[UK-CONTEST] GM1J EU92 IOTA Report

Sun Aug 14 02:02:59 PDT 2011

Hello Jim
Interesting reading all of the different
ideas on how to get the 18m in the
air..single handed.

I suspect different climatic conditions call
for different solutions. My first use of the
18m pole was to support a 160m antenna in ZS3
with 4-top loading wires and rope
extensions.I discarded the two top sections
as being far too thin to support anything and
removed them. I have always used the approved
clamps above each joint to avoid slippage.
The ZS3 QTH had daily morning fog so
condensation ran down the pole like a tap..we
collected a washing bowl full in two days.
This was an ideal lubricant for slipping
sections hence the extra care. Being a
coastal site winds regularly above 20mph I
took care in guying every 5m or so using 4mm
marine rope at the lower two levels and 2mm
higher up and for top loading extensions.
Having laid out slack side guys I also had a
simple hinge, falling derrick (2x10ft), and
in my case a lower pipe into which I slot the
bottom of the Spiderpole. Fortunate the poles
for the 20ft pipe were available locally.

Although much easier to lower the antenna
great care should be taken to avoid spiking
the far end as it comes down almost
"U-shaped" and you can easily break the
thinner top sections. This is the point when
the falling derrick comes into it's own by
supporting the thinner actions avoiding
cracking.

At J7 I had no falling derrick so simply
walked the pole up hand over hand and used
the back guys to avoid over rotation.
This used a simple base anchor to allow the
pole to move horiz>vertical with no
obstruction.

At 3B9 the mounting had to be a fence post 9"
OD with a stone wall at right angles, I could
only put out the back ropes but pushed the
bottom of the tube up against the wall/post
having laid it out carefully bisecting the
angle between wall and post. Again a simple
walk up steady but no stopping and secured
the lower section against the post using
3x12mm wide tyraps. In this case guying was
at 120-degrees due to site limitations so the
top loading wires (only 3-this time)acted as
a loose top set. It is very important once
vertical that each guy level is adjusted to
provide a firm hold but not over tight to
cause downward thrust on the joint
immediately below the tie point. As a one man
session it involves a lot of walking but well
worth it when the wind blows, you can sleep
at night..

On 160m I usually have 8-1/4-wave radials on
the ground but on J7 this was not practical
so I went for 2 raised resonant 1/4-wave
using a rope tied at the 20ft level, anchored
20ft out from the base and halfway up the
hypotenuse a plastic egg insulator. From the
base of the antenna, up to the insulator, and
then horizontal (10ft above the ground). An
additional rope was added from the insulator
back to the pole (10ft up the pole)to act as
a back anchor when each radial was pulled
tight.

For 80m like Jim I wind on 70ft of wire kinda
helically with closer spacing at the bottom
for resonance adjusting.
Usually comes out around 25-ohms so a 2:1
transformer and 8-10 radials works well.

I am about to move into new uncharted
territory having aquired the beast (27m pole)
to allow serious testing of a pair of phased
160m verticals at this QTH. Construction has
started on a suitable base arrangement and
guying anchor points.
Once mastered I will report back on results.
So many ropes required I have decided to
colour code various levels to avoid
accidents.

73

John G3LZQ

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com]On
Behalf Of mm0bqi
Sent: 14 August 2011 07:40
To: uk-contest at contesting.com
Subject: Re: [UK-CONTEST] GM1J EU92 IOTA
Report

Hi Chris
Very much the same way as Ian.
 I locate the base by driving in a couple of
three foot rods and use rope to
create the flexible swivel joint. Very
important it is well secured because
as you walk the pole up all the base wants to
do is to lift out of the
ground.  As you can imagine if it does spring
out of the ground it has a lot
of force behind it so as always there should
be no one hanging about the
base of the pole. Once the base is secured
lay out the guys at 90 degrees
(two sets) as you woud for any mast then walk
up.  Do NOT be tempted to
'support' it or pull it up using the un
attached guys.  Walking it up keeps
all the stresses along a straight line, the
pole will bend dramatically on
the way up but no harm will be done.
The other way to do it is to use a falling
derrick arrangement (I thing
Bristol may use this?)
For me the golden rules are secure base, walk
it up straight and to ensure
there are clamps at all the joints.  I
suspect one of my sections slid
inside another during the storm a couple of
years ago and then with slack
guys the pole just self destructed!
There are a couple of ways to set it up.
Hellically wind the wire round the
pole, slack twists will use up all the wire
and does away with the need for
six feet or so coming away from the top of
the pole.  Not sure what the
performance difference would be but suspect
it may be very little.  I am
also unsure as to whether the use of the wire
extension with the additional
guy wire securinging it to the ground could
add unwelcome stresses to the
pole in adverse weather.  I have tried all
the above and they have worked
well in portable situations.
There was some chat on the various user
groups about using the pole to
support horizontal wires.  Generally this
seems to be frowned upon as they
are designed not to have much horizontal
strees once they are vertical (If
that makes any sense!!)
Although I am one of the few folk who have
managed to destroy an 18m
SpiderBeam pole I think they are a great
solution for LF antennas.  As such
a new one is on the shopping list for next
years IOTA contest.
Good luck with the trip.
73
Jim,  MM0BQI

On 13 August 2011 19:59, Ian Pritchard
<g3wvg at btinternet.com> wrote:

> Hi Chris ..
>
> If you're going to use a spiderbeam you may
be intersted in this ...
>
> Some of the pictures in this link show the
arrangement I used with my
> spiderbeam
> >>>>
>
>
http://www.g3txf.com/dxtrip/MW5B/MW5B-10.html
> >>>>
>
> They are quite easy to erect single handed
...providing the ground is
> horizontal!  I made sure the geometry was
correct for four way guying and
> then simply walked the mast vertical.
> The key to sucess is to allow the base to
pivot 90 degrees without it
>  twisting. I made a simple short wooden
"cage" to fit over the bottom of the
> spiderbeanm pole, this then swivels on a
steel rod which passes through the
> top of a short piece of scaffold pole
sriven into the ground.
>
> 73 Ian
>
>
> --- On Sat, 13/8/11, Chris Tran GM3WOJ
<zl1ct1 at gm7v.com> wrote:
>
> > From: Chris Tran GM3WOJ <zl1ct1 at gm7v.com>
> > Subject: Re: [UK-CONTEST] GM1J EU92 IOTA
Report
> > To: uk-contest at contesting.com
> > Date: Saturday, 13 August, 2011, 18:38
>  > Hello Jim et al
> >
> > Thanks for the interesting IOTA report
and the 5 QSOs with
> > GM7V - being so
> > close to you makes working you difficult
on some bands.
> >
> > A bit off-topic, but what is the
recommended method - or
> > your experiences -
> > for erecting an 18m Spiderbeam pole ?
We've got one
> > for our upcoming
> > DXpedition but want to make sure there is
no 'snap' sound
> > when we install
> > it.  I'm guessing the method may differ
depending on
> > what wires etc the 18m
> > pole is supporting.
> >
> > This may be of interest to others on the
reflector...
> >
> > 73
> > Chris
> > GM3WOJ
> >
> >
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> >
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