I Need Help - AI Part 2310

Prompt: I would think the the asymmetric aspect would not be so much of a bad thing given the small size of the sections and it would allow a lot more flexibility which would be a good thing. Besides, if the asymmetric settings don't work very well, don't use them. The other issue missing is here is the ability to short the unused portions on the ends of the coil. A 9 position, 10 wafer switch would accommodate all this. I think. Position 1: use only C, short M1 to M4, P1 to P4. Position2: use C + P1, short M1 to M4, P2 to P4. Position 3: Use M1 through P1, short M2 through M4... and so on. I'm still just exploring ideas.

You make a very solid point on the asymmetry. Given that your antenna system is inherently unbalanced (a 35-foot wire interacting with a massive metal roof), the theoretical "perfect balance" of the secondary coil is already compromised in the real world.

Using asymmetric configurations (like adding P1 but not M1) effectively acts as a half-step for fine-tuning the inductance. It shifts the magnetic center slightly, but if it gives you a better signal peak on a stubborn frequency, it’s a win. As you said, if a specific asymmetric setting introduces too much noise, you just turn the knob to the next one.

However, we need to talk about that 10-wafer switch.

## The RF Reality of a 10-Wafer Switch

While the logic of shorting the unused sections is fundamentally correct—it is exactly how commercial antenna tuners deal with dead-end parasitic resonance—a 9-position, 10-wafer switch is a mechanical leviathan.

Here is why that specific hardware approach will likely sabotage your design:

• The Rat's Nest Penalty: Wiring 10 wafers requires dozens of crisscrossing wires connecting the switch decks to the coil taps. At 2 MHz, this is messy. At 30 to 42 MHz (Band 6), that bundle of wire becomes a complex network of stray capacitance and parasitic inductance. The switch itself will act as a secondary antenna, completely destroying the careful low-capacitance characteristics of your 22 AWG silicone winding. * Mechanical Feasibility: Sourcing a 10-deck switch outside of vintage military radar surplus is incredibly difficult, and the torque required to turn 10 heavily sprung wipers simultaneously is substantial.

## A Pragmatic Path Forward

Before engineering a massive, complex switching network to short out the dead ends, let the physics tell you if it is actually necessary.

Since you have the coil wound and tapped, hook it up to your OWON function generator and sweep it while monitoring the response on your Tektronix scope. By injecting a signal into the primary and watching the secondary, you will immediately see if the floating M4 or P4 sections are creating resonant suck-outs (sharp dips in the waveform) within Bands 2 through 6.

If the self-resonance of the floating ends falls neatly *between* the SX-28's bands, or outside them entirely, you don't need to short them at all. You can just use a standard, simple rotary switch to select the active taps and leave the ends floating.

If the scope shows that the floating ends *are* acting as traps right in the middle of your desired listening frequencies, we can accomplish the shorting behavior with much less hardware than 10 wafers.

Comments

Words go here about how the response was received.

Next

Page: /Antenna_box_2/Gemini_2310.shtml

Last modified: Wednesday, 29 Jul 2026