AMATEUR RADIO FOR THE GREAT OUTDOORS
Antennas including linked dipoles, telescopic poles also ham radio kits - everything you need.
If you are thinking of leaving your ham shack with your radio, take a look. We can help.
Now shipping with more compact PCB V1.1 - see revised instructions (from 17 Jan 2017)
Low pass filters for 40m, 80m and 160m (all three supplied). Our lowpass filter kit builds up to a neat pcb with low pass filters for 7 MHz, 3.7 MHz and 1.8 MHz. The filters are selectable with movable jumpers. The kit is supplied with a pre-wired co-ax tail with SMA plug to connect directly to your WSPRlite and a board-mounted SMA socket for connecting your antenna: no fiddly connectors to install!
The PCB has been designed with new builders in mind. High quality through-hole components have been used throughout including Grade 1 Murata/TDK C0G/NP0 capacitors, Grade 1 solderable enamelled copper wire and gold plated jumpers.
Each filter is a 7 element low-pass with great performance and low loss. The kit is rated at 25 Watts - suitable for general QRP transmitter use. Board has M3 mounting holes for easy use.
Easy to make, easy to use! Click here for the instructions.
PCB V1.1 size 73 x 97 mm. Mounting holes M3.
Posted by Egon, PA3AAT on 23rd Feb 2017
It took about 3 hours to build. Put it on air and within 15 minutes on 7 MHz already 65 spots! Fantastic! Thanks SOTABEAMS team :-)
Posted by Richard G8ITB on 22nd Feb 2017
Nice and simple addition to the WSPRLite - consider details for 60 metres and a simple switch circuit (I built my own) for inclusion in the next version. Nice concept!
Posted by Duncan G3WZD on 15th Feb 2017
I purchased this kit as I wanted to user my WSPRlite on 40M. This was the first kit I had built for many years and my first experience of winding small toroids. The PCB is of high quality and very clearly marked; components were easy to identity (thanks to the colour coding on the carrier strip Richard!) which eliminated the potential for error. My bench magnifier was a big advantage and total build time was less than 3 hours (including winding the toroids).
Posted by Ryan WC6Q on 5th Feb 2017
This was my introduction to winding my first torroids. It was as simple ass could be, a little time consuming but a nice learning experience. The kit itself was easy to build as well. No SMC.
Posted by John VK6JB on 2nd Feb 2017
Does exactly what it should do. Great starter for those who have never wound toroids before. Nice size board, good for older eyes.
Seems typical of the SOTA Beams stuff, great quality.
Posted by Steve G8KNC on 16th Jan 2017
Well made circuit board and very good instructions. Took me about 2.5 hours to complete, including winding the toroids.
I had to use a headband mounted magnifier because of dodgy eyesight these days, but managed without any issues. They even mark the different value capacitors for you as the writing on them would need a jeweller's eyeglass to read!
Posted by David Silkstone M0VGA on 13th Jan 2017
Following my purchase of the Sotabeams WSPRlite WSPR beacon a few weeks ago I have just built the optional Low Pass Filter (LPF) kit for operation on 40/80/160m which I will primarily use for 40m. You can see my review of the WSPRlite unit on my local club’s website Ripon & District Amateur Radio Society.
The first stage of the build is to wind the inductors - I haven’t wound a toroid before so my first attempts were a little daunting but the instructions from Sotabeams included a link to a website at Genesis Radio offering some simple guidance which seemed to work well. It’s a bit fiddly and with some toroids needing 30 or more turns so you do need to keep count! I stripped the enamel coating ready for soldering by scraping the required length with a sharp scalpel. Once complete these were soldered into place on the board and continuity tested both in isolation and in series using the solder pads for their neighbouring capacitors as handy test points as per instructions.
Soldering the tiny capacitors into place was straightforward, as were the header pins, coax tail and SMA socket.
Next step is to test the LPF in operation, Maybe you’ll spot my (clean, filtered) 200mW WSPR transmissions soon ☺
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