Base Maco V58 model

[Marconi]

Eddie do you have anything that says two masts is OK for comparing antennas from respected sources ?

Nope! but I've read and heard guys for years reporting and asking for signal reports. I figured to do the same and do some videos to maybe show what I see. I did it because I was always surprised when guys reported 2-3 Sunits of difference among many of the same antennas I have worked for years, so I reported if the vertical CB antennas are mounted fairly with the current maximums even close to the same heights...I seldom see such differences.

So, this still leaves us with a question...are all the guys that are reporting seeing 2-3 Sunits difference between their 5/8 wave antenna compared to their 3/4 wave antenna using a radio with a meter response like you suggest is correct or is this difference due to something else that is non-apparent to us mortals?

I never said I could detect the peaks & troughs, that was NB, I don't think they exist unless you have multipath,

Maybe I misread your comments above where you said you had some similar experiences with NB Maco V58 model

I guess that is often my point in conversations with you, I'm never really sure about what you see Bob or what supports your observations. You asked me to read up on diversity antenna systems a while back. Again, I don't know specifically what article you have in mind but I will look the subject up and get back if I have questions.

fixing the meter as seen in the video makes the meter more generous but it reduces the ability to see small changes in signal strength, its not a mod I would do, its for meterbaters & cybernetics,
the video shows cb s-meters are far from 6db/s-unit,

I asked you how reliable you though this guys was and I found out you could not vouch for him. So, was that an example or not of why my meters don't show what your meters show in regards to this discussion?

 

[Marconi]

Its not too difficult to swap antennas in 2 or 3 minutes,

It typically takes me longer if I'm changing antennas in order to test on the same setup system like you claim to do.

On my best day it would take me more time to simply get the old antenna coax off, disconnect the antenna mount, put another fully assembled antenna in its place, reconnect the coax, then make sure I didn't mess something up that changed the match, check the tune, and then get it all raised up and secure.

Several years ago I sometimes could mount 2 maybe even 3 antennas during the course of a day, but I seldom if ever looked for help...so I can't make such a claim as you in such a short time.

You guys must practice like an Indy car racing team. You need to get some of your buddies to video an antenna install, and show us all how its done Bob. It would only take a few minutes and getting a video on YouTube is really simple and fast.

 

[Marconi]

Here is an article on diversity antenna systems. http://blog.rfvenue.com/the-myth-of-half-wave-diversity-antenna-pl

and I did not have to dig deep to find it with a Google search.

Did not work, try this one.

http://blog.rfvenue.com/the-myth-of-half-wave-diversity-antenna-placemen/

Bob is this sorta' what you had in mind?

 

[HomerBB]

@Marconi
No, I never botgered to dig into why the A99 could not read the mobile I was reading. I figured there might be all kinds of reasons. The base of his antenna as high as the top of mine, nulls, objects in between them I didnt have to deal with, maybe better receive in my old cobra . . .
I can only guess.
The point was simply things are not always equal, and I was happy my homebrew was doing as well as it did.
It is coming down, though. Any rain and the SWR goes way up.

 

[bob85]

I don't need to do anything doubting Thomas,
all a video of a sub 1 minute antenna change would prove is you were not setup to do tests in a timely manner fannying around with pushup poles with no help from locals,

what good would that do apart from make you feel like you should have kept your mouth shut about how fast antennas can be swapped,

1 hour or more to swap antennas is ridiculous but it won't ruin the test. Testing in AM while skips rolling using unwitting participants takes care of that,

yes I did work for a race team, I worked for two of them,
got the superflow cap, you want a video of that too THOMAS ? .

 

[Needle Bender]

A rotor? does this mean you put your vertical on a long arm and rotated it to a different position, say on a 9' arm from the center mast and swung it through an 18' arc so you could test the same mast and coax within mere seconds of being in each position?
...

Yessir, a 14 foot offset or 28' diameter circle, a hair over 3/4 wave.

I believe I saw right about 2-3 S-units dip/peak on everyone as I rotated it in the circle.
This is one of the things which has me believing that it was more than just the odd reflection/cancellation bouncing off a tree, tinted window, bridge overpass, etc., which was fully responsible for the change, it was far too uniform.

I see the main or "fundamental" RF coming straight in my direction from their antenna, maybe 6(?) miles away, and hitting my antenna somewhere along that 36' sine wave, at a high current node or at a low current node, or somewhere between.
As the antenna is revolved around in the 3/4 wave arc, the signal's point of impact on my antenna is changed within that 36' wavelength until the peak or null is found.

I could hear Dave with S7 but Dean with only S6, then revolve it a bit and drop Dave to S5 and bring Dean up to S8, selecting which I wanted to hear should they be rivals trying to out-talk one another, for instance.

It was fun, and writing about it forcing my memories of it kinda makes me want to build another with maybe a GainMaster or Sigma IV.

... NB, what was going on in your thinking at the time that gave you this idea you needed to answer by the experiment you site here?

Just that, well, - while some signals dropped and others increased but only one stayed the same, when I relocated the A99 to the other side of the cabin, made me think that something about the 36' wavelength was hitting the antenna at a different point within the sine, except the on the guy directly perpendicular to an imaginary line drawn from where the A99 had been to where it was moved to, who's signal didn't change, leaving me curious & hunting for the reason why.

 

[Marconi]

Yessir, a 14 foot offset or 28' diameter circle, a hair over 3/4 wave.

NB, other than your peculiar shaped mast does this A99 model at 32' feet look anything near like the offset setup you tested in your comments above?

 

[HomerBB]

Thanks for the reply, NB. That's just the kind of 'nutty' thing that gets my attention. Love it. Surely your neighbors weren't looking while you whizzed that thing back and forth??

 

[Marconi]

Just that, well, - while some signals dropped and others increased but only one stayed the same, when I relocated the A99 to the other side of the cabin, made me think that something about the 36' wavelength was hitting the antenna at a different point within the sine, except the on the guy directly perpendicular to an imaginary line drawn from where the A99 had been to where it was moved to, who's signal didn't change, leaving me curious & hunting for the reason why.

Did you consider the mast, not being directly below the antenna, as having any skewing effects on the A99 pattern? What if skewing made the antenna show directionality...with more gain in the direction of the 14' offset boom section and far less gain in the opposite direction?

 

[Marconi]

Homer, when you had a CF yagi element vertical and offset 2'-3' feet from the mast...did you notice any skewing effects?

 

[HomerBB]

Homer, when you had a CF yagi element vertical and offset 2'-3' feet from the mast...did you notice any skewing effects?

Nope. Behaved like any other vertical dipole best I could tell. Mast was to the south of it where I rarely talked. Since then all the vertical dipoles I've used are fed running the cable up through the lower tube to the center feed point and mounted atop the mast.
I wasn't looking for skewing, so didn't notice.

 

[HomerBB]

@Marconi

 

[Marconi]

Homer, that is the model and it does not show much if any skewing in the pattern. However, when I make the offset boom longer the pattern skews badly and is almost beam like due to the mast offset.

 

[HomerBB]

I dont see the pdf...
Is it above in the thread?

 

[Marconi]

Sorry Homer, I misspoke.

I didn't do a model for post #88. I was thinking about the model I posted #82 above where I made the offset boom longer and it has an A99 up there.

I will do a search here and see if I posted a model for your offset dipole idea. I do seem to remember seeing your setup in the past.