Antenna Box #2

This is another page inspired by Mickey's peculiar antenna configuration and the attempts to make it work with the radio.

The box was designed with the extensive help of Google's Gemini AI large language model (LLM). The prompt/response sequence starts here. You can follow the entire conversation by clicking the links at the bottom of each page.

This is pretty much it in a nutshell:

The bill of materials:

• Box. I used a roughly 5 x 8 x 2.5 plastic box from Amazon. $16. It worked well. (same as 1st box)
• Rotary switches (2). $24 for both. 6 pole, 5 position, 3 deck. $25
  
  
  
• 7 inches of half inch PVC water pipe. (same)
• 22 silicon insulated solid wire for the secondary. This is hard to find. I had purchased a bunch of it in preperation for my SX-28A build-from-scratch project that got abandoned. Spend time to find it.
• 18 AWG enameled (or bare) wire for the primary (same)
• Banana post sets (2). (same)
• Couple of long mounting screws. (same)
• Foam two-sided adhesive tape. (same)
• 22 AWG stranded hook-up wire. (same)

Primary winding is 8 turns of ________ with the ends going to the left bananna terminal (red and black)

For switches, wafer 1 is next to frame, 2 is in the middle and 3 is away from frame.
Each wafer has 2 switches: A is closest to coil, B is away
Counter clockwise terminal is next to wiper. For the left switch, that is M-5. For the right, CP.
The switch positioning tabs/holes are definitly needed. Suggest smallest hole possible. The switch detent is pretty tough.
For the switch to be positioned properly, the positioning hole needs to be near 11 o'clock when viewed from the outside of the box.
Wire colors are, of course, random.

Tables of Truthiness¹

Left switch wafer 3 (away from frame) switch A (next to coil)
Wiper to right banana, black post

Right switch wafer 3 (away from frame) switch A (next to coil)
Wiper to right banana, red post

First attempt:

Band 6: nothing Band 5: a possible Cuban station at 13.5 MHz (more or less), S meter 8-9
A few others near by. Knobs 0 and 0
Band 4: one station near 9.7 MHz. Knobs didn't seem to do much. Box didn't seem to do much. Band 3: nothing yet Band 2: nothing yet

The verdict?

A waste of time.

The switches (-4, -3 ... +3, +4) didn't appear to do much of anything.

When set to 0, 0 the higher bands seemed to work a tiny bit better but not enough to justify using them.

The application of the primary was pretty sloppy. Will remove and try something different.

Footnotes:

1. Yes, that Stephen Colbert

Page: /Antenna_box_2/Antenna_box_2.shtml

Last modified: Wednesday, 5 Aug 2026