++++++++++++++++ Date: Thu, 1 Aug 2002 09:53:47 -0400 (EDT) From: kc4kgu at EnterZone.Net To: DHK2BOB at aol.com Cc: elecraft at mailman.qth.net Subject: [Elecraft] Motorola communications speakers On Thu, 1 Aug 2002 DHK2BOB at aol.com wrote: > Would everyone agree that an external speaker will provide more than enough > volume in any situation? I picked up a Motorola external speaker at a > hamfest (probably ripped out of a police car some place) and I get ear > splitting volume from the K2 and even from the tiny Kenwood THF6a HT. I find > that audio amps often provide plenty of power and it is just the speaker that > isn't delivering to the ears. 73, > Bob WB2DHK There is, BAR NONE, no finer communications speaker in the world than the Motorola. I have several of them in service in my vehicles. I have one very old one (It weighs about 3-lbs and is in an original metal case vs the new plastic cased ones) that I use as an external PA speaker. With the TM-D700A, I can drive it (volume at 1 o'clock) loud enough to hear inside a store (plainly) when the vehicle is in the parking lot. We're talking about make-your-ears-bleed, mind-melting volume. These are 6" (I believe) 4-ohm speakers though. They are designed to be audible with a 460 cubic inch police interceptor turning 6000RPM at 140Mph, window down, siren on. 73 de John - KC4KGU K2/100 #2490 ++++++++++++++++ Date: Thu, 01 Aug 2002 10:00:15 -0500 To: kc4kgu at EnterZone.Net, DHK2BOB at aol.com From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Motorola communications speakers Cc: elecraft at mailman.qth.net John - KC4KGU wrote: >There is, BAR NONE, no finer communications speaker in the world than the >Motorola. I have several of them in service in my vehicles. I have one -- snip -- I went one better (I think). I found a couple of the new(er) AMPLIFIED Motorola speakers...! Dunno how much they'll put out (I'd guess 5W-8W), but they 'crank'! I drive mine from the K2's SPKR output and power it from the 3A supply used for the K2. VERY good quality audio, and (finally) enough of it... esp. when I'm giving a demo of the K2 at a hamfest or a radio club meeting. These speakers can be found for $15-$20 at hamfests, and are worth every penny. They DO require a bit of rewiring of the connector, but this is not significant and can be easily performed by anyone whose built a K1 or a K2. 73, Tom Hammond N0SS +++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] Motorola communications speakers Date: Thu, 1 Aug 2002 09:16:15 -0700 I went one better (I think). I found a couple of the new(er) AMPLIFIED Motorola speakers...! Dunno how much they'll put out (I'd guess 5W-8W), but they 'crank'! Tom Hammond N0SS ---------------- When I worked on that gear in the 1980's, Motorola (and their nemesis in Land Mobile, E. F. Johnson) had speakers with a very pronounced peak at about 800 Hz. The audio response up around 2 kHz was darn near 'nil, to minimize the sound of the digital subcarrier on the "trunking" radio systems that tended to peak up around there. Similarly the low end rolled off very quickly down around 300 Hz. Their response was very close to what Wayne/Eric say they designed the K2's SSB filter to provide. And they do provide incredible punch in very noisy environments (ambulances, etc.). They were GREAT for what they were designed to do - provide maximum clarity of speech for brief verbal communications under adverse conditions. Personally, I always found their audio characteristics irritating to listen to over time with that obvious peak in the response, but then I never went to a rock concert either and I avoid modern movie theatres. >From what I read, the hearing of people under 30 today is substantially worse than that of many older people. As one doctor pointed out to me recently, it used to be "grandpa" who wore a hearing aid. Now he fits them on more people under 40 than he does people over 60, and he said that was just the "tip of the iceberg". For every case needing an aid, there are thousands living with damaged hearing who have learned to compensate for it and don't even realize that they are half deaf. Wow... Ron AC7AC K2 # 1289 +++++++++++++++ From: "Mike McCoy" To: Cc: Subject: Re: [Elecraft] K2 volume Date: Thu, 1 Aug 2002 11:28:05 -0500 Easy, Check eBay. I picked up a nice tan (to match my car interior) NOS one for $12 for a mobile VHF rig. For example: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1370362494 or for the amplified version (unnecessary IMHO) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1369173924 Mike - AD5IU > Bob - I believe I know the speaker you are talking about. Does anyone know > where I can locate a Motorola comm speaker? I saw one do wonders on a rig once. > 73/Tim NZ7C +++++++++++++++ From: "Milt Jensen" To: , Cc: Subject: Re: [Elecraft] K2 volume Date: Thu, 1 Aug 2002 14:38:07 -0700 I have used them for years on my HF, VHF and UHF radios in the mobile environment and in the home stations. I concur with the statements already posted. You can check with your local 2-way shops for surplus speakers. Or you can usually get them for $5-$10 at locations such as http://www.air-comm.com/ http://members.aol.com/cwwolfecom/ Lots of 2-way dealers go to the ham fests to unload their older, less commercially saleable equipment. All the older trunk mount radios had the external speakers as part of their accessory group. Don't pass by the GE, RCA, Johnson, Standard, etc. speakers as they are in the same class as the Motorola. There are many other similar sources. 73 de Milt, N5IA +++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] Motorola Speaker VS Bookshelf Speaker ? Date: Sun, 4 Aug 2002 11:27:21 -0500 Hi This is why I think a PA speaker would be the best choice. Not the outdoo= r horn speakers but the indoor type that are mounted in a simple box or t= he ceiling. This type of speaker is designed for voice frequencies and lo= w power with a lot of punch to get your attention. They are usually stiff= cone short throw with small magnets. The common HiFi speaker is a long t= hrow with a huge magnet so it can move enough air at low frequencies. Jus= t the opposite design goal. =20 The Motorola speaker is fine for what it does best but may not be the bes= t choice for the shack. Don Brown KD5NDB =20 ----- Original Message ----- From: Bob Lewis (AA4PB) Sent: Sunday, August 04, 2002 10:53 AM To: elecraft at mailman.qth.net Subject: Re: [Elecraft] Motorola Speaker VS Bookshelf Speaker ? I think in general, flat frequency response and efficiency are at odds with each other when it comes to speakers. The better the frequency response, the more power it takes to drive it. Since the frequency response of a SSB receiver is limited to about 300 to 3000 Hz, there's not much benefit in having a speaker with a range of 20 Hz to 20,000 Hz. A wide range speaker can be a detriment since it may reproduce the hum, noises, and pops that are not heard with a communications type speaker. ++++++++++++++++ Date: Mon, 05 Aug 2002 08:06:57 -0500 From: Mike To: kc4kgu at EnterZone.Net Cc: R Hirst , elecraft at mailman.qth.net Subject: Re: [Elecraft] Speakers kc4kgu at EnterZone.Net wrote: > On Sun, 4 Aug 2002, R Hirst wrote: > >> I have used the MFJ 281 speaker for a number of years on various >> rigs and had good audio quality with both CW and SSB signals. > > Lets see: $12.00 for a "Made from Junk" speaker. (I *hate* that > company!!!) I've never understood the animosity some have towards MFJ. When one considers the very reasonable prices, MFJ generally offers a good product. I've not been happy with *everything* I bought from them, I've not liked their tendency to omit schematics from the manuals for the more complex items they offer, and I've found them to be very erratic in providing tech support via e-mail (but great by phone). The speaker in question, the MFJ-281, is sometimes sold for less than $10 at hamfests. I've found it to be the best speaker *for the money* that I've ever used (I've got five of them, for my mobile, fixed, and portable stations). Yes, I've used some old Motorala and other two-way radio speakers on my rigs over the last 35 years, but today I'll take the MFJ. A good recommendation, Rowland! 73, Mike / KK5F +++++++++++++++++ Date: Mon, 05 Aug 2002 09:35:29 -0400 From: "Mark J. Dulcey" To: elecraft at mailman.qth.net Subject: Re: [Elecraft] Speakers I've been thinking that a forward-facing speaker might be a nice addition to my separated KPA100. When the KAT100 comes out, and I find out how much room (if any) is left in the box after installing that, it will be time to think about it. +++++++++++++++++ Date: Mon, 05 Aug 2002 16:01:06 -0400 From: JimWMiller at aol.com To: elecraft at mailman.qth.net Subject: [Elecraft] Motorola Speaker: Where to Buy for $14.95 Motorola Speakers have are very efficient and are supposed work very well with the K2. They are available for $14.95 as follows: http://www.hosfeltelectronics.com/ 1-888-264-6464 Motorola External Remote Mount Speaker: Mfg. # HSN4024A 73, Jim WA2UMP K2:2679 +++++++++++++++++++ From: "Stuart Rohre" To: "Don Brown" , "Elecraft" Subject: Re: [Elecraft] Motorola Speaker VS Bookshelf Speaker ? Date: Mon, 5 Aug 2002 16:35:51 -0500 I believe, the Motorola, RCA and GE mobile speakers were optimized to the voice band in a high noise police car environment. That makes them a good ham band speaker. Probably have a pretty good magnet on them, to move the cone for good efficiency in an open window car. 73, Stuart K5KVH +++++++++++++++++++ Date: Fri, 09 Aug 2002 18:39:48 -0500 To: elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] Wiring docs for Motorola Amplified Speakers Folks: I've received several requests for my wiring info on Motorola (Plastic-Cased) Amplified Spearers. Instead of sending a number of individual files, I have now placed the data (in PDF format) on the DOWNLOAD page of my web site at: http://home.earthlink.net/~n0ss When you get to this page, drop down to the bottom of the page and click on the DOWNLOAD page. Then drop down to the last enter under "General QRP-related 'stuff'..." and you'll find the file listed there. By the way, I've reqorked the power/audio wiring of my Motorola speakers and eliminated all the connectors and extraneous wiring. Now I have only a 2-conductor (shielded) line going to the speaker. If anyone wants this mod, it'll take me a short while to write it up, but I'll be happy to do it for ya'. Enjoy. 73, Tom Hammond N0SS ++++++++++++++++++ From: "Art Horne" To: "Weymouth Walker" , "Elecraft Reflector" Subject: RE: [Elecraft] Motorola Amplified Speakers ... Date: Sat, 10 Aug 2002 12:05:21 -0700 Success at last! While this info wasn't exactly for my speaker it got me there. The key was the green wire. I don't have a yellow wire but if I connect the Red, Orange, and Green wire to +13.8v and connect the Brown, and Black wires to GND, and bring in the audio on the White wire it works great. I have a Blue wire left over that I don't have a clue as to it's purpose. I did attenuate the audo input by a facctor of two as I could just barely turn up the volume from minimum before it was too loud. It does seem to work as advertised and looks nice too. Thanks to all who helped provide this information. 73's Art K6KFH > -----Original Message----- > From: elecraft-admin at mailman.qth.net > [mailto:elecraft-admin at mailman.qth.net]On Behalf Of Weymouth Walker > Sent: Saturday, August 10, 2002 9:18 AM > To: Elecraft Reflector > Subject: [Elecraft] Motorola Amplified Speakers ... > Importance: High > > > I cannot find my Motorola Amplified Speaker > (which had documentation with it!), but I did > find this text on a discussion board ... > > I HAVE NO IDEA IF THIS IS CORRECT OR NOT! > > 73 de K8EAB in Georgia ... > ====================================== > > Red, yellow, and green wires connect to +13.8v. Black and white > wires connect to ground. Brown is audio signal + and the shield > is audio signal - (ground). Power and signal grounds should be > connected together at the end of the cable opposite the speaker. > > The green wire operates the mute circuit, which mutes the amp > when switched to ground and turns the amp on when supplied with > any voltage greater then a few volts. Connecting the green wire > to +13.8v keeps the speaker on whenever power is applied. ++++++++++++++++++