The most complex piece of radio equipment in the shack is usually the receiver. This puzzle is about those invaluable devices that can pick out a signal comprising all of a micro-nanowatt and distinguish it from one a million million times stronger, just a few kHz away. Yowsers! Here's to our hearers.

Across

1. Measure of signal strength (compound word)
6. Group that hates antennas (abbr.)
8. Hams advance this aspect of radio
11. Shield that mounts on back of an SO-239
12. Spurious gain control system response
14. Receiver section that varies the receive frequency
16. Add "I" to get an apology
17. Numeric performance metric (abbr.)
18. The ability to reject unwanted signals
20. Liquid that flows in antenna supports
22. Connector that joins three cables
24. Prefix of home to Macchu Picchu
25. Backlight for LCD (abbr.)
26. Doesn't work (abbr.)
28. Touch tones (abbr.)
29. System that turns off audio between signals
33. Type of signal
35. Not relevant (abbr.)
36. DX ..!
37. Video system
39. Listen
41. What a hot receiver does well
44. Historic effort or DXpedition
46. Excessive signal
50. Above audio (abbr.)
51. Transformers that use transmission lines (abbr.)
52. Where rigs are built (abbr.)
53. Defunct manufacturer of impedance bridges (abbr.)
54. Reference oscillator for slaved oscillators (abbr.)
55. Energy from the sun (abbr.)
56. Sharpen one's skills
58. Spurious signals in a superheterodyne receiver
60. Raw material refined to get pure metal
61. Primary gain stages in a superhet
62. Circuit to lock on to a signal's frequency
63. Small or unimpressive
64. Label for volume control
66. Execute or act
67. Use two VFOs to operate
68. Misbehaving equipment

Down

1. Small adjustment to avoid interference
2. English satellite abbreviation
3. Ultimate limit to signal reception
4. Identifying mark or code (abbr.)
5. Thanks! (CW abbr.)
6. Maker of test equipment now computers (abbr.)
7. Reduces signal strength
8. Insects or skyhooks
9. Complex complement to Im
10. Tuned circuit to capture a single frequency
12. Increases incoming signal strength
13. Cutoff receiver during transmit
15. Russian prefix
16. Antenna made from a hole in metal
17. Olympian prefix
19. Radio system that guides aircraft landings
21. Receiver system that controls gain
23. These get in the way of good operating
27. Material with a 0.3V forward drop
28. Stage that recovers modulation from an AM signal
30. Check in (Q signal)
31. Three most common passive components (abbr.)
32. Famous receiver or ham store
33. These combine signals to change frequency
34. Provides input signal to 33 Down
38. Complex power (abbr.)
39. Millions of nanoseconds (abbr.)
40. Stellar explosion
41. CW chuckle
42. Receiver fine tuning control
43. What hams chew
45. Used to be a micro-microfarad (abbr.)
46. Frequency difference between transmit and receive
47. Signals returned from a reflection
48. Faithfully reproduce the input signal
49. A receiver that slowly changes frequency
54. Abbreviation for microphone
55. Conductors that make transistors
57. Homonym for 60 Across
58. Oscillator required to receive SSB
59. Numeric signal manipulation
62. Sales pitch
65. Material used in inductor cores