# Weird Morse code-ish beeping at the end of the AM dial **URL:** \ **Category:** Factual Questions\ **Created:** [October 18, 2004, 7:51pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887 "2004-10-18T19:51:51Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![rfgdxm](https://avatars.discourse-cdn.com/v4/letter/r/c0e974/32.png) [@rfgdxm](https://boards.straightdope.com/u/rfgdxm)\ **Post date:** [October 19, 2004, 1:23am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/21 "2004-10-19T01:23:37Z")
> [@Una Persson](#): > > So…was I right, wrong, or somewhere in-between? Honestly, no snarkasm, I don’t know if an “LOM” is the same as a “navigational beacon”…at least I get points for posting a WAV, right? You were correct Una. LOM stands for “locator outer marker”, and this is a kind of beacon that is used with an Instrument Landing System (ILS). ---
**Author:** ![Berkut](https://avatars.discourse-cdn.com/v4/letter/b/a88e57/32.png) [@Berkut](https://boards.straightdope.com/u/Berkut)\ **Post date:** [October 19, 2004, 1:24am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/22 "2004-10-19T01:24:48Z")
You’re right, it’s a navigation beacon. It’s an LOM, which basically means it’s a Compass Locator (non directional beacon) co-located with an Outer Marker Beacon. That particular one serves as an initial approach fix for the runway 18 localizer approach into the airport, as well as where you should hold if you have to go missed on the approach. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [October 19, 2004, 1:30am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/23 "2004-10-19T01:30:32Z")
Whew. My memory is so bad sometimes that I really worried I mis-remembered the prior thread. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 19, 2004, 4:05am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/24 "2004-10-19T04:05:33Z")
> [@rfgdxm](#): > > With some very old cordless phones the frequency of the base unit was just above the AM band. Eh? No, that’s not right at all. The very oldest cordless phones used the 47/49 MHz bands. This is _well_ above the top of the broadcast AM dial, which is currently allocated from 530 to 1700 kHz (.53 to 1.7 MHz). It’s also well below the FM roadcast band, which runs from 88 to 108 Mhz. ---
**Author:** ![Rico](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rico/32/3582_2.png) [@Rico](https://boards.straightdope.com/u/Rico)\ **Post date:** [October 19, 2004, 4:23am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/25 "2004-10-19T04:23:03Z")
No, **Q.E.D.** It’s not very often I catch you in an error, you always seem to be catching me in one. I got my first cordless phone in 1982. The handset transmitted to the base in AM format between 1695 and 1825 kHz. [Look for the 6 channel mode - warning - popups.](http://hem.passagen.se/communication/telebug.html) ```auto All frequencies in MHz. Name Base Handset 01A - 49.930 / 1.695 06A - 49.830 / 1.705 13A - 49.860 / 1.765 19A - 49.875 / 1.795 25A - 49.890 / 1.825 27A - 49.845 / 1.735 ``` ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 19, 2004, 4:30am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/26 "2004-10-19T04:30:46Z")
Learn something new every day. Looks like this 6-channel system wasn’t around very long. Small wonder I never encountered it. ---
**Author:** ![rfgdxm](https://avatars.discourse-cdn.com/v4/letter/r/c0e974/32.png) [@rfgdxm](https://boards.straightdope.com/u/rfgdxm)\ **Post date:** [October 19, 2004, 4:31am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/27 "2004-10-19T04:31:33Z")
> [@Q.E.D.](#): > > Eh? No, that’s not right at all. The very oldest cordless phones used the 47/49 MHz bands. This is _well_ above the top of the broadcast AM dial, which is currently allocated from 530 to 1700 kHz (.53 to 1.7 MHz). It’s also well below the FM roadcast band, which runs from 88 to 108 Mhz. I’d have expected better from someone with over ten thousand posts here. 😉 > **[What does 900 MHz mean in a cordless phone?](https://electronics.howstuffworks.com/question320.htm)** > > I've been looking at cordless phones and have noticed that this area has gotten fairly complicated! For example, what is the difference between 900 MHz and other systems? "Cordless Phone Frequency Bands “1.7 MHz - The earliest analog models used this frequency band, just above the AM broadcast band. They are no longer in production, and were very susceptible to interference from fluorescent lights and nearby automobile ignition systems.” I owned one of these phones way back in the 1980s. While the handset was in the 49 MHz band, the base transmitted in the medium wave band around 1.7 Mhz, using AM. One thing about these phones was that with the base transmitting in the medium wave band using AM, the signal could travel quite some distance. I remember monitoring other people’s calls with a scanner, and could listen in to conversations a couple blocks away from where I lived. ---
**Author:** ![rfgdxm](https://avatars.discourse-cdn.com/v4/letter/r/c0e974/32.png) [@rfgdxm](https://boards.straightdope.com/u/rfgdxm)\ **Post date:** [October 19, 2004, 4:39am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/28 "2004-10-19T04:39:28Z")
> [@Q.E.D.](#): > > Learn something new every day. Looks like this 6-channel system wasn’t around very long. Small wonder I never encountered it. Dang, Rico beat me. 😉 According to that link he provided: “Six-channel systems are pre-1984, and are all but obsolete. They differ from the other systems in that they use radio spectrum just above the AM radio band for the base transmit frequency. An AM radio slighly detuned or shortwave receiver is all it takes to capture a signal from one of these, and their transmit range can be quite good.” Cordless phones IIRC came out in the late 1970s, so these frequencies were used for a number of years. ---
**Author:** ![Meeko](https://avatars.discourse-cdn.com/v4/letter/m/e495f1/32.png) [@Meeko](https://boards.straightdope.com/u/Meeko)\ **Post date:** [October 19, 2004, 5:06am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/29 "2004-10-19T05:06:53Z")
I have similar beeping. I thought it was my Cell phone? ---
**Author:** ![rfgdxm](https://avatars.discourse-cdn.com/v4/letter/r/c0e974/32.png) [@rfgdxm](https://boards.straightdope.com/u/rfgdxm)\ **Post date:** [October 19, 2004, 5:16am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/30 "2004-10-19T05:16:47Z")
> [@rfgdxm](#): > > Cordless phones IIRC came out in the late 1970s, so these frequencies were used for a number of years. [http://www.radioshackcorporation.com/about/](http://www.radioshackcorporation.com/about/) “1979 First RadioShack cordless phone.” I doubt if someone else was selling cordless phones, RadioShack would quickly start making and selling them. Thus indeed cordless phones came out in the late 1970s. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [October 19, 2004, 12:49pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/31 "2004-10-19T12:49:15Z")
Since the OP is answered, here’s more radio interference: I live in Columbia County, NY. Here, when I tune my radio to 103.9 FM, I also tend to pick up what sound like air-traffic conversations! They break in and overpower the radio station’s signal, then stop and the commercial broadcast returns to normal. We’re surrounded by a number of small air fields, so I’m not surprised by the air traffic, but I am surprised the conversations would break into commercial FM broadcasts. (And no radio transmitters are visible anywhere nearby, so it’s not like the tower is 100 feet away, or something.) ---
**Author:** ![rfgdxm](https://avatars.discourse-cdn.com/v4/letter/r/c0e974/32.png) [@rfgdxm](https://boards.straightdope.com/u/rfgdxm)\ **Post date:** [October 19, 2004, 12:56pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/32 "2004-10-19T12:56:54Z")
> [@toadspittle](#): > > Since the OP is answered, here’s more radio interference: > > I live in Columbia County, NY. Here, when I tune my radio to 103.9 FM, I also tend to pick up what sound like air-traffic conversations! They break in and overpower the radio station’s signal, then stop and the commercial broadcast returns to normal. We’re surrounded by a number of small air fields, so I’m not surprised by the air traffic, but I am surprised the conversations would break into commercial FM broadcasts. (And no radio transmitters are visible anywhere nearby, so it’s not like the tower is 100 feet away, or something.) Search Google for “image frequency”. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [October 19, 2004, 1:42pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/33 "2004-10-19T13:42:17Z")
My dad used to have a multi-band radio, and as well as the shipping frequencies, the FM band went up above the normal range… the highest FM stations here in the UK are around 107.5 - 108 MHz, but this one went up to 115 or so, and you could listen to the police radios. I used to listen to that lots as a kid. I always hoped I’d hear of some exciting crime taking place, but it was usually fairly boring stuff. I hope that wasn’t illegal, but I rather think it might have been. Oops. ---
**Author:** ![meowpossum](https://avatars.discourse-cdn.com/v4/letter/m/848f3c/32.png) [@meowpossum](https://boards.straightdope.com/u/meowpossum)\ **Post date:** [October 19, 2004, 3:33pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/34 "2004-10-19T15:33:16Z")
Thanks for the information and for the extra trouble folks went to (recording a .wav of the beeping? wow!). Y’all have sold me on this board – I ponied up my $14.95 this morning. – Mary ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [October 19, 2004, 5:52pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/35 "2004-10-19T17:52:20Z")
and to think - that’s just the beginning. Welcome. xo C. ---
**Author:** ![Shrinking\_Violet](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@Shrinking\_Violet](https://boards.straightdope.com/u/Shrinking_Violet)\ **Post date:** [October 19, 2004, 6:23pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/36 "2004-10-19T18:23:28Z")
> [@Colophon](#): > > My dad used to have a multi-band radio, and as well as the shipping frequencies, the FM band went up above the normal range… the highest FM stations here in the UK are around 107.5 - 108 MHz, but this one went up to 115 or so, and you could listen to the police radios. I used to listen to that lots as a kid. I always hoped I’d hear of some exciting crime taking place, but it was usually fairly boring stuff. > > I hope that wasn’t illegal, but I rather think it might have been. Oops. Same here … nothing on the telly, we used to tune into the police for entertainment! Pity we lived in a Suffolk backwater … :rolleyes: Glad you ponied up **meowpossum** - I’m sure you’ll find it’s worth every penny. 🙂 ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [October 19, 2004, 7:52pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/37 "2004-10-19T19:52:36Z")
> [@meowpossum](#): > > Y’all have sold me on this board – I ponied up my $14.95 this morning. Welcome! Next stop, the SDMB Wing of the Betty Ford Clinic. 🙂 ---
**Author:** ![choie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/choie/32/7829_2.png) [@choie](https://boards.straightdope.com/u/choie)\ **Post date:** [October 21, 2004, 12:15am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/38 "2004-10-21T00:15:08Z")
I got nothin’ to add to this very interesting & informative discussion, but … > [@Early Out](#): > > If it’s “O-E-O,” you’ve clearly stumbled onto the broadcasting service of the Castle Guards of the Wicked Witch of the West. This? Was freakin’ hilarious. I don’t often “LOL” literally, but I just let out a cackle that startled my cats. Nice one, **Early Out**. ---
**Author:** ![Berkut](https://avatars.discourse-cdn.com/v4/letter/b/a88e57/32.png) [@Berkut](https://boards.straightdope.com/u/Berkut)\ **Post date:** [October 21, 2004, 12:21am UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/39 "2004-10-21T00:21:30Z")
> [@Meeko](#): > > I have similar beeping. I thought it was my Cell phone? If it’s at the low end of your AM dial, it could be a radio navaid nearby. If it sounds like morse code, post it here and someone will figure it out. ---
**Author:** ![muffinismydog](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@muffinismydog](https://boards.straightdope.com/u/muffinismydog)\ **Post date:** [October 21, 2004, 11:23pm UTC](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887/40 "2004-10-21T23:23:35Z")
Re:beeping/aliens Beam Me Up Scottie… I’m Drunk And Wouldn’t Friggin Notice Anyways. P.s. No Anal Probing…big, Big, No-no!!! [Previous page](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887.md?page=1) [Next page](https://boards.straightdope.com/t/weird-morse-code-ish-beeping-at-the-end-of-the-am-dial/269887.md?page=3)