LPAM Broadcast / Top Bander

[Zozo]

Recently started a new project for the handful of AMers on here. Basically a re-design of published designs from a many years ago from various sources all put together.

Typical series modulator with IRF510 final, and 4000 series logic for the PLL. Most AMERS will know this topology. Designed to cover the upper region of Medium Wave and 160mtrs for the Hams.

I hope to have the sample PCB's here before Xmas, but we're see how that goes. Undecided whether this will be open source project yet. But I plan to put many kits together available for sale.

LPAM BC.png

[Zozo]

Update, PCBs have finally arrived.

Kits will be likely be available from late January after testing and completion of all accompanying documentation.

MK1 PCB.jpeg

[SidB2]

That looks to be a good project Mr Zozo. I've built a couple of AM tx's in the past which have been based around the 10 watt IRF510 design, but they have been xtal controlled. As these are almost impossible to get now your PLL design looks like a good solution.

(apologies if this is a duplicate post)

[Zozo]

That looks to be a good project Mr Zozo. I've built a couple of AM tx's in the past which have been based around the 10 watt IRF510 design, but they have been xtal controlled. As these are almost impossible to get now your PLL design looks like a good solution.

(apologies if this is a duplicate post)

Thank you SidB2, I had to delay this project for a few weeks, but I've spent today assembling one of the boards.

It turns out I needed to make some changes to the IRF510 matching network. It's now the cooked-book design from the EMRFD manual.

The changes I've made required a couple of tracks to be cut, with one capacitor being dead-bug bodged on the bottom.

Anyhow I've reworked the PCB, and will order a new batch shortly. I will also upload the schematic and photo of the assembled board I put together earlier today.

[Zozo]

Here's the schematic of the board. it's capable of just over 1.5 Watts carrier, with around 6 -7 Watts PEP.

Schematic_AM MK2 .png

[Zozo]

Here's the assembled PCB. Updated version addressed the vacant capacitors regarding the modifications.

PCB ASM.jpg