Homemade antenna Issue High SWR

[BJ radionut]

Actually I like the base set-up...
However the sweep does have an issue...Did you sweep it to see if it fell in anywhere?
I have this thought. The screws you used to hold the two elements together, were those self tapping sheet metal screws? If so I wonder if on the bottom section one was long enough to pierce the coax?
Possible also heating that shield to solder to the bottom section melted the insulation on the center. I say this due to your report that the VSWR in a 100KC sweep shows "infinity"...which means pretty much a dead short somewhere.
Also it's possible the center conductor solder is cold...meaning it is open and making poor connection
Check the coax with a VOM and check...center of coax to shield and see if it's shorted.
Also check coax center conductor to the top element to make sure you have continuity. Same with the shield.
The readings showing that high normally mean either a dead short or and open circuit!
All the Best
Gary

PS: where were you standing when testing? Just using the short piece of coax?
Could be you were standing in the "Field" of the antenna...I do believe though one of the issues is above as I mentioned.

 

[Gunner357]

Actually I like the base set-up...
However the sweep does have an issue...Did you sweep it to see if it fell in anywhere?
I have this thought. The screws you used to hold the two elements together, were those self tapping sheet metal screws? If so I wonder if on the bottom section one was long enough to pierce the coax?
Possible also heating that shield to solder to the bottom section melted the insulation on the center. I say this due to your report that the VSWR in a 100KC sweep shows "infinity"...which means pretty much a dead short somewhere.
Also it's possible the center conductor solder is cold...meaning it is open and making poor connection
Check the coax with a VOM and check...center of coax to shield and see if it's shorted.
Also check coax center conductor to the top element to make sure you have continuity. Same with the shield.
The readings showing that high normally mean either a dead short or and open circuit!
All the Best
Gary

PS: where were you standing when testing? Just using the short piece of coax?
Could be you were standing in the "Field" of the antenna...I do believe though one of the issues is above as I mentioned.

The infinity is just what you get when you don't input a frequency .... the screws are very short the tip just peek threw and I tested for that already with my VOHM Im positive the soldering is good not only it was tested with the VOHM it was inspected its shiny plus the tip of upper antenna shows a OL when I touch the soldered ends and the heat didnt penetrate any of the cable iit also would show on the VOHM and the pipe at that point was heat from outside of pipe at the exposed wire being soldered and for blocking the antenna there's a 5 foot mast attached I was sitting below any part of antenna that RF is used. I remeasured everything its at 102 I even went longer and shorter on the upper beem it dropped to the 7's no further now that was without messing with the lower its at 102 for sure U just wanted to see if the upper was off any any way I moved from 102 to 109 to 100 7:1 all I got so Dont know. Realistically I should be getting at least a 2.0 match

 

[Gunner357]

Well OK guys I really really appreciate all your time thank you... I'm going to bring this thing in one last time check it out if all checks out I'm calling it quits I'm spending way to much time on it and getting way too many failures and wasting your time Ill just save and get a store bought Imax 2000 or a Hygain 500

Actually I like the base set-up...
However the sweep does have an issue...Did you sweep it to see if it fell in anywhere?
I have this thought. The screws you used to hold the two elements together, were those self tapping sheet metal screws? If so I wonder if on the bottom section one was long enough to pierce the coax?
Possible also heating that shield to solder to the bottom section melted the insulation on the center. I say this due to your report that the VSWR in a 100KC sweep shows "infinity"...which means pretty much a dead short somewhere.
Also it's possible the center conductor solder is cold...meaning it is open and making poor connection
Check the coax with a VOM and check...center of coax to shield and see if it's shorted.
Also check coax center conductor to the top element to make sure you have continuity. Same with the shield.
The readings showing that high normally mean either a dead short or and open circuit!
All the Best
Gary

PS: where were you standing when testing? Just using the short piece of coax?
Could be you were standing in the "Field" of the antenna...I do believe though one of the issues is above as I mentioned.

Ok I just got done messing with this.... Got the SWR to drop a bit by putting on all the coax that will be used and only adjusting the upper so far Ive been marking for reference here are some Analyzer pictures Im still learning some of this so if you can translate Id appreciate it

 

[HomerBB]

It just looks white in the pics I got NO worries Well OK did you see my connection? are they OK

Connections look fine.

 

[HomerBB]

Do you have a simple SWR meter and a radio you can hook up to the antenna?
I am not familiar with your analyzer, but if all you've done with the antenna is correct, then I wonder about the analyzer itself.
My analyzer has a simpler screen. Not so fancy.

 

[Gunner357]

Do you have a simple SWR meter and a radio you can hook up to the antenna?
I am not familiar with your analyzer, but if all you've done with the antenna is correct, then I wonder about the analyzer itself.
My analyzer has a simpler screen. Not so fancy. View attachment 39555

I had the same analyzer but sold it, I thought I would change pace a lil and went with this one Analyzer is new just got it 2 weeks ago and I tested it on my Mobile And it checks out the same as with the MFJ and My Dosey on SWR


I got the SWR to drop last night I need to trim equal amount off the lower now maybe it will drop more if you see the picture its away from building and I put the cable Im using as main feed line and hooked to it.. and standing 60 feet away

 

[HomerBB]

Looking forward to the results.
I just am not familiar to your analyzer interface.
If I read it right it seems to say it is resonant at 29Mhz...? Yet, the sweep was for 26.965 to 27.405...?
That would mean it is way short, so I either don't know what it's saying, or somethings wonky. Now you see why I can't help with your analysis vis-á-vis the analyzer.

 

[S&W357]

Epic Thread in the making.

Hope you get it squared away Gunner357.

 

[BJ radionut]

That would mean it is way short, so I either don't know what it's saying, or somethings wonky. Now you see why I can't help with your analysis vis-á-vis the analyzer.

Homer: Agree...Looking at the full sweep it shows 2.8 :1 at around 30 megs
Which would indicate, the antenna is TOO Short (?)
I, like you are not familiar with the operation and usage of that tester (I know they are rated as good ones) However, not having "played" with one though, the results "as I am reading" show resonance way to far up the band.
All the Best
Gary

 

[The DB]

Yet, the sweep was for 26.965 to 27.405...?

This isn't what is being scanned. Look closely at the symbol between those numbers, 26.965 MHz was the center frequency, and he was sweeping 27.405 MHz out from that frequency in both directions. If he wants just the CB band, the first frequency should be 27.185 MHz, and the second should be 0.22 MHz. That being said, I would personally recommend going past the CB frequencies to some extent so I would increase the second to 0.44 MHz, with this number the middle half of the screen will be the CB band.

I did a quick check of the manual to confirm this.

Also, those vertical blue bars are spaced and sized that at first glance look like they are showing where the various ham bands are...


The DB

 

[HomerBB]

Ahh...

 

[HomerBB]

We can test the "way too short" theory pragmatically.
Get some aluminum foil and roll it like a tube around each end of the dipole. Attach it firmly for good contact using zip ties, rubber bands, etc.
Start way too long on both ends, then start sliding it inward both ends at a time same amount to see what happens.

Goofy idea? Call me goofy. I've done it more than once.

The same can be done with two antenna stingers and hose clamps.

He can always go back to a standard made dipole and a taller mast.



Two fishing poles and wire, or two tubes. The tube one was made of fence top rail.

 

[DainBramage]

I have an AA 55 Zoom analyzer.
His options are to either:
Set a freq in the CB band and then set an offset above and below that freq . this will set the bandwidth to be analyzed

OR

scan with the analyzer as it is currently set and then use the left/right key arrow to continue the plot above/below the shown graphed bandwidth, it will then show both the min SWR freq and the freq where X=0

 

[Gunner357]

i just went out again totally disassembled it I re-soldered everything even though they all checked out i wrapped the connection point with tape and used a piece of the fiberglass pole to hold the 3 inches of non shielded coax rigid i remeasured assembled with ever screw I tested Now I went out and ran the SWr chart again 2.8 @25mhz 3.5 @ 27.205 ok so I'm still high and meter is showing its too short even though Im at exactly 204" total "and that is for 27mhz I need 27.205 which should be 17 feet and 8' 7" each for the elements which yes Its too short

 

[HomerBB]