Hopefully we get an allocation around 500 KHz. It seems to be an interesting band. At the moment a few hams are permitted to use 500 KHz on a temporary base. I was too late to apply for a license.
Nevertheless I start building an synthesizer for 500 KHz and 137 KHz. When it is ready I can use it for a 137 KHz transmitter. And hopefully for a 500 KHz TX too.
What I have here is a PLL synthesizer that works from 5 MHz to 5.5 MHz. It has TTL output. It was intended for a HF transceiver project. It works but it produces to much phase noise for a receiver. For a transmitter it is good enough though. Especially when when frequency is divided.
For 500 KHz Dividing is done in 2 steps. First divide by 5 then by 2. The divide by 2produces a signal with 50% duty cycle. That is important for the power amplifier.
For 137 KHz the divided by 5 signal is divided by 8.
I made a small print for the dividers. It works, the signals sound good on a HF receiver. A picture will follow soon.
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