Home
Search
Today's Posts
Login
Register21
Technical Corner / Re: Stereocoder design
« Last post by MonTaylor on February 10, 2026, 08:40:03 am »when i get some free time ill look into making this into a PCB
Keeping the airwaves alive for the next generation!
News:
Radio Builders Forum Established 10th June 2024
Recent Posts
22
Outer London Pirate Radio / Re: MDR 1575KHz LPAM MW Pirate
« Last post by ZoZo on February 10, 2026, 04:28:40 am »It's been rebranded as FreeRadio1575.org and relays other stations mostly, but you can send your syndicated shows to their email address to be aired.
23
Technical Corner / Re: Chinese Rigs
« Last post by Albert H on February 10, 2026, 02:33:41 am »ALL of those "audio sender" ICs are horrible. They're fine for their intended use - to send stereo audio from a CD or MP3 player to a car radio - but amplifying them is a stupid thing to do.
NONE of them are anything like "clean" (despite the Youtube nonsense), and you'd be better off building a proper rig!
NONE of them are anything like "clean" (despite the Youtube nonsense), and you'd be better off building a proper rig!
24
Technical Corner / Re: Stereocoder design
« Last post by Albert H on February 08, 2026, 05:01:52 pm »I designed a replacement for the 15kHz filters in the Pro IV, using op-amps with gyrators emulating inductors. It was published some years ago in EDN. I'll dig it out and post it here.
is this it?
https://www.edn.com/brick-wall-lowpass-audio-filter-needs-no-tuning/
That's the article. There was a small error in one of the inductor values, but the values given in the gyrator circuit are substantially correct. However, there's a slightly simpler circuit I now use which I've added to this thread.
25
General Discussion / Re: Radionecks is down
« Last post by Schmellenschmellen on February 08, 2026, 03:57:53 pm »It would be nice if he at least looked if it is online every day, surely there is some webmaster or hosting company "alarm" that could email you
if it is down.
if it is down.
26
Outer London Pirate Radio / Radionecks down again a bit of SDR...
« Last post by Schmellenschmellen on February 08, 2026, 03:56:31 pm »https://servers.fmdx.org/
Been listening to the Wakefield again for bit.
This site was going super slow yesterday but is better today.
Been listening to the Wakefield again for bit.
This site was going super slow yesterday but is better today.
27
Technical Corner / Re: Stereocoder design
« Last post by Radioclick1fm on February 08, 2026, 06:17:35 am »
when necks go down , you switsh and tune in here .28
Technical Corner / Re: Stereocoder design
« Last post by Albert H on February 08, 2026, 02:03:06 am »Here you go: the 15 kHz LPF I've been using lately.
29
General Discussion / Re: Radionecks is down
« Last post by Carlos2 on February 07, 2026, 02:50:59 pm »It's down again today with the same thing...Does he want to run a website or not is my question and if he doesn't why doesn't he give it someone else who wants to for the right reasons...It seems to me that he's only running it because he's a builder and seller of nrg transmitters which are well loved by people who have used them!
30
Technical Corner / Re: MC145151P2 Low Phase Noise
« Last post by Albert H on February 02, 2026, 12:16:59 am »The "Smartkit" circuit works well enough. It takes a few seconds to lock, but you're not going to be changing frequency all the time! The version of that circuit that we used to use had differing filter resistors, switched in by a 4066. This would allow lock in about 4 seconds, then would slow the filter down by 12 times to allow really low bass through, and prevent bass tilt.It added to the circuit complexity but avoided the normal compromise between lock-up time and bass response.