Comments are moderated before they will appear on the website, this is a manual process and may take some time. Please be patient.
Author Name is a required field.
Email Address is optional, but without one I won't be able to contact you back. It is never shown or linked on the website. You can always just email me if you'd rather not post a public comment. I generally reply in-line with a comment rather than email you back, unless I want to discuss something in private or off topic. Please check back to see when I reply.
Website URL is optional, if supplied the Author Name will be hyperlinked to this URL.
You may use wikitext in the body, preview may be handy here. Don't worry if you can't figure them out, just give me a hint what you want linked to what and I'll do it during moderation. Wikitext is not BBcode!
Spammers: Please don't bother wasting your time scripting up posts to this form. Everything is moderated, your post will never be seen on the web even transiently, there is no way to even view it by its internal ID, it will never be indexed. I will simply delete your post in the moderation interface. If I'm your target audience you're really on the wrong track; I'll never click on a URL in your garbage. The post content is not emailed to me (and I don't use a Win32 mail client anyway), I view the posts in plain text in the moderation interface so no clever tricks of any kind will make anything you type be interpreted by anything other than me, a human. Just give up and go elsewhere please!
15th June 2014 04:00
Doh! If you put the thing on the web number of turns would be a minimum, preferably a circuit.
20th August 2011 07:10
Hello, how are you doing? I would like to know how to make the bridge of swr, if possible
27th December 2007 14:19
Peter, yeah that is pretty close. The SWR bridge in mine has a transformer instead of direct connection of the rectifier and LED. The turns ratio is 5:25 on an FT50-43, but that isn't too critical. The secondary has the larger turn count, feeding a 1N5711 rectifier, 100 nF capacitor and a 1 kΩ current limiting resistor through the ultra-bright green LED. A lower forward voltage ultra-LED like a red is probably a better idea.
I used a T68-2 (red) core for the actual matching circuit, not a ferrite one. Both gangs of the polyvaricon in parallel are needed to resonate the secondary on 80 metres.
I had to experiment with the primary a little to get a good match, as I had selected the secondary turns count to resonate at 3.2 MHz with the available capacitance (about 210 pF) and that needed quite a few turns. I think I ended up with 3 turns to get a good match into 4.7 kΩ, but I can pull it apart and check.
27th December 2007 10:40
Alan, is this the circuit you built.
(Hey, great that you now have comments!)
15th June 2014 08:21
Alan Yates wrote...