DX IN KANSAS CITY September 10, 2016 ANTENNA CONTROL: The original 7-1/2 minute musical tragedy, in pictures and proclamations

DX IN KANSAS CITY September 10, 2016 WHEREAS: Antennas that can be tweaked must be tweaked

DX IN KANSAS CITY September 10, 2016 WHEREAS: Antennas that can be tweaked must be tweaked Antennas are anti-social (leave me alone!) ON THE OTHER HAND…

DX IN KANSAS CITY September 10, 2016 WHEREAS: Antennas that can be tweaked must be tweaked Antennas are anti-social; DX-ers are often human DX-ers require comfort (aka “the shack”)

DX IN KANSAS CITY September 10, 2016 WHEREAS: Antennas that can be tweaked must be tweaked Antennas are anti-social; DX-ers are usually human DX-ers require comfort (aka “the shack”) THEREFORE: “Remote antenna control” is good for the USA

DX IN KANSAS CITY September 10, 2016 WHEREAS: Antennas that can be tweaked must be tweaked Antennas are anti-social; DX-ers are usually human DX-ers require comfort (aka “the shack”) THEREFORE: “Remote antenna control” is good for the USA Remote antenna control has been used since 1878

DX IN KANSAS CITY September 10, 2016 ……WHEN THEY LEARNED THE HARD WAY... …just kidding

DX IN KANSAS CITY September 10, 2016 TWO LOOP-ANTENNA CONTROL PARAMETERS Adjusting for best front-to-back (“F/B”) directivity 2. Reversing antenna main-pickup direction

DX IN KANSAS CITY September 10, 2016 HOW TO GET THAT SCRUNCHED PATTERN Null-network “balancing”

DX IN KANSAS CITY September 10, 2016 IF YOU WERE LOOKING DOWN ON THIS ANTENNA (NEXT SLIDE)

DX IN KANSAS CITY September 10, 2016 WHY WE LIKE LOOPS Often: better directionality than Beverages Are usually easier to set up Don’t require good grounds (except EWE) Require far less geography

DX IN KANSAS CITY September 10, 2016 LOOP-ANTENNA CONTROL PARAMETERS Null-network “balancing” is best when the null- adjustment controls the “F/B”…but doesn’t otherwise degrade antenna performance.

DX IN KANSAS CITY September 10, 2016 In an ideal world of F/B adjustment, the “RF TAKEOFF” node and the “BALANCE” (NULL) MODE are electrically identical.

DX IN KANSAS CITY September 10, 2016 A great deal of empirical work has been done in an effort to match the IMPEDANCE of the two ends. ‘Pure resistance’ has proven the most practical and repeatable for the “Balance” node.

DX IN KANSAS CITY September 10, 2016 And no single resistance value works best for all cases. So we turn to variable resistance.

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016 Bruce Conti www.bamlog.com

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016 VACTROL CONCERNS 1. Not a lot of granularity in the desired resistance range (i.e. a little adjustment can go a long way).

DX IN KANSAS CITY September 10, 2016 VACTROL CONCERNS 1. Not a lot of granularity in the desired resistance range (i.e. a little adjustment can go a long way). 2. Vactrols exhibit a drift in resistance due to ambient temperature change. Not a major issue.

DX IN KANSAS CITY September 10, 2016 VACTROL CONCERNS 1. Not a lot of granularity in the desired resistance range (i.e. a little adjustment can go a long way). 2. Vactrols exhibit a drift in resistance due to ambient temperature change. Not a major issue. 3. Vactrols may be sensitive to electrostatic hits.

DX IN KANSAS CITY September 10, 2016 VACTROL CONCERNS 4. Vactrol prices climbing as availability decreases. Current device: VTL5C4 (sources disappearing) Alternate (Connelly): API NSL-32**

DX IN KANSAS CITY September 10, 2016 VACTROL CONCERNS 4. Vactrol prices climbing as availability decreases. Current device: VTL5C4 (sources disappearing) Alternate (Connelly): API NSL-32** 5. Roll your own? Dxer.ca---Colin Newell

DX IN KANSAS CITY September 10, 2016 LEAD-INS: COAX OR TWISTED-PAIR?

DX IN KANSAS CITY September 10, 2016 300-foot cables at 1 MHz RG-58 RG-8 Cat-5e RF Loss 1.2 1.5 2 Balanced No Yes Pair-to-pair N/A 65db isolation Stray pickup Moderate Minimal

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016 ANTENNA-REVERSAL “Instant” switch-change of pickup direction Many useful approaches (Mark Connelly et al)

DX IN KANSAS CITY September 10, 2016 ANTENNA-REVERSAL “Instant” switch-change of pickup direction Many useful approaches (Mark Connelly et al) Generally requires copper lash-up

DX IN KANSAS CITY September 10, 2016 ANTENNA-REVERSAL “Instant” switch-change of pickup direction Many useful approaches (Mark Connelly et al) Generally requires copper lash-up Can be more complex when tuning/nulling

DX IN KANSAS CITY September 10, 2016 ANTENNA-REVERSAL “Instant” switch-change of pickup direction Many useful approaches (Mark Connelly et al) Generally requires copper lash-up Can be more complex when tuning/nulling But it’s PHUN to change same-channel signals!

DX IN KANSAS CITY September 10, 2016 Cat-5: First klew that a reverser is do-able

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016 RESOURCES HANDOUTS DX MONITOR Vol 53 # 35: Reversible project IRCA ONLINE MARK CONNELLY http://www.qsl.net/wa1ion/ MARK4@DURENBERGER.COM

DX IN KANSAS CITY September 10, 2016 KAZ!

DX IN KANSAS CITY September 10, 2016 “BSEF” Broad-Side EndFire He’s even found a way to make it steerable…

DX IN KANSAS CITY September 10, 2016

DX IN KANSAS CITY September 10, 2016 “NEBE” is next