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 . 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!) Master Chief !
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 . 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!) Master Chief !
