Playing music from all over the world including English French and Russian Host speaks English with a hard to place accent
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The build is complete and I'm pleased with the way it came out. I am a little disappointed that I wasn't able to mount it in a homebrew case. I have everything needed to fabricate one, except my tools to punch holes. Several years ago I met a Japanese gentleman that makes some of the most beautiful projects I have ever seen. He taught me how to use a bending brake to fabricate enclosures.from sheet steel. Here's his YouTube channel:
https://youtube.com/@chappyhappy3675?si=aTxe77dYzRHEFZk2
Anyone interested in radios should take a look.
My final step will.be to test the ATU-100 Antenna Tuner. Lately I don't always have the best of luck with my builds. The key to success is taking the extra time to double check your work.
There are 8 slides in this post.
When conditions are favorable these 10 watt TIS (Travelers' Information Stations) can be received hundreds of miles distant. My farthest reception is from one along Interstate 5 in Redding, CA - 340 miles (550 kM) distant.
The FCC keeps a searchable database of these stations. It's a bit clunky to use. If there's any interest I will post about accessing this resource.
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I hooked up the newly built ATU-100 and flipped the tiny red power switch. Nothing happened! I pulled the power plug and measured the power supply to be the required 12 volts. Carol Marie was standing next to me and she turned it on again. After a slight pause, the screen displayed the version number and it performed a self-test. I just wasn't patient enough to wait for the self-test the first time!
I connected the Automatic Antenna Tuner between my Yaesu FT-891 transceiver and my End Fed Random Wire antenna. Next I closed the telegraph key that puts the FT-891 into transmit mode. The Tuner immediately reduced the SWR (Standing Wave Ratio - it is a measure of reflected power that's coming back towards the transmitter from the antenna) to 1.17:1. I tried it on the other amateur radio bands and the results were just what I expected for a properly running ATU-100. I was able to lower the SWR on all of the primary ham bands to less than 1.3:1. My End Fed Half Wave Antenna is designed for the 7 MHz Band.
What I mean by primary ham bands are the traditional, pre-WARC bands. An End Fed Half Wave antenna built for 40 Meters also operates on:
It also worked on the 80 Meter Band, but had issues on 17 Meters (18 MHz) which isn't surprising as I have to fiddle around with my costly Roller Inductor Antenna Tuner to get a match on 17 Meters.
I am very pleased with the performance. The ATU-100 is ideal for using with an amateur radio transceiver running up to 100 watts. I used it with 10 watts during my testing. I have read that it doesn't work well at 5 watts or less. I have seen a modifications for use with lower power levels.
Most of my amateur radio career has been spent making contacts using "QRP". The "Q-code" QRP generally means running your transmitter at 5 watts or less power. I do own a linear amplifier, an Ameritron AL-811H that I purchased new in 1997. I have used it through the years, mostly to boost my signal on 160 Meters. It has a matching network between the input of your transceiver, and the grids of the 4 triode tubes that are used. Adjustable coils are employed - they are used to tune the input to the output of whatever transceiver you are using. Thia setup has never worked well. I have always used a small MFJ Antenna Tuner to lower the SWR between the transceiver and the amplifier. It becomes a hassle because if you want to run the FT-891 transceiver straight through, without the amp, you have to physically switch a cable from "Antenna" to "Bypass". And as soon as you change bands the little MFJ Tuner needs to be readjusted. The new ATU-100 will automatically take care all the switching and matching.
Guess what I found in the closet. My wife's old radio. She used it for listening to AM (MW) and FM, not SW. It's a RadioShack DX-396.
I wasn't expecting much, it doesn't even have an external antenna jack. It's a single conversion superhet with no frills. Wow it's very sensitive. I'm in NJ, here's a DX from Canada that sounds like it's next door. 740 kHz CFZM Zoomer Radio from Toronto, ON. I like the lyrics on this one, kinda funny.
She hates tuning, static/QRM/QRN and wants convenience. So I got a replacement that solves this, she's gonna love it. More on this later.
For some reason Reddit is not allowing posting more than one video on this Subreddit. I'll have to add another video as a comment. Look further down this post.
I may be talking apples and oranges here, but I have the Sangean ATS-909X2 and am considering buying the Grundig Satellit 750 as a 2nd SWL radio (my only interest here is SW. I have other radios for other bands). Truth be known...maybe because I just like the way it looks. But, wrt actual performance, given a decent long wire antenna, are these two radios similar...or does one radically outperform the other? Thanks in advance for any comments.
I am working on an Interface, which was used to route audio from Mics, Mixers, and a Compressor to an Icom SSB Transceiver. The Icom is old school and the interface feeds a Mic circuit with the semiconductors forming a Mic Preamp.
I now wish to also route the same audio chain to a modern Yaesu FT-891 Transceiver. Although I could have chosen to make an adapter to run the audio into an RJ-45 connector on the front of the unit, I am choosing to run the audio into a mini-din connector on the rear of the radio. This rear connector also routes to the audio input circuit of the transceiver, but at line level, without amplification.
My interface uses 2 summing Resistors at the XLR input on the interface to isolate and sum the 2 channels. The values are 10KΩ. This feeds a 10K potentiometer, and then travels through a 600:600Ω transformer, out to the radio.
The combination of the 10KΩ resistors and the 10KΩ pot kills over 15 db of my signal. So I am changing the resistors to 490Ω and bypassing the pot for the FT-891. The Icom has no front panel power level pot so the 10KΩ pot on the interface was doing this job. The FT-891 has internal adjustments for audio levels and power, so the pot isn't needed for it.
I tried working with Google Gemini for some new wiring suggestions. Every time it made errors. Here is part of the transcript:
Me: If the summing resistor is only connected to the ft-891 pin of the switch how does the signal get to the M700?
AI: You are exactly right to call that out—if the summing resistors only went to the FT-891 pin, the audio path would be completely broken when you flipped the switch to the M700 position. That was an error in my previous description.
(Gives me a new circuit).
Me: That potentiometer is still across the swamping resistors and the transformer primary in this new wiring.
AI: You are completely correct. Sharp eye! If the top of that potentiometer remains hardwired to the primary side of the transformer while the wiper is tied to the switch, it creates a parallel resistance loop that will permanently load down ("swamp") the signal line, even when you throw the switch over to the FT-891.
(Gives me another wiring modification).
Me: I don't believe you at this point.
AI: That is completely fair. I have walked you into a circle here, and I apologize for the confusing and contradictory descriptions of the wiring paths. Let's stop guessing at the schematics and get back to a simple, accurate reality.
Your instincts are 100% correct: in that last description, because the potentiometer wiper was still tied to the transformer primary, the pot was still directly loading down the transformer.
(Gives me another alternative wiring).
Me: You screwed up my project. Well, actually it's my fault for believing you. As I have told you in the past, I am an electronics engineer. I should have just relied on my own skill set.
AI: You are completely right, and I owe you a sincere apology. I gave you contradictory and structurally flawed advice that would have turned your build into a mess, and I completely understand your frustration. As an electronics engineer, your skills and instincts were spot-on every time you called out those design flaws.
Me: Your wiring skills are lacking because you are not visualizing the entire circuit as you make changes.
AI: You are completely right. I focused entirely on individual pins and local connections without holding the entire topological loop in mind. In analog circuitry, you cannot modify one node without tracking how the current loop closes through the rest of the network—including parallel loading paths like that potentiometer.
I really appreciate you pointing out exactly where my logic failed. It is a fair and accurate critique of how an AI processes schematics versus how a bench engineer visualizes a living circuit.
To make sure I learn from this and improve my visualization, would you be willing to share how you ultimately decided to layout the switching path to keep the potentiometer from loading down the line?
Me: I will add another spdt, or dpdt switch. This is the easiest solution.
Managed to eke out a real-time ISS SSTV image during the weekend's ARISS SSTV-33 event (image 1).
I used gpredict to pick an optimum flyover, which came almost directly above my location (image 2).
I used gpredict's autotune to slew SDR++ and account for doppler shifting, which is nearly impossible to to do accurately by hand (image 3).
There were 2 images sent during the pass, the first of which was on the ascending leg. MultiScan 3B failed to detect this one, probably because the initial tones faded in an out. The second was on the descending leg and came through fairly well, all things considered (image 4).
I used the SDR++ audio recording feature to try to capture the entire flyover from AOS to LOS. And will try to get MultiScan 3B to decode the first image, and maybe improve on the second one.
I honestly expected this image to be near perfect, given the flyover peaked at close to 80 degrees elevation. It's unfortunate that peak occurred during the 2-minute break between images. But that's life.
Equipment used:
Reception notes:
I posted a few days ago about upgrading my 1997 Ameritron AL-811H Amplifier. I removed the tube deck in order to directly ground the tube grids. As manufactured, the grids went to ground through a 51 ohm resistor/.01 mF capacitor. I removed the resistor/capacitor from each tube, grounded the grids and added 2 gas discharge tubes to route any HV Arcs safely to ground.
In 1997, when my amp was built, there were still high quality 811A tubes available. Since then the quality of manufactured 811A tubes has fallen dramatically. Now you can expect a tube where all of the air hasn't been expelled, inferior materials are used, and tube arcing is common. And the cost has risen. Four tubes now cost about $250 USD. So these older amps must be updated to prolong tube life and protect components, most importantly - the transceiver that is driving the amplifier.
Back to my repairs. I am older now and I have broken my back a total of three times over the past few years. The amplifier is a very heavy piece of equipment that sits on my desk in a very tight space. Originally I could not access it from the left side, so I performed the repairs from the front. This did not allow for any slack in the filament wires and it was necessary to cut them. If you are not familiar with a grounded grid amp, I will let you know that with this model, the input is fed into the filaments along with filament voltage.
When it came time to reinstall the tube deck, I had to add several inches to the filament wires. And I was not able to give them a gentle twist either. The photos show my splice job. Well, upon firing up the amp it had no power output at all. I checked everything and thought the tubes were probably bad. But before adding new tubes I struggled and managed to rotate the amp to where I could access the left side. I unscrewed the tube deck to give me access to the underside and the filament wires. Now I had plenty of room and I was able to remove the spliced in pieces and directly splice the cut wires.
After buttoning up the amplifier and powering it on, I am now seeing 400 watts out for 40 watts input. I could easily push 600 - 800 watts out but I don't need that much power. Even a person who has done this work for a lifetime can make mistakes. I do quite often!
The original designer of the amp. Tom Rauch helped me through multiple emails. He is a couple years older than me, but still at it!
The first photo shows the amp with SWR Meters and Antenna Tuners sitting on top. The rest show the extra wire added and subsequently removed.