Hi Matt,
I agree totally with you, however, if I look at 20 random OCF dipoles, I
find only three or four of them actually installed correctly, hence my
comment, and suggestion it was an OCF, (which it is), in the first place.
With regards to antenna performance, I was not speaking about antenna
performance with regards to DX, but performance with regards to RFI.
The OP is actually burning things up in his shack, and destroying
speakers, so I suspect that takes priority over DX at this point. It
also indicates a massive RFI issue. I like OCF dipoles, if as you said,
they are installed correctly with the proper chokes on them, which most
are not. With regards to the vertical or Dipole suggestion; that is to
move the Op to an antenna that does not require quite as much choking as
the OCF does.
I live by Jim's papers! They have been the most useful work I have
found for day to day solutions. Take a look at Jim's talk here:
http://audiosystemsgroup.com/KillingRXNoiseVisalia.pdf
73s and thanks,
Dave
NK7Z
http://www.nk7z.net
On 12/02/2017 04:43 PM, Matthew King - KK4CPS wrote:
Dave, there's nothing wrong with an OCFD *IF* it's fed properly, i.e.
through *proper* baluns & chokes. The fundamental band of the antenna (40
or 80, for example) and the exact split make huge differences.
Clearly you've had a bad an experience with a bad OCFD if you think ANY
vertical, even with decent radial field, will outplay it! Having used
both, I can tell you with certainty that it's simply not the case.
Read the links that I posted earlier in this thread and you can learn a
lot. The OCFD can be an outstanding antenna, but not if it's thrown up over
a roof with a 33%/67% split on 80m with a 4:1 voltage balun in it. THAT is
a recipe for disaster!
Jim's publications on the subject illustrate *proper* chokes. Check 'em
out....
73, y'all
Matt
AK4MK
On Sat, Dec 2, 2017 at 7:34 PM, Dave Cole (NK7Z) <dave@nk7z.net> wrote:
I'm with Jim here... This is a recipe for RFI...
If it were me, I would replace the OCF dipole with almost anything else,
especially if you are running power. That type of antenna causes more RFI
issues than almost any other type of antenna, save an end fed...
You made a comment about needing the power to get out, that might indicate
an antenna issue, so maybe replacing the OCF with a good vertical and a
decent radial field, or a dipole, up as high as possible, is in order
here...
73s and thanks,
Dave
NK7Z
http://www.nk7z.net
On 12/02/2017 02:50 PM, Jim Brown wrote:
On 12/2/2017 1:59 PM, Joe wrote:
I use coax as a feed, not twin lead. Twin lead will not survive 100 mph
winds, which are common at my location.
N6BV, retired ARRL Antenna Book and Handbook editor, wrote a great piece
that ran in QST about two years ago showing that even with coax, a choke
will fry very quickly when feeding an antenna not matched to the feedline
(that is, up in the air).
73, Jim K9YC
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