SoftRock External LPF for 40m operation

Now as time marches on we’re getting closer and closer to the point at which I won’t be sitting here just listening to everyone else having all the fun!

Once the antenna conundrum is sorted, it’s only a cable connection away to transmitting, which is why a little advance planning is needed.

The SoftRock needs an external low pass filter for 40m operation and the components to build one are shipped with the kit, which is half the battle won.

The topic is discussed on the SoftRock group and there’s a page in the constructors notes which, after a bit of internet rummaging, I found.

To make life easy the key piece is reproduced here, so I don’t have to go looking for it again when I’ve got a hot soldering iron in one hand and capacitors in the other.


Screenshot 2014-11-26 13.37.30


My next quest was some sort of enclosure to put this tiny device into to keep it mechanically safe. God knows how I found this site but Yowzer!

Every conceivable question answered in one! All connections for the antenna and to the radio secured to an aluminium chassis and solidly built!

Is it silly to get emotional over an inanimate object? Don’t even answer that one!


The good people at Digikey stock these

Now this is the really impressive bit. From clicking “purchase” to the man from UPS delivering this to the door took less than 36 hours. This is for an item that was US stock!

Next trick is to lash the filter up and get it plumbed into the enclosure, but that’s for another day.