Sunday, 22 August 2021

LPF for 70 MHz

The RF output of my 28 - 70 MHz transverter shows an irritating 3rd harmonic at 210 MHz. 

I found a simple Low Pass Filter for 70 MHz at dutchrfshop.nl 

The filter should be able to handle RF powers up to 150 Watts.

4 ATC capacitors and 3 coils is all you need:


Arranged on a PCB as follows:



Some finetuning using the nanoVNA shifted the dip @ 70 MHz;


Next step is to test the LPF with the transverter..

Off-topic: Old QSL card







Crypto for radio gear

A couple of months ago I started to trade a bit crypto currency. The idea was to obtain some extra cash for the radiohobby.

I was intrigued by what was going on in the crypto currency community. Learned a lot about altcoins, bullish, bearish, blockchain, ECB, Elon Musk, whales, graphs, quantitative easing. With some trading of Bitcoin, Ethereum, ADA and  Dogecoin I have been able to gain some extra's to buy radio stuff.

What's your opinion on crypto currency ?