maco 5/8 nightmare help

[C2]

Here's the other's...

 

[HomerBB]

Hey,
Thanks for the plot.
My question was legitimate, no rancor intended.

Others in other places suggested the large sized vertical element (1 1/4" at the base, 1/2" at the top, 22' long) might have accounted for the bandwidth. This was the first I'd read suggesting there could be an undesirable irregularity.

Just wanted some informed input.

Does the plot still seem to indicate something off? another honest question...

(Thanks for letting me ride on your tail-wind 1342.)

 

[HomerBB]

the maco is 40ft to the base with 80ft of belden 9913.cheers!

my coax is Belden RG58 50 feet long. It was mounted only 35' at the feed point. I put a coax coils choke on it to assist with any possible CMC.

 

[C2]

HomerBB, aside from the theory, I was only accounting my experience with the V58.

Different designs have different results, one result does not fit all designs.

Determining the performance of an antenna is far more complex than simply looking at an SWR plot.

 

[HomerBB]

HomerBB, aside from the theory, I was only accounting my experience with the V58.

Different designs have different results, one result does not fit all designs.

Determining the performance of an antenna is far more complex than simply looking at an SWR plot.

Fair enough.
I can go back to feeling smugly satisfied with my homebrew for now.

 

[Marconi]

hello all my imax snapped and someone gave me a maco 5/8.i put this bugger on 10ft mast and started adjusting and after 2 days i gave up.i then decided to pull the radiator out and it was bolted through the base at the bracket (some idiot drilled a hole through it)so now the match is adjusting well heres my problem 1.i had this at 1.1 at one time and cant get it back,i got my dip at 27.475 right where i wanted it after many many adjustments.

my swr is:

1.4 27.385
1.3 27.475
1.4 27.555

the ring gap is 1 inch like the instructions call will making this gap larger or smaller bring the swr down? 2.when it rains my dip drops down to 26.805 or so is this common my imax never did that?any info would be great.

well hello again with some fine tuning of the tuning ring, radiator and tap point i was able to achieve flat line on those same bands and also made my antenna more broad banded by 3 bands of 40. i do not want to sound cocky but i do not like a 1.3-1.4 match and my antenna was not workable before more than 1 band of 40 channels but now its able to work 4 bands of 40 so that little bit of difference that some may not see a problem i see potential, but thank you for the responses.73s all

sorry for the confusion guys my flat line was for the frequencys i listed not all bands this was on an external meter.the dip came out at 27.475 thats where i wanted it.

26.865-1.8,
26.965-1.6,
27.385-flat,
27.475-flat,
27.555-flat,
27.855-1.4
28.005-1.8

I could have checked it to 2.1 but i dont like to run my radio at 2.1. 73s all

In your first post you said you had achieved a 1:1 SWR and could not get back to that tune. After that I was a little confused I think. I rearrange your numbers so I could better visualize what you were trying to explain to us. I think now I understand what you meant, but the problem for me was not understanding what you were meaning when you said you had a flat line on those same bands, as you mentioned 3 & 4 bands of bandwidth. The word flat is not a very good descriptor of SWR, and you see that Bettle mentioned how you made your notations for SWR, possibly leaving questions in the minds of the reader.

But thanks for trying to make the issue more clear.

 

[Marconi]

good job homer that was funny i had an imax 2000 up with a flat match on at least 2 bands of 40 but thats got a tuning coil.hey i will remember that if any of my radio buddies tell me there match is flat i will tell them there must be something wrong lol. the maco is 40ft to the base with 80ft of belden 9913.cheers!

1342, here you go again using bad information that you just tried to explain to us in a previous post.

i had an imax 2000 up with a flat match on at least 2 bands of 40

I think you are taking what is said here all wrong being a bit snipy with how you will respond to friends on this subject in the future.

"...hey i will remember that if any of my radio buddies tell me there match is flat i will tell them there must be something wrong lol.."

I won't try to explain further, except to say you are using the word FLAT without really describing accurately what you mean. Flat usually refers to a perfect match of 1.01:1 or 1.0:1 and that is not what you had except maybe at the first when you could not get it back as you stated. You can of course use the term FLAT to describe your bandwidth as flat even if your lowests SWR is not FLAT, but indicating the numbers can be improtant for good understanding.

C2 gives us some nice bandwidth curves using the info you and Homer supplied. I'm not sure about Homer's numbers, because I don't remember if his antenna showed a flat swr of 1.0:1 or not, but C2's chart for your numbers are noted wrong in the chart and that is because of the way C2 interpreted what you ill-described.

I think most here in this thread are trying to work with the idea as you present it, but you owe good and accurate info and not just talk that might be good on the street when you say:

"...hey i will remember that if any of my radio buddies tell me there match is flat i will tell them there must be something wrong lol.."

If you are not just Wolf talking and are in fact serious about your issues, you will find help comes with no expense, which is totally different than saying "...it is cheap!"

 

[Marconi]

Marconi, all I was trying to say was something similar to

I agree C2.

1342 seemed to be indicating that

which to me sounded like 160 channels with an SWR of 1.4 or less.

I didn't see it that way, but he had numbers all over the place and I think that is part of the confusion.

which to me, considering a standard, well known antenna that is the V58, is way too wide for that design.

I agree here also.

However, 1342 has clarified his readings, which seem more reasonable, as I interpret them (and yielding to some loose measurements):

26.865 - 1.8:1
26.965 - 1.6:1
27.385 - 1:1
27.475 - 1:1
27.555 - 1:1
27.855 - 1.4:1
28.005 - 1.8:1

This is were I think your using the ill-described info that 1342 gave us, lead you to consider 27.385 - 27.555 were all 1.0:1. I think if you will check, that is not what he originally told us in his original post. After he started talking about bandwidth and multi-bands above and below CB is when he started talking about being FLAT and this is the reason for my argument for presenting good numbers. If that don't happen, confusion can set in and then we end up just saying all kinds of nonsense.

I'm thru with this thread.

 

[HomerBB]

Marconi.
Thanks for the info and the help.
I started CB in the early nineties, and had life changing events take me to other places with no time for CB. My interest returned in Dec '08. Amazingly, I found a wealth of info and help from you guys on the internet, a resource not readily available to me at the previous time. I am learning. All my questions at any time are sincere, and any miss-statements are from my ignorance.
I ask on several forums, and I value the answers I get.

Thanks again to all of you.

BTW, this is the SWR


28.305 2.0:1
27.855 1.2:1
27.405 1.0:1
27.185 1.0:1
26.965 1.0:1
26:515 1.2:1
26.065 1.5:1

 

[1342]

ok guys let me try this again when i said flat line i was talking about a 1.0 so when i check it the needle in the meter appears to be broken not a 1.1 a 1.0 or what i call a flat line or perfect swr !

 

[C2]

I'm thru with this thread.

It is as I said.

Just trying to help...

 

[1342]

i could never get it under 1.3 before at the dip but very happy now.now i am thinking of making a top hat for it like the old avanti 101s and the i-10k.by the way c2 that was a pretty neat plot table you made there! 73s guys happy dxing

 

[CDX-007]

Well Homer, if the antenna is doing a good job on-air and is responsive, then the large bandwidth probably serves you well. It is unusal though for a typical 5/8 wave or longer vertical antenna to have that much bandwidth. But, like I said earlier, Bob85 has a convincing idea that might cast some light of truth on what you and 1342 are experiencing.

It is my opinion that an antenna with excessive bandwidth (2> megs below 2:1) is probably also showing some excessive losses as well. This almost 5x compromise however could be an advantage to some operators where the losses may not be a problem as long as efficiency is not also sacrificed...

Just fer 'grits and shins'...

My Hy-gain Penetrator:

2:1 @ 1.64mHz wide, 1.5:1 @ .94mHz wide, 100w, no common-mode choke... yet.

BTW, Homer, I was the one who's posts were deleted for not reading the fine print and first posting an introduction.

Congrats on an excellent job of accepting the challenge of a home-brew 5/8 and succeeding! I'm impressed.

 

[1342]

hey marconi i think we are on the same page now i was not a big fan of the maco up till now but i will give it a chance now thanks for the responses i think i will try a top hat and see if it works out. 73s my freind and thanks again.

 

[1342]

marconi i am not being snipy a flat line is a 1.0 not 1.1 a 1.0 perfect swr hope this clears something up!