Maintenance : 2011-6-2011:Phase-1
Spent the day at
Kloof Microwave tower installing the new phased 2 stacks for the 145-625
repeater. One 2-STACK on the west side and one 2-STACK on the East .These
are phased together in order to overcome the isolation due to the tower.
The results were
positive and this is Phase-1 of the upgrades taking place.
being given as favourable and improvements noticed on all round coverage.
HF Turnstyle 2011-6-10: Converted my
inverted V 40m dipole to a Turnstyle HF antenna to experiment with CP.
The antenna looks the same as a turnstile used for Sat
work , which is common for VHF /UHF.
From the tests made it definitely has improved on the air
reports for local comms and reports received form other stations noting
an improvement over the OCFD comparison.
wanted to put up a 4m and 6m antenna , I tried these designs and
them to be well worth the time.
from junkbox and cost no money .
antenna is the 6m and below that is the 4m version.
using cadweld wire :
length being approx 4,55 m(txmer match =660mm 75 ohm RG59)
length being approx 6,35 m(txmer match =990mm 75 ohm RG59)
deltas have the same 75 transformer matching type.
Homebrew CW KIT
Our club had cw decoder kit by IK3OIL .(All the PIC credit
is for IK3OIL.)
primarily for learning CW, new and experienced CW ops are sure to like
this simple and inexpensive CW decoder.
The decoder uses a PIC16F84 microprocessor and a NE567 PLL as
analog interface. The software automatically adapts to incoming CW at
speeds between 5 and 30 WPM.
The circuit has been published in QST and appeared on the cover as
I put this kit together and then did one mod after the
My box I did the following :
Added audio amp with volume control on faceplate.
When earphones are plugged in , audio amp is
Added clip on heatsink to 7805 .
Added a Vu meter which simulates a radio to some
Added a RCA rear connector to monitor audio (for
scope or recordings.)
Added a 12V relay activated via a mosfet (IRF640) to
rear RCA connector
to key a separate radio or light
or any other device.
7) Added a fuse
and toroid on the power supply input .
8) Added in
parallel, an RCA connector on the Key input.
I did test this unit in receive ,
off the PC and ran it all night on 30 wpm –passed.
Just need to do labelling to
complete the project.
With this mod one could crossband
an incoming receiver to outgoing CW radio – just an idea.
My homebrew 600 Ohm ladderline:
Decicded to make
homebrew 600 ohm feeder to feed into my James Millens tuner .
spreaders from years back .
pieces of copper to fix spreaders.
4)About an hour
for the 25m length.
2)Transmatch: James Millens :92200 manual
antenna tuner to be used with the new antenna .
1)This is the midband radio for which I am looking for the
2)Some pictures of
the pic controller designed by Dave VK5DJ , and modified for my purpose .
My proto-type including DTMF decoder to 7 sement:
Wiring harness is laced with lacing twine –tubetype.
After testing the basic needs I did add some CMOS gates to
indicate COS-PTT and COS-LINK as well as Alarm-INPUT
This is the replacement Ch 6 uhf