Has anyone tried putting a Cushcraft XM-240 and a M2 75/80 meter rotatable
dipole on the same mast?I'd like to keep the distance from the dipole to the
beam as close as possible because of windloading on the mast.I also want
them to work OK though.
I was thinking about 3.5 to 4 feet because the M2 needs 33 inches for
its linear loading/support rods.I thought if I'd go a bit above that.
Also if I did that I could reach the support ropes for the 40 meter beam
while standing on the top plate..or if I really had to I could put my mast
steps on the mast and climb that a little bit.I REALLY don't like doing that
though!
My mast is 1026 DOM 2 inch by quarter inch wall.
On a different note about lengths of towers.I'm having the crane come back
and do some more tower work and I getting ready to top off my 75-80/160
tower.I'm using the Array Solutions box.It requires the insulated tower to
resonate at 3.8 or so and then uses loading to get it to go to 3.5 and
1.8.I'm trying to get it as close as possible length wise.The tower is made
from 5 straight sections and 1 tapered Rohn 25.I know that is not long
enough and plan to use a peice of conduit inserted in the tapered section to
bring it into resonance.My question is about how long should I install the
pipe?Could someone please model that for me?
One more thing,I ( crane ) installed my new 85 foot Rohn 45 2 weeks
ago.I've been working on getting the conduits buried AND on getting it
grounded as best I can with little cost while doing a reasonable job.I
truely believe if you get a DIRECT hit nothing will help that but I think
nearby's can be handled.I ended up with 4 ground rods driven all the way
down into trenches I had dug for the grounding.I used some #2 copper wire I
had aquired from a freind.I just used burial rated clamps and spaced the
ground rods out 10 feet and connected them on 2 of the tower legs.Measured
the resistance and it is VERY VERY low so I have good connections.Last
Monday night we had a pretty good little thunderstorm roll thru here and I
was in my shed building my 75/80 meter dipole and talking with my wife who
was "helping" me.We decided to stop and just watch the storm roll thru when
suddenly I saw my new tower take a direct hit and then saw a return stroke
go from the tower back into the sky.Cool very cool but I thought about the
dipole I had installed for FD with the cable going into the shack,it wasn't
connected to anything though.I ran in the house and went in my shack and
expected to see flaming hulks of radios and amps.NOTHING HAPPENED.I was so
happy I gave my wife a big kiss!!I waited till the next day and sunshine to
go check out the tower and I couldn't see ONE sign of anything happening to
the tower or grounds,its like it didn't happen.I must have done something
right.My point is to do what you feel comfortable spending on your grounding
of towers and then maybe spend a little time praying. Thanks for reading and
hopefully someone can help me out with my questions. Gregg K9KL
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