Sirio Preformer 5000 Magnet Mount Antenna

[The DB]

I did a quick run through of his site and can't find "SWR NODE" used as you are using it. I can't find "SWR NODE" even mentioned, doing some quick searches I can't even find only the word "node" on his site. That being said, I only looked through the pages that looked like they were related to SWR and coax in general and a few other semi-related pages. It is possible I missed it. Would you happen to have a direct link?

In the last decade I have been all through his site, a lot of good stuff there. I don't recall anything like that being on his site. That is not to say it isn't, I just don't recall ever seeing anything like that while on his site.

The word, node, when referring to antennas, is mostly used referring to "current nodes" and to a lesser extent "voltage nodes". These are on the antenna and not the coax itself. If such an SWR node exists in your setup, then, as mentioned above, you have other problems that need to be dealt with. Actually, one of the pages on K0BG's site talk about one of those problems and how to fix it. What can I say, his site is a descent resource.


The DB

 

[fourstringburn]

I did a quick run through of his site and can't find "SWR NODE"


The DB

You can't read can you or know where to look...If this is wrong, then argue with Allan Applegate himself since you always seem to have the antithesis of what we all say.

"Antenna manufacturers often tell their customers to cut their coax feed lines to a specific length in order to get a good match. All this does is mask the problem, by moving the SWR node to a different position along the feed line."

 

[222DBFL]

Here is the entire paragraph.

Antenna manufacturers often tell their customers to cut their coax feed lines to a specific length in order to get a good match. All this does is mask the problem, by moving the SWR node to a different position along the feed line. While this may appear to fix the problem, it doesn't fool most automatic controllers. The truth is, if the antenna is properly matched, it doesn't make any difference how long (or short) the feed line is.

This is straight from K0bg's site.
He also states the following:

In the following sections, it is necessary to know the exact resonant point (X=Ø) of the antenna we're trying to match. This fact alone, should not infer that exact resonance is a requirement; it isn't! Rather, in this case, it is only a means of arriving at the end point (wide-band match). Once the matching is complete, whatever the SWR is (assuming it is under ≈1.6:1) is irrelevant. However, it should be mentioned that measuring the SWR at the transceiver end of the coax feed line will usually result in more overall loss, and may make matching nearly impossible to achieve. The reason is that any reactance (±jΩ) the antenna exhibits, will be transformed by the coax. While the SWR may be low at the transceiver end, it may be excessive at the antenna end, resulting in additional coax losses, and a possible increase in IMD.
Hope this helps clear up some of the air. Let's not argue, but rather all work together to all learn from what is being said. There is much more to be read and the site k0bg.com. Good read. And some good info. Let's keep the bickering to a minimum though as it doesn't help anyone. JMHO.

 

[The DB]

I stand corrected.

Thanks for the help 222DBFL, I wasn't trying to be argumentative, I am just in the habit of confirming sources, and I apparently missed that one page on his site. Being told someone said something and reading what they actually said are two different things. To often I have been told someone said something only to later find out that they actually said the exact opposite. Last night I went through all of K0BG's pages, right down the list from his main page, and searched for the word node, and my browser got no hits. Maybe I was tired, maybe I just skipped over the page on the list.

Fourstringburn, if you bother to read what K0BG said, namely completing the paragraph you quoted only partially, you would find that he and I are not actually in disagreement, in fact what he is saying matched what I am saying almost to a T, yet you automagically assumed that I was taking the opposite side of everyone else. There was no disagreement, I simply wanted to see how the reference used a certain term. A term that is, for the record, uncommon at best. You should seriously stop reading things into what I say and do, your not any good at it in the end only causing trouble.


The DB

 

[Mudduckmobile]

I did a quick run through of his site and can't find "SWR NODE" used as you are using it. I can't find "SWR NODE" even mentioned, doing some quick searches I can't even find only the word "node" on his site. That being said, I only looked through the pages that looked like they were related to SWR and coax in general and a few other semi-related pages. It is possible I missed it. Would you happen to have a direct link?

In the last decade I have been all through his site, a lot of good stuff there. I don't recall anything like that being on his site. That is not to say it isn't, I just don't recall ever seeing anything like that while on his site.

The word, node, when referring to antennas, is mostly used referring to "current nodes" and to a lesser extent "voltage nodes". These are on the antenna and not the coax itself. If such an SWR node exists in your setup, then, as mentioned above, you have other problems that need to be dealt with. Actually, one of the pages on K0BG's site talk about one of those problems and how to fix it. What can I say, his site is a descent resource.


The DB

NO problem:
K0BG.com. Last Modified on $/11/2016.
"ANTENNA MATCHING"
Paragraph #4
Line #2.
"by moving the SWR NODE to a diffrent position along the feed line..."

 

[fourstringburn]

You should seriously stop reading things into what I say and do, your not any good at it in the end only causing trouble.

That's exactly what you do and when your wrong, you spin it around in way to make it look like your were miss-taken.

And once again you have to get the last word since you can't leave it at that...the floor is yours.

 

[Mudduckmobile]

Here is the entire paragraph.

Antenna manufacturers often tell their customers to cut their coax feed lines to a specific length in order to get a good match. All this does is mask the problem, by moving the SWR node to a different position along the feed line. While this may appear to fix the problem, it doesn't fool most automatic controllers. The truth is, if the antenna is properly matched, it doesn't make any difference how long (or short) the feed line is.

This is straight from K0bg's site.
He also states the following:

In the following sections, it is necessary to know the exact resonant point (X=Ø) of the antenna we're trying to match. This fact alone, should not infer that exact resonance is a requirement; it isn't! Rather, in this case, it is only a means of arriving at the end point (wide-band match). Once the matching is complete, whatever the SWR is (assuming it is under ≈1.6:1) is irrelevant. However, it should be mentioned that measuring the SWR at the transceiver end of the coax feed line will usually result in more overall loss, and may make matching nearly impossible to achieve. The reason is that any reactance (±jΩ) the antenna exhibits, will be transformed by the coax. While the SWR may be low at the transceiver end, it may be excessive at the antenna end, resulting in additional coax losses, and a possible increase in IMD.
Hope this helps clear up some of the air. Let's not argue, but rather all work together to all learn from what is being said. There is much more to be read and the site k0bg.com. Good read. And some good info. Let's keep the bickering to a minimum though as it doesn't help anyone. JMHO.

I have gone over K0BG"s site so meany times...I find it to be very good, and at the same time confusing. I wish I had an ELMER I could talk to here where I live. I just dont see anyone around, and its all C.B. people some who try but like myself are learning too, and to be honest dont know one thing about antenna theory.
Whit that said there good folk, and some are trying..some not.
I want to KNOW not assume.

 

[The DB]

Don't ever stop learning Mudduckmobile. When it comes to antennas there is always more to learn, you can spend years studying aspects of the theory and their real world counterparts and end up with a better understanding, yet still more questions. If you have any questions on what is on K0BG's site, there are many people gere who can answer them for you.


The DB

 

[Mudduckmobile]

Don't ever stop learning Mudduckmobile. When it comes to antennas there is always more to learn, you can spend years studying aspects of the theory and their real world counterparts and end up with a better understanding, yet still more questions. If you have any questions on what is on K0BG's site, there are many people gere who can answer them for you.


The DB

Thank you.

 

[Mudduckmobile]

Well guys I got some time now so off I go to see if I can get this antenna a bit better.
I will remove the mfj 915, and see if I can get a better "x" and then I will try with the Bonding strap removed from the antenna mount too.
I may also try Remounting the Bonding strap to the antenna mount, and running it non-stop to the frame.
I do have One question first.
At this time my BEST "X" = 0 is at 26.834
My best "R" = 50 is at 27.272
QUESTION:
How do I get my "X" closer to 27.385 at "X"=0 ?
Do I need to cut more?
Right now I am sitting at:
26.964 R=64 X=7 swr =1.2 @ 26.965 R=64 X=7 swr = 1.3

27.554 R= 41 X= 11 swr = 1.2 @ 27.555 R= 41 X= 11 swr 1.3
I would like to call 27.385 the center of my band. I do 99% SSB so dont care much about anything below 27.385 but still might go there.

 

[The DB]

I do have One question first.
At this time my BEST "X" = 0 is at 26.834
My best "R" = 50 is at 27.272
QUESTION:
How do I get my "X" closer to 27.385 at "X"=0 ?
Do I need to cut more?

That is two questions... But yes, you need to cut more. The shorter the antenna the higher the frequency it is resonant, so if it resonant at a frequency lower than where you want it you need to shorten the antenna to tune it. Many antennas come with a longer whip with the expectation that they will need to be cut. Some installations on some vehicles require the antenna be longer than some others, so to make sure the antenna will work on more vehicles as opposed to less, they make the stingers longer.


The DB

 

[222DBFL]

From where you are at I would not cut more than 1/8 inch at a time from here out until you reach X=0. Things should start to fall in line at this point. JMHO. Better to take small bits off than large ones as you can't get them back once they are cut off. Again, JMHO. Hope this helps, and hope you get it where you want it. Trial and error is how most people learn. Keep at it and take your time.
But before I did any cutting of the whip I would remove the 1:1 balun and see what happens, then remove bonding strap as well if needed. It's not a simple 1,2,3 process. It takes time for a good install. And you appear to be doing a good job. Just don't cut any whip off until you first try the other things listed though. Again, this is JMO.

 

[Mudduckmobile]

From where you are at I would not cut more than 1/8 inch at a time from here out until you reach X=0. Things should start to fall in line at this point. JMHO. Better to take small bits off than large ones as you can't get them back once they are cut off. Again, JMHO. Hope this helps, and hope you get it where you want it. Trial and error is how most people learn. Keep at it and take your time.
But before I did any cutting of the whip I would remove the 1:1 balun and see what happens, then remove bonding strap as well if needed. It's not a simple 1,2,3 process. It takes time for a good install. And you appear to be doing a good job. Just don't cut any whip off until you first try the other things listed though. Again, this is JMO.

Just came back in..Better news.
"X"=0 27.143 - 27.805
27.143 X=0, R=58 swr=1.1
27.385 X=0, R=67 swr= 1.2
27.805 X=0, R=58 swr=1.6
1:1 Balun removed
Bonding strap removed from antenna mount.
Test Preformed by way of 16in. rg8x jumper w/ mfj 259c
I removed (cut) 3/16in. from stinger as well.
I dont know if I should cut more....
What do you think?
I am almost afraid I cut too much as is, stinger is at the lowest setting in the mount at this time.

 

[70cst]

This isn't scientific but I recently replaced a new Wilson 5000 Mag mount with a Siro 3/8 Mag mount and I can say - the RX is much better ... Radio is a 99V with a MV4 amp

 

[222DBFL]

You could cut a bit more. Get it more toward the center of the band. 27.205. It appears that you have plenty of antenna if it's bottomed out. Cut 1/8" at a time like I said, do one cut and see what happens. You can always raise the whip 1/8-1/4". JMHO.