Kongsfjord - 70°43'N 29°21'E

Collection of useful modifications and projects
by Dallas Lankford

All articles on this page (c) copyright Dallas Lankford. 

Dallas Lankford of Ruston, LA, for has for many years been a reference for the DX community in general, and especially for us at kongsfjord.no. His in-depth investigation and documentation of solutions to common problems for our type of listening has been very valuable. Since many of his early works only exist on paper (the recent ones are available electronically though), we thought that it could be good idea to digitize some of them, and to create a single point of reference for his many articles. We got Dallas' permission to put this on kongsfjord.no. This page will be a project under development, notification of updates will appear on the front page.

Please note that you need Acrobat Reader 5.0 or newer to view or print these documents properly. 

The articles are organized according to the bookmarks below - click on the bookmark to go directly to the section.

The articles in The Dallas Files are provided as is.  Dallas does not have adequate free time to provide technical support or answer lengthy questions.  Also, due to circumstances beyond his control, Dallas has stopped disclosing his email address.

Antennas and preamplifiers

DX-peditions

Software Defined Receivers

Antenna phasers

Hammarlund

Racal

Audio Processing

Icom

Telefunken

Collins

Japan Radio Company

Watkins-Johnson

Antennas and preamplifiers

Close Spaced Phased MW Vertical Receiving Antennas   122 kB 22-SEP-2007
Common Base Transformer Feedback Norton Amplifiers 1.7 MB 8-JUN-1994
Flag Theory 217 kB 31-JAN-2009
High Reverse Isolation Push-Pull Norton-Rohde Feedback Amplifiers  78 kB 5-NOV-2009
Low Noise Active Antenna AC/DC Power Supplies 1 MB 26-NOV-2006
Measurements of Some Antennas Signal to Man Made Noise Ratios   913 kB 20-SEP-2006
MW And LW Noise Reducing Antennas  296 kB 21-JUL-2005
New MRF581A Transformer Feedback Amplifiers 74 kB 26-AUG-2008
New Norton-Rhode Feedback Amplifiers 163 kB 31-OCT-2009
Null Steered QDFAs  234 kB 8-NOV-2009
Phased Delta Flag Arrays   1 MB 21-FEB-2009
Phased Flag Arrays   125 kB 25-DEC-2008
Some Recent Results For MW Antenna Arrays  UPDATED !!! 65 kB 2-NOV-2009
The Best Small Antennas for MW, LW and SW 249 kB 5-MAY-2008
Variations Of Misek's Center Fed Micro SWA 2 MB 21-AUG-2007

Antenna phasers

New Improved Passive Phasers 554 kB 2-AUG-2007
Phased MW Receiving Verticals 222 kB 15-AUG-2005

Audio Processing

AM Synchronous Detector Experiences 385 kB 19-JUL-2006
Elliptic Low Pass Audio Filters 678 kB 4-JUL-2005
Audio special: On The Causes And Cures Of Audio Distortion Of Received AM Signal Due To Fading 346 kB 6-FEB-2006

Collins

Collins R-390A: 3TF7 Substitutes 96 kB 24-SEP-2004
Collins R-390A: A new AGC Mod 336 kB 21-JAN-2005
Collins R-390A: AF LF fidelity distortion power modifications 100 kB 5-APR-2004
Collins R-390A: Alignment - from Hollow State Newsletter #29 398 kB JAN-1993
Collins R-390A: BFO fine tuning 310 kB 24-DEC-2003
Collins R-390A: Carrier Meter Mods And Replacing Worn Gain Controls 281 kB 24-SEP-2004
Collins R-390A: Cosmos PTO Linearization 274 kB 10-JUL-2004
Collins R-390A: End Point Alignment and Linearization #1 #2 #3   85-151 kB 20-JAN-2005
Collins R-390A: Full Wave Bridge AM Detector 192 kB 15-FEB-2005
Collins R-390A: ILO AM Synchronous Detector Mod 3 MB 1-JUN-2006
Collins R-390A: Inside the Cosmos PTO 274 kB 6-FEB-2005
Collins R-390A: K5OP Audio Derived AGC Mod 145 kB 8-FEB-2005
Collins R-390A: Noise blanker 425 kB 17-JUL-1995
Collins R-390A: Roofing filters 199 kB 1-SEP-2004
Collins R-390A: Sensitivity measurements 103 kB 7-JUL-2002
Collins R-390A: SSB filters, I & II 402 kB 5-SEP-2004
Collins R-390A: St. Julian Creek Annex R-390A's cracked brown tubulars ... 160 kB 19-JAN-2005

DX-peditions

Grayland Quad Delta Flag Array Report 815 kB 2-MAY-2009
Quoddy Head, ME - October 2008 948 kB 21-OCT-2008

Hammarlund

Hammarlund HQ-180(A): AGC Mod 166 kB 6-JUN-1990

Icom

Icom IC-703 Slow AGC Release Mod   185 kB 30-NOV-2005
Icom IC-703 MW and LW Attenuator Removal Mod  
(see also Bjarne Mjelde's impressions of the IC-703 here)		 157 kB 29-NOV-2005
Icom IC-746 Pro: Impressions and mods  
(see also Bjarne Mjelde's impressions here)		 802 kB 13-JUN-2004
Icom IC-746 Pro: Internal Noise Blanker Adjustment 175 kB 27-SEP-2004
Icom IC-746 Pro: Line Out Mod 520 kB 30-OCT-2005

Japan Radio Company

JRC NRD-525: A technical review 184 kB 28-JAN-1993
JRC NRD-525: AM AGC mod 2 179 kB 1-DEC-1992
JRC NRD-525: Filter Leakage 982 kB 15-APR-1993
JRC NRD-525: Narrower Bandwidth Noise Blanker 120 kB 8-JUN-1998
JRC NRD-525: S-meter Damping 267 kB 28-JAN-1993
JRC NRD-92M Noise Problems 348 kB 5-NOV-2002

Software Defined Receivers (SDR)

Perseus Review 
(see also Bjarne Mjelde's impressions here)		 143 kB 2-FEB-2008
SDR-IQ Overload Characteristics 1 MB 14-JAN-2008
SDR-IQ Preamp Mod  390 kB 27-JAN-2008
SDR-IQ Spurs and Intermod  95 kB 29-JAN-2008

Racal

Racal RA6790/GM: A brief review 237 kB 13-DEC-1993
Racal RA6790/GM: AGC modification 363 kB 11-NOV-2004
Racal RA6790/GM: Volume Control Modification 400 kB 18-MAR-2005
Racal RA6793(A): uP Crud Noise Elimination Mod 164 kB 6-FEB-2005
Racal RA6830 Digital S-meter mod 856 kB 21-NOV-2003
Racal RA6830 Encoder shaft mod 161 kB 14-NOV-2003
Racal RA6830JD: Microprocessor Noise Fix 233 kB 13-NOV-2003

Telefunken

Telefunken E 1501 Adventures (see also Bjarne Mjelde's impressions here) 890 kB 13-FEB-2005

Watkins-Johnson

WJ-8711A: Microprocessor noise fix + impressions 266 kB 10-JUN-2004

 

 

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