
The
station utilizes modern day equipment with a pair of manually switched, link
coupled balanced tuners from the past.
WW8J
station information with photos and information of station.
This
is my back up transceiver, (on left) Kenwood's hybrid TS-830. This used rig was purchased on E-bay. After six months of
operation it was necessary to replace the power supply filter capacitors . Kenwood no longer stocks the original caps and they offer no
substitute caps of the same rating. Newark electronics stocks a close substitute.
The TS-830 has since performed to it's expectations. The
transceiver to the right is Kenwood's TS-870.
The
station's primary transceiver, Kenwood's TS-870 with (at right) Astron 70amp
13.6 v.d.c. supply, which handles all of the direct current supply needs of this station.
The
matchboxes or link coupled balanced antenna tuners also shown below are (from left lower to right upper)
Johnson Viking, and Home Brew. The only coaxial cables that I use at this
station are for connecting the transceiver (s) to the antenna tuners. I
employ 450 ohm and 600 ohm open wire transmission lines for two outdoor antennas, a non resonant
vertical dipole made by Sigma and an extended Lazy H. These are used
for 80 -10 and 40 -10 meter operation respectively. For signal
optimization, I switch antenna tuners. Because of their narrow bandwidth
this may not be a good solution for
contesting, but I'm not a contester. Upper right, on top of the
homebrew tuner is another homebrew link coupled tuner for the 2 meter
band. Specifications for the 2 meter tuner were taken from the 1988 A.R.R.L. antenna handbook.
The
renowned Johnson Viking Matchbox 275 watt model. I purchased this unit on e-bay for about 30 dollars. It was hand painted
an olive drab color, and the control knobs were badly tarnished. A few
hours of work and it was presentable again. I added a modification (upper
left input coupling) that is
part of the homebrew matchbox shown below. The modification employs a
series variable capacitor to adjust coupling (or input impedance) from
transceiver to primary inductor of the tuner. See Annecke tuner
information at Cebik
W4RNL web page regarding link tuners. I can't begin to describe the
before and after difference in tuner performance as a result of this
modification.
This
home brew antenna tuner was designed and built (circa 1950) by my uncle and mentor
W8MAS (Bernard Parafin) now a
silent key. I have used this tuner for all balanced wire
antennas since 1970. The tuner is designed to be wall mounted.
As
you can see in the photo, the inductors L1, L2 are radial mounted. Banana plugs
are mounted to Lucite strips and the coil assembly is mounted to the top of the
strip. This allows removal of the coil assembly to move the taps on the
secondary L2 (Band Changing). In the past, I have used this tuner with a Drake
L4-B linear,
and experienced no arcing on the C1 capacitor plates as long as the SWR is kept
below 1.5:1. The plate spacing is insufficient for this capacitor in this
circuit. This is a very basic tuner that performs extremely well with
all types of balanced wire antennas at low and medium power levels.
A
very similar but much larger tuner High
power link coupled tuner may be found on my home brew link coupled
tuner web page.
I measured the caps and inductors (noted in schematic) with a digital
Inductance/capacitance meter L/C I l B manufactured by Almost
All Digital Electronics. C1 was added to L1 of the above
Johnson Viking Matchbox. I used a 400pf variable in place of the 20 -
350pf
in the schematic.
The MFJ 259-B analyzer is used for tuning the link coupled tuners. This unit takes the
work out of tuning up on the air without interference. It is used so much
that I just leave it plugged into a charger.
Tigertronics interface for PSK31 and other data modes. This is pretty
straight forward, and works flawlessly.
My Non-Iambic keys for CW from left to right are Kent SP-1,
Home brew single paddle made with putty knife & junk box parts, and a Bencher RJ-2 straight
key. The Kent single paddle is my favorite.
Last in the station equipment is my home brew crystal radio. I will be
moving this item to another section of this web when I find time to
develop the page. The concept of a passive powered radio has always
interested me. These radios used in the early days of radio broadcast seem
to interest a great number of ham operators. This radio covers the A.M.
broadcast band, and has received signals from 31 stations across the U.S. and abroad. The
coils were wound on a fabricated coil winder and inductance values checked
with the above described L/C l l B meter. Variable coupling from the
antenna circuit to the detector is accomplished by moving the coils to and away
from one another.

Copyright © 2000 – 2006 Richard
Flake All Rights Reserved