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Discussion in 'CB Antennas' started by silvereagle1, May 23, 2012.
That’s an interesting thought, lol.
It would cause flutter at a rate equal to the difference in frequency as the two carriers arrive in and out of phase. If the carriers are off by enough they will beat together and cause a heterodyne squeal at the same frequency that the two TX differ by.
Now you gave me something to think about, thanks!
Like having a “key down” all by yourself.
So...just thinking here.
1. One radio into one amp into two antennas.
2. One radio into two amps into two antennas.
3. One mic, two radios, two amps, two antennas.
Option 3 is the problem, correct? By my understanding, the radios couldn’t be “synched”, even if any differences in feed lines were worked out.
Option 1 works. Right?
So what about option 2...two amplifiers into two antennas? Seems possible. Couldn’t you even achieve CP before the amplifiers?
With the 203 amplifiers going for $115 a pair, I have thought about it. Maybe use a coax T and a little CB antenna tuner between radio and amps. The doubling of radiating surface should get you 3 db and the doubling of power should get another 3 db. Can we just keep adding amplifiers and antennas? How far apart should the antennas be? This could be fun....
I wonder if the amplifiers would be ok with their inputs connected? Might need a splitter transformer choke thing.
How about a beam with multiple driven elements? I can't get this out of my head. Haha
I agree...fun to talk about, Shade.
My thoughts on the options 1,2, 3... the amp can only produce what goes in...as we often say garbing in garbage out. But, so long as that’s coming from the same source (radio), with a proper harness that resolves impedance issues, it would be true parallel and “in time” or synchronized, right?
I don’t really know...just having fun with the idea(s).
Option 2 is the interesting one. Never had time to try it.
One radio..so the exact same freq..
2 identical pieces of coax at the same length.
2 identical amplifiers tuned the same.
2 of the same beams, one vert and one horizontal.
What could go wrong,?? Honestly it seems like it should work..right?? But let the smart guys pick me apart.
That will increase the bandwidth, (assuming each radiator is a different length).
The MFJ TH5-MK2 is an example.
Thank you gentleman this is a lot of fun for me and my father 81 y/o. He goes by the handle Pinwheel. He's a target shooter indoor 22, 3 position. Used the same handle since 70's. He's helping me put up the vertical antenna Monday. Once its up and working the we will do the horizontal. Dad likes that I am recycling old 102 stainless whips for a vertical dipole. Just having a base again making him happy he with be able to call be without the cell phone. He runs a Uniden 510, echo board, Superstar coffin mic, as a mobile with a Tiger 2 foot Super Flex on a hood mount so he can pull in his garage. . He can talk a few miles and talk in traffic jams which is what he wants. People see at and ask where he got the hood mount because his friends just assumed you can not put a CB antenna on a modern vehicle.
FWIW circular polarity is NOT as simple as feeding a vertical element and a horizontal element at the same time. There MUST be a phase delay to one element or the other. Leading the vertical element will give you right hand circular but leading the horizontal element will give you left hand circular. I think I got that right. If not it is the opposite. Simply feeding both elements in phase will NOT give you circular polarity but rather a combined vertical and horizontal which is NOT circular polarity. For terrestrial comms one station needs to be RHC bit the other needs to be LHC. IMHO completely forget the idea of circular on 11m. It is useless and more to it than you think. Circular pays off in VHF and UHF satellite comms where the signal may be subject to rotation due to spacecraft spin. Not saying it is not possible but rather impractical on 11m. FWIW my next experiment might be a circular polarized helix antenna for 70cm. MUCH easier and MUCH more practical on 70cm than 11m.
Hi All !...
I think if said it before here on forum. I asked a acquaintances of mine who works as a propagation analist for "radio world services" ...
He said....on 11 meter.... from a "wave" point of view it isnt important which polarisation you use.
(keep in mind..im not talking about additioinal bennefits like ground gain etc) .
As soon as the "radiation" hits the layers it will start to rotate... and thus fast you can not "guarantee" any polarisation can have any favour at a "set time". But overall the majority will be so fast in rotation there isnt any polarisation to favour.
There obvious will be times where one has the bennefit....but even then: While one procedeeds his own tests it will be hard to tell the difference between polarisation or take-off angle. (and dont forget things like gain differences......and reflections etc)
For "overall" best "DX" performance on CB it is best to setup a high plazed horizontal beam. (for its additional ground gain...most likely lower radiation angle (compared to a vertical) and possibly less noise).
That is logical...as most "big guns" and "contest" stations us such a setup. Infact those world radio services try really hard (when they use F2 layers) to put up hugh masts with ....a lot of horizontal antennas.
In the past i have made a circulair omnidirecitonal for "monitoring".
Attached is a picture of it.
It its possbile to construct something "circulair" without phasing lines.
K6STI has some good examples.:
Kind regards Henry
All this and Silvereagle1, has been long gone for nearly 8 years. I really don't think his question was about circular polarization.
Early on in this SE1 thread, Robb mentioned the idea about circular polarization regarding the Maco harness noted above. I knew very little to nothing about circular polarization, but I disagreed wtih Robb's description of this Maco Harness, and that it was for the purpose of Circular Polarization.
I remember a big ole' junkie CB SWR/Power meter I had with 3 antenna switches and 3 coax ports, Vertical, Horizontal, and Combined.
Working DX I could NOT tell any difference when switching to Combine. I could most often tell a notable increase in Rx when switching from Vertical to Horizontal, and I could also say there were likely a few exceptions too.
Working my horizontal beam with another horizontal beam locally...was always a win-win contact...even in the days when the airways were full of vertical CB radio signals 24-7.
Just my recollections and observations.