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Antenna measurement device

Antenna measurement device needed. Could you reccomend an antenna measurement device. I have a watt meter in my shack and its showing a large swr and about 20 watts output power rather than 100. The flex 6700 autotuner is reporting succesful but im still wondering if i have an antenna problem causing the repeater problems i've posted.'thanks Jim

Answers

  • Jim Gilliam
    Jim Gilliam Member ✭✭
    edited July 2016
    You want an antenna analyzer. There are many available at varying costs depending on the type of display and measurements. MFJ makes a variety of analyzers you might check out.
  • James Madden
    James Madden Member
    edited May 2018
    Thanks ill check. I dont want something in the ham shack im thinking a portable device that i can take outside. Jim
  • DH2ID
    DH2ID Member ✭✭✭
    edited May 2018
    James, I use this one http://www.eham.net/reviews/detail/9678 and find it great for HF.
    There are other models for VHF/UHF, but they are more expensive.
    For SHF and up to 6GHz I use a spectrum analyzer.
    73, Alex - DH2ID
  • James Madden
    James Madden Member
    edited November 2016
    Thanks Alex. I think this is exactly what i want. I dont see ant recommendation for a portable antenna to attach for measuring antenna field strength. Do you have any reccomendations. Jim
  • Kevin Va3KGS
    Kevin Va3KGS Member ✭✭
    edited June 2017

    Hi James

    I use both the LP-100A from Telepost Inc., and RigExpert AA-600.

    The LP-100A stays connected to the station for continuous HF Power and SWR readings. (not VHF/UHF).

    The RigExpert is my portable unit,  and covers up to 600Mhz. 

    Check these out. 

    Good luck

    Kevin, Va3kgs

  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    Remember, that you want to analyze the entire antenna "system" which includes the antenna and the coax connected to it.
  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited May 2018
    Whatever you use, if you place it between the output of your rig (following the ATU) and the antenna system, and there is a mismatch that the ATU has tuned out, you are NOT going to see that as a match on your external meter, because it is most likely built for a 50 Ohm nominal impedance. Similarly, your power measurements, both forward and reflected, will not be accurate either. So, be sure you are using the meter correctly! Hope this is helpful.
  • James Madden
    James Madden Member
    edited June 2020
    Thanks for this very useful information. That explains why i'm seeing such low power witha wattmeter. What is the best practice to get correct measurements?
  • Greg N8GD
    Greg N8GD Member ✭✭
    edited June 2018
    Why not try out the "SWRPlotter6K" program by K9DUR that essentially makes your 6700 a complete antenna analyzer?  You can save the plots for entire bands for future reference.  Here's the link:

    http://k9dur.rnaconsultingservices.com/smartsdr_utilities.html

    Scroll down the to the download link for "SWRPlotter6K" and click on it to download the program to your PC.  It works quite well!

    Greg - N8GD

  • ka7gzr
    ka7gzr Member ✭✭
    edited December 2016

    Thanks Greg! I went to Rays site and got the "Plotter". What a slick program!

    Jim

    ka7gzrt

  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited July 2016
    To get a correct measurement on the external wattmeter you will need to use an external antenna tuner and not the internal. It would be connected Radio -> Wattmeter -> External tuner -> antenna Dave wo2x
  • James Madden
    James Madden Member
    edited November 2016
    I like this and downloaded the software. It unfortunately doesnt seem to work on my windows 10 64 bit computer. Jim
  • Greg N8GD
    Greg N8GD Member ✭✭
    edited December 2016
    It works FB on my Windows 10 64-bit i7 machine.  You need to have SSDR running with a single slice open.  Turn off the ATU.  When you start SWRPlotter6K, a window will appear displaying your radio and asking to connect.  Highlight the radio and click on "Connect" below.  You might want to reboot your PC before running it for the first time.  A local Ham friend rebooted his system after the program failed, and then it worked OK.  I just ran it on my system again to confirm it.  You do not need DAX or CAT running.  There is a PDF manual that installs with the program in the "C:Program Files (x86)RNA SoftwareSWRplotter6k" folder.

    Greg - N8GD

  • James Madden
    James Madden Member
    edited June 2018
    Ill try again. Imlaunched the plotter before my radio, perhaps thats the problem.
  • James Madden
    James Madden Member
    edited November 2016
    restarted my computer, turned off atu. a window appeared in swplotter but my radio didn't. sigh
  • Greg N8GD
    Greg N8GD Member ✭✭
    edited December 2016
    Might be a firewall issue.  Are you running a firewall or security suite other than what's built-in to Windows 10?  The SWRPlotter6K passes info via TCP/IP so if the firewall blocks it, that may be the reason you don't see the radio.

    Greg - N8GD

  • Mike W8MM
    Mike W8MM Member ✭✭
    edited July 2019
    I absolutely LOVE my RigExpert AA-600.

    I already had an AA-520, which worked well.  I had to replace the Li-ion battery after it sat unused for an extended period.  I decided to purchase the AA-600 because it had some more features than the 520.  Polar impedance measurements for one.  Replaceable AA cells for another.

    The absolute best enhancement for my use is the time domain reflectometer.  It's done by wide-band sweeping of the analyzer and performing an inverse fast Fourier transform on the frequency/phase data.  It's all automated and takes about half a minute for the measurement.

    Big deal, you might say.  Well ... this feature saved me some serious time/effort/expense when I had an unexplained screwy VSWR problem "somewhere" between my equipment and the tower-top connector on a run of LDF4 1/2" Heliax.  I had invited the tower crew over to work on it, but didn't quite know what to expect.  

    I decided to try the TDR function and to my amazement it showed a perfect transmission line until 152.3 feet from the bottom end of the feed line.  After that point, the reflection display showed all manner of wiggly departure from 50 ohms.  The cable was 165 feet long and had some extra length I could sacrifice to make a repair.  The work crew pulled 15 feet up the tower and cut it off.  The TDR display then showed all was perfect to the open end.  A new connector was attached and all is well.  No more screwy VSWR.  The 15' cut off "bad" section measured bad when TDR'd during the post mortem on the ground.  No mystery anymore.

    I didn't have to replace the entire cable.  It only cost a spare connector to fix the problem.  I would have never been able to find such an elegant solution without a TDR of some sort.  The addition of the TDR function to RigExpert antenna analyzers makes them number one in my book and well worth adding to one's tool kit.
  • Kevin Va3KGS
    Kevin Va3KGS Member ✭✭
    edited July 2016

    Afternoon Greg

    Just ran the SWRplotter6K and it worked great.  Plotted 6-80m on my Dipole antenna.  Had all the bands plotted within 5 minutes.  80m is the only band I can't operated on with such a high SWR.  I now know where to play in each band!!  Thanks for the suggestion.

    Cheers

    Kevin, Va3kgs 

  • George KF2T
    George KF2T Member ✭✭✭
    edited February 2019
    There is, of course, no better starting point than scrupulously following any antenna's construction and installation instructions, and the use of high-quality transmission line.
  • James Madden
    James Madden Member
    edited November 2016
    Thanks very much. I hear lots of transmissions here in Seattle and i have even talked to people a fair distance away on 20 meters inillinos forminstance. But im having a lot of problems making routine connections with people even though imhear them quite well. Any advice would be greatly appreciated. Jim

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