave radiator, that is very effectively center fed...similar to the Gain Master in that it has a balanced design. I believe this, because recently when I installed them side by side with the centers of the antennas at the same height, I could not see any RX signal differences. I did not take any readings for TX signals, but guys say all the time that antennas are recipocal in this regard, but I'm not sure that is always true in real world test...I see differences sometimes on a rare occassion when I get a feedback signal report with two antennas up and folks say they see a big difference on their end while I'm seeing the signals about the same. That said however, this may be the same thing going on with my radios, and my location which ever is true.

Fortunately I also discovered that the mount I had the AP mounted on was noisy compared to the new mount I just built next to my shack where I had my GM mounted. I could not detect any significant signal differences between these two locations, but I did notice the noise differences and at first I was giving the GM the credit for being quieter...without knowing it was the locations making the difference. This was sort of like you felt when you noticed the noise differences...albeit your were comparing from the same mount, which is better. I don't know as I would be able to pick up such difference, however, with my hearing problem.
I've never had an opinion on the AP, except I thought they performed well when on the receive end of a transmission.
Yes, I'm on the same mount. One thing I've discovered is that I am located on one of the noisiest spots on my street. I noticed this when I was in my mobile. Oh, well, it is what it is. Can't move the house.
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If you can, how would you compare your AP to your other antennas regarding your local contacts at about the same height?
So far the AP seems to do as well in terms of the clarity of the audio. What seems different is the S-units are down on the local signals. I know S-units are not proof positive of things given the variety in radios, but this is exactly the same everything, radio included.
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  #42  
Old 01-14-2011, 01:49 PM
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Homer, how much lower, if at all, is the top of the AP than was the top of the 5/8λ?

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Old 01-14-2011, 01:50 PM
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If the imagination is allowed to roam unrestrained, the AP somewhat resembles a V4k upside down.
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Old 01-15-2011, 02:00 PM
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Originally Posted by Marconi View Post
Homer, again a good report. I have found much the same type results over the years with my AP's. In 2006, I published this link: The Radio Operators Roundtable: AstroPlane . You may have seen it before, but just in case...you might be interested.

I've changed my mind a little on the AP being a 5/8 wave however, and that is because I could never account for the bottom loop in the antenna. I just assumed it was a 90* bent bottom 1/8 section of a 5/8 wave. I now feel certain that it's a 1/2 wave radiator, that is very effectively center fed...similar to the Gain Master in that it has a balanced design. I believe this, because recently when I installed them side by side with the centers of the antennas at the same height, I could not see any RX signal differences. I did not take any readings for TX signals, but guys say all the time that antennas are recipocal in this regard, but I'm not sure that is always true in real world test...I see differences sometimes on a rare occassion when I get a feedback signal report with two antennas up and folks say they see a big difference on their end while I'm seeing the signals about the same. That said however, this may be the same thing going on with my radios, and my location which ever is true.

Fortunately I also discovered that the mount I had the AP mounted on was noisy compared to the new mount I just built next to my shack where I had my GM mounted. I could not detect any significant signal differences between these two locations, but I did notice the noise differences and at first I was giving the GM the credit for being quieter...without knowing it was the locations making the difference. This was sort of like you felt when you noticed the noise differences...albeit your were comparing from the same mount, which is better. I don't know as I would be able to pick up such difference, however, with my hearing problem.


If you can, how would you compare your AP to your other antennas regarding your local contacts at about the same height?
Hey Marconi, I just got to reading that, now I'm wondering how long you needed to make the top tube when you tried the AP without top hat radials? How was it's performance compared to stock configuration?

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Old 01-15-2011, 03:00 PM
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Originally Posted by CDX-007 View Post
Homer, how much lower, if at all, is the top of the AP than was the top of the 5/8λ?
1.5' lower top to top AP to 5/8

AP - 54.4'
5/8 - 56'
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Old 01-15-2011, 03:24 PM
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Homer, how much lower, if at all, is the top of the AP than was the top of the 5/8λ?
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Originally Posted by HomerBB View Post
1.5' lower top to top AP to 5/8

AP - 54.4'
5/8 - 56'
Close enough.

Same results I got many decades ago when, as a teen, I compared every antenna I could get my hands on and found the Hy-gain Penetrator.64, Taylor GLR-4.64, Wilson AlphaV5/8 & Avanti Sigma5/8 outperformed all others, including the Starduster & Astroplane, when mounted atop my 45' mast over the then 12' high roof, 57' to the mast top.

I never even thought about adding another section to the 5 section mast to 'even things up a bit'. I just figured you buy an antenna, install it on the highset mast available and let it do it's thing, ...and may the best performer win.

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Old 01-15-2011, 06:34 PM
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Close enough.

Same results I got many decades ago when, as a teen, I compared every antenna I could get my hands on and found the Hy-gain Penetrator.64, Taylor GLR-4.64, Wilson AlphaV5/8 & Avanti Sigma5/8 outperformed all others, including the Starduster & Astroplane, when mounted atop my 45' mast over the then 12' high roof, 57' to the mast top.
.
When I said this:

"So far the AP seems to do as well in terms of the clarity of the audio. What seems different is the S-units are down on the local signals. I know S-units are not proof positive of things given the variety in radios, but this is exactly the same everything, radio included."

I think I would have said it better had I said the clearer sounding audio was because it seemed to be louder. I think this is due to the fact that I have less white noise with the AP so that the audio stands out and is more readily understood, particularly to stations 10 - 20 or 30 miles out. Very close in local stuff is quite clear and loud, and the S-units are lower than the 5/8. Perhaps this is because all of the AP is higher than the longer antennas? I can't definitively say so . . .
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Old 01-15-2011, 06:56 PM
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Originally Posted by CDX-007 View Post
Hey Marconi, I just got to reading that, now I'm wondering how long you needed to make the top tube when you tried the AP without top hat radials? How was it's performance compared to stock configuration?
As per the following Antenna Work Sheet reports, I made three iterations to get my AP resonant at 27.205. Started with a full 1/4 wavelength of 79.5".

Report #1, using the 1/2" x 45" tip element from my Sigma4, the report shows I was short and high in frequency up near 27.605 mhz.

Report #2 shows I then went to 89.75" length, and the VA1 showed I was about 8 channels low at 27.105 mhz. That was fine considering the antenna is so broadbanded, but it wasn't where I wanted it.

Report #3 shows I changed the length to 87.5" using the same 5/8" element on the Top One and hose clamped the Sigma4 tip element to its side. The VA1 then showed a very nice dip at 27.205, but the data recorded after that also was skewed...as you will note on the report. This sometimes happened, I think, when someone in the area of my station keyed up some big-time RF. You'll see that the RF did not seem to affect the SWR inline meter scan that I did soon after the VA1 scan. Also I noted later, when I rehashed the reports, that I made an error in the final adjustment or I recorded the info wrong. I made an error that looks like about 1", so I'm not too sure what the actual top element length really was. It had to be close to 87.5" however to make my Top One center at 27.205 with a straight full length 1/4 wave top element.

Based on the report dates and other reports of the time, I had this full 1/4 wave TO configuration up only a few days. I do have two reports #13 &#14 dated 08/1/09 for the AP vs. Sigma4 showing the Sigma4 besting the AP by .9 Sunit on average, but the reports around that time were random reports only and were not even close to showing the reliable differences I was expecting...even if it's not possible to make reliable signal reports.

Based on the fact that I took the thing down and fixed the TO back to its original top hat configuration suggest to me...that I didn't like the results of making the top a full 1/4 wavelength. I didn't even make notes. Soon after that I started remodeling my house and I stopped all testing. These Signal and Work Sheet reports are all posted in my albums. http://www.worldwidedx.com/members/m...gust-2009.html

AstroPlane Antenna Work Sheet 073109.pdf

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Originally Posted by CDX-007 View Post
Close enough.

Same results I got many decades ago when, as a teen, I compared every antenna I could get my hands on and found the Hy-gain Penetrator.64, Taylor GLR-4.64, Wilson AlphaV5/8 & Avanti Sigma5/8 outperformed all others, including the Starduster & Astroplane, when mounted atop my 45' mast over the then 12' high roof, 57' to the mast top.

I never even thought about adding another section to the 5 section mast to 'even things up a bit'. I just figured you buy an antenna, install it on the highest mast available and let it do it's thing, ...and may the best performer win.
You're right 007, when we're just installing antennas, but I like to think my comparison work is devoted to testing or comparing rather than the simple process of our CB buddy "Fried Chicken Livers" installing his new antenna his mommy got him for Christmas. I'm not telling anyone to follow my instructions, I'm just relating my limited experiences doing "what if" experiments. I became inst rested long ago when a buddy of mine had a Starduster and he talked to guys in the distance I could not copy. Even back in the late 70's guys complained that the SD and the AP, both very short antennas were junk, while Johnny talked all over with his Washington radio and SD antenna. Other guys heard this too and went out and bought these same antennas and installed them, but they put them on a 10' or maybe an 18' foot mast and they failed to be able to do what Johnny could do. So, they all talked bad about his little antenna. I discovered later that Johnny live in a very high two story garage apartment that was about 30' to the peak. He had two 10' sections of Schedule 40 conduit screwed together with a 50' foot pushup pole inside about 4' feet. His antenna was well above 60' and that made the difference folks were seeing. Johnny was notorious in the area and everyone figured he had a big amp, but Johnny only had a 80 watt modulator that talked like it was a 1000 watts. Of course if he had installed a big old Vector 4000, Penetrator, or an I-10K up there he likely would have done even better, but then he had to worry about the wind with such a flimsy install.
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