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Repeater antenna
maintenance: DKW Kloof Tower 28-02-2013
The day was spent isolating the
faulty connector at the base of the tower in order to repair the second
X-200 as the current X-200 was blown to pieces by the lighhtning .
This was the sweep before
repaired faulty connector at base of tower.
This one below shows normal
expected sweep for the x200 .
This
sweep showed problem at 20,8m which was at the base of the tower and this is the place I
repaired the corroded water damaged 7/8 connectors.
Photo’s to
follow
6m loop :Feb
2013
This
antenna I made using a circular aluminium loop with a ganged capacitor from
a piece of old equipment .
It tuned
up straight away and have done some short distance testing on it and it
has good side-null characteristics as expected .
Bicycle_Rim_multiband
loop antenna: Feb 2013
I have
had this idea for a few years but have never found the time to try it out
.
I then
found that there were other hams
around the world that have tried the use of an aluminum bicycle wheel so
I put mine together in one afternoon (mountain bike rim used.).
The results
are quite remarkable for such a small antenna.
I have
been using this antenna on 50 W
having good comms with Capetown ,USA and Canada on the 20m band.
With the
current 200 nF capacitor I have the 20m /17 /15/12 bands that tune up well .
The reading
material one reads on the net and books tell you that the antenna is
extremely narrow.This is true but one does not have to retune every few
Khz for RX .
My
experiemce when comparing this antenna to my fixed wire antennas is that
the receive is superior in that it is much quieter and thus the preamp
can be used in the way it should be used..I have also made a few
comparisons with other stations in my area that can hear a station but
not make out the inteligence – with that same station being Q5
readability on my loop .I have also made a number of comparisons with my
own wire antennas off the AH-4 and the loop is definitely my choice on
reception .
I have
been operating this antenna for two weeks from inside my radio shack
changing the direction and tuning by hand .I look forward to taking this
antenna on camping and other trips and experiment with this antenna in
the outdoors.
For
those that are stuck in town houses or Flats , this is the ideal antenna
to get active on the bands.
I am in
the preocess of making a base-plate with a bearing mechanism to steer the
direction of use.
I have
noted that the antenna has great directivity being narrow in the
direction of the physical plain of the antenna.The radiating loop is
½’ coaxial cable with inner shorted to outer on botyh sides.
I did
not follow any other design except for the standard suggested
transmitting loop diameter being about 1/5th .
Good
luck with your building and let me know how it goes.
HF AH-4 project:
Been looking
at a way to get some antennas up for HF in my radio workshop .
Having
an AH4
Icom automatic tuner I needed a way to extend my options.
This
lead me to the Relay switching control box.
Consists
of a Control unit that selects the various unbalanced antennas such as ;
Vertical
108” whip / two long wires and more to follow.
This
should allow a wider variety of options and the beauty of this design is
that one can select any combination of verticals or horizontal long wires
– all remaining antennas if not selected are added onto the ground.
This I
believe is the best option for multi unbalanced antenna elements.
Here are
some pictures leading through the project – does not include the
surge arresing nor lightning pspark- gap as yet .
26 Aug 2012:
Mounted
selector .
 
I would be interested in hearing from other hams regarding
similar projects.
Once I have it all wired uo in a week or two I will upload
my findings.
Ch6-UHF
Kensington : 439-275 (-7.6 Mhz) 31\12\2009
Finally got to place the CH6
repeater back at Kensington site .
This repeater will cover in and
around the new Mosis Mabida Soccer stadium in Durban central.
Please update the CTCSS tone to
88,5 hz encode/decode.
The pic controller is the
great VK5DJ Pic controller which I
have modified for my own workings, included are COS indicators and a dual
alarm indication .
Thanks must go to John Drew
, VK5DJ who has done a great
service to all those using his code.
Here is the early stages of the
micro Controller made on vero
board and lacing twine .
Saber Battery
repack /modification: Dec-2009
I decided to try something
different when I repacked a few of my saber battery packs .
I added a small charging housing from
an old ICOM type battery pack and this is the result .
This allows the use of the
charger as well as a wall charger or cigarette charger as used for Icom
radios .
Now the radio can trickle and get
topped up wherever I go and one does not need to lug the big charger
around .
05 October 07:
Repeater update:
The Alverstone HUB repeater has been problematic and it
has been decided to redo the old Storno 662 with more recently produced
hardware.Special attention to the flat audio to negate the associated
problems with multi-staged hardware issues.The new test repeater will
consist of m120 motorolas modified , and an audio graphic equalizer to
maintain the flat audio repose required for the HUB.
New power supplies and antennas have been ordered for the
UHF hub and the 145-600 repeater sites.This has been forth-coming due to
the renewed interest in getting these back up to spec .
Current Repeater
Project: 1)The
channel 7 Umhlanga repeater project has been discontinued at this point
.. 2)Channel 5 soak test September 2006 3)Channel 4 antennas replaced
4)Kloof cable s to be pulled through pipes to container
16 June 2007:
The 145-625 (CQF900) repeater has been mounted on the
wall brackets.
Below the repeater is the TX cavity .The cables have
been pulled through tto the base of the tower and connected to the
existing cables to the top of the Tower.
Cable reroute and 145-625 relocation to external container
.
Thanks to Brad ZS5Z , Lawrie ZS5HV , Paul ZS5PS and of
course Brad junior who also worked hard assisting on the day.
Current Project
: Naturn Repeaters: :
The rope has been pulled through the draw-pipes and
in the next week or so we should have the 1/2 inch cables pulled through
these pipes to the base of the tower to join up with the 7/8 inch feeder
to the antennas at the top of the 85m tower.At the same time the new
crystals should be arriving to run up a repeater to replace the existing
UHF on channel 1 .......
.....
.......
. 
Comrades
Marathon Communications :
The Highway
Amateur Club is proud to be able to supply the repeaters, below , that will be used on the day . The purpose to relay message handling of emergency
communications between central communications centers and field stations
situated at various points along the route of the comrades marathon .This
exercise plays a vital role in the safety of runners and the public
alike.
The number of
ham radio operators on the day is
approximately 40 .The communications control room also houses other
parties form the Police services , Ambulance , Fire and rescue as well as various
other logistical staff. In the past both VHF and UHF repeaters along the
route covering Pietermaritzburg and the greater Durban areas will be used.At
this stage HF has not been used but due to the recent unrestricted
allocation to the HF band there may be some experimentation done on the
day.
There will be
also be a 144-800Mhz APRS digi-repeater requested for some runners that
will be running with handie APRS stations.This digi will repeat the GPS
co-ordinates to the I-Gate situated at Pietermartzburg .
The IRLP node
will be limited on the day due to the nature of the event –restored
early eve local time.
 NAT.U.R.N. (Natal Uhf Repeater Network)
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