Create radio receiver circuits with the LM386 audio amplifier
I didn’t have much luck using an LM386 as an audio amplifier (I needed more output power), but perhaps I’ll have more success using it to make a regenerative receiver. I think that I even have all the parts in my junk box.
Here’s a schematic from the article:
Is Ham Radio a Hobby, a Utility…or Both? A Battle Over Spectrum Heats Up
This was actually last summer’s controversy, but while the arguments about WinLink have cooled down, it’s still an issue. I used to be quite anti-WinLink, but since it seems to really be useful for emergency communications, I’m less strident about it than I used to be. I just searched fcc.gov to see if I could find out what’s going on with RM-11831, and was surprised to see that as recently as April 3, 2020, there were still comments being filed. So, I guess it ain’t over until it’s over.
Determining Resonator Q Factor from Return-Loss Measurement Alone
The author uses an expensive VNA from his employer, Copper Mountain Technologies, but with a little ingenuity, you can probably do with your $60 NanoVNA.
Ron Kolarik K0IDT says
“This was actually last summer’s controversy, but while the arguments about WinLink have cooled down, it’s still an issue.”
Dan, RM-11831 was never about Winlink. The petition identified several long standing problems with certain digital modes and practices, addressing only two of the problems. Specifically the identification / decoding of digital signals and moving all ACDS activity into defined sub bands. Winlink simply assumed the petition was all about their somewhat sketchy operation and filed multiple times to kill the petition while offering no solutions to the existing problems.
The ARRL Board of Directors agreed with moving all ACDS operations regardless of bandwidth into the current ACDS sub bands, Minute 31 July 2019 Board meeting, but something happened between what the Board requested be submitted to the FCC and what actually got there. To date there has been no explanation forthcoming from the ARRL on the discrepancy.
I have no problem with Winlink being used for emcomm but that isn’t the way it’s currently used. It acts as a general purpose email bridge to the internet 24/7, handling traffic between hams and non-hams. The question was posed to both the ARRL and WInlink, would there be any objection to limiting Winlink activity to scheduled drills, practice sessions, and actual emergencies? ARRL chose not to answer, WInlink copped out with the excuse that on advice of counsel they wouldn’t respond to anyone critical of WInlink in FCC proceedings. Only one response from a Winlink gateway operator that fairly represents the thinking and attitude I’ve come to expect from anyone associated with Winlink. The whole ugly story is available on the ARRL band planning group at groups.io https://groups.arrl.org/groups Oh, some of the Winlink “emergency” traffic that I’ve seen, from actual “emergencies”, is more comedy than emergency. I posted some of those messages in my last filing on RM-11831, https://ecfsapi.fcc.gov/file/1218085188644/ARSFI%20reply.pdf
RM-11831 was never about Winlink, never, until they made it so. I will say this much, since they brought unwanted attention on themselves they have been forced to make changes to the system to keep their users in compliance with various rules that had been ignored for several decades. Problems still exist and recently I flagged an Extra class, ARES, county EC, prominent in the Winlink organization, for using 3611kHz for email transfers. Now if someone in that position can’t follow the rules what about the others out there that only got a ham ticket to use the ‘free’ email–boaters and RVer’s mostly.
At this point it’s up to the FCC to make a decision one way or the other on the 2 items in RM-11831. I can live with whatever comes out of the FCC, the question remains, can Winlink do like wise?
Ron K0IDT
Dan KB6NU says
Thanks for the clarification, Ron.
Dave New, N8SBE says
I just so happen to have that particular model Copper Mountain Technologies VNA on my desk at work. I met the Copper Mountain guys at Dayton one year, and ended up ordering one for our use as a nice, compact, accurate unit that covered up to over 1 GHz.
Our frequencies of interest are 315 and 433 MHz, so it worked just dandy for us.
Unfortunately, it has a low end of several hundred KHz, so it wasn’t useful for our 125 KHz antennas. So, $26K later, I also now have a R&S VNA that goes down to 9 KHz, thus covering our LF antennas. I can see using the same trick with our R&S, to do Q measurements.
Thanks for the link!
Ed KC8SBV says
Dan,
I wonder who owns these LM386 radio projects?
http://theradioboard.com/rb/viewtopic.php?f=4&t=9341
Ed KC8SBV