Crystalizing the design HFSPP V3 Amp

I am speaking about the low-cost version in this post.  Getting this first version operational will pay dividends for the more advanced model to follow. I describe the two new circuit boards for your consideration. Solutions are coming more into focus now. For a long time, I could not perceive a clear path to the finish line. Now, a path has opened since deciding to do the lower-cost version first. It makes the most sense for the greatest number of builders. The AMP and LPF will be applicable to either model.

The three modules are:

  1. CONTROL: HFSPP V3 Module
  2. AMP: MOSFET Amp Module HFSPP V3
  3. LPF: Low Pass Filter Module (LPF-140R1 released)

I foresee a super-sized HF PackerAmp V4 enclosure with the CONTROL module attached to the front panel with the switches and LEDs mounted on the backside of the circuit board. This would eliminate internal discrete wiring with lots of good benefits to the builder. The front panel CONTROL will have these items:

  1. Ready/Standby Switch
  2. Green Power LED
  3. Power Switch (controls electronic switch that activates amp)
  4. Red Transmit LED
  5. CW/SSB Switch (mode choice controls hold-time after RF ceases)
  6. 6–position LP Filter Switch with band indicator LEDs

In addition, we have these outputs:

  1. Meter (0–5V current monitor)
  2. Fan  (control optional fan)
  3. PTT  (SMA coax to rear panel PTT jack)

I desire to use pre-fab coax cables with BNC on one end and SMA on the other for the RF Input and RF Output. The coax cables to and from the LP Filter use SMA connections. This again has benefits for the builder in reliability and kit building fun. The power cable is also prefab using PowerPoles to high-current push-on attachments on the AMP.

This CONTROL module will have a 6–pin mini-flat CONTROL cable to the AMP module and the CONTROL module will have a 10–pin mini-flat cable to the LPF module. These are pre-fab snap in place flat cables.

The case will be approximately 9 x 3.5 x 3.5 inch with a corresponding larger heat sink suitable for 100W operation. The AMP module mounts centered to the heat sink and chassis. The LPF module will mount to the other half of the case. When opened the cables do not need to be detached. The two halves lay side by side for inspection or operation.

I would like to hear your feedback on this approach. Schematics will be available soon. If you are not currently supporting the project, please consider the boost that would give the final stage developments.

73, K5OOR –  Virgil

HF Projects




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