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

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

3. 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…

4. 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”)

5. 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

6. 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

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

8. 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

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

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

11. 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

12. 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.

13. 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.

14. 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.

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

16. DX IN KANSAS CITY September 10, 2016

17. DX IN KANSAS CITY September 10, 2016
Bruce Conti

18. DX IN KANSAS CITY September 10, 2016

19. DX IN KANSAS CITY September 10, 2016

20. 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).

21. 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.

22. 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.

23. 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**

24. 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

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

26. 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

27. DX IN KANSAS CITY September 10, 2016

28. DX IN KANSAS CITY September 10, 2016

29. DX IN KANSAS CITY September 10, 2016

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

31. 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

32. 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

33. 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!

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

35. DX IN KANSAS CITY September 10, 2016

36. DX IN KANSAS CITY September 10, 2016

37. DX IN KANSAS CITY September 10, 2016

38. DX IN KANSAS CITY September 10, 2016

39. DX IN KANSAS CITY September 10, 2016

40. DX IN KANSAS CITY September 10, 2016
RESOURCES
HANDOUTS
DX MONITOR Vol 53 # 35: Reversible project
IRCA ONLINE
MARK CONNELLY

41. DX IN KANSAS CITY September 10, 2016
KAZ!

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

43. DX IN KANSAS CITY September 10, 2016

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