Messages

16

North American Shortwave Pirate / Outhouse Radio 6950 LSB 0147 UTC 24 MAR 2024

« on: March 24, 2024, 0151 UTC »

EDM. Best reception I have found so far is in Montana but still looking.

0250 - Appears to be off.

17

North American Shortwave Pirate / Re: Solar Federation Radio 6970 USB 0041 UTC 24 MAR 2024

« on: March 24, 2024, 0148 UTC »

SINPO 44344 / S6 on peaks from the Montana transmitter. Listening on my portable with a wire antenna while camping (more like "glamping") at the beach in Southern California . (Montana isn't the "west coast" though.  )
If I go back to listening on a New England SDR, I can sometimes hear a little bit of polar flutter now.
Pretty cool that you have the ability to transmit from two different locations.

0137 - The Rolling Stones, "Honky Tonk Woman"
0144 - AC/DC, "Back in Black"
0146 - Aerosmith, "Walk This Way"

0158 - I tuned away for a bit and came back and now hear a lot of polar flutter out here. I guess you switched to the "east coast", huh?
0158 - Led Zeppelin, "Communications Breakdown"
0200 - Led Zeppelin
0221 - Inaudible direct. Only on east coast SDRs.
0222 - "Audio test" "Attention all of the planets of The Solar Federation." (repeated 3x) "We have assumed control." (Taken from Rush's album 2112.)
0225 - Audio frequency sweep from ~200 to ~3200 Hz, then off.

18

The RF Workbench / Re: U-LULU (Updated LULU) for 48 meters, 20 Watt Class-E AM Transmitter

« on: March 21, 2024, 0748 UTC »

Albert - Sounds very interesting and thank you for nudging this project along.

I'm very interested to see how you implemented the envelope feedback. I never thought to do something like that because - as far as I could tell - much of the distortion came from the Class-D amplifier. I assumed this because I was operating it at essentially max load on peaks, plus a DC load on top of it (which it was never really built for). The THD dramatically increases from ~10 W to ~100 W (max) output and I just assumed that short of implementing some sort of pre-distortion (which I really was not interested in delving into), that there was probably not much I could do about it, other than use a much bigger Class-D amplifier. Apparently I was wrong.

As for other the use of other transistors, there are a limited supply of TO-220-packaged transistors that could be used and of course it must be said that the TO-220 package is going the way of the dinosaur over the coming years. As far as I know the Nexperia PHP18NQ11T that I used in the U-LULU has not been put on NRND ("not recommended for new designs") or EOL ("end of life") status yet, the former being the precursor to the latter. The Infineon IPP530 is really good in this application too. The TO-220 version is now in EOL but they have a TO-252 version that will likely be available for quite some time. The Toshiba TK11S10N1L should work too, but it only comes in a TO-252.

I have already made the schematic and created the PCB layout for a follow-up that is similar to what you describe:
1) frequency source of either a) a selectable crystal oscillator (with a real crystal driver chip that is designed to work at HF) or b) an external oscillator input.*
2) selectable audio preamp circuit for those that want to use laptop computer, mobile phone or MP3 player as the audio source
3) RF filtering on the input of the preamp to keep the amount of RF injection hopefully low enough
3) continue to use a Class-E output, tuned for a lower Q than the U-LULU that should be able to deliver roughly equal power output from 6200-6300 KHz,
4) probably with an output somewhere between 30 to 40 Watts, better than U-LULU, largely due to being able to run the gate drive voltage much higher than 6 Volts.
5) PCB footprint currently equal to the Sure audio module I recommend for U-LULU so that the two PCBs can be stacked one on top of the other.

Well, I did eventually get the bare PCBs back from fab but I have had to devote a lot of time to activities other than radio in the past 6 months. As a result nothing has been done to test it out.

19

The RF Workbench / Re: Distance with 10W on A.M. (M.W.)

« on: March 21, 2024, 0702 UTC »

ON4UN's book on low-band DXing is a good reference for this since 160 meters is reasonably close to the top of the MW band.

Chapter 9 on vertical antennas shows the effect of bottom loading (with a coil), center-loading (again with a coil) and top-loading, along with the effects of a capacity hat. Bottom line: a vertical with a capacity hat is incrementally more efficient than a top or center-loaded vertical, both of which are incrementally more efficient than a bottom-loaded vertical.

Of course, if you aren't using a vertical (or near vertical) wire, a cap hat may not be possible and there may be other practical reasons for using some of the less efficient coil loading described. The horizontal portion of an inverted L is perhaps a little bit like a cap hat but that's not really why the inverted L works reasonably well, assuming it's long enough.

20

North American Shortwave Pirate / Re: Thunder Chicken Radio 6951 USB 2322 UTC 15 MAR 2024

« on: March 21, 2024, 0632 UTC »

A seemingly important reception detail, but for some reason no one else in this thread bothered to mention it:

The op announced that he is going through some "life changes" and he has to move house. ("The chicken has to cross the road.") The end result is that he expects to be off the air for 6-8 weeks.

21

North American Shortwave Pirate / Re: Unid CW 6930 USB 0137 UTC 21 MAR 2024

« on: March 21, 2024, 0628 UTC »

Is this CW or is it USB? Seems like it was CW, so the thread title should reflect that.

22

North American Shortwave Pirate / UNID 4090 LSB 0615 UTC 21 MAR 2024

« on: March 21, 2024, 0626 UTC »

Someone playing various older popular music tunes. Best audible in New England. Frequent changes in modulation level and QRN made it difficult to tell if they were still transmitting at times.

0621 - The Guess Who, "These Eyes".
0633 - Assumed lost.

23

Amateur Radio / UNID 3725 AM 0810 UTC 22 JAN 2023

« on: January 22, 2024, 0821 UTC »

Religious preaching by male with Southern US accent. SINPO 43343 in SDRs in New England.

Recording: https://voca.ro/18l9ATooE0SS

Seems to be the same as this: https://www.hfunderground.com/board/index.php/topic,120966.0.html

Transmitter off some time between 0815 and 0822 UTC.

24

The RF Workbench / Re: Stretchyman “40W TX” Failure Investigation and Remediation

« on: January 01, 2024, 0301 UTC »

Bumping this thread.

TLDR; Stretchy has a known spotty record of quality, an at times questionable record of technical decision making and a somewhat abrasive style and many people (but not all) agree with my conclusions. I want people to be aware of that before they enter into a commercial relationship with him.

I have no commercial interest in putting him down. I am not selling anything. I just don't like being lied to nor do I like seeing innocent people getting taken for granted.

25

The RF Workbench / Re: 15-Watt SHORTWAVE BROADCAST TRANSMITTER

« on: January 01, 2024, 0155 UTC »

Chris just doesn't want to deal with the legal liability of allowing commercial traffic of questionable goods on his site.  He pays the bills, that's his right to do so.

Yes and for those of you not clear on what this is, do a search for the Ramsey Electronics debacle with the FCC of the 1990s. Ramsey supplied FM transmitters. Being associated or being seen in any way as promoting illegal activity - in this case, allowing him to advertise - could be seen as reason for scrutiny from the feds. I have seen such scrutiny from the feds a few times (in completely different domains than radio) and it is not pretty.

You also have proven over the years to be rather obtuse and abrasive when confronted with concerns about your commercial activities, and that leaves a bad taste in peoples mouths.

You got it.

26

The RF Workbench / Re: 15-Watt SHORTWAVE BROADCAST TRANSMITTER

« on: January 01, 2024, 0141 UTC »

BTW, the pirate act only covers MW and FM not SW. The pirate act has been the “reasoning” that Stretchy can’t advertise here, which doesn’t make any sense.

As far as I know, Chris hasn't discussed the reason(s) so I'm not sure how you reached that conclusion.

Also, nobody is forcing you to buy his transmitters.

If you need to make accusations to make you feel better about a purchasing decision you may have made, that's not my problem, dude.

No one said anything about forcing anybody to do anything. I prefer to have an educated public understanding what they are getting into. Treating with kid gloves a supplier with a known spotty record of quality, an at times questionable record of technical decision making and a somewhat abrasive style is not helping anybody. He only came clean and fixed the problems (or at least claimed to) with his 40 W TX after I wrote a whole document about it, even though it was obvious that he knew about the problems before I ever did. He just couldn't be bothered.

If he feels entitled to advertise then I feel entitled to make people aware of what they may be getting into. I have no commercial interest in putting him down. I am not selling anything. I just don't like being lied to nor do I like seeing others being lied to and innocent people getting taken for granted.

To that end, I'll just leave this here: https://www.hfunderground.com/board/index.php/topic,67747.msg230885.html#msg230885
TLDR: See above.

27

The RF Workbench / Re: Distance with 10W on A.M. (M.W.)

« on: January 01, 2024, 0128 UTC »

Assuming that they aren't planning to boost output power significantly, the best things that this person could do is 1) make the earth/ground radial system as extensive as possible and 2) add a capacity hat to the top of the (presumed) vertical antenna. Both can have dramatic effects upon antenna radiation resistance and thus antenna efficiency.

28

The RF Workbench / Re: What to Know About Three-Terminal Voltage Regulators. Radio World rip...

« on: December 30, 2023, 0641 UTC »

Two things to note about what the author wrote:

1.

Three-terminal voltage regulators are high-gain devices to keep up with fluctuating input voltages and circuit loads. With high gain comes the possibility of breaking into oscillation and making their own high-frequency alternating current. They will sometimes start oscillating at a couple hundred kilohertz. The regulator will continue to put out its rated voltage, but with an additional 200 kHz or so of unwanted garbage. An oscilloscope will show that.

While the author is right that high gain enclosed in a small area often leads to stability problems, the problem in this case is not because of "high gain". Though we often don't think of it this way, linear regulators really are amplifiers but if the input to output gain was "high", it would not only be able to "keep up with fluctuating input voltages and circuit loads", but it would be wild and uncontrollable. The slightest change in the input voltage would lead to large changes in the output voltage. The fact that they exhibit fairly high Power Supply Rejection Ratio (PSRR) below ~500 KHz should dispel the notion that they have "high gain" there. There is gain but it enclosed within a feedback loop and this mitigates the input to output gain. The oscillation problem is the result of a change or degradation in the gain and phase margin of the regulator circuit, which is often the result of the input or output filter capacitors aging, which must be the case here. So, change the caps, as the author did, and presto....


2. "You gotta do what you gotta do", and I have done similar things many times myself but man, this is ugly:

29

The RF Workbench / Re: 15-Watt SHORTWAVE BROADCAST TRANSMITTER

« on: December 30, 2023, 0602 UTC »

Been making the same for years but I'm not allowed to advertise on here.

But then you proceeded to advertise in your post anyway.

Funny that!

Do you know what is REALLY funny? That you continue to think that you are somehow entitled to advertise here anyway.

30

North American Shortwave Pirate / Re: Radio Barcelona 6960 AM 2100 UTC 14 Dec 2023

« on: December 14, 2023, 2258 UTC »

I'm late to the party and I do not know if I'm hearing the same thing but if so, the the audio is a lacking high end (treble) but tolerable. ("Communications audio", for sure.)  I see no current sign of FM'ing and the sync detector has no problem locking.

S9 / SINPO 45444 on an SDR in Massachusetts.

2252 - Unknown music (to me) potentially APB that definitely sounds post-punk/New Wave.
2310 - ID by computerized female into a remake of "The Harder They Come" ("The Harder They Fall")
2314 - The Clash, "London Calling". There is a pesky with laryngitis (and a lot of auroral flutter) underneath on LSB.
2317 - The Clash, "Spanish Bombs". Voiceover by computerized voice but I was not able to understand.
2321 - The Clash, "Police and Thieves"
2326 - Carrier off briefly after "Police and Thieves" and a brief announcement that I did not understand.
2327 - Carrier back on briefly with The Clash, "Lost In The Supermarket". Off again.
2328 - Carrier back on briefly with a snippet of something from Sandinista, but I've forgotten the exact title.
2330 - Presumed gone for good.