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Topics - Kage

Pages: [1] 2
Not sure where I saw the schematic but there was one someone made showing it was possible
to get around 5W(?) out on the low side of the FM broadcast band. Can't remember if it was the
IRF510 but it was in that ballpark. I'm sure the efficiency would be laughable but possibly still

I'd think the gate capacitance would become so high that they would be useless in the lower VHF
range but I've never actually tried to see the limits.

Seems there are hams who use them in the 6m band so if they can do 50MHz that begs the question
where will the maximum usable frequency of amplification become basically unity gain (if I should
call it that), or useful amount of amplification before it's useless?

Just a tip for anyone who owns this radio and suddenly AM stopped working.
The symptom is kind of odd, FM and shortwave all work fine but going to AM results
in loud static with no stations picking up unless you have a transmitter right next to the radio.

Opened it up and nothing obvious looked wrong so I start injecting a 800kHz signal from my generator
into various areas and found the first stage AM antenna amplifier seems to be weak or dead.
To confirm it I check on the scope at the Drain of Q26 while injecting a signal into its Gate.
The waveform looked fishy and didn't seem to be amplifying as much as it should.

So after much headache I unsoldered the smaller than rice sized SMD component which is a BF510 n-type FET.
Digging around in my part box I found a through hole 2SK161 which at least has the same pinout even if it's 8x
the size of the SMD part!
Matched pin for pin touching the board by hand and the BCB came back alive.

I ended up soldering it in place bent over for now. The sensitivity is not as good as it was with the original
transistor so I need to find a legit replacement but have no idea where to look that won't cost much.
Only other idea is to replace it with a part that has close to the same specs  :-\
With any luck maybe I will find a better part than stock and actually increase original performance but that
would be a crazy hack that would deserve its own post.

As to how the transistor died is a complete mystery. The radio was fine one day, then dead the next. I did not have it
plugged into an outdoor antenna. The gate and source of the FET are in parallel with the loop stick inductor so
how on earth the ferrite antenna could have generated a big enough pulse to fry the FETs gate is beyond me!
If I didn't know better I'd say the front-end got cooked by sitting under a broadcast antenna, but no
it wasn't from me  :o

I will say one thing that was odd is that this happened while I was camping out by a river with no houses around or stations.
While out there right before the AM died I was hearing some really strange wooshing click sounds which my friend found
strange sounding. It was strong sounding interference. Wonder if something was out there that fried my radio!?  ???
Probably just a coincidence.

The RF Workbench / Tecsun PL-880 external MW antenna idea
« on: June 29, 2020, 1714 UTC »
So this radio does not allow MW external antennas. There is supposedly a menu option by pressing a bunch of buttons like a game
controller to get hidden features including temporary MW antenna jack enable while playing but it does not work on my firmware of this radio which is the newest.
The 880 does have an external jack for SW, but it's disconnected from MW circuitry from the schematic I looked at floating around the internet in russian.

I got to thinking besides the obvious loop antenna and inductive coupling, would it work to loop enough turns around a ferrite bar and match it to my longwire outdoor antenna and grounding and place it near the radio on top where its internal ferrite bar antenna is?
Not sure if this would couple correctly or if it needs to be horizontal to the internal bar antenna?
Just thinking of ideas so that I don't have to modify a perfectly fine working radio.

The only other idea I have without going the loop method is to make a simple box to set the radio inside when listening to MW DX and make a loop around the box and match it to the outdoor longwire.

This is really my largest gripe with this radio. The fact that there is no easy way to connect an outdoor antenna for the 100kHz-1710KHz range. Otherwise this would be a killer on LW and MW.
On SW and FM broadcast bands so far I put this radio as my alternative to my ATS909, it's on par for performance so far, but lacks some RF/antenna features, but God damn the audio out of the 880 is impressive and selective bandwidths up to 9kHz on MW makes the thing a great station monitor compared to anything else I own outside of a TRF barndoor wide set. Then there is down to 500Hz for CW even. So for that it's a step ahead of my ATS909. With both these radios I am setup. They have quirks but make good brothers, one gets the job done when the other doesn't.

10/11 meters / What the hell is this noise?
« on: May 12, 2020, 1750 UTC »

I am pretty ticked right now. Been investing a lot of time in building a new EFHW monoband antenna now that I got some type 6 yellow toroids to play with. Literally the same day I received them in the mail and started experimenting I turned on the radio only after a day of having it off and now this plagues multiple channels.
Like many I monitor 27.185 so I first noticed it there, then channel switched around to find the culprit, happens to be ch16, but it's actually a zero, 27.150MHz.
Looked up anything on the frequency, zilch. Harmonics are not alive. It's specifically this frequency.

So after a few days of this now I walked around, noticed it was covering the whole damn area. Took my DX398 and biked around in anger and narrowed it down to a fenced in house 1/8 mile away.

I stood outside on bike with my radio and monitored it to make sure, yup, it's this house.

WTF kind of appliance would cause that noise at that great of a distance?
The tone does not change. It's a constant ... that. At first I thought it was some kids RC car remote stuck on ON, because it sounds like it. This thing is covering 1/8-1/4 or more mile of reception and I don't know what to do except pray they turn off whatever it is!

I don't make this much interference as a pirate radio operator lol. This crap has to be some chinesium flame thrower over powerlines or something. I had a hell of a time narrowing it down to the house because the power lines were carrying it. WTF?

ID and Translation Requests / 4020kHz music station, pirate?
« on: December 02, 2019, 1531 UTC »
Tuning around last night around 10pm cst. Don't recall any stations on this frequency but know of pirates using frequencies nearby recently. Not sure what the music was, sounded a bit like rock that I couldn't identify but lots of fading.

Ever since I was a kid I wanted to be a radio DJ. I built small FM transmitters as a teen starting out with rigging in audio to the internals of another FM radio and using the local oscillator to rebroadcast a few houses down from mine. Grew up and pirated FM with higher power, got up to 10 watts or so on FM and a 40' tower. Covered most of my town. Had friends come over and we'd do shows and had the local Taco Bell guy a mile away call in just to hear his voice echo over the cell phone and his radio.

I got paranoid after a while and part of that was my own doing trying to get the word out and I was always getting high and/or drunk at the time. Had a bad cough syrup habit but that's another story. Anyway.. after learning not only did my friends know about our FM station.. the whole damn town knew which surprised me. Doesn't help it is a 11k population so word gets around, but not in the way I wished.

So I switched up, went to AM because my strength is electronics and having fun with electronics. Got on medium wave and still have it setup for the occasional power switch flip to start broadcasting. I'm saving it for winter though when conditions are best and FCC is stranded.

Thing is the lack of interest now. Radio in general is dying. Any of us who deny that are clinging to memories. I sure know I cling to those FM days in the late 90s to 2008 or so. I had a lot of fun then and we had a ton of listeners. I had a phone patch, aka: cell phone with cord spliced into the mixer, but hey.. it worked!
My point here is the medium itself is dying because in general most broadcasts on AM/FM are talk radio and music, and not good stuff. It's all syndicated garbage, no local calls, no requests.

Us pirates aren't doing so great either in my opinion and I know I will take hate for this but I tune into shortwave on 69xxkHz and it's always the same boring music I can get on FM radio, the DJs don't talk much and some of them resort to computerized voicing.
What happened to broadcasting with actual talk, maybe a friend or co-host? No offense to those who don't, I believe everyone with the ability should get on the air, but the programming has become stale lets face it. We get out our tablet computers or phone to see what song is playing if we don't know just to type up a reception report. Yeah hooray you emitted RF and we could hear it. There are some really good pirates still around and I won't name names, but they can carry a program and often blast a radio. So if you got low power make that programming count or else you just become another log note.

Sorry I don't mean to sound like a dick. I just remember pirates of the 90s and so, there was more effort rather than running a play list. I say this because I realized that is exactly what I was doing with my AM radio station on 1710kHz. Wondering why I didn't get more listeners, then sat back and thought... would I continue listening to this just because it's on the radio? 

I'm just wondering what is the way forward? I seem to be going backward with AM now instead of FM broadcast band pirating simply because it's literally getting to the point where FM radio has killed itself and no one wants to listen to Hotel California one more time without shooting their brains out. At least AM offers more fun, which is so damn backward when you think about it. What has become of all this?

Equipment / To weep hole or not to? That is the question..
« on: October 12, 2019, 2103 UTC »
Replacing my old EFHW antenna match box I built a few years ago. It progressively climbed in SWR slowly over time until it became unusable.
Took down the vertical today and disconnected the box, opened it up and you guessed it.. water came gushing out.
Thought for sure I had that thing waterproofed well with RTV silicone but the antenna mount bolt is on top so rain ran down the antenna pole on top of that bolt and nut and somehow worked its way through the bolt threads into the box even being on there as snug as I could twist along with sealant.

So would it be advisable to make my new box waterproof with some other method/sealant or have a bottom weep hole to let water out?
This raises another issue in that humidity could get through the weep hole causing its own damage so not sure which is better practice in proofing it.
Luckily my coax didn't get water down it, or not enough to damage it but I definitely checked it with a dummy and meter to make sure and crossed my fingers.
I'm worried if the weep hole is at the bottom which is where my coax will connect that it will let water out which can then drip towards the coax connection. Thinking of maybe gluing a tiny tube into the hole so it runs past the connector

Ugh Midwest weather season is brutal on antennas  ::)

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.

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!  8)

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.

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...

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...

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.

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.

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? :'(

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.

10/11 meters / What is with 11m lately?
« on: May 24, 2018, 1157 UTC »
Anyone else notice that even though we are on the low end of the 11 year cycle the CB band is picking up big at times I never recall? Yet lower frequencies are completely dead. It seems 10+MHz is doing swell but anything lower is worse than ever! I tuned in 80m last night and heard two hams and that was it, yet at the same time I heard hundreds of people on CB 11m.
Right now as I post this, 6:55AM EST I am hearing skip from all over, that's not normal. Even at night lately and last night I heard people talking skip into the moon hours.
What is up with the sun? I thought when we are on the cycle low we are working local only but I am hearing stuff that reminds me of years ago when the solar cycle was high.
What gives? Am I going nuts?
Meanwhile I can't even tune in coast to coast am at night, how will I sleep w/o george snoory telling me bedtime stories?

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