Long Delayed Echoes

     Listening to Art Bell tonight and he related an incident where he heard his own 80 meter signal come back 3-4 seconds after transmitting.  While the distance to the moon and back is about right for that, generally moon bounce requires full legal powers, high gain antennas and frequencies much higher so that they penetrate the ionosphere, and even then voice is almost impossible, only narrow band Morse code which is very narrow bandwidth, is generally usable.  More over, the echo was a 20db over S9 signal not just above the noise threshold barely as you would expect with moon bounce.

     He tuned his transmitter up and down to make sure it wasn’t just someone sending it back to him somehow and it followed.

     I have also experienced this phenomena, but not as long of a delay and on 1200 Khz.  Back before 1210 Khz was in local use, I operated a pirate radio station on 1200 Khz, this was back in the mid 1970’s.  I had a radio to monitor our transmission in the studio.  One night when I signed off I heard the last second or so of our transmission after I cut the transmitter power.  A second at the speed of light is 186,000 miles, we were lucky if our signal reached 20 miles.

     I have read of many accounts of this phenomena, some with delays as long as 15 seconds.  I’ve yet to read a reasonable explanation.  The Wikipedia contains five theories, but none of them seem to account reasonably for the typically very strong signal strength of these echoes.

     I’m fascinated by these because I wonder if they aren’t tickling a much more exotic phenomena such as portals or some oddness in time.  All the theories given on the Wikipedia don’t seem to account for the signal strength of some of these phenomena.

     All of the incidents I’ve heard of have been relatively low frequency, 80 meter, 160 meter, AM broadcast band, but the Wikipedia documents cases at 432 Mhz and 1296 Mhz.

     Having been interested in TV and radio DXing for many years, I will note that there are many rare but interesting forms of propagation.  Even at optical frequencies interesting things occur.  One of the photos I use in my headers has a ship floating up in the sky.  Obviously the ship wasn’t really in the sky but differences in the density of the air bent the light reflection to make it appear so.  The same things and many others happen at radio frequencies.  So it might be something ordinary but at present unknown.  I find it fascinating none the less.

Voice of Vashon 101.9

     Today I heard one of the new low power FM stations while driving, “The Voice of Vashon”, on 101.9.  It had adequate signal to listen to except for interference from another station on the same frequency even though I was in Shoreline, probably 25 miles north north-east of Vashon.

     I wasn’t able to identify the other station.  The program material that was on was all in Russian and I don’t speak Russian.

     The station sounded reasonably well run, good audio, announcing, no dead air, and the signal was usable even out in Shoreline.

Dark Matter Digital Network

     I’ve added a new entry to the Resources list, the Dark Matter Digital Network.  This is an Internet broadcasting network that was assembled by Keith Rowland, Art Bells Webmaster.  It is absolutely superb.

     The audio quality of the Dark Matter Digital Network is very high quality throughout, and since unlike the old shows where guests were interviewed by telephone, with the attendant audio quality of a telephone, they are now interviewed via Skype and the network hosts, including Art Bell, also take calls via Skype.  As a result the show sounds like everyone is live in the studio.

     There are two audio feeds available free, MP3, and there is an AAC audio feed which is very high quality.  The show is in stereo so either listen with headphones or connect your sound card to your stereo.  You’ll want to take full advantage of the audio quality to fully appreciate the listening experience.

     The streaming feeds are free, even the AAC feed.  For an additional $5/month you can download podcasts of all past shows.

     In addition to Art Bell, Whitley Strieber’s Dreamland is there.  Art Bell airs 9-midnight weekdays, Dreamland airs 6-9pm Saturday.  Airing after Art is Richard Hoagland’s Other Side of Midnight show from midnight-2am.  They’ve got him listed on the website as midnight-4am, and he’s been wanting to do a longer show, but so far it’s been ending at 2am.

     Amateur Radio Operators will appreciate the QSO Ham Radio Show from 4-7pm on Sundays.

     This network is radio done right, technically superb, interesting, and fun.  Check it out.

Maximum Usable Frequency > 21 Mhz

     I am currently receiving a station in the Chinese language on 21550.00 Khz varying in strength between -76 dBm and -88 dBm (s7-s9) while my propagation widget is telling me 160 meters is fair and everything above that non-existent. 

     There are some deep fades and very bad selective fading that occasionally renders the signal unintelligible even when the signal is strong. There are some quite strong signals above 17 Mhz.  Given that it’s almost midnight local time this is somewhat unusual, especially given the relatively weak solar cycle.

     There is another station receivable on 21690.00 Khz but it is -90 dBm or less in strength and although I can tell there is a male voice, I can only hear it during peaks and there is too much noise to even discern the language.

     I scanned higher and found nothing and in ten minutes time 21690.00 Khz is no longer receivable, not even detectable.  The station on 21550.00 Khz is also gone.  Nothing above 19Mhz is receivable now.  There is a very strange periodically recurring signal between 18990 Khz and 19001 Khz that is almost like they’re trying to create an image in a spectrograph.  Check it out.  Tell me that isn’t weird.  It repeats about every 30 seconds or so.

19mhz

     This is one mysterious weird signal.  Now 17,985 is the lowest frequency I can receive any voice transmissions on.  The propagation has changed dramatically in half an hour.  Time for me to call it a night.

Art Bell – Retaking the Night

     Art Bell opened his show with Midnight In The Desert, “Taking Back the Night”.  It badly needs to be taken back!

     One of the really cool things about this show is that not only can you listen to it via streaming media but that includes an AAC stream.  AAC is a lossless compression, the audio is absolutely perfect.  There were some odd clicks on the first night but that was resolved by the next show.

     It is SO refreshing to see something done in radio by someone that actually cares about audio quality as well as content.

     Tonight they have Linda Moulton Howe, one of the very few remaining investigative researchers and reporters.  She is always an interesting guest, especially when you have a host that asks intelligent questions.

Anybody Remember the Loran Navigation System?

     On a “marine band” radio, these were radios that used to cover roughly from 1.6 Mhz to 3.6 Mhz, you could receive a sound around 1.8 Mhz that was the sound of the arrival of radio pulses from various Loran Navigation system transmitters.  It was a fairly broadband signal with a distinctive sound that selective fading would do weird things to.

      They discontinued those transmitters in 2010, they’ve been obsoleted by GPS systems.  However, this year eLoran is being brought online as a replacement.  Satellite GPS is accurate but it can be spoofed, jammed, and it doesn’t penetrate some areas such as canyons or inside some buildings.

      I have not been able to find much information on eLoran, can anybody tell me what frequency it will operate on?

      Also, if anybody has an audio recording of the old Loran signal as it sounded on an AM receiver, I would much appreciate it, especially if captured during a period of significant selective fade.

Wideband Web Software Defined Radio

Software Defined Radio PC

     This is the coolest radio related thing I’ve seen on the web. It is a wideband web based software defined radio operated by the ETGD Amateur Radio Club at the Faculty for Electrical Engineering, Mathematics, and Computer Science at Twente University in Enschede, Netherlands.

     It allows multiple users to listen to different frequencies simultaneously.  Right now, as I am using it, there are 137 other users listening to different things.

     It covers basically from 0 Khz to 30 Mhz, the lowest audio signal I was able to find was on 126 Khz in the long wave portion of the space, and right now the maximum usable frequency is around 15 Mhz, so beyond that can’t really receive anything at present.  Right now I’m listening to a station playing opera type music at 153 Khz in the long wave band.

     You can dial in the type of modulation, SSB (USB / LSB), CW, AM, and FM, the frequency, and the bandwidth.  It is quite extraordinary.

     The hardware is home brew and the circuit board work is incredible.  The software allows each web user to individually tune and listen to different things at the same time.

Hello LPFM, Goodbye DX

     13 licenses have been granted to new low power FM stations in the Seattle area. Happy to see that the FCC is allowing LPFM to become a reality.

     The bad news? Almost all the frequency assignments have high power FM stations that are presently using those frequencies and have a signal that is usable here in Seattle, most are Canadian, one is a station in Wenatchee. These stations happen to be my favorite radio stations to listen to in the car. Won’t be for long. Not a happy camper.

    The side effect is that these low power FM stations will be very limited in range even if you own a good receiver and antenna because of the existence of high power stations on the same frequencies.

     My take on this is that it was the FCCs way of giving these new LPFM stations a back-handed bitch slap.  They knew the public and congress overwhelmingly support LPFM, so they couldn’t deny it outright, so instead they chose to assign it to already populated frequencies to minimize the reach of low power FM stations and maximize the interference they will cause to traditional broadcasters.  This is an old tactic for getting people to agree to what you want, create a reason for them to want it, which is to say no LPFM because it’s not usable or because it interferes with something you want to use.  This will of course get the NAB up in arms and cause them to ramp up their opposition to LPFM.

     I can’t say there is much of anything the FCC does that I agree with. In particular, the choice of digital systems here in the United States destroys two adjacent channels, so now one high power commercial station essentially occupies three frequencies. If they had gone with Radio Mondale instead of this horrid IBOC they chose to use here in the states, we wouldn’t have destroyed the two adjacent channels with digital hash and those would then be usable frequencies, the audio quality would have been better and the usability in low signal areas would have been better.

     Fortunately, most stations are online now and can be listened to from anywhere but not the case for the car until some form of affordable mobile Internet becomes available.