[CQ-Contest] Diamond CP-6 Vertical on Fire

[Barry Merrill]

Having had reasonable success with the Diamond CP-6 Ground Plane antenna,
which I used in IOTA and CQ WW SSB, and having noted that antenna in my
3830 postings and comments, I now have a different opinion:

a. I bought the antenna here in Ireland, and it turns out that the 
   CP-6 model CANNOT be loaded above 3575.  The vendor NOW says I
   need the "USA" model, the CP6-A.  There is nothing in the CP-6
   manual stating the above frequency limit; I only realize there
   was a limit when I saw their table of lengths showed it was
   impossible to change the 80 radial lengh enough to get above
   about 3620.  Today, their technical support stated the actual
   upper limit frequency of the CP-6 is 3575.

b. The published specs show power limit of 200 watts (SSB).
   I have only the Icom 756PROIII here, with a real maximum of
   100 watts.  Worked find for SSB Iota and SSB CQ WW.
   Saturday I was operating CW in OK/OM test, and I came down
   to 3525 about 10pm local time.  I made a few Qs, and then noticed 
   what I thought was the reflection on the inside of the window of
   a house light that was getting rfi, as the reflection flashed with
   each dot and dash, a fairly bright yellow.  But I could not find
   a light in the house flashing, let alone one in that reflection.
   
   Hitting F1 and going to the window, I discovered the yellow light
   was actually a yellow flame arcing thru the top insulator of the
   CP-6 antenna!!!

   Today, Diamond pointed out the very small note in the bottom of
   the instructions that the power limit for CW was only 1/3 of the
   SSB power specification, or about 70 watts.

   I can still use the antenna of 10/15/20, but both 40 and 80 provide
   a brilliant light display when keyed.


73

Barry, EI/W5GN

P.S.  If the gale force winds subside tomorrow, I hope to install the
      BigIR for 40-10 (their 80 meter coil is still a concept and not
      a product), two 40 foot masts for an 80 dipole, and the half
      wave end fed zepp for 160, to see if they will stay up until 
      the CQ WW CW weekend.