High SWR Reading Flex vs Antenna Tuner and Direct

  • 1
  • Question
  • Updated 2 years ago
  • (Edited)
I am running a 6300 into a Fan Dipoles 80-10 (just put today)  I ran through an MFJ 989D direct
and also the antenna directly into the 6300.
Going through the 989D Bypass mode , the tuner reads 1.3 on 20m and around the same readings on the other bands. However, the Flex swr meter is showing "pagged " status.
So I bypassed the tuner and put the antenna directly into ant 1 of the 6300, again the swr meter reads pegged. I put the 259 analyzer on the antenna and the swr is in the same vicinity as the tuner in the bypass mode. 
I would like to believe the tuner but also dont want to burn up the 6300 with the high swr.. The fan has NOT cut on.
Any ideas.
Thanks and 73 
Marty W8AKS

Doing more testing, the 6300 into the dummy load shows an swr of approx 1.3
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes

Posted 2 years ago

  • 1
Photo of K1UO - Larry

K1UO - Larry

  • 740 Posts
  • 120 Reply Likes

Anytime that happened to me (don't ask) it was because I had the wrong antenna selected for the Transmit antenna.  By chance do you have Ant 2 selected?


Regards

Larry  K1UO

Photo of Larry Emery

Larry Emery

  • 4 Posts
  • 0 Reply Likes
If  the RX is ant #1, and the active TX slice is Ant #1 and your Flex SWR reads infinite into a known good antenna then the coax is open between your tuner and the Flex .  Especially if , as you indicated below, a dummy load connected to the Flex indicates proper swr readings.
Photo of Tony C kc2dis

Tony C kc2dis

  • 74 Posts
  • 4 Reply Likes
Can you get the SWR to change on the flex when NOT in bypass mode on the outboard tuner? In other words, switch to a tuned mode on the trans-match, vary the settings and see if you can dip reflected power say at 30 watts. While doing this, notice if influences the swr readings on the flex in ANY WAY? ALSO if you are running the latest version of SSDR I think fold back protection was added to protect the finals.
(Edited)
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Yes I can tune the antenna down to 1.2-3 using the tuner in the tune position. Also tuning the Flex down also.
Photo of Tony C kc2dis

Tony C kc2dis

  • 74 Posts
  • 4 Reply Likes
This seems to rule out faulty SWR metering on the flex. It also occurred to me that you should probably have the automatic antenna tuner ON THE FLEX set to BYPASS when doing these tests. (That is if you have one installed) Using the internal tuner on the flex in conjunction with an outboard tuner can lead to all sorts of weird problems with SWR. Do you run an amplifier? If not just take the MFJ tuner out of the line altogether and go directly from antenna to flex let ting the tuner on the flex take care of it.
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
No flex tuner installed, no amp either.
Photo of Tony C kc2dis

Tony C kc2dis

  • 74 Posts
  • 4 Reply Likes
OK, if you are getting a flat SWR straight into a dummy load from the flex (as you mentioned) then the culprit seems to be the MFJ tuner. Here is a test you might try before changing tuners. Find the resonant frequency of the fan dipole on each band. Do this with your SWR analyzer.without flex or MFJ tuner attached. Write down that frequency. Next, attach the antenna feedline directly to the flex. tune the flex to each of those frequencies by using the TUNE function on SSDR to throw a carrier. Note the SWR on the flex. Still pegged?
(Edited)
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Way ahead of you on this one, did that last night, here are the results.
3505. F:pegged. A:3
7010. F: 1.2. A: flat
14033. F: pegged. A: 3.1
21012. F: pegged. A: 2.9
28014. F: pegged. A: 2.5
Photo of Tony C kc2dis

Tony C kc2dis

  • 74 Posts
  • 4 Reply Likes
OK. I think the highest SWR that the meter on SSDR for the flex displays is 3:1 so at those SWR's the meter on the flex would seem pegged. From what I can see the lowest swr you can get out of that dipole is on 7010. Everything so far seems consistent. Next, attach the flex to the antenna tuner.'s transmitter INPUT. Then attach the antenna tuner's OUTPUT to the line going out to the antenna. Can you get a flat SWR on the MFJ TUNER at 3.505 using the TUNED side of the MFJ tuner? If so, what does the meter read on the flex at that point?
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 2489 Posts
  • 562 Reply Likes
Good thing is, The radio is almost impossible to harm with a high SWR, It is very well protected. The chance of burning it out as you put it is next to none.

I wonder about the SWR between the radio and the amp, if you have one.
Photo of Luis del MOlino

Luis del MOlino

  • 45 Posts
  • 3 Reply Likes
What kind of balun do you have on the center of your dipol? I am right asuming you have none? 

When there is no balun on the center of a dipol antenna you'll have RF ciriculating outside the braid of your coaxial cable through earth via your tuner and your rig until the power supply and the readings on the SWR meters are mislading.

Try to put a balun on the center of your antenna and all your SWR problems will dissapear.

Luis EA3OG
Photo of Bill -VA3WTB

Bill -VA3WTB

  • 2489 Posts
  • 562 Reply Likes
Or just a good line chock at the apex. Ugly balun will work.
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Luis, the antenna is made by your countrymen, it is a EAntenna EA1015204080DXS with a balun.
Photo of Kevin K4VD, Elroy

Kevin K4VD, Elroy

  • 775 Posts
  • 171 Reply Likes
How does it look with a dummy load attached to the rig's antenna jack?

Correct antenna selected on the rig?

GL,
Kevin K4VD
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
With the dummy load, the Flex is flat . Double checked , right antenna.
Photo of Rick  WN2C

Rick WN2C

  • 234 Posts
  • 29 Reply Likes
Marty, if you have the analyzer connected to the antenna and it shows 1.2:1 and directly connected to the Flex, what does the Flex show with the Flex tuner in bypass? Have you checked the jumper between the Flex and the MFJ tuner? Put it on the analyzer and connect to the dummy load and then put it it on the tuner and connect it to the dummy load and see if there is any difference. Also move the coax jumper at the connectors to see it it may be an intermittent problem.
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Here is the latest and not so greatest. At the suggestion of many (Thank you all). I have changed out cables between tuner, flex , antennas, etc.  No Joy.
The antenna is a fan dipole from EAntennas in Spain covering the legacy bands 80-10.
Tonight I changed out all the cables and this is what is  coming up and it's weird.
On 80,20,15, 10  The Flex reads pegged swr , no matter if the tuner is in the bypass mode or if the antenna is plugged directly into the Flex (Ant1) and yes double checked antenna selections.
But then the fun starts.
ON 40 (7010(, the tuner AND  the flex agree on the swr (1.3). It does NOT matter if it is going through the tuner in bypass mode or directly into the 6300.  1.3 is there.
Now I can put the tuner in the tune mode and try to tune the antennas which are supposed to be 1:1 no tuner needed. I've been around tuners long enough to realize that if it takes a lot of knob tweaking to tune and still not get it down right, something is wrong.
At this time, I dont know, I just dont know.
I appreciate all help I've been given. Thank you.
back to work. 73
Marty 
w8aks
Oh yes, one last point, the flex is showing zero swr when plugged into the dummy load.
Photo of Roy - W5TKZ

Roy - W5TKZ

  • 121 Posts
  • 12 Reply Likes
Marty,

I have been following your problem since you posted it. It is a confusing situation to say the least.
From your description of what you have done in your testing, my thinking is pointing to a problem with your MFJ tuner. I have several pieces of new and used MFJ equipment in my shack and I had problems with all but one. Most were bad solder joints.
Let me suggest you use your analyzer as your source instead of your radio.
From the analyzer, connect input cable to Coax 1 on the tuner.
Connect the antenna to Coax 1 output. 
On the tuner. set all controls to 0.     
Set the antenna selector on the tuner to dummy load.
Pick any amateur band (say 80?) and set the analyzer to somewhere near the middle of the band.
On your analyzer, you should read close to 50 ohms on the digital display and close to 1 on the SWR meter.

Now switch the antenna selector to Coax 1. You should see a high SWR on the meter. 
Start turning the inductor and watch for a dip in the reading. Once you get the lowest SWR reading you can start making small adjustments to the antenna and transmitter and inductor knobs for the lowest SWR reading.

Here is what I'm leading up to: If you have no response on the SWR meter on the analyzer, it is time to check for problems in the MFJ tuner.

I wish you the best of luck.

Roy - W5TKZ
 
Photo of Michael Coslo

Michael Coslo

  • 786 Posts
  • 183 Reply Likes
Marty, how much tuning did you do of the the individual fan elements?
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Just finished. See below comments.
Photo of WH6HI - Pat

WH6HI - Pat

  • 263 Posts
  • 37 Reply Likes
You may want to check your grounding of the radio and tuner. Another thing is length of feed line vs wave lengths used.
Photo of HCampbell  WB4IVF

HCampbell WB4IVF

  • 154 Posts
  • 34 Reply Likes

Since this is a brand-new antenna, have you tried reconnecting your old antenna and seeing how it works?   If the old antenna still behaves normally there must be a problem with the new antenna/balun (common mode RF maybe, since your MFJ259 reads low SWR on all bands?), or its feedline/connectors.  Also, since you say SWR on 40M suddenly dropped to normal after switching cables I'd still be suspicious of the cables/connectors.

You said the MFJ259 agrees with the tuner meter.  When you connected the antenna analyzer, did you connect it where the radio would connect keeping all the cables the same?

By any chance do you have another radio to switch with the 6300 for testing?

Howard

(Edited)
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
This is it. I'm not one to quit or give up (kept me employed) but we are beating a dead horse or soon to be dead.
I got up early to beat the heat. Raised the far end of the antenna to approx 20ft in the air(before 8-10 up).
No joy. Oh yes, I had my analyzer with me outside. Dropped the antenna and replaced the coax with a short piece 50ft of new rg8x. 80/40 are on the top wire with a coil in line(80). To adjust those bands would literally disassemble the antenna . Started on 20, spend considerable time, adding/subtracting, retuning all to no avail.
Moved to 15/10 also with no joy.
I was unable to get the antenna to resonant on any of the 3 bands. Analyzer problem, very possible. Called for backup but holiday weekend, not available.
Speaking of holiday, I wish you all a "Happy Holiday" and with that I am going to shut this thread down and enjoy what's left of the weekend. Thanks again everyone for your help. Take care.
73
Marty
W8AKS
Photo of HCampbell  WB4IVF

HCampbell WB4IVF

  • 154 Posts
  • 34 Reply Likes

Sorry Marty, but no horse is too dead to beat!  (-:

Let us know what the problem was when you resolve it.

Howard

Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

  • 1538 Posts
  • 546 Reply Likes
Marty, does the SWR on the analyzer change if you ground the coax shield while taking a reading? If so, we could be on to something. If not, well...
Photo of Marty Bluhm

Marty Bluhm

  • 38 Posts
  • 0 Reply Likes
Haven't tried that, will do