[Antennas] CUSHCRAFT ANTENNAS

Sun, 10 Mar 2002 12:17:33 -0000

Hi Bill..
>
> First, thank you for the lively and interesting discussion.  Good points!
>
>
> >What's a " Real antenna"????
>
> This is like asking someone what is the best auto :-) But in my opinion a
> "Real Antenna" is a 1/2 wave dipole at least 1/2 wave above ground and
> hopefully over a good type of ground terrain.

 The W8UR,K1WA, W3LPL, G4BUE, N6LF , G3LNP, K3LR (All based on vertical
dipoles or wires) arrays meet none of the above requirments... If a more
"real" antenna exists than these examples, I'd sure like to hear about it..

> Another way to see a "real antenna" is to visit you nearest AM Broadcast
> station and oggle their vertical set up.

Most that I've seen are no more "real" than a lot of amateur verticals (1/4
w/l). They usually have much better grounding systems, and are of "fat wire"
construction (i.e the radiator is tower sections... like the HyGain 18AVT).
They are very often compromised in the same way as amateur verticals, in
that they are not full length, and are compromised by loading of one sort or
another.  The approach is the same, the solutions usually more
expensive...and therefore more effective...but the "commercials" can afford
it.

> >
> >Efficiency is the ratio of the radiation resistance of an antenna, to
it's
> >feedpoint impedance..no more...no less.
> >
> >In the real World, Effectiveness, is as important as efficiency...e.g. A
> >typical HF mobile whip...efficient?? definately not..Effective?? yes.
>
> Exactly -- because of size, difficulty of installation, cost -- ham
> antennae are usually a compromise.  I just happen to think that Cuschcraft
> and all the other "1/2 wave vertical no radials" folks are deep into
> compromise and way far from efficiency considering the very substantial
> price.

 They are no more compromised, than the many loaded 1/4 w/l commercial
verticals out there...Again, if we take for instance, my HF2..On 40 m, on a
GOOD ground...no compromise. On 80 m, it's half length, getting pretty
inefficient, but still effective.On 160m it's less than 1/4 of the proper
length, extremely inefficient, and also pretty ineffective. So what??? If my
lack of space, or lack of interest in 160m is the deciding factor, then the
HF2 is probably adequate. If I really want to "get out" from a small
backyard, I'll either have to build my own, or buy something like a
Titanex..

>Of course they do work and if I were living in a condo with antenna
> limitations that might be the solution.  (heaven forbid) :-)

That's generally the situation for which these antennae were designed... If
you're lucky enough to live where you have no restrictions, then you'd
probably not be putting up anything less than full size anyway.

  But to get back to the original reason for this exchange...Which was...

     >> Why does a half wave antenna become less efficient by turning it on
end
     >> (vertical ve horizontal half wave)
     >> -bob
     >
     >It doesn't...

Rotating a dipole 90deg to a vertical position...

  DOES NOT make it less efficient..
  DOES make it LESS effective as an NVIS antenna..
  DOES make it MORE effective as a DX antenna.

   73
    John EI7BA

>
>
> >
> >
> >
> >> And I might add very expensive.
> >
> >Only if you use the commercial variety....ALL my antennae are homebrew,
and
> >cost little or nothing.
>
> Now, you deserve a GOLD STAR!
> >
> >As it happens, I have a variety of verticals...one vertical dipole for
160m,
> >a pair of phased vertical dipoles on 80m, a 40m horizontal dipole, an HF2
> >ground mounted vertical (1/4 Lamda on 80/40m),
> >and a homebrew copy of the Cushcraft R7 (40 thru' 10m) mounted 20ft over
> >ground.
>
> Now that IS interesting.  And, since you homebrewed it you solved the
other
> problem: being able to get replacement parts.  Bravo!
>
> >On 40m I can compare the horizontal dipole with the Butternut and
Cushcraft
> >copies...
> >The comparisons are fairly predictable...
> >  On the close in stuff..UK and EU, the horizontal beats out both
> >verticals...
> >On DX, both verticals are equal on TX generally speaking.    The R7 is
> >usually quieter on RX than the HF2.
>
> >in other words they are both very effective on 40m. However, the R7 is
> >easier to deploy, as a ground system is not mandatory, whereas with the
HF2,
> >it definitely is...
> >  My ground mat consists of 40 x 60ft radials  10 x 30ft radials, and 8 x
> >130ft radials....Not perfect, but reasonably adequate.
> >  If I had to get rid of either the HF2 or the R7, I would get rid if the
> >HF2... because the R7 gives me all the other HF bands as well as 40m, and
it
> >takes up the least space of any other antenna that I have.
> >Obviously, I don't give valuable space to antennae that DON'T WORK....!
The
> >fact that I have them means that they are EFFECTIVE...Whether they're
> >EFFICIENT or not....???  'Tell you what..I DON'T CARE....!!!
>
> I understand!  BTW, in the ARRL Antenna Book there is a page about radials
> with a chart showing Broadcast Engineering specs for radials.  I had a 20m
> home brew vertical in the backyard on the ground.  i was happy to read
this
> chart cause it told me that 20 10 foot buried radials was fine and anymore
> wire was a waste.  Of course, since I was digging the radial trenches I
was
> happy to read that :-)
>
> Good talking, nice to hear from a ham who really has put some energy into
> his antennas.
>
> 73  Bill K6ER
> >
> >
> >73
> > John EI7BA
> >
> >
> >>
> >> Bill k6erq
> >> >
> >> >>
> >> >> GoJolly wrote:
> >> >>
> >> >> > I have been casually reading all the posts about the Cushcraft
> >Verticals
> >> >> > with amusement.
> >> >> >
> >> >> > First thing is a "half wave vertical" with no radials is about the
> >same
> >> >as
> >> >> > putting a 100W lightbulb on the end of you coax and putting it on
a
> >> >fence
> >> >> > post.  The laws of physics are not subject to interpretation.  The
> >> >> > efficiency is about 15%.  So, if you are satisfied with 15W out,
then
> >of
> >> >> > course the verticals work great.  Lot of money to pay for that.
ANY
> >> >kind
> >> >> > of wire antenna would be better with a little tweaking.  And with
the
> >> >poor
> >> >> > customer support that is reported...
> >> >> >
> >> >> > Seems like it's time to re-think using these products :-)
> >> >> >
> >> >> > My 2 cents worth.
> >> >> >
> >> >> > Bill K6ERQ
> >> >> > - - -
> >> >> >
> >> >> > Your moderator for this list is:
> >> >> > Larry Wilson KE1HZ [email protected]
> >> >> > _______________________________________________
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> >> >> >
> >> >> >
> >> >>
> >> >>
> >> >> - - -
> >> >>
> >> >> Your moderator for this list is:
> >> >> Larry Wilson KE1HZ [email protected]
> >> >> _______________________________________________
> >> >> Antennas mailing list
> >> >> [email protected]
> >> >> http://mailman.qth.net/mailman/listinfo/antennas
> >> >>
> >> >>
> >> >
> >>
> >>
> >
>
>