SWLing Post Message Board

Oh and as for the ATU check out this one https://pa0fri.home.xs4all.nl/ATU/FRImatch/FRImatcheng.htm for RX only (or for QRP use) it can be built using a pair of polyvaricons https://pa0fri.home.xs4all.nl/ATU/FRImatch/pa4mf1.jpg also, while the original design covers the range between 3 and 30 MHz, w...

forgot, if you want to build your own impedance transformer, it's easy, just follow the directions here http://www.aytechnologies.com/TechData/9-to-1_XFMR.htm as for the core, 77, 73 and 43 materials will be ok, one turn is counted each time the two ends of the wire enter the binocular holes and exi...

willing to avoid an ATU and to have a better S/N ratio, you may consider putting up a different type of antenna, I'm referring to the T2FD https://cdn-bio.qrz.com/b/vk2evb/Home_Brew_T2FD.jpg?p=baf653982e2e9d35e4b85b25d46b36fe it's basically a folded dipole with a termination resistor, it can be easi...

A good size for a random is an 84ft antenna wire and a 17ft counterpoise wire, to connect them to the coax you may use this 9:1 https://www.nooelec.com/store/balun-one-nine-v2-barebones.html enclosed in a small weatherproof box, add an adapter to connect the SMA to whatever coax connector you use (I...

I'm having good luck with my End-fedz SWL antenna but I want to experiment with a longer-wire version of that general approach. I have an old Radio Shack random wire SWL antenna and I want to feed the receivers with coax, so some kind of unun transformer seems correct. Is there a proper ratio that ...

Yep Egil, know that, all in all I wrote that post

Here are some suggestions, in case you decided to buy it, that is :) First step, improve the loop; either use some copper pipe or alumium strip to make a wider and BIGGER loop (easy) Second step; match the impedance, the preamp has an impedance ranging from 1.5K down to 450Ohm, now ler's find a bala...

in such a case http://www.qrp.gr/tmaf/ :D [edit] the original filter along with infos about its working can be found here http://www.qrp.gr/tmaf/The_Magical_Audio_Filter.pdf it's basically a double audio filter implementing both a passband and a notch, the original one was mostly aimed at CW, but wi...

let' s start from an example of the kind of unit I'm referring to https://www.amazon.com/Eliminator-X-Phase-Bands-Aluminum-Signal/dp/B09B37KQ12 but there are several others using the same approach, a connection to our antenna and a connection to a so-callled "aux antenna", "noise ante...

did you already see this ?

https://rsgb.org/main/operating/beacons ... f-beacons/

also

https://www.ncdxf.org/beacon/beaconlocations.html