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Low Power 12 Meters

Lou N2TULou N2TU Member
edited September 2019 in SmartSDR for Windows
Lower power on 12 meters....

Tried this with two different power supplies....an Astron 35 and a SAMLEX 1235M. Each with its own Powerpole ****. No other unit plugged into the strips. West Mountain, not MFJ strips. In other words, two different set-ups. The Powerpole strips are within 5 feet of the power supplies and the original F6500 power cable is used. The Flex 6500 RF Power slider all the way to the right.

Using a LP100A and a Palstar DL2K dummy load, I get the following readings....notice the 12M reading.

160 102W
80 106W
40 103W
30 95W
20 98W
17 98W
15 90W
12 73W *****
10 93W

So the question is why the power drop on 12 m?

Any reasonable answer accepted! Hi Hi!

73/ Regards

Lou N2TU


  • K2CMK2CM Member ✭✭
    edited September 2019
    I have had this happen to me on a couple of bands. I found a problem with my dummy load, so changed dummy loads and put an external wattmeter in line with the dummy load. This solved my problems. I have also had problems with occasional low output traced to RF feeback. Ferrite cores and better grounding solved this.
  • KY6LA_HowardKY6LA_Howard La Jolla, CA. Paris and Sablet FranceMember ✭✭✭
    edited January 2017
    Resonant length of coax. Try a different lengthy of coax
  • Lou N2TULou N2TU Member
    edited February 2016
    Ground is excellent....copper braid...and a common junction point...no ground loops...and ferrites everywhere....

    I used an external wattmeter...the LP100A...and the dummy load meter was within a few watts of the LP100A, so I am confident the reading is accurate. Also, the readings coincided with readings when the rig was connected to my antenna. Again verifying the accuracy of the readings. 

    Trying a different length of coax is out...seeing the readings are almost identical when using the antenna...


    Lou N2TU

  • KY6LA_HowardKY6LA_Howard La Jolla, CA. Paris and Sablet FranceMember ✭✭✭
    edited January 2017
    Next Guess... Gremlins....
  • Jerry WilkJerry Wilk Member ✭✭
    edited August 2017
    Lou, I have the same situation on 12 meters.  Did you ever resolve the problem?   AA7SN

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