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Maco M103 flatside for local????

TIN_CAN

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Nov 23, 2011
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Ok well I have an original wilson shooting star that I just dont have room for till I get a free standing tower further away from the house, so I have decided to put up a maco m103 horizontal with an imax 2000 mounted 2 feet above it, my question is will the m103 still talk ok on the flatside for local talk? it will be around 60 feet in the air.
 

The signal from the 3 element flat side will be noticeably weaker than your Imax to all vertically polarized local stations. The cross polarization will cause an approximate 20db loss of signal on both RX and TX.

The simple solution if you want more local signal would be to place the beam in the vertical polarization. Unfortunately the 3 element Yagi is perhaps the worst possible choice for a vertical beam due to severe coupling of the driven element to the supporting mast.
 
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The M103 will work fine with the Imax mounted above it.
But if you are going to talk to locals that use vertical antennas, I would use the Imax and not the M103 for the same reasons that Shockwave said above.
 
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Thanks for the heads up then...mabey I will go for a 2 element gizmotchy instead so I can still work local on vertical? or a maco comet
 
Thanks for the heads up then...mabey I will go for a 2 element gizmotchy instead so I can still work local on vertical? or a maco comet

What can be said for a vertical having a transmit/receive pattern that is omnidirectional cannot be said for any beam. If you live anywhere near the middle of your local talking group; then a omni is the right way to go. Otherwise, you will be getting some of them well and the others will be in the nulls if using a beam.

Still nothing wrong with an Imax on top of a horizontal Yagi; some guys do very well with that arrangement . . .
 
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What can be said for a vertical having a transmit/receive pattern that is omnidirectional cannot be said for any beam. If you live anywhere near the middle of your local talking group; then a omni is the right way to go. Otherwise, you will be getting some of them well and the others will be in the nulls if using a beam.

Still nothing wrong with an Imax on top of a horizontal Yagi; some guys do very well with that arrangement . . .

Robb, you are right the horizontal beam will suffer some attenuation of vertical signals, and maybe some more loss due to rejection, but I know several old hands in CB radio that I've know for years, and they ever worked anything but their Moonrakers or Shooting Stars, among others. Most would tell us when they could not copy someone that us guys with omnis were hearing just fine, but to be honest...that didn't happen very often among the guys I know.

I ran a homemade 4 element I built in 1990 until 2006, and I sensed some issues at times like you describe, but it seemed like I could still copy and work the guys around the Houston area...and do it with out wearing my rotor out.

Now when it comes to DX contacts...there is where I see the difference when using my beam.
 
Thanks Rob I saw what you said about the interference from the mast, look like a maco y-quad or a a pdl2 or similar will do.
 
if ya get out ok locally off the imax just use it for local chat. then switch
to beam for dx. you put up the maco on a 60 foot tower w/ mast and imax
above it that should be all ya need.if your locals are horizonal then thats a whole another
story.
 
What about the new Penetrator? I have both that and an Imax and the Penetrator gives about a full s-unit more signal on both TX & RX and gets about 2-3 s-units less static compared to my Imax.

You have an old original Wilson Shooting Star? That's a fantastic beam, why not get a fantastic omni to go with it and use it until you get your tower & beam up?

I now leave my Imax for camping trips.
 
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For about a week now, since this thread started, I have been interested in the topic. I have been redoing my M103 to make sure the specs are correct as noted in the manual.

I have also reconfigured this same horizontal model in the vertical field to insure everything is the same as the horizontal model.

I have a full comparison presentation between the Gizmotchy3 and the M103, that I'll post soon. I took the vertical M103c from this project to make the post below showing the effects with the mast attached and without, so you guys can see what my Eznec suggests when I remove the mast from the antenna. Will the results be as bad?

Shockwave it right, the mast does effect the pattern, but I'm not sure we could casually notice this difference...just using our radio.

You might also notice that the model with the mast does not show a significant amount of CMC on the feed line or the mast, so I take that to suggest there is likely enough decoupling going on at this particular height (feed line length)...even though I did not model the feed line into the model.

View attachment Maco 103c with and without the mast..pdf
 
For about a week now, since this thread started, I have been interested in the topic. I have been redoing my M103 to make sure the specs are correct as noted in the manual.

I have also reconfigured this same horizontal model in the vertical field to insure everything is the same as the horizontal model.

I have a full comparison presentation between the Gizmotchy3 and the M103, that I'll post soon. I took the vertical M103c from this project to make the post below showing the effects with the mast attached and without, so you guys can see what my Eznec suggests when I remove the mast from the antenna. Will the results be as bad?

Shockwave it right, the mast does effect the pattern, but I'm not sure we could casually notice this difference...just using our radio.

You might also notice that the model with the mast does not show a significant amount of CMC on the feed line or the mast, so I take that to suggest there is likely enough decoupling going on at this particular height (feed line length)...even though I did not model the feed line into the model.

View attachment 10861
I'll be very interested in seeing how those two compare!

Have you ever tried this website, Marconi:
Martin E. Meserve - K7MEM - VHF/UHF Yagi Antenna Design

Since you have six 1/4 waves on your Maco 103, you could fab a 2 element Gizmotchy, which would offer switchable polarization if you added a 2nd gamma & feed line/ switcher.

You could also consider adding four 6' fiberglass rods on a hub of tubing, plus wire, as a Quad reflector and have a 3 element 'GizQuagi' :unsure:
 
I'll be very interested in seeing how those two compare!

Have you ever tried this website, Marconi:
Martin E. Meserve - K7MEM - VHF/UHF Yagi Antenna Design

Since you have six 1/4 waves on your Maco 103, you could fab a 2 element Gizmotchy, which would offer switchable polarization if you added a 2nd gamma & feed line/ switcher.

You could also consider adding four 6' fiberglass rods on a hub of tubing, plus wire, as a Quad reflector and have a 3 element 'GizQuagi' :unsure:

No, I haven't tried a beam calculator yet, I use an idea that I got from my old radio mentor a long time ago, and that gets me real close. Then I start tweaking the model until I see trends start and stop.

I'll check this out however, it may be a lot more simple to use, cause my way requires a calculator.

My first beam was a Y-Quad, and I didn't find it particularly effective, but that was long long ago and I've learned a thing or two since. I did finally put a conventional yagi reflector on the Y-quad and I thought it was better...but that could have been my bias working too. It would be an interesting project to see what my Eznec idea for a quad reflector could predict.

I have heard guys that prefer the quad as the reflector comment how much better it works in the real world, but I've never modeled the idea. I could be wrong, but as I usually find, I doubt it will make that much of a difference.

I could be surprised though at what Eznec might predict. This is often why I do my models...just to see how they line up with what is reported by others.
 

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