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Messages - Kage

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The RF Workbench / Re: Stretchyman 40w GaN TX is sick
« on: September 23, 2019, 1943 UTC »
Damn I was hoping this post would be about how sick, as in awesome his transmitters are. He seems to be quite the tech guru and knows a hell of a lot more than me on class D and E hands on work. Sure he will chime in :) Really no idea why I am replying, just thought the title of the post was about how cool his little rigs are and I probably drank a few too many beers or something.

Glad others caught it. I listened while working on a project and didn't have my SSTV software handy and didn't catch ID but the signal was really strong through the storms here in the midwest. Wondered if the DJ was playing live guitar for a bit.

Equipment / Re: Yet more KitchenAid stand mixer RFI
« on: September 06, 2019, 1554 UTC »
<reply to: ChrisSmolinski>
I think that's a matter of muntzing. I hate to say it but I often do that to my own circuit too but only to the point to simplify things, not malfunction it. Think Apples Woz style muntzing. However these imported electronics take it to another extreme and don't care about our standards and that's how we end up with junk that causes RFI at best or a burnt down house at worst.
BTW I updated my last post since you replied. Sorry I have a tendency to do that thinking no one is online to read it.

Equipment / Re: Yet more KitchenAid stand mixer RFI
« on: September 06, 2019, 1542 UTC »
Reminds me recently of a wallwort transformer. Had two 24v 500ma ones from different manufactures but looked identical on the outside with same plug. One I used plugged in would cause the nastiest RFI I have ever experienced. Thought it wasn't that big of a deal as I was using it on an audio device until I used it while transmitting and it caused my transmitter to hum like crazy. After pulling out hair and going nuts I remembered I had the other almost identical one and swapped them. Problem gone!
It makes me wonder sometimes how this shit is built. Sure I can open it up and investigate but there are times even when doing so I find myself stumped. It's like the chinese have some special ability to make the most noisy RFI devices feasible, and I couldn't generate that much RFI if I tried and I know how to build electronics that can!

Food mixers have a special place in my heart though. My mother had one when I was a kid and back when we had cable TV, yes cable.. not antenna. When she'd fire that thing up to mix stuff the TVs in the whole house would get visual lines going through them. I could hear the motor through the audio on the TV. Still no idea how such a simple device caused so much RFI. Kind of astounding to me now considering what I know about transmitters. All I can figure is that the thing was a giant spark gab transmitter motor somehow. Remember every weekend she'd make mashed potatoes and use it and... there goes The Simpsons for 10 minutes lol.

Equipment / Re: Inverted L ground plane
« on: September 05, 2019, 1758 UTC »
I actually replied without actually responding to your post here by accident, didn't even see your post until now here but over on that other forum we use I talked about ground planes for Inverted L's.

There's a claim that placing an equally length wire along the ground as the horizontal; aired part of the vertical section is beneficial. I'm not sure if that's fact though, might take some computer analyses. That horizontal section is not really radiating much anyway so I feel the most important part of that section acts as a loading coil for the vertical section or capacitance hat, and by placing a length of ground plane along the same direction will simply add to aerial capacitance thus probably plays with overall loading efficiency.

Now as far as directional qualities of the L, the long part horizontally longitudinal is the direction with a possible loss of 1dB. Put the length of the inv. L behind the area you want to give the strongest signal, but 1dB is so little it probably will have little effect anyway.

I've also noticed that sloping L's exhibit some interesting features. If you slope the inv. L the sloped section seems to have a far lower angle of radiation, thus if you are on the outskirts of town like me and want to hit your town strongest with frontal ERP, you put the sloping section toward your town and the ground screen same direction.

I may be wrong on some of this, but these are my observations in reality when testing.

Both the seaweed and Pepto Bismol are pink, coincidence?

Sorry to raise an old thread but that audio processor I was working on is now complete. It has all of the features of the SW200 but with some differences under the hood including a much steeper NRSC compatible filter reaching out to 9.5kHz instead of 6kHz. Included is the ability for asymmetrical modulation, optional VU and clip/AGC LED lights and other features.
Full schematics and R&D from the beginning to the end can be found here... Page 2 of the thread gets more in depth with progress snapshots.

I designed this for the pirate and part 15 community for those willing to take the effort to roll their own but trust me it's no easy undertaking. In time we will have PCB files online to simplify a lot of it for hobbyists who don't want to solder the insane protoboard work I did which took many months and instead slim it down to a few days worth of soldering onto a prefab board. This is simply my "thank you" back to the pirate community for all the incredible schematics and information you have all shared that helped me with my interests in broadcast audio and RF.
Not here to take the steam out of the SW200, I'm sure it's a fine audio processor too and is offered as a complete unit, however I wanted to design something similar *from scratch* and release the full design as open source for those wanting to build their own.

Video of my complete AM broadcast processor here..

Components like the Schlockwood SW200 are all generic for easy to source parts. Only exception is the VCA chip I used but that's still available from a few part sources. Tried to keep simplicity in mind and was inspired by the Dorrough DAP 310 and Texar Audio Prism circuits and sound from the 70s and 80s.

Huh? / Christmas time
« on: July 31, 2019, 0504 UTC »
Sometimes when I put my step button to 1kHz intervals and tune across the AM MW band it sounds like slay bells and steel drums between stations. Sometimes it sounds like Charlie Browns adult. Good way to fall to sleep if the static and blips on longwave doesn't work or Radio Havana Cuba isn't enough fun on acid. To each their own.

Propagation / Re: Is my radio dead though?
« on: July 13, 2019, 1344 UTC »
Last night things were mostly back to normal. Lots of strong SW stations and every MW channel packed pegging my S meter.
I think it's just these summer conditions and I should know that since it's nothing new to me during this time of year. I do think the solar cycle is playing a hand in it though because when things get quiet they get real quiet. Sure there's static when connecting the aerial but there are times when I wonder if my radio is dead but of course it isn't. I have other rigs and antennas to compare it to  8)

Even my friend who I helped convince to buy an ATS909 like mine asked me the other day if there are less stations to listen to or what the deal was. He's new to DXing so he was confused why he wasn't pulling in the stations he normally hears in winter. Had to explain to him that summer kind of sucks to begin with for MW and that we're at the lowest part of the 11 year cycle which effects SW. Glad I'm not the only one living here wondering.

Huh? / I love you all
« on: July 11, 2019, 1746 UTC »
Feeling pretty, might delete later.
God bless the pirate radio community!  :D

Propagation / Is my radio dead though?
« on: July 05, 2019, 0401 UTC »
I've never heard it this bad before. The last week has been a clustersuck of thunderstorms and local stations only. I'm not talking just SW either but even the MW band that I trust in has been getting weak in the X-band range.

I seriously thought for a bit that it was my radio or antenna or a lightning storm that deafened my radio because I have never heard it get this quiet. Doesn't help that this data station on LW around 300Kc I use as a test station to make sure everything is fine that usually gives me a full signal strength reading is now gone quiet but I think it finally went off air.
The only station that helped me confirm things are still working somewhat was the pirate X-FM with his booming signal and WBCQ, but even those were below the norm I am used to (outside of the superstation).

It's not my radio though, I tested a few radios, then really thought either I am losing my mind or my antenna broke connection somewhere. I have an inverted L up 35' with about 100' horizontal that I also use for AM pirating when the itch hits. Well just for shits I ran a low power TX test through my usual untouched tuning unit and sure enough my SWR was fine through the old wire, so it's not my antenna or ground system.
It is REALLY THIS QUIET! Time to toss the radios and go to stringed can communication? :'(

Lots of those older emergency CB radio walkie talkies that were meant to be kept with a road kit used RCA jacks for the magmount antenna and they worked just fine for TX. I suspect because in emergencies they are one of the fastest connectors to plug in and most familiar to ordinary people.
I've also used RCA jacks for <30MHz without problem but wouldn't trust them for anything other than QRP since they can easily be yanked out and would cause a PA transistor to pop.

If you have some of the higher quality A/V RCA cables around and are like me and often split the audio cables from the video and toss the video (yellow) cable to the side often those video cables have better shielding and can be used well into the higher SW frequencies with low power since they are made to carry wideband composite video. Impedance may be unpredictable but at low power it's not much of an issue. I often keep the yellow video RCA cables around for mono only interconnects too for the same reason.

This reminds me that I found 50' of 5 connector A/V RCA cables (red/green/blue left/right) in the trash and should try to push some RF down one to a dummy and see what kind of SWR and power loss they have on 11m since I have RCA to PL259 adapters :P

Awesome replies so far. My curiosity was peaked on this topic because of the analog audio processor I am designing and picking filter frequencies. Currently have an 8 pole overshoot corrected NRSC-1 compliant filter designed for the final stage which is flat that sharply rolls off around 9.2kHz and is down 15db at 10kHz, 25db at 11kHz and so on, but was thinking of adding a toggle to flip between that and something else which is part of why I asked.

Can't decide if I should add a 5kHz or maybe wideband 12kHz+ filter as the option. Guessing the earlier would be more useful for shortwave broadcasting but my ears say otherwise :-\
I guess as the old saying goes.. if they can't hear it with their radio why broadcast it? Going out past 5kHz is probably fruitless but for now I will stick to the mediumwave broadcast standard that is the NRSC mask and after looking at the replies will probably add the 5kHz filter as an option for restricted bandwidth 8)

If anyone is curious about the audio processor project I am working on you can find it here. It's slowly coming along and is a blog style post so always updating it. Only recently got the overshoot corrected filtering soldered up. Hopefully when it's all designed the info will be useful to other pirates that are electronics hobbyists too that want to get their feet wet in audio processing. In the meantime I will use Stereo Tool which is simply the best option out there on the digital side, I just prefer real-time analog.

Found this topic from 2015 on bandwidth but few replies and I never hear people discuss emphasis usage.

With mediumwave broadcasting it's almost necessary as listeners radios will have 75 microsecond de-emphasis built in, so the old standard NRSC mask 10db up near 10kHz with the sharp cut gets the job done like the big stations. Most audio processors will take care of this so no reason not to use it and I've noticed when not used the broadcast sounds muddy on AM radios able to pass the highs.

On shortwave I'm guessing there is no real need for it since standard audio bandwidth is out to 5kHz or so. What about some of you running higher bandwidth? I'd imagine most of the standard multi-band radios use de-emphasis on all the AM bands including shortwave since it's easier in circuit, and leave the FM broadcast section to do its own thing. Maybe some pre-emphasis on the shortwave transmission would help? Boosting up to 7.5dB at 5kHz and then brick walling it at that point to accommodate peoples average analog receivers using the mask on all AM bands internally?

Also wondering if anyone here has tried any practical bandwidth tests to see if lower/higher on both transmit/receive being equal made a difference in long distance listening?
I'd think that technically speaking lower bandwidths would conserve transmit power thus increase broadcast range slightly but the difference between 5kHz and 10kHz audio bandwidth is so small compared to something like FM upwards of 200kHz to AMs 10-20kHz occupied space that it probably doesn't matter so why not use higher fidelity audio on AM to make everyone happy from cheap radios to SDRs set wide open? We're talking pirating anyways, so no need to follow strict bandwidth rules unless the pirate band gets congested.

Just some caffeinated thoughts ;D

Edit: Discussion of SSB bandwidth welcome too! I'm so used to AM mode that I forgot this applies to SSB as well.

Does 34 count?  8)

Yeah I'm a bit over the age of your question but I am no 50 or 60. The local library was my best friend as a preteen/teen and though I always had a burning interest in pirate radio there were books like Pirate Radio Stations - Andrew Yoder, 200 Meters & Down - Clinton Desoto, and Underground Frequency Guide -  Donald W. Schimmel that threw me into obsession. Add in the ARRL/QRP Notebook books and an interest in electronic circuitry that grew from my earliest childhood memories of the wonder of electric lighting and my first transistor radio that put me to bed when I was probably 6 y/o or so.

Earliest memory I have that fascinated me with transmission was having two radios, probably not much older than when I got that first AM/FM radio and finding that if I tuned one nearby to a frequency near the one tuned in on the other it would blank out the static. This made me realize these radios weren't only listening, but also sending out a weak signal on their own (internal oscillator). It didn't take long being one of those kids that charred his hands by shoving things in the wall outlet and later tore apart all his brothers electronics to his dismay to figure out how those radios were working. Was probably only weeks later that I was poking wires around inside one from an audio amplifier output to see if I could modulate it, which I somehow managed to do and had neighborhood friends tune into by using a random wire connected somewhere near the oscillator/tuner variable capacitor as an antenna, and injected audio going God knows where into that radio.
Also had a lot of fun knocking out my mothers TV set from fun little escapades like that. Hopefully no aircraft comm. interference lol.

Years later as a teenager the bug hit me hard after toying with CB radios back in the late 90s when skip was otherworldly. At that point I was well accustomed to small RF electronics thanks to those Radio Shack springboard kits and the radio projects in the manuals. Soldering iron came next, breadboarding, Ramsey FM kits, and the rest is history.
Finally got on the air with some serious power and antenna height via 40' self erected tower in my 20s covering all of my town on FM and later the AM broadcast band which took another serious level of effort thanks to mediumwave antennas at such shortened lengths. Had some decent second or third hand equipment at that point and knew how to repair electronics so trash picked stereos and audio mixers and other gear could be had free with just some fixing. Like redhat I also managed to connect with the local station and get some basement equipment they were going to junk. Wish I still had some of that old Gates stuff.
Mics and music started coming to me as friends grew heavy interest in getting on the air with me so lots of equipment and broadcast material flooded in until things got a bit too big were we knew we were on the radar of the wrong people.
Now I mostly hang low but still tinker and run shows, just not to those extremes anymore and prefer using my knowledge to help others new to the hobby, hence the forum I run dedicated to the more technical aspects of the art.

RF will always fascinate me, and I will always be an avid SWLer and RF engineer. It's simply in my blood. Pirate radio is a life mission for many I believe. Just sucks for us 30 somethings or younger that we kind of missed the boat now that most of the younger generation are mostly listening to digital mediums, but the airwaves still need to be occupied in my opinion, especially now more than ever that commercial stations are killing listenership with their trash.

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