Messages

706

North American Shortwave Pirate / Re: WDDR 4015 was 6950 USB 0059 UTC 01 JAN 2021

« on: January 01, 2021, 0617 UTC »

I've been listening on and off while doing other things since you first came on the air, over 5 hours ago now.  I admire your endurance.  Happy New Year.
0632 - Off

707

North American Shortwave Pirate / Damn Skippy 4020 USB 0543 UTC 1 Jan 2021

« on: January 01, 2021, 0544 UTC »

I hear music, definitely electric guitars. Perhaps some death metal.
Tough copy out west. I am getting better reception on N1NTE's SDR but still poor.
0556 - SSTV
0613 - off after SSTV

708

General Radio Discussion / Re: Pirate radio station shown on Google Maps

« on: December 26, 2020, 0416 UTC »

I bet it is a high priority for the British Ofcom to fly down there and bust them. 

709

North American Shortwave Pirate / Re: Ball Smacker 3480 AM 0158 UTC 26 Dec 2020

« on: December 26, 2020, 0405 UTC »

Back on at 0400. ID at 0404 UTC. Seems to be a repeat of what was on at 0200 UTC.

710

North American Shortwave Pirate / Re: unid 6935 AM 0127 UTC 26 December 2020

« on: December 26, 2020, 0345 UTC »

I have to admit that I did not get an ID (and did not hear SSTV) so I cannot be sure either. Just a reasonable guess.

711

North American Shortwave Pirate / Re: Ball Smacker 3480 AM 0158 UTC 26 Dec 2020

« on: December 26, 2020, 0343 UTC »

Being an asshole doesn't mean you're wrong.
 

rgg

 

712

North American Shortwave Pirate / Re: Ball Smacker 3480 AM 0158 UTC 26 Dec 2020

« on: December 26, 2020, 0304 UTC »

No one asked me and no doubt I'm going to be labelled as an asshole but I suggest that operating on 3480 KHz, where your LSB is directly over NAT-F HF international air traffic control frequency of 3476 KHz is less than ideal, unless of course you are seeking "attention at a high level", if you know what I mean.

I noted Gander Radio telling several aircraft that they were "completely unreadable" during your broadcast and re-established communication on another frequency. Gander did not specifically mention interference so I can't say you were a problem but if it were me, I wouldn't want to be anywhere near them.

713

North American Shortwave Pirate / Re: unid 6935 AM 0127 UTC 26 December 2020

« on: December 26, 2020, 0219 UTC »

Understood. Their signal was pretty good tonight. I caught the last 10-15 minutes of their broadcast and noted the sign off at the same time as you.

714

North American Shortwave Pirate / Re: unid 6935 AM 0127 UTC 26 December 2020

« on: December 26, 2020, 0147 UTC »

It was likely this: https://www.hfunderground.com/board/index.php/topic,76033.msg251577.html#msg251577

715

General Radio Discussion / Re: Electric car chargers, new RFI ?

« on: December 24, 2020, 2216 UTC »

Agree, though your RFI could be coming from many items.

I can guarantee that the hybrid vehicle chargers are not linear supplies; they are for sure switching supplies. Hence the noise. This has been documented by others.

I noticed that my iPhone battery charger for my automobile has one of those (what I call) "wandering oscillators" - Randomly hops around +/- a few hundred Hertz, like a very, very unstable VFO. Of course, one of locations of the output products is right in the 43 meter band.

My house came with mains power outlets for the bathrooms that have built in LED night lights. These outlets produce incredible amounts of HF noise and will be replaced. Fortunately my recessed ceiling LED lights, which would be much more complicated to replace, do not seem to produce much noise.

My refrigerator, my washing machine and my clothes dryer are noise generators.

716

North American Shortwave Pirate / Re: WJAN 6925 USB 0210 UTC 24 Dec 2020

« on: December 24, 2020, 2156 UTC »

I caught the tail end of this too while I was goofing around with my portable and a long wire.
Clear ID heard at 0217. Good signal despite some local QRM from my automobile, I think.

717

Other / Re: UNID 3840 LSB 0314 UTC 13 Dec 2020

« on: December 21, 2020, 0519 UTC »

This is believed by many to be the former W6WBJ ( https://www.hfunderground.com/board/index.php/topic,67306.msg229625.html#msg229625) playing music on 3840, though usually what you describe (including the reverb laughing loop) is on AM, not LSB.

It's been happening pretty much daily since Crowell lost his license earlier this year.

In any case, a case of "ex-hams behaving badly".

718

The RF Workbench / Re: NOT A Replacement For Your Stretchy Audio Amp

« on: December 21, 2020, 0505 UTC »

Also there's some dumb audio filter on there that gives a huge mid boost, easily remedied by removing it completely!

Speaking of filtering, boosting and such:

I dropped in a Drok 100 W mono amplifier (Drok model number is on my schematics in case wants to know) in place of the original one I broke and it is not at all happy with your modulation transformer impedance at low frequencies. I have to cut audio frequencies below ~300 Hz otherwise the amplifier freaks out and goes into protection mode at any sort of reasonable output level.

The modulation transformer on its own can pass down to ~130 Hz without too much distortion and not huge attenuation (from what I remember) so I knew that something else was at fault.

To some degree, it may be partially a problem with (core) saturation since the bass cut is less necessary at lower audio drive levels and/or lower RF FET drain current, i.e., lower standing DC current in the transformer secondary.

The other thing is that the RF FET and everything attached to the modulation transformer secondary is inherently a low-impedance at audio so that it can be a low impedance at DC as well. That low impedance on the secondary is even lower as seen at the transformer primary because of the impedance transformation.

So I assumed that the low-frequency impedance seen at the primary, which was probably very low, was causing the audio amp to freak out. I added two 0.75 Ohm, 50 Watt wire-wound resistors in series with the primary and the amplifier appears to be happy because it has at least a 1.5 Ohm load to work with. It's wasteful but you can make up for the gain loss easily and 100% modulation is still achievable. Best of all, the amp no longer freaks out and I don't have to cut the bass as much.

I tried putting some big capacitors across the two resistors to make an R//C network (so that the added R would be "invisible" above a certain frequency) but I was unsuccessful in making any effect. I left the resistors in, without the C.

Seems OK.

719

The RF Workbench / Re: Watch out for those cheap components

« on: December 21, 2020, 0417 UTC »

You can tell by the font printed on it where they originate from... very distinctive, not used elsewhere.

That was the first thing I noticed too.

720

The RF Workbench / Re: Stretchyman 40 W TX Reliability Modifications

« on: December 21, 2020, 0416 UTC »

There some text around the net explaining another designers issues showing the same problem. Using any Xtal controlled transmitter will show the same Fming issues if viewed on an SDR.

Quote from the text follows....

I tried various means of making an oscillator for 3.615MHz along with a VFO to cover that frequency but I couldn’t get one stable enough. It varied only a few Hertz but that was enough to cause asymmetric sidebands (one sideband output higher than the other). A crystal oscillator would be the ideal solution but as with most components these days, they are not readily available and more than one will be needed for other frequencies. There is a UK company that can make these but they will not be cheap because they are not mass produced. I tried ‘pulling’ a ceramic resonator to frequency and although I could cover the required frequency, it was varying by a few Hertz. This is not detected on air because it’s only a tiny fluctuation but on SDR it can be seen as asymmetric sidebands on the AM transmissions. This shows on average a 6dB difference in levels in the sidebands at low frequencies. It’s not quite so noticeable above 1kHz but it’s there and because it’s there it will be noticed and will commented upon. Fig. 2 shows perfectly symmetrical sidebands at 300Hz. Before SDR no one would know or even care but with many operators using SDR they look for any imperfections! So, a stable oscillator had to be found. I tried a GPS and etc etc...

I find that explanation a bit problematic:

1) The author of the text you lifted (without attribution or reference, BTW) is talking about a few Hertz of variation. Chris' image shows much more than that.

2) Back in the day, every ham used to use crystals exclusively. Many didn't have VFOs until the early 1960s. I can totally believe that crystal generated signals hop around a little bit. How much? Who knows and if there was only a few Hertz of variation on a CW signal generated from a crystal, it might not have been noticeable in 1950, especially with all the other key clicks and whatever going on. But more than ~20 Hertz variation would have been very obvious on a CW signal. So you are saying that dudes back in the day with their FT-243 WW2 military surplus crystals were FM'ing ~1 KHz all the time? Pffft.

No, I'm sorry, but no one would have been able to make a CW QSO if that were the case and RST 599 reports would have been unheard of.

To be clear - I'm not saying that crystals are perfectly stable; I'm sure that they are not. However, I don't think that the fact that the reference was a crystal in your old transmitters explains all the FMing that Chris shows (and others have reported). So I'm suggesting that there might be something else going on in addition.