From wang!elf.wang.com!ucsd.edu!info-hams-relay Thu Apr 4 19:59:43 1991 remote from tosspot Received: by tosspot (1.64/waf) via UUCP; Thu, 04 Apr 91 21:33:00 EST for lee Received: from somewhere by elf.wang.com id aa27869; Thu, 4 Apr 91 19:59:42 GMT Received: from ucsd.edu by relay1.UU.NET with SMTP (5.61/UUNET-shadow-mx) id AA09399; Thu, 4 Apr 91 13:49:56 -0500 Received: by ucsd.edu; id AA07677 sendmail 5.64/UCSD-2.1-sun Thu, 4 Apr 91 08:48:35 -0800 for brian Received: by ucsd.edu; id AA07659 sendmail 5.64/UCSD-2.1-sun Thu, 4 Apr 91 08:48:29 -0800 for /usr/lib/sendmail -oc -odb -oQ/var/spool/lqueue -oi -finfo-hams-relay info-hams-list Message-Id: <9104041648.AA07659@ucsd.edu> Date: Thu, 4 Apr 91 08:48:27 PST From: Info-Hams Mailing List and Newsgroup Reply-To: Info-Hams@ucsd.edu Subject: Info-Hams Digest V91 #266 To: Info-Hams@ucsd.edu Info-Hams Digest Thu, 4 Apr 91 Volume 91 : Issue 266 Today's Topics: Any Fancy frequency standard enthusiasts out there? ATV ATV: AM or FM Boy Scout RADIO Merit Badge (2 msgs) Can you really learn Code from tapes? Guide to the Personal Radio Newsgroups HF rig names? IAMBIC keyer - What does IAMBIC mean? (2 msgs) KNWD TS-430S PROBLEM/SOLUTION RG8U (4 msgs) Ultrasonics. (2 msgs) Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Info-Hams Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/info-hams". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 4 Apr 91 15:33:19 GMT From: mojo!chuck@mimsy.umd.edu Subject: Any Fancy frequency standard enthusiasts out there? To: info-hams@ucsd.edu Hi gang, Well, we have discussed the accuracy of TV stations, and concluded that some are wonderful, and others suck rocks. Now lets get into the real discussion: Are there any frequency standards enthusiasts out there? You know who I mean, those of you who have closet LORAN-C and GPS receivers tracking your Rubidium Vapor Frequency References. People who get giddy when they talk about 1 part in 10E12 accuracy. Who know who Austron is, and what "996" means. Who can discuss the heratage of Varian, Efratom, Tracor, Hp, Sulzer, Kode, .... You are out there, I can feel it. (or maybe it is just the radiation from my RVFR) Lets talk. Chuck Harris - WA3UQV C.F. Harris - Consulting chuck@eng.umd.edu ------------------------------ Date: 4 Apr 91 12:20:18 GMT From: news-mail-gateway@ucsd.edu Subject: ATV To: info-hams@ucsd.edu I am interested in getting involved in ATV. I am particularly interested now in FSTV. Could someone please post or send me (or both) the frequences in the 430-440Mhz area which covers ATV and the corresponding UHF TV channels. Thanks. Scott, KA1WNU/AG (internet: sehrlich@lynx.northeastern.edu) ------------------------------ Date: 4 Apr 91 15:13:10 GMT From: pa.dec.com!rust.zso.dec.com!shlump.nac.dec.com!sousa.enet.dec.com!sndpit.enet.dec.com!smith@decwrl.dec.com Subject: ATV: AM or FM To: info-hams@ucsd.edu In article <1991Apr3.222646.9527@ux1.cso.uiuc.edu>, phil@ux1.cso.uiuc.edu (Phil Howard KA9WGN) writes... >smith@sndpit.enet.dec.com (Willie Smith) writes: >>OK, so even at small deviations (and 6 MHz bandwidths), doesn't FM win over >>AM just for greater average power? > >Not necessarily. Given that the lower frequency portions of the video >get more benefit from a constant deviation, being as the modulation index >is much higher, I'd expect that the high average power level is effectively >being dedicated unevenly, favoring the lower frequencies. >[...] OK, if I understand you correctly, this means the lowest frequencies will be at least as good as AM and the higher frequencies might be noisier, yes? If this means that my sync and monochrome stuff is going to work well but my color (and some fine detail) might be noisy, I can live with that. In fact, black and white is probably OK (though a waste of a good color camcorder :+). I can always throw more power at it, eh? >With a given drop in signal strength, AM S/N drops linearly whereas FM >drops very non-linearly, the curve of which depends on the parameters. What parameters does it depend on? Does this mean that within a certain radius of my transmitter (with an omni antenna) the signal will be good but outside that it will drop off rapidly? If so that's good, as my teleop vehicle will have a limited range and not interfere with other ATV folk far away. If anyone can do the math, I'm planning on using a color signal with no sound (giving 3.6 MHz baseband bandwidth?) on a 900 MHz FM transmitter with the deviation turned down so as to fit into a 6 MHz ATV sub-band. With transmitter power of 5 watts into a 1/4-wave whip, and the possible presence of trees and houses, what's my usable range? [Like I said, no-one knows, but hopefully I'll know soon....] >I use my spare credit cards (the ones with expire dates in 1990 and earlier) >as insulation tabs for my HT batteries. Just cut them to size and don't use >the part where the number is. That's a neat idea! Willie Smith smith@sndpit.enet.dec.com smith%sndpit.enet.dec.com@decwrl.dec.com {Usenet!Backbone}!decwrl!sndpit.enet.dec.com!smith ------------------------------ Date: 4 Apr 91 11:21:30 GMT From: sdd.hp.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!gvlf3.gvl.unisys.com!gvlv3.gvl.unisys.com!ean@ucsd.edu Subject: Boy Scout RADIO Merit Badge To: info-hams@ucsd.edu The following text is from the 1940 edition of the Boy Scouts of America Radio Merit Badge Manual: To obtain a Merit Badge for Radio, a Scout must: 1. Receive and send correctly a straight text at not less than five words (25 letters) per minute. 2. Know what, if any, licenses are required by Federal Lay for operation of: (a) a receiving station; (b) a trans- mitting station. 3. Know at least five of the most frequently used "Q" signals. Explain the meaning of each. 4. (a) Draw a wiring diagram of a complete receiving set for use on short wave with vacuum tube detector and one stage amplifier. Use correct symbols and show all essential ap- paratus, including antenna and telephones. Describe each detail of apparatus and explain briefly the use of each. (b) Using the above diagram, explain how this receiving set could be made to operate also as a miniature transmitter. 5. Construct a working receiving set and demonstrate its op- erations by receiving signals from at least ten different stations. 6. Explain how to install an antenna for use in receiving equip- ment and how to ground it properly and protect it against lightning and power wires. NOTE: The holding of an amateur operator's license and a regular amateur station license will exempt the holder from examination on all requirements above except 4(a) and (b) and 5. Such licenses must be in force at the time the Badge is awarded. +------------------------+-----------------------------------------+ ! 73 de Ed ! Just wondering, how many hams obtained ! ! W3BNR @ N3LA.PA.USA.NA ! their license through the BSA or GSA? ! +------------------------+-----------------------------------------+ ---- Ed Naratil (All standard disclaimers apply) Amateur Packet: W3BNR@N3LA.#epa.PA.USA.NA ean@gvlv3.gvl.unisys.com ------------------------------ Date: 4 Apr 91 12:56:34 GMT From: soleil!mlb.semi.harris.com!trantor.harris-atd.com!su19f!jhobson@RUTGERS.EDU Subject: Boy Scout RADIO Merit Badge To: info-hams@ucsd.edu In article <1991Apr4.112130.4496@news.gvl.unisys.com> you write: > >The following text is from the 1940 edition of the Boy Scouts of >America Radio Merit Badge Manual: > > [...] > >+------------------------+-----------------------------------------+ >! 73 de Ed ! Just wondering, how many hams obtained ! >! W3BNR @ N3LA.PA.USA.NA ! their license through the BSA or GSA? ! >+------------------------+-----------------------------------------+ I didn't earn Radio Merit Badge, but did learn Morse Code (dots and dashes) as a Boy Scout. I think it was to for First Class. Anyway, before I got too old, I decided to learn code by dits and dahs. Then got my first ham ticket. -- Harv Hobson Harris GASD WB4NPL P.O. Box 94000, M/S 101/4827 jhobson@su19f.ess.harris.com Melbourne FL 32902 407-727-6642 USA ------------------------------ Date: 4 Apr 91 09:21:00 GMT From: news-mail-gateway@ucsd.edu Subject: Can you really learn Code from tapes? To: info-hams@ucsd.edu >In article <8346@crash.cts.com>, wlup69@pro-harvest.cts.com (Rob Heins) writes: >|> >|>Seriously though, with the new Technician Class, why waste time using code >|>you're never going to use. At least, I know I won't...If I ever decide to >|>get a Ham license, (or a ham for dinner) I'm not gonna spend a lot of time >|>to learn something I'll never use. and Patrick writes *items deleted* >|> > >I'd be careful about making life-long decisions with no experience. >Let's say you decide to skip the ham dinner and get a license. Probably >it's a good bet that you'd get a Technocode. Fine. But from there on, >you'll be exposed to the ham experience and there's no telling if you'll >decide to use CW or not. and then the code people have got >you.... >-- > >>>==>PStJTT > Patrick St. Joseph Teahan Taber, KC1TD My Turn..... ============================================================================ I just can't help but to respond to this. I have been trying sense I was 10 years old to get my Ham License, I'm 34. Now that the "NEW" NO-CODE License has came into effect, I am going to get my NO-CODE with the hopes that it will inspire me to go on for my General and go further up the scale. I have tried the ARRL tapes, The tapes supplied with Heath Co's Novice Kit, Gorden Wess (sp) Tapes and some others some friends have made. It seems that once every year I get this urg to try again and again it doesn't happen. I've even set in for 6-8-and even 15 week NOVICE CLASSES given by my friends and future Ham Brothers and sisters and still I'm unable to even comeup with the required 5 wpm for novice. The Radio Theorey (sp) is easy. So I'm going to keep trying. Just wanted to get it off my chest. I don't like anybody bashing Ham Radio. No matter what shape form or fashion it is in. Wish me LUCK..... Tim Wright Future Ham. Morehead, Ky. WRIGHT@morekypr ------------------------------ Date: 4 Apr 91 12:46:01 GMT From: dog.ee.lbl.gov!ncis.tis.llnl.gov!lll-winken!elroy.jpl.nasa.gov!usc!cs.utexas.edu!bcm!lib!thesis1.hsch.utexas.edu@ucsd.edu Subject: Guide to the Personal Radio Newsgroups To: info-hams@ucsd.edu This message describes the rec.radio.amateur.*, rec.radio.cb, and rec.radio.swap newsgroups. It is intended to serve as a guide for the new reader on what to find where. Questions and comments may be directed to the author, Jay Maynard, K5ZC, by Internet electronic mail at jmaynard@thesis1.med.uth.tmc.edu. This message was last changed on 2 April 1991. History ======= Way back when, before there was a Usenet, the Internet hosted a mailing list for hams, called (appropriately enough) INFO-HAMS. Ham radio discussions were held on the mailing list, and sent to the mailboxes of those who had signed up for it. When the Usenet software was created, and net news as we now know it was developed, a newsgroup was created for hams: net.ham-radio. The mailing list and the newsgroup were gatewayed together, eventually. As the net grew, and as packet radio came into vogue, packet discussion began to dominate other topics in the group and on the list. This resulted in the logical solution: a group was created to hold the packet discussion, and another corresponding mailing list was created as well: net.ham-radio.packet and PACKET-RADIO, respectively. These two groups served for several years, and went through Usenet's Great Renaming essentially unchanged, moving from net.ham-radio[.packet] to rec.ham-radio[.packet]. Readership and volume grew with the rest of the network. The INFO-HAMS mailing list was originally run from a US Army computer at White Sands Missile Range, SIMTEL20. There were few problems with this arrangement, but one was that the system was not supposed to be used for commercial purposes. Since one of hams' favorite pastimes is swapping gear, it was natural for hams to post messages about equipment for sale to INFO-HAMS/rec.ham-radio. This ran afoul of SIMTEL20's no-commercial-use restriction, and after some argument, a group was created specifically for messages like that: rec.ham-radio.swap. This group wasn't gatewayed to a mailing list, thus avoiding problems. While all this was happening, other folks wanted to discuss other aspects of the world of radio than the personal communications services. Those folks created the rec.radio.shortwave and rec.radio.noncomm newsgroups, and established the precedent of the rec.radio.* hierarchy, which in turn reflected Usenet's overall trend toward a hierarchical name structure. The debate between proponents of a no-code ham radio license and its opponents grew fierce and voluminous in late 1989 and 1990. Eventually, both sides grew weary of the debate, and those who had not been involved even more so. A proposal for a newsgroup dedicated to licensing issues failed. A later proposal was made for a group that would cover the many recurring legal issues discussions. During discussion of the latter proposal, it became clear that it would be desirable to fit the ham radio groups under the rec.radio.* hierarchy. A full-blown reorganization was passed by Usenet voters in January 1991, leading to the structure we now use. The Current Groups ================== I can hear you asking, "OK, so this is all neat history, but what does it have to do with me now?" The answer is that the history of each group has a direct bearing on what the group is used for, and what's considered appropriate where. The easy one is rec.radio.amateur.misc. It is what rec.ham-radio was renamed to during the reorganization. Any message that's not more appropriate in one of the other groups belongs here, from contesting to DX to ragchewing on VHF to information on becoming a ham. The group rec.radio.amateur.packet is for discussions related to (surprise!) packet radio. This doesn't have to be the common two-meter AX.25 variety of packet radio, either; some of the most knowledgable folks in radio digital communications can be found here, and anything in the general area is welcome. The swap group is now rec.radio.swap. This recognizes a fact that became evident shortly after the original group was formed: Hams don't just swap ham radio gear, and other folks besides hams swap ham equipment. If you have radio equipment, or test gear, or computer stuff that hams would be interested in, here's the place. Equipment wanted postings belong here too. Discussions about the equipment generally don't; if you wish to discuss a particular posting with the buyer, email is a much better way to do it, and the other groups are the place for public discussions. The reorganization added two groups to the list, one of which is rec.radio.amateur.policy. This group was created as a place for all the discussions that seem to drag on interminably about the many rules, regulations, legalities, and policies that surround amateur radio, both existing and proposed. The neverending no-code debate goes here, as does the New Jersey scanner law, the legality of ordering a pizza on the autopatch, what a bunch of rotten no-goodniks the local frequency coordinating body is, and so on. The other added group is rec.radio.cb. This is the place for all discussion about the Citizens' Band radio service. Such discussions have been very inflammatory in rec.ham-radio in the past; please do not cross-post to both rec.radio.cb and rec.radio.amateur.* unless the topic is genuinely of interest to both hams and CBers - and very few topics are. The rec.radio.amateur.misc and .packet groups are available by Internet email in digest format; send a mail message containing "help" on a line by itself to listserv@ucsd.edu for details. A Note on Crossposting ====================== Please do not crosspost messages to two or more groups unless there is genuine interest in both groups in the topic being discussed, and when you do, please include a header line of the form "Followup-To: group.name" in your article's headers (before the first blank line). This will cause followups to your article to go to the group listed in the Followup-To: line. If you wish to have replies to go to you by email, rather than be posted, use the word "poster" instead of the name of a group. Such a line appears in the headers of this article. -- Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can jmaynard@thesis1.med.uth.tmc.edu | adequately be explained by stupidity. "You can even run GNUemacs under X-windows without paging if you allow about 32MB per user." -- Bill Davidsen "Oink!" -- me ------------------------------ Date: 4 Apr 91 13:48:56 GMT From: genrad!dls@husc6.harvard.edu Subject: HF rig names? To: info-hams@ucsd.edu Hi, I need to get names of popular (and not so popular) HF rigs. I pulled out the HRO catalog and got some already, listed below. Anyone else got other suggestions I may have missed? Email me if you do. THANKS! Transceivers: ICOM IC781, IC725, IC726, IC765, IC735, IC751A Kenwood TS950SD, TS940S, TS440S, TS140S, TS6805 TenTec OMNI V562, Paragon 585, Argonaut II 535, Delta II 536 Yaesu FT1000D, FT1000, FT767GX, FT757GX Mark II, FT650, FT747GX Transmitters: NONE LISTED....do hams only buy transceivers, not transmitters? Receivers: ICOM R9000, R7000, R71A Kenwood R2000, R5000 Yaesu FRG8800 Other than short wave listening, what function do receivers serve if there are no transmitters to go along with them? Do hams use a transceiver AND a separate receiver? ->Diana L. Syriac dls@genrad.com Ham: KC1SP (Sweet Pea) <- ->I'D RATHER BE FLYING! P-ASEL, INST CAP: 1LT, Freedom 690 Mobile<- ->GenRad AD ASTRA, PER ASPERA <- ->MS/6, 300 Baker Ave, Concord, Mass. 01742 (508) 369-4400 x2459 <- ------------------------------ Date: 4 Apr 91 13:01:40 GMT From: news-mail-gateway@ucsd.edu Subject: IAMBIC keyer - What does IAMBIC mean? To: info-hams@ucsd.edu Ted, An "Iamb" is a rhythmic/poetic structure where the first syllable is unstressed and the second is stressed, sort of like ta-DUM. To whit: To be or not to be... ta DUM ta DUM ta DUM or, if you prefer diDAH diDAH diDAH If you hold both paddles in on an iambic keyer, you will get a continuous stream of diDAHdiDAHdiDAH... --Charlie Ross, NC1N rossjr@gtec3.gte.com NC1N @ WA1PHY nc1n@nc1n.ampr.org ------------------------------ Date: 4 Apr 91 13:14:00 GMT From: news-mail-gateway@ucsd.edu Subject: IAMBIC keyer - What does IAMBIC mean? To: info-hams@ucsd.edu > Subject: IAMBIC keyer - What does IAMBIC mean? > To: info-hams@ucsd.edu > > The subject tells it all. And Webster says it all: iamb - a metrical foot consisting of one short syllable followed by one long syllable ... iam.bic - adj or n An iambic keyer will send automatic dits when you push the paddle in one direction, and automatic dahs in the other direction. BUT...when you depress BOTH paddles (squeeze), you get alternating dits and dahs, the first character being a dit or a dah depending on which paddle connected first. THEN...when you release the paddles, the keyer completes the character it was making at that time, AND THEN sends the opposite character. If it is forming a dit when you release the paddles, it will complete that dit and then send a dah. You use this feature in iambic keying. Say you want to send an "F". Push the paddle to the right (most keyers are set up for dits to the right) and the keyer will start sending a string of dits. As the second dit is forming, squeeze the other paddle to the left. Since both paddles are now connected, the keyer goes into the alternating dit/dah mode and therefore next forms a dah. As soon as the dah begins, let go. The dah will complete and will be follwed by a dit: dit-dit-dah-dit. Voila: "F". In practice, you depress the dit paddle, tap the dah paddle, and let go: "F". That's only two motions of the wrist (or fingers) versus three motions with a straight, non-iambic keyer, where you have to go back and form the final dit. Your timing varies these things for the other characters. steve - W3GRG ------------------------------ Date: 3 Apr 91 00:35:01 GMT From: hpcc05!hpldsla!bruno@hplabs.hpl.hp.com Subject: KNWD TS-430S PROBLEM/SOLUTION To: info-hams@ucsd.edu Re: My TS430S intermiten power output problem has been solved. First I would like to thank to all of you (23) who responded to my note of last month. Simply I was overwhelmed by the support and stream of notes pouring in. Another testimony that HAMS are true friends helping each other. In summary following was the distribution of problems/solutions: Mike connection (1 case) Dead MOSFET (1) Final POWER TRANSISTOR (2) RY in the RF filter deck (2) Bad feedthrou rivets on PA BD (3) Bad/coroded conntact (14) WELL, it didn't take a genius to make the decesion whot to try first! After disassembly and reassembly of power module connectors to the main unit I am running the unit on dummy load for 10 days without failure. NOW everybody in the club tells me that the standard procedures with any of " modern technology " ham gear is to reconnect every and each connector every 3 to 5 years. Thanks again & 73 de AA6AD ------------------------------ Date: 4 Apr 91 13:57:49 GMT From: fs7.ece.cmu.edu!o.gp.cs.cmu.edu!andrew.cmu.edu!paul+@sei.cmu.edu Subject: RG8U To: info-hams@ucsd.edu I SURE DID! I connected up to RG8U.DUMMY.LOAD.BELDEN_CONGO.AF.? The packet connection was sort of erratic and BRAIDED. Belden mentioned to me that the WX was sort of nasty in the Coaxial Islands that day, so he slipped on his NON-CONTAMINATING jacket. His wife Dialectric had been threatning to TERMINATE their relationship on a 1:1 basis. She claimed that he REFLECTED too much on the past and was BRIDGING the gap between their marrage and his ham carreer, but thats another LINE all together. Belden bid me a hearty 73 and said he had to disconnect since his ATTENUATION span had been growing short lately ( due, no doubt to his marital problems with dialectric). As the last disconnect packet slithered it's way into my TNC, I thought: "What a SILVER PLATED opportunity this had been". [had enough yet?] 73 \paul WA3TLD ------------------------------ Date: 4 Apr 91 15:09:37 GMT From: usc!zaphod.mps.ohio-state.edu!caen!news.cs.indiana.edu!att!cbnewsh!nd2k@ucsd.edu Subject: RG8U To: info-hams@ucsd.edu >Did anyone manage to work Belden, RG8U, during his DXpedition to the Coaxial >Islands on April 1? > > >Todd, KB6JXT >>Hmm, I thought RG8U was in the Belden Congo. Has the ITU reassigned >>the prefix? >> >>Phil The Coaxial Islands are part of the Belden Congo, an attempt was made to get seperate DXCC country status, but these efforts were attenuated by the DXCC advisory committee. Al Schwarz ND2K honet4!nd2k ------------------------------ Date: 4 Apr 91 16:13:11 GMT From: news.larc.nasa.gov!grissom.larc.nasa.gov!kludge@uunet.uu.net Subject: RG8U To: info-hams@ucsd.edu In article <20360005@hplsla.HP.COM> charlier@hplsla.HP.COM (Charlie Panek) writes: >>in rec.radio.amateur.misc / tjonz@caliban.Sun.COM (Todd Jonz, KB6JXT) sez: >>Did anyone manage to work Belden, RG8U, during his DXpedition to the Coaxial >>Islands on April 1? >> > Yeah, I worked him in the Poisson d'Avril contest.... Didn't you? > Anyone got a QSL route? He hasn't been replying to QSL requests because he's been grounded for the last couple of weeks. With any luck though, he should be back on the air with a new linear because he's got a lot to gain. --scott ------------------------------ Date: 4 Apr 91 16:15:24 GMT From: sdd.hp.com!uakari.primate.wisc.edu!news.larc.nasa.gov!grissom.larc.nasa.gov!kludge@ucsd.edu Subject: RG8U To: info-hams@ucsd.edu In article <20360005@hplsla.HP.COM> charlier@hplsla.HP.COM (Charlie Panek) writes: >>in rec.radio.amateur.misc / tjonz@caliban.Sun.COM (Todd Jonz, KB6JXT) sez: >>Did anyone manage to work Belden, RG8U, during his DXpedition to the Coaxial >>Islands on April 1? >> > Yeah, I worked him in the Poisson d'Avril contest.... Didn't you? > Anyone got a QSL route? He hasn't been replying to QSL requests because he's been grounded for the last couple of weeks. He's also been off the air since coming back from the Islands. With any luck though, he should be back with a new linear because he's got a lot to gain. --scott ------------------------------ Date: 4 Apr 91 15:05:21 GMT From: news-mail-gateway@ucsd.edu Subject: Ultrasonics. To: info-hams@ucsd.edu I know of someone who once made an ultrasonic down-converter and hooked it to a number of different ultrasonic transducers (the sort you get from doppler burglar-alarms). Apart from hearing people with the usual garage door openers, TV remotes etc, he discovered a new one; BATS! They could be heard quite clearly, with a 'fluttery' swept signal. It was quite fun to stand outside a cave known to contain bats, with the 'Batphone' on, and listen to the clicks as the bats were waking up for their evenings hunting, then the intensifying noise as they got ready for flight. I guess anyone experimenting with high-power ultrasonics might run the risk of causing temporary or permanent deafness in their local bat population! Pete Lucas PJML@UK.AC.NWL.IA G6WBJ@GB7SDN.GBR.EU ------------------------------ Date: 4 Apr 91 16:43:09 GMT From: sdd.hp.com!caen!math.lsa.umich.edu!spsd4360a.erim.org!hideg@ucsd.edu Subject: Ultrasonics. To: info-hams@ucsd.edu In article <04.Apr.91.16:07:10.BST.#3428@UK.AC.NWL.IA> PJML@ibma.nerc-wallingford.ac.UK (Pete Lucas, NCS-TLC, Holbrook House, Swindon) writes: > I know of someone who once made an ultrasonic down-converter and hooked it > to a number of different ultrasonic transducers (the sort you get from > doppler burglar-alarms). I think there was an article in one of the U.S. electronics magazines about building such a device. > I guess anyone experimenting with high-power ultrasonics might run the risk > of causing temporary or permanent deafness in their local bat population! The Heath Company now sells a device called the Dazer, that transmits an audio (tone?) at a frequency that only dogs can hear. It supposedly "stops dogs in their tracks". Is this a myth? What frequency does it transmit on? ____________________________________ Steve Hideg N8HSC hideg@spsd4360a.erim.org ------------------------------ End of Info-Hams Digest ******************************