-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Maco V5000
- Thread starter husk 269
- Start date
Although it never hurts to lower SWR, 2.1 is an acceptable level. it won't hurt the radio unless you're using a lot of power. An antenna tuner can usually lower it further.
269 I have looked over the docs a few times but not recently. I have read guys post with similar complaints. Are you sure that you have the overall length correct and that you have measured between the top and the very bottom of the antenna base mount? That is very important.
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!
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!
Master Chief, I appreciate the instructions also. I bought one of these this weekend and almost hit 1.1 the first try. I adjusted the top section and never touched the ring on the bottom. I had a MFJ 269 analyzer and it was a piece of cake. Its nice to have the information that this forum provides. Even with the fussing that happens every now and then, its good to get other opinions.