Search found 275 matches

by Andrew (grayhat)
Sun May 19, 2024 12:11 pm
Forum: General Discussion
Topic: Simple, effective preselector
Replies: 0
Views: 1001

Simple, effective preselector

The schematic is here http://ve2azx.net/technical/FMT/L-C_FilterSchematic.pdf the inductors are molded ones, that is "nothing to wind", the variable capacitor can be a "plastic polyvaricon", so it's simple to build, now... look at the response curve, a nice "bell" with ...
by Andrew (grayhat)
Thu May 16, 2024 8:41 am
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

OMG, hope you'll get better soon !! As for the antennas, I believe that the "pipe" may be able to survive harsh weather better than the SULA, if you look at the image, you'll notice that everything is enclosed/protected by the pipe, including the coax connector, and then the pipe is small ...
by Andrew (grayhat)
Wed May 15, 2024 3:46 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

If you can/want, it will be interesting to see a video comparing that antenna with the stock one (or with some other antenna) Right now I am in Trondheim, but I am planning to do just that when I return home at the end of this month. Forgot to say that I made the SULA made with some break line had ...
by Andrew (grayhat)
Wed May 15, 2024 2:10 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

Also, a DUE note ! The idea came after a request from my dear friend Kostas ( SV3ORA ); he asked me if it was possible to make the "SULA" smaller and less visible (basically it shouldn't look like an antenna) and told me that ideally he needed some given dimensions At first, knowing all th...
by Andrew (grayhat)
Wed May 15, 2024 1:28 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

Hi Egil !! Happy to read that my impressions have been confirmed; while that antenna isn't "par up" with the SULA, its main advantage is the fact that it's really compact; as for the resistor value, yes, that one should be changed if the antenna size isn't the same as the one I posted, and...
by Andrew (grayhat)
Thu Mar 14, 2024 11:59 am
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

here's a better setup for the antenna; notice that the choke MUST be installed otherwise the cable could (would) become part of the antenna and totally screw the cardioid pattern; in this setup most of the wire runs inside the upper pipe so it's protected from UV and weather, same goes for the 9:1, ...
by Andrew (grayhat)
Wed Mar 13, 2024 2:35 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

Here's a general idea to build the antenna, notice that the resistor may be placed inside the upper pipe, by drilling two holes, also, the two pipes are both PVC ones, the top one is sealed at top with a cap and all holes used to pass through the wire are sealed with good sealant, the 9:1, preamp an...
by Andrew (grayhat)
Wed Mar 13, 2024 1:35 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

Thats a great idea! Thanks for sharing. This version should be much easier to build for beginners than the SULA. And a suitable balun and preamp can be found at very low cost on the web. 73 Egil - LA2PJ Egil, notice that the BalUn is the same used with the SULA, and may either be bought (e.g. the N...
by Andrew (grayhat)
Wed Mar 13, 2024 11:31 am
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

and since we're at it... I "squeezed" the SULA :D The idea was to find a more portable antenna, and after some fiddling I came out with this design https://postimg.cc/56N9FqM4 https://i.postimg.cc/5N8XTn7C/recloop-dir.png the loop is made of 1.5mm insulated wire and the whole antenna could...
by Andrew (grayhat)
Fri Mar 08, 2024 9:23 am
Forum: General Discussion
Topic: Another directional RX loop
Replies: 14
Views: 35887

Re: Another directional RX loop

For a fixed installation - looks like a worthwhile project! For portable usage and small spaces, well -> SULA! :) Well, sure, that 4-loops isn't as easy to bring around as the SULA Oh and if anyone is interested... I was curious to see if I could simplify that project while still having an "el...