Messages

556

General Radio Discussion / BBC 198 KHz LW To End?

« on: June 14, 2022, 1703 UTC »

Embedded in this article on the BBC Radio 4's shipping forecast is the nugget that the latest cuts are to close longwave 198 KHz.

https://www.theguardian.com/media/2022/jun/03/shipping-forecast-radio-4-long-wave-broadcast

Yet the announcement that Radio 4’s long wave signal will be shut down as part of the BBC’s latest cuts has left many wondering how the country’s fishing fleet will cope without access to the four-times-a-day updates.

The BBC plans to end dedicated programming on its Radio 4 long wave frequency next year, which could mean the loss of two of the current four shipping broadcast updates.

but then later it appears to contradicts itself:

The long wave signal – which has been threatened before and currently relies on a small supply of metre-high historic glass valves to keep broadcasting – will survive for a few more years.

No surprise but some clarity comes from an industry website:

https://rxtvinfo.com/2022/multiple-bbc-channels-to-close

The content is embedded in javascript and I can't copy and paste it easily but the gist appears to be that Radio 4 will go off 198 at some point in the near future and then that transmitter may stay on after that, but the programming on 198 isn't described here, if it known at this time.

Of course, 198 has been threatened with closure many times in the past. LW DXers might want to try to QSL them this coming northern hemisphere winter just to be sure anyway.

557

The RF Workbench / Re: Beyond 45/48m

« on: June 14, 2022, 1544 UTC »

In the modern era of 56V power tools, higher voltage operation is no longer a challenge.  My Ego trimmer has enough battery on it to run a 50 watt transmitter for over two hours, and recharges in 15 minutes!

It's funny that you brought this up since that same day that you wrote this my new Ego leaf blower arrived. I bought it without the battery since I already had one with my Ego weed trimmer; you can share batteries among their equipment, saving ~$100 or so.

In any case, I saw the amp-hour capacity of those batteries a few weeks ago and thought, "you could run a transmitter off this bad boy." 

558

Equipment / Re: Who here doesn't have a MFJ ATU?

« on: June 14, 2022, 0444 UTC »

I have two of their tuners. When I go shopping, I'm not seeking them out but given the amount of them on the used market, you will see some for sale and given my needs and time schedule, I have gone for them.

They seem to work OK but I also haven't come close to stressing them either. I'm always careful not to hotswitch them, for example. Some of their other equipment reportedly suffers from some workmanship issues but these seem OK in that regard.

559

The RF Workbench / Re: Beyond 45/48m

« on: June 13, 2022, 2149 UTC »

Are you sure?

The Qg = 68nC

That Qg is too high for me!

Str.

It's actually 64 nC, not 68, but yeah, I noted the same thing.

Keep in mind that with higher power, Qg tends to go up. It has to because in order to meet the required current density demand and preserve other relationships, they make these by replicating unit cell transistors in parallel, meaning there are multiple smaller gates in parallel, which means multiple Qgd and Qgs in parallel too. It adds up. The other thing that matters is the breakdown voltage. The higher the BV, typically/often the input capacitance and Qg increases too. The FET channel will be longer, which means larger surface area of the gate capacitance, which likely means larger Qg.

The Cree C3M0280090 is small (900 V, continuous drain current 6.8 A continuous at 100 C) compared to that Microsemi FET (1200 V, 26 A continuous at 100C), so of course the Cree is more "nimble". Side note: the Qg of these transistors are at different conditions so not exactly comparing apples to apples but still...

I'm about ready to populate a board with the Transform TP65H035G4WS: only 650 V but Qg = 22 and Id continuous at 100 C = 29.5 A. Potentially not the best solution for me but at least it is available right now, which is more than I can say for some other choices!

In any case, if he was trying to run that MicroSemi FET at 15 MHz (picking a number out of the air), it might be low(er) efficiency compared to other solutions due to the higher Qg. (Maybe.) On the other hand, I'm only aware of him using 6285 and 4185 KHz, so maybe he doesn't care about anything above 6.3 MHz.

Also, at some point it may make sense to use RF transistors - as opposed to switching transistors - to meet the performance goals you want, particularly at higher frequencies. (That's why they exist.) Personally, I'm nowhere near that point but I have thought about it.

560

North American Shortwave Pirate / Good Times Radio 6935 AM 0249 UTC 13 June 2022

« on: June 13, 2022, 0251 UTC »

0250 - "Eye of the Tiger". Audible on many eastern kiwiSDR.
0253 - Theme from Top Gun (1986).
0256 - "Hooked on a Feeling"
0303 - "25 or 6 to 4"
0341 - ID. Didn't get all of the spoken words due to fading and noise but got the ID.
0342 - TX Off

561

North American Shortwave Pirate / Re: UNID 6925 USB was 6930 USB 0013 UTC 13 June 2022

« on: June 13, 2022, 0030 UTC »

0029 - Moved down to 6925.
0239- Close down with "...stay hydrated. We're out."
0241 - then back on again, unless it is someone else. Blues with electric guitar. (Pretty sure its someone else.)

562

North American Shortwave Pirate / Re: Captain Morgan Shortwave 6950.2 AM 2348 UTC 12 JUN 2022

« on: June 13, 2022, 0009 UTC »

Listening via an east coast SDR. Sorry to say that it sounds like you are having some problems with RF getting into your audio equipment and causing all the distortion and occasional squealing I hear. I hope that you can get that sorted out.

TX off around 0023 UTC after a series of issues. 

563

North American Shortwave Pirate / Re: Skippy Radio 6925 USB 0230 UTC Jun 11 2022

« on: June 11, 2022, 0337 UTC »

SSTV image just before presumed signoff at roughly 0334 UTC.

564

North American Shortwave Pirate / UNID 6860 USB 0454 UTC 07 June 2022

« on: June 07, 2022, 0456 UTC »

Tailending Mix Radio after they signed off. Listenable on the west coast but lots of fading and static crashes.

0454 UTC - Moody Blues.

Mentioning me after song. I thought it might be you, Mr. Outhouse.

0505 UTC - I had to step away for a few minutes, came back and then I heard: The Clash, "Charlie Dont Surf". Go home man, you're drunk. 
0509 UTC - SSTV.  Shit, no ability to decode right now.
0512+   surf guitar music.

I have to go to bed. Early morning tomorrow. Thanks for the tunes.

565

North American Shortwave Pirate / Re: Mix Radio/Cool AM WW2 show 6860 USB 0125 UTC 7 JUN 2022 S9+20

« on: June 07, 2022, 0244 UTC »

Not quite strong enough at my location at 0245 UTC to make it pleasurable so here is a recording from KPH up the coast with a much better antenna. https://vocaroo.com/19aSx0dJLhH7

Sundown out here is at roughly 0300 UTC these days. Reception improved as the evening went on and I've been listening from my home RX from 0330 UTC or so. It is rare to hear an east coast station so well here.

sign off at 0452 UTC after playing taps on a bugle.

566

North American Shortwave Pirate / UNID 6965 USB 0140 UTC 06 June 2022

« on: June 06, 2022, 0157 UTC »

At tune in - Replay of BBCWS news report of Gorbachev being replaced as head of the Soviet Union (1991).
~ 0155 Slavic operatic vocals
0207 - music stopped, Off, I guess.

567

European Pirates and Private Stations / Re: The Vault 6985 AM 2125 UTC 5 Jun 2022

« on: June 06, 2022, 0014 UTC »

0000  off?

Seems that way.

568

European Pirates and Private Stations / Re: Zenith Classic Rock 15060 AM 2015 UTC 5 June 2022

« on: June 05, 2022, 2052 UTC »

Making it to North America. The signal is not fantastic everywhere but audible in many locations. It might improve as the evening goes on.

SINPO 25322 on W3HFU kiwiSDR (northern Maryland/Pennsylvania border, USA)
SINPO 25322 on N1NTE (Massachusetts/Connecticut border, USA)
SINPO 35433 on K3FEF (northeastern Pennsylvania, USA) - pleasant listening
SINPO 35433 on WA2ZKD/1 (coastal Maine, USA, magnetic loop antenna)

Of course, the signal is good in Iceland too:
SINPO 35444 on Bjargtangar
SINPO 45444 on TF3GZ

2104 - Iron Maiden
0014 - still on the air, signal slightly better than before but not by much. Best reception I found is on K3FEF. Grand Funk Railroad, "I'm Your Captain".

569

The RF Workbench / Re: Beyond 45/48m

« on: June 05, 2022, 0638 UTC »

Some folks on this side of the ocean have been using 30-31 meters (9500-9900 KHz) lately with some reasonable success. I have been thinking about transmitters for 22 meters at the low end of the broadcast allocation, and staying above the North American beacons in the ISM allocation (~13550 KHz). Propagation predictions showed that this band would have been quite useful for transcontinental and perhaps transoceanic use earlier this year, maybe not quite as much now in northern hemisphere summer.

I typically see significantly better bandwidth in an optimized CMCD configuration than I do with Class E. In order to get reasonable losses and lower transistor dissipation in Class E, I end up running loaded Qs in the 25-50 range. The simple LC tank circuits that I have been using for CMCD probably have not been that high yet still work well and are very efficient. I guess that I could go to higher Q but the circuit optimization algorithm has been leaving off elsewhere.

After all your cheerleading for Class E, I'm surprised to see a CMCD from you. Also... STOP THE PRESSES. It looks like a Cardinal Components crystal oscillator! Well, well, well. We've gone from "crystals are unnecessary" (paraphrasing your words) to "crystals are in use" in a short amount of time.

570

North American Shortwave Pirate / Re: UNID 6950 USB 0001 UTC 03 June 2022

« on: June 03, 2022, 0015 UTC »

Stopped again at ~ 0013 UTC.

This doesn't look like SSB to me. Looks (looked, past tense) like AM with carrier at 6950.56 and the same information on both the lower and upper sidebands.