Messages

61

The RF Workbench / Re: Stretchyman 40w GaN TX is sick

« on: October 07, 2019, 0354 UTC »

And this is why I don't sell my old homemade transmitters to people. I've been asked before but always feared something like this would happen and I don't even build on a professional level like stretchy does. Oh those multiple pops... sure someone wasn't making microwaved popcorn in the other room? I could use some reading this thread.

62

Huh? / Old TV reception phenomenon

« on: September 27, 2019, 1057 UTC »

Many TV repairmen from times past have a story many of them have experienced along with some ordinary TV viewers while alone where when tuning the rabbit ears and touching the antenna just right they would see the usual signals of distant stations go out of sync.

Once in a great while through the rolling signals they would see a fuzzy or oddly distorted colored live video of themselves, or even childhood memories or family events that would roll up the screen only for a moment that could never quite be tuned in before it would vanish to static. Only problem is there were never any video cameras or recorders in the room and the image seemed to come from a position in the room or past event where no camera could possibly be.

Most people who have noticed this phenomenon would refuse to tell anyone about it in fear others would think they've gone crazy and often couldn't shake the creepy feeling that something unexplainable is watching them while they watch it.

63

Equipment / The greatest radio ever, teh Bell Howell 9 band prise

« on: September 23, 2019, 2146 UTC »

I spelled teh on purpose.
Yeah here is all the glory of this $1 radio I just bought at the thrift store. It has world band, so... You know how radios are, if it has shortwave you have to buy it because we're suckers.

Well this little goofball of a radio covers medium wave from 530 to 1610kHz or so, talk about a killer for me. I listen to the X band AM mostly. To make things a little more gentle though it does have a barn door IF stage which makes AM listening like listening to FM if you don't mind going out into the deep woods to hear a broadcast far away from your local 50kw. It's easy to modify though to cover up to 1710kHz as I found by a simple adjustment on the 4 gang capacitor variable, but don't expect the readout to be right of course.

FM is even better, it actually performs as good as my breadboard FM radios. It almost has the ability to have selectivity if you hold it just right.

Oh and did I mention shortwave? This has the feature but I think they forgot to enable it. I picked up Havana and oooooh weeeee!

Okay I'm giving this little radio a harsh time. It's cute, performs okay for camping, and for being a radio that was a gift if you purchase other crap prizes on TV then voila. It at least has no birdies and after opening it up and damn near breaking the antenna connection from only removing the cover that is held together by... get this... ONE SCREW, and clips, I adjusted the 455kc oscillator and touched up the 4 screw tuning capacitor for peak. It's on par with dollar store gizmos and well it had shortwave... who will let a cheap radio with shortwave sit around for $1? Gumballs cost that much these days. I say we replace gumballs with shortwave radios! 



BTW that arrow pointing to that screw, that is literally the ONLY screw holding the thing together, it's all plastic clips  besides that one real loooong screw lol.

64

10/11 meters / Re: Fuchs antenna.. LC end fed antenna.. tapped coil, EFHW resonate

« on: September 23, 2019, 2107 UTC »

BTW there is one good thing about my playing with this stuff, I learned about toroidal cores and what the numbers mean. Sounds silly to the experts I am sure, and honest to God I have built RF electronics and it took me this long, but now I know the first number means size, the next number means mix. I feel like such an idiot lol. We all learn something new every day. Built radio transmitters for years but never knew that lol, just went by frequency spec, or tested them the hard way  by winding equals and sending RF through to see if they'd pass it, but I was over-complicating things like usual. Though it doesn't hurt to do the wrap and test method to test, never know if these companies sell legit core material until hitting them with RF.

65

10/11 meters / Fuchs antenna.. LC end fed antenna.. tapped coil, EFHW resonate

« on: September 23, 2019, 2045 UTC »

Going a bit nuts here as usual from my manic state of mind.

Been researching to replace my DIY resonant fuchs 1/2 wave end fed antenna for 11 meters. Original design I used was a 1:8 ratio coil with two windings primary and 16 secondary going into around 15 or so pF capacitance using of all stupid things a trimmer cap. Well I learned my lesson with weather and rain using this as a base antenna. Thought I had it waterproofed but every rain or humidity would climb SWR and lower frequency. NP0 trimmers are useless in outdoor weather and moisture.

This time I am going with a straight up lumped LC tuned stage, long story short there are three kinds of these end fed antennas for 1/2 wave end fed feed, the fuchs (better known as EFHW transformer coupled pri:sec transformer, sometimes resonate air core or powdered iron core, or non-resonate on ferrite which is lossy by a dB or more for multiband but gives flat SWR at expense of low efficiency and energy transfer). The single coil tapped version to convert a range of 1:6 to1:9 ratio (50 ohm to 2500-4700 ohm end fed), and my current setup which simplicity wins for efficiency the LC coil, a coil in series with transmitter output to antenna input and a capacitor across antenna to ground to convert current to voltage fed. There has to be very little loss using this method because it's direct and no cores used or lossy link coupling.
I think the drawback is the fact it isn't linked coupled will cause more standing waves on coax back to the shack.

With CB radio and 4 watts of power, got to make every watt count!

My question here before I complicate shit more is how many people have used these? I know the Antron/Solarcon a99 and other antennas use the same exact thing. The 99 uses an LC coil/cap, one coil inside of the other to act as a hairpin impedance match but I'm not even sure it's really that, it just looks like an RF coil to ground so that the antenna is connected to ground for static, otherwise the A99 is a simple LC match network into a 1/2 wave wire.
Here is an article on the A99 deconstructed to show how overpriced hype this thing is, it's literally an ordinary LC coupled half wave end fed...
http://www.radiomanual.info/schemi/ACC_antenna/Solarcon_A-99_review.pdf

I love EFHW antennas because the simplicity of mounting being in a small lot, got to use whatever I can. Wire types allow inverted V and other configs too.

I'd love to know if using an LC with a 130-2 toroid is as effective as an open air coil at 27MHz. I am testing both but can't figure out which is less lossy. The toroid seems to give less SWR across the CB band which leads me to believe it has a bit of loss, so I am currently testing with house copper stripped wire to make my coil, and a coax stub for the high voltage capacitor.

It looks ugly as shit right now but so far it tunes up with ~1.2 SWR over 26.5 to 27.5MHz but the coil is so sensitive to size change, it will take some glue to clamp it and lots of RTV silicone to seal it up before connecting the top bolt to my 18' adjustable 1/2 wave conduit pipe in the air...
https://imgur.com/a/jmUv4GI

Not even sure how well the open air core copper coil will do. Seasonal changes here are extreme and rain got into my last "fuchs" coil match which led me to this simpler design. I want to use my 130-2 toroid donuts for this but I feel they have some sort of loss at CB since they technically are good to 10MHz on the paper, no idea how to calculate loss over air wound when used as purely an inductor like this.

After this coil cures the RTV silicone I plan on making the same coil but using the red 130-2 coiled torroid in place of the air coil design in a different water proof unit with snipped coax capacitor and compare the two. Hard to do at my location because CB is dead right now. Hoping to get some skip in with that short spirt in wintertime. I guess there is always field strength metering. If torroidal wins out or comes in equivalent I think we just found the new best DIY end fed design for goofed setups like I have. Though only a few hundred watts can run through them, but I honestly run barefoot and enjoy the challenge of antenna design over idiotic power into thimble antennas.

66

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.

67

North American Shortwave Pirate / Re: Pee Wee 6955 USB 2147 UTC 21 Sept 2019

« on: September 22, 2019, 0335 UTC »

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.

68

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.

69

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.

70

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.

71

Huh? / Re: Scientists prepare to farm puffy pink seaweed that stops cows burping methane

« on: August 29, 2019, 1732 UTC »

Both the seaweed and Pepto Bismol are pink, coincidence?

72

Equipment / Re: The SW200 LPAM, Part #15, Amateur Radio AM, Audio Processor.

« on: August 27, 2019, 0831 UTC »

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.
http://darkliferadio.proboards.com/thread/1029/diy-audio-broadcast-processor-scratch

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..
https://www.youtube.com/watch?v=utZTQc_K0j0

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.

73

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.

74

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 

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.

75

Huh? / I love you all

« on: July 11, 2019, 1746 UTC »

Feeling pretty, might delete later.
God bless the pirate radio community!