Search found 280 matches

by Andrew (grayhat)
Tue Nov 12, 2024 4:50 pm
Forum: General Discussion
Topic: Another directional RX loop
Replies: 15
Views: 53292

Re: Another directional RX loop

For the interested ones, here's another idea to build the compact loop, the attached image shows all the relevant details, the resistor may be a regular one (although a non inductive one would be better), the 9:1 can be the commercial NooElec BalUn or can be built using a #73 binocular core, the PVC...
by Andrew (grayhat)
Wed Oct 23, 2024 2:18 pm
Forum: General Discussion
Topic: The SULA antenna
Replies: 65
Views: 205638

Re: The SULA antenna

I was wondering if it would be worthwhile to minimize losses within the antenna elements and if that's even possible? For example, I was using PE or PVC insulated stranded wire with a velocity factor of maybe 0.7 or something. Somewhere I picked up the idea that this slowdown in the dielectric come...
by Andrew (grayhat)
Sat Oct 05, 2024 12:13 pm
Forum: General Discussion
Topic: Using AI and KiwiSDR TDoA
Replies: 1
Views: 2973

Using AI and KiwiSDR TDoA

Maybe it's a crazy idea, but... let's start from this https://www.rtl-sdr.com/kiwisdr-tdoa-direction-finding-now-freely-available-for-public-use/ now, let's suppose to put together some code which, by leveraging the above and some map API, may feed an AI to gather further infos (e.g. using search en...
by Andrew (grayhat)
Wed Jun 26, 2024 2:05 pm
Forum: Questions & Advice
Topic: SDR list
Replies: 0
Views: 7972

SDR list

Attached is a (zipped) "csv" file containing a list of web published SDR receivers

nothing special, but may hopefully be useful to someone
by Andrew (grayhat)
Sun Jun 23, 2024 11:29 am
Forum: Questions & Advice
Topic: K-480WLA any good ?
Replies: 0
Views: 7121

K-480WLA any good ?

I was reading infos about this active loop https://www.amazon.com/GOOZEEZOO-K-480WLA-Shortwave-0-5MHz-500MHz-Battery%EF%BC%88Built/dp/B0CMD3LD9Z avaipable from amazon and aliexpress, according to the infos I gathered the amtenna has a masthead wodeband amplifier as many others, but the "shack&q...
by Andrew (grayhat)
Sun May 19, 2024 12:11 pm
Forum: General Discussion
Topic: Simple, effective preselector
Replies: 0
Views: 12753

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: 15
Views: 53292

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: 15
Views: 53292

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: 15
Views: 53292

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: 15
Views: 53292

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...