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Antenna from GI JOES

undertaker

undertaker

Undertaker
Apr 5, 2006
3,171
3,354
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Texas
Got the antenna from gi joes and yes it is a maco v5/8. But you know the price was right and all i have heard about these antennas are they are very good...
 

They are a good antenna! Now go to Home Depot and buy a bottle of NOALOX! Just a thin film on all the element joints is all you need! You could also do a search for my post on how I assemble and tune these antennas.
 
Master Chief said:
They are a good antenna! Now go to Home Depot and buy a bottle of NOALOX! Just a thin film on all the element joints is all you need! You could also do a search for my post on how I assemble and tune these antennas.
Click to expand...

Could I use c o p p e r or nickel anti seize it is suppose to be water replant too I have plenty of that from working on cars which would be better?
 
I liked the article that you wrote about the V58 so much Master Chief, I saved it. Here it is....

Master Chief:

I have never failed to get a Maco to 1:1. Maco has never failed to have the wrong dimensions in their instruction sheet. Sure, you will get close, but usually the published lengths are too long and Maco says, "...however, the chart length is not sacred and may be changed...", so they give themselves an out.

Not knowing what your set up is, I suggest the following:

I set every element for 6" of overlap and adjust the TOP section for resonance (ground plane elements are 4" per instructions). Maco suggests adjusting "T43P" (second section). I'd much rather have a solid 6" of overlap here. You will find that the top section will have close to 12" overlap. Since they use the weaker .047 material, this overlap will actually strengthen the top of the antenna.

Take your antenna down and double check all measurments. Especially check the location of the wire tap. It's VERY easy to have the tap on the wrong side of the loop! The wire should tap closer to bottom bracket (P08P).

Set the antenna up on a 10' mast in your yard. Have a friend hold it. Check for frequency with lowest SWR. If your radio goes out of band, keep checking until you find the frequency with the lowest SWR. If it below channel 1, then your antenna is too long. Tip the antenna over and adjust the TOP section in 4"! Yes, 4"!!! Check SWR again and see if the frequency is now closer to where you want it to be. Keep adjusting the TOP section of the antenna until your lowest SWR is on the frequency you want (for me, it's ALWAYS channel 20).

Then, using a 6' ladder, move the tap in one direction and then the next until you get a dip in the SWR. It may read as low as 1.5:1 now.

Here is the important step that 99% of the people out there mess up on (except for English Bob; he gets it). Check the FREQUENCY for lowest SWR again. It may be above or below your desired frequency. Adjust the top section in or out to bring the SWR down even further on your desired frequency. Then re-adjust the tap on the loop! You will see your SWR drop even more! It should only take a couple of adjustments to get a PERFECT 1:1 SWR on your Maco.

What we have done here is adjust your main antenna element for resonance on your desired frequency, and adjusted your feedpoint matching network to allow your 50-ohm cable to feed a 5/8 wave antenna. Don't be suprised if you can hear better and talk farther. 2:1 SWR may work, but it is far from efficient.

Once you're done adjusting your antenna, then re-install it on your tower. The SWR may change a bit when you put it up in the air, but it will only be slight. Adjusting an antenna 10' off the ground has worked for 30+ years and is much easier than trying to so it on top of a tower! Good luck!

==============================================================

I pretty much covered it in the original post.

Double check your exposed lengths...

T43P, T18P, TI5P = 42" exposed.
Set TO1 for the desired frequency.

TO1 on the ground radials should have 68" exposed.

Check the locaion of the radial hub (spider)! It should be 1/2" down from the bottom of the bracket (PO8P).

Double check the location of the wire tap! It should be closer to the bottom bracket. Bend the wire to split the difference between the base section and the loop. In other words, make sure the wire is in free space and not up against the base section. I usually bend it into an "S" using my fore finger and thumb.

Double check all your connections!

Make sure the little screw that holds the vertical element to the insulator is NOT also touching the base tube!
(for all you big watt guys out there, this is a weak spot in the Maco design! That small screw is so close to the base tube that it will actually arc and melt the insulator. Yes, I know the antenna is DC grounded. Maybe you can better explain the burn marks and the melted insulators I've seen on V58 and V5000s!)
Click to expand...

Thanks for taking to write that Master Chief! It is very helpful!

Mopar
 
"I set every element for 6" of overlap and adjust the TOP section for resonance........"

you adjust for resonance according to what exactly?

"What we have done here is adjust your main antenna element for resonance on your desired frequency........"

no you haven't.
 
the only condition under which vswr is any indication of resonance is when the load is purely resistive, otherwise vswr readings are NO indication of resonance. i didn't see any measurements of X being made in the instructions. an antenna is resonant when X=0, regardless of vswr unless the load is purely resistive. either a noise bridge, grid dip meter or network analyzer is required to determine X.
 
the instructions are fine i'm sure but resonance is not what's being adjusted. what has been done is the antenna has been adjusted for minimum vswr, not resonance. only measurements of Xc and Xl are able to determine that and those measurements cannot be made with a vswr meter.
 
the instructions are good for the adjustment of minimum vswr and i have no doubt in that respect that they are accurate. your mistake is equating that 1:1 vswr with resonance. one has nothing to do with the other UNLESS THE LOAD IS PURELY RESISTIVE AND YOU CAN'T DETERMINE THAT IF YOU CAN'T MEASURE X.

you do not mention the measurement or adjustment of X and there is no adjustment information there as to how to achieve X=0. if you don't know what X is then you don't know whether the antenna is resonant or not. bob knows about that too. he knows how you can see a flat swr and resonance at frequencies 600khz. apart from one another.

vswr meters don't measure reactance, the 269 and minivna do.
 

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