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Link Coupled Tuner

WW8J Station Information

 

The station utilizes Kenwood transceivers and amplifier with a pair of manually switched, link coupled tuners.

 

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Home Brew Link Coupled Tuner and E.F. Johnson Matchbox 

 

 

 

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The homebrew Link Coupled Tuner and Kenwood 922A Linear were added  in 2005

 

 

 

 

WW8J station information with photos and information of station.

Kenwood TS830 Hybrid Tranceiver Backup RigBack 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.

 

Kenwood 870 Tranceiver for all HF workThe 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 the station. 

 

Photo of the EF Johnson Viking 275 Watt Match BoxThe 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's Web Site  regarding link tuners.  I can't begin to describe the before and after difference in tuner performance as a result of this modification.  

 

Photo of W8MAS Link Coupled TunerThis 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.  It was recently taken out of service.   A very similar but much larger tuner High power link coupled  tuner may be found on my home brew link coupled tuner web page.

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.  For legal limit output, the plate spacing is insufficient for the capacitor (C1) 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.

 

tunerschem.jpg (18773 bytes) 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.

 

MFJ SWR Analyzer 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 Signal Link Tigertronics interface for PSK31 and other data modes.  This is pretty straight forward, and works flawlessly.

 

My CW Keys 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.

 

AM Band Crystal Radio Detector 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. 

 

 

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Copyright 2000 2011 Richard Flake All Rights Reserved

 

Page last updated on 01/18/2011