1924 Alexanderson machine transmitter in the air!!!

[PA0NVD]

At Christmas eve there will be a 1924 200 kW LF machine transmitter fired up and sending a Cristmas  message
Listen, listen listen!!!

[WA2SQQ]

Evey year I intend to listen, but forget. What is the Dec 24th - time (Z) and freq?

[W7TFO]

http://www.arrl.org/news/saq-alexanderson-alternator-transmission-set-for-christmas-eve

73DG

[SM6OID]

Hi!

I live approx. a two hour drive (?) from the site, have been there a couple of times and seen it live.
It is truly an amazing piece of machinery!

Needless to say, copying the transmission from where I live a piece of cake.

[AJ1G]

I am going to try to copy with my Wandell und Goltermann AT-611 Selective Level Meter which tunes from 6 kHz continuously to 18 MHz.  Essentially a quadruple conversion receiver with a product detector ,no AGC, and a dBm meter that can measure from about -120 dBm to maybe +40 dBm.  Will take it down to a quiet shoreline location in the Tacoma and use just my 75 meter Hamstick for an antenna.  This setup has copied the various MFSK naval VLF stations really well,  NPM from the west side of Oahu comes in with about 20 dB SNR down at Stonington Point around local sunrise here.  I tried to copy SAQ from there a couple of years ago but overslept my alarm and by the time I was on the Point the transmission had ended.  

Last weekend when we all were chasing the 3890 mystery broadband, I noticed that the Penn State KiWi SDR had very good reception down at VLF.  Not many of the others I have listened to do.  The one out in the Mojave desert in CA is also good. The NA5B SDR in northern VA which call itself a VLF SDR has a so-so reception with lots of spurs EMI and a high noise floor.  Will see if I can copy SAQ on maybe the PSU SDR on my iPhone.

May try Point Judith RI as a prime reception spot.  Public access  privately owned parking lot used by surfers and fisherman, lot sits above the water on a cliff about 50 to 75 feet. Ill throw a big surf rod in the truck as a cover for why I will be parked there at 0200 local!  Or I may drop over to the W1NZR compound just above Beavertail Point in Jamestown RI and cliplead onto his ex-1900 kHz radio location 90 foot vertical. Would be interesting to see how the GRC-9 in the Tacoma loads up to that on 75, will give that a try as well.

[N1BCG]

I May try Point Judith RI as a prime reception spot.

...or catch an Interstate Navigation ferry from there to Block Island, the ultimate listening spot!

[AJ1G]

The PJ location is pretty spectacular!  Here’s a couple of pix I took up there a few weeks ago.

The BI sugguestion is pretty tempting.   Maybe I’ll book a room  at a B&B for Monday Night and Diane and I will have mini getaway, I’ll go down to Southwest Light and listen from there.  Been many years since we’ve been there.  One of our first dates when we were at URI was a day trip trip over there on a warm Sunday December day, we at least went wading down on the beach below the light.

The ride back that night to PJ was really rough.  Two huge St. Bernard’s in the passenger salon on the ferry got seasick, we went topside and hung out in the fresh air aft of the bridge for the remainder of the trip.  

I think I brought my GRC-9 over there on a Boy Scout camping trip when sons Ben and Dave were in Scouts.  

[W1ITT]

Here's a VLF receiver software setup that uses the sound card in your laptop computer as the front end.It's not an SDR, just an old fashioned "straight" receiver.

https://sites.google.com/site/sm6lkm/saqrx

Be careful that there's no precipitation static or loads of nearby RF on whatever antenna you use, as you don't want to blow the front end of the sound card.  The antenna plugs into the microphone input.   I have received the Cutler VLF station here in Maine with it.

[N1BCG]

Here's a VLF receiver software setup that uses the sound card in your laptop computer as the front end...

That's fantastic! In fact, a simple opamp can be added to the mic input to isolate it from possible static damage and as an impedance converter so a much smaller antenna can be used.

In the case of most JFET opamps like the LF353, the positive input has an impedance in the megohms and would require minimal, if any, feedback (output to - input). Perhaps the chip could also be run off the bias voltage present at soundcard mic inputs. The downside of this is the reduced input impedance due to the bias resistors. An audio choke would need to be connected between the mic connector and VCC and a DC blocking cap added at the output of the opamp.

Can you tell this is "on the fly thinking"? Hmmm...

[AJ1G]

With snow in the forecast for the overnight, will stay close to home and try for SAQ down at Stonington Point.  Did a dry run down there early this morning around 0600 local and received signals with from good to rockcrushing (NAA) from all the naval VLF transmitters in Maine, North Dakota, Washington State, Hawaii, and Northwest Cape, Australia with just the 40 meter Hamstick on the Tacoma into the Wandell u Goltermann AT-611.

[N1BCG]

Well this IS interesting!  Now it's just a matter of finding out if I'm hearing actual stations or the neighborhood plasma TVs...

https://en.wikipedia.org/wiki/List_of_VLF-transmitters

[AJ1G]

Start by looking for NAA on 24.0. They should be very loud.  Just saw them at -62dBm with the WuG set for 75 ohm input bridge mode, which I assume is an unterminated input, as signals are about 20 dB louder in bridge vs non bridged input.  About 32 dB SNR with 400 Hz bandwidth, using the Tacoma 40 meter Hamstick parked in th driveway.  

Now here’s something else interesting.  Hooked up about 100 feet of two conductor thermostat wire ( tied in parallel of course) to the Tacoma mobile antenna feet point on the left rear corner of the truck instead of the Hamstick,ran the wire approximately east about 5 feet off the ground, Beverage style on trees and shrubs big opportunity. Results pllwere disappointing, levels actually down several dB for NAA re the Hamstick. Re positioned the wire so the truck feed point was at the head vs tail of the wire, and lay it on an axis NE/SW with the feed point at the NE end.  WHOA!  Levels went up to -48 dBm up 14 from the Hamstick-62 dBm. So, will have to figure out how to deploy in a quiet location for SAQ in the overnight.  Good luck on your attempt Clark.  Can’t emphasize enough how important a quiet location is for VLF.  What is showing on your spectrum at about 21.5 might be NPM Oahu should sound like narrow shift RTTY.

[N1BCG]

The SAQ program tunes up to 22kHz, so no NAA on that one, but I just discovered that the RSP1A SDR tunes the whole VLF spectrum! Yeah! I am also experimenting with an L-match to optimize reception for my 3AM (OMG) reception of SAQ tomorrow.

Amazing how a 0.01uF disc across the input actually helps.

[N1BCG]

After a lot of experimenting on improving VLF reception, I decided to try something very different for antenna matching... an audio transformer. Incredibly, this led to a *dramatic* improvement in reception, so much so that I was able to hear stations I hadn't heard previously.

A simple 1k to 8 Ohm transformer worked wonders, and I found a 10k to 1k line matching transformer to be ideal. The antenna and ground connect to the high impedance windings. It's important to note that this was with a 100' longwire and an RSP1A SDR receiver, however, I'm sure this will help other receivers as well.

Not only does it provide impedance matching and isolation, but it also gives the antenna a D.C. ground as well as shunting higher frequencies that could desense VLF reception.

Incredibly, even frequencies at 60kHz and higher were received better with the small transformer compared to a direct connection.

[KL7OF]

https://time.is/London
0730 tune up.....0800 message...

[Opcom]

Racal R1307A/GR for me!
http://www.bunkerofdoom.com/lit/rycom/index.html

I'll give it a spin!

[AJ1G]

There they are.  CQ de SAQ!😊 Snowing here on Stonington Point.  539X -93dBm on the WuG. 100 foot wire lying on the rip-rap stones along the east side of the Point.  Generally NE-SW.  Merry Christmas!

[AJ1G]

Here’s a pix of the WuG deployed in the jump seat of the Tacoma, uses little 100 watt DC to AC inverter, it only draws 20 watts.  And weighs about 50 pounds!

[N1BCG]

I decided to sleep in and catch it on a European SDR at 0800Z rather than have to be up at 3am (!) EST in order to listen here. Much more convenient!

[KL7OF]

I couldn't stay awake ...I missed it......

[Opcom]

A pity they do not bring out the old water cooled carbon mike and do a little AM Fessenden style!

But I did not pick up the stattion, unfortunately.

[N1BCG]

For those who missed it, it's out on video!

https://www.youtube.com/watch?v=shqi43EV07c

[PA0NVD]

Unfortunately, I couldn't receive it There was a whole lot of noise, probably LED lighting or so.
But thanks for the youtube link, I did enjoy seeing it

[W2PFY]

Where are the tubes? I didn't see a single tube? I wonder if those Morse senders are metric?

All kidding aside, From what I have read on the net, all you need to receive that signal and others in that band, is your sound card on your computer. I guess it would be helpful to be in a very quiet area? I also found a sdr just for that low band but the download site is no longer working. That sdr had filters on it to focus on the part of the band that you were interested in. The one I downloaded was called SiDiRa 099 but I don't have the antenna here near Albany, NY to try it out. I'll try it on a long wire at camp before the static picks up in the spring.

So AG1G Chris, I guess you are the only one in our area to hear it? Any recordings?

Terry
 

[AJ1G]

I didn’t make a recording.  While the signal was solid copy the SNR was not that high and lthere was a fair amount of buzz in the noise floor probably from the inverter powering the WuG AT-611.  There are now a number of YouTube videos put up by folks who copied it, mainly from Europe.  Beautiful CW, note shaping seemed on the soft side.