Article: 97092 of rec.radio.amateur.homebrew Message-ID: <4436989f$0$3893$91cee783@newsreader01.highway.telekom.at> From: Heinz Schnait Subject: Re: Plexi, Lexan or ??? Date: Fri, 07 Apr 2006 18:35:28 +0200 References: Rick Mintz wrote: > I could use some help in choosing the material, such as Plexi or Lexan. Hi Rick, Lexan has a higher melting point than Plexi. Therefore it's easier to drill or cut. Plexi tends to stick to the drill bit once it becomes hot. Lexan is more robust from a mechanical point of view, while Plexi tends to break. So if you have both available I think Lexan is the better choice. 73 Heinz, OE5EEP Article: 97093 of rec.radio.amateur.homebrew From: - exray - Subject: Re: Plexi, Lexan or ??? Date: Fri, 07 Apr 2006 13:07:00 -0400 Message-ID: <123d71rdq3apq5f@corp.supernews.com> References: Rick Mintz wrote: > Hi. > > I am building an amp and will be using a clear plastic over the front panel > graphics. > > I could use some help in choosing the material, such as Plexi or Lexan. > Since I will be drilling couple of 2" holes to mount panel meters, I need > some suggestions for which material is the best to work with. A hole saw in > Plexi is prone to crack and maybe there is a better choice. There also may > be a better method for creating the holes than a standard hole saw. > Suggestions??? > > de Rick W1TY > > Email: Rmintz@Rochester.rr.com > > In my experience...Lexan is much less prone to cracking but on the other hand it seems like the surface of Lexan scratches much easier than Plexiglass. A wipe with a dry cloth or paper towel will leave a 'smudge If you're gonna use a fairly thin plastic, say 1/8th, I think you'd be ok with plexi and thats what I would use personally because of that reason primarily. Some of the cheapo hole cutters can be rather crude to work with but if you take it slow you should be ok. Article: 97094 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: ECG736 or NTE736 Date: Fri, 07 Apr 2006 13:14:06 -0400 Message-ID: References: <1144344701.254899.208940@z34g2000cwc.googlegroups.com> In article <1144344701.254899.208940@z34g2000cwc.googlegroups.com>, pdrunen@aol.com wrote: > I been searching the net for the specification on the ECG/NTE 736 which > is an FM gain block 8-pin dip. > > I have an old ECG catalog which gives me the pin out, I have tried the > NTE website which does not have a downloadable spec sheet. > > If you have a spec sheet, would like to get a copy. KJ4UO- If you don't find one, I suggest you "reverse look up" the original part number. (Could it be a Fairchild uA736? A National Semiconductor LM736?) In other words, you may have better luck finding a data sheet for the original manufacturer's part, and trusting that the ECG/NTE part meets the same specs. 73, Fred, K4DII Article: 97095 of rec.radio.amateur.homebrew From: "James Thompson" References: <1144344552.349256.25410@e56g2000cwe.googlegroups.com> Subject: Re: Radio-Electronics Sept 89 Date: Fri, 7 Apr 2006 14:29:34 -0400 Message-ID: <947e0$4436af92$438c8615$24445@ALLTEL.NET> "jack" wrote in message news:p-ednclHqeA2-qvZRVn-tA@comcast.com... >I have it, will scan it today. > > Jack > > wrote in message > news:1144344552.349256.25410@e56g2000cwe.googlegroups.com... >> Hi All, >> >> I am looking for a spectrum monitor article, part 1 which appears in RE >> Sept 89. >> If you have the issues, would like to get a copy of this article, >> either scanned or otherwise. >> >> de KJ4UO >> > > I want that one too. I have the second part of that , oct 89. Let me know where you have that scan. Thanks.. Article: 97096 of rec.radio.amateur.homebrew From: Ted Subject: Re: Plexi, Lexan or ??? Message-ID: References: <4436989f$0$3893$91cee783@newsreader01.highway.telekom.at> Date: Fri, 07 Apr 2006 14:50:19 -0400 Lexan, being polycarbonate, is much tougher than Plexiglass, which is acrylic. Ploycarbonate is used in everything from RC car bodies to soft drink bottles to bullet-resistant windows in aircraft. Ted Article: 97097 of rec.radio.amateur.homebrew From: "James Thompson" References: <1144344552.349256.25410@e56g2000cwe.googlegroups.com> Subject: Re: Radio-Electronics Sept 89 Date: Fri, 7 Apr 2006 14:59:39 -0400 Message-ID: On the subject of electronics mags: Does anyone still publish any for the experimenter or is that all in the past? Jtt (k4fhuf). Article: 97098 of rec.radio.amateur.homebrew From: "James Thompson" References: Subject: Re: Plexi, Lexan or ??? Date: Fri, 7 Apr 2006 15:15:05 -0400 Message-ID: "Rick Mintz" wrote in message news:aMtZf.40370$Da7.3033@twister.nyroc.rr.com... > Hi. > > I am building an amp and will be using a clear plastic over the front > panel graphics. > > I could use some help in choosing the material, such as Plexi or Lexan. > Since I will be drilling couple of 2" holes to mount panel meters, I need > some suggestions for which material is the best to work with. A hole saw > in Plexi is prone to crack and maybe there is a better choice. There also > may be a better method for creating the holes than a standard hole saw. > Suggestions??? > > de Rick W1TY > > Email: Rmintz@Rochester.rr.com > > Why not just use acetate sheet to cover the panel. Like what is used with overhead projectors. If it is just to protect the graphics and not for mechanical strength that is. Jtt. Article: 97099 of rec.radio.amateur.homebrew From: Silfax Subject: Re: Plexi, Lexan or ??? References: Message-ID: Date: Fri, 07 Apr 2006 19:48:03 GMT On 2006-04-07, James Thompson wrote: > Why not just use acetate sheet to cover the panel. Like what is used with > overhead projectors. If it is just to protect the graphics and not for > mechanical strength that is. Jtt. > or just put a good coat of clear lacquer over the front panel graphics When I have needed to cut holes in plexi in the past, I always created a plywood / plexiglass sandwich. Just place the plexiglas betewwn two thin sheets of plywood and drill thru the whole thing with a hole saw. On the other hand, you could just mount the plexiglass on top of the meters, this would protect the meter faces from scratches also. This way, you only need to drill holes for switches and knob shafts. Article: 97100 of rec.radio.amateur.homebrew From: "Alex" Subject: IC756/TL922 keying - Any Suggestion? Message-ID: <27AZf.72889$A83.1739689@twister1.libero.it> Date: Fri, 07 Apr 2006 20:40:30 GMT Hi, i'm searching a simply amp keying circuit, just to control a Kenwood TL922 with an ICOM IC 756 Pro III. What do you suggest to me? 73 de Alex ik8xir Article: 97101 of rec.radio.amateur.homebrew From: "john graesser" Subject: Re: Plexi, Lexan or ??? Date: Fri, 7 Apr 2006 16:15:05 -0500 Message-ID: <123dlf5rudmnu81@corp.supernews.com> References: "Rick Mintz" wrote in message news:aMtZf.40370$Da7.3033@twister.nyroc.rr.com... > Hi. > > I am building an amp and will be using a clear plastic over the front panel > graphics. > > I could use some help in choosing the material, such as Plexi or Lexan. > Since I will be drilling couple of 2" holes to mount panel meters, I need > some suggestions for which material is the best to work with. A hole saw in > Plexi is prone to crack and maybe there is a better choice. There also may > be a better method for creating the holes than a standard hole saw. > Suggestions??? > > de Rick W1TY I seem to recall someone mentioning in the past that glass can be drilled if it was kept in a bath of kerosene, and drilled while submerged. thanks, John. KC5DWD Article: 97102 of rec.radio.amateur.homebrew From: Butch Magee Subject: penetrating glass with rf Date: Fri, 07 Apr 2006 18:28:22 -0500 Message-ID: <123dtcnd0ul0tff@corp.supernews.com> Depress the PTT, then just chatter away with mouth 3-4 inches away from mike If this doesn't penetrate the glass,.....check the battery. This should make it through the window pane, however, in the event it doesn't make it through put a through-the-glass-connector on, this capacitive mount outa do it, however, ife'n it don't, shoot it with (the radio) a .22 calibre / caliber (spl chk lists both, I have a very expensive spel chk or a very cheap one that really doesn't know how to spell calibre anyway)pistol which should should disable the broken little piece of crap. If RF made it through before the .22 killed it (if in fact it actually did)load up a 44 magnum 180 grain hydroshock bullita, TexMex pronunciation, be carefull with this one, it'l hurt 'ya big time. Be sure to place this shell into a 44 calibre/caliber fram designed for this shell Like I shoulda said before (this is the disclaimer) you cannot just put the 44 shell in just any 44 frame, ....now shoot the window this time, it should pass rf, if not you probably killed a perfectly good transceiver because you didn't know whut you were doing. Sorry 'bout that rig man! Butch KF5DE Article: 97103 of rec.radio.amateur.homebrew From: Butch Magee Subject: cover sheet Date: Fri, 07 Apr 2006 18:30:56 -0500 Message-ID: <123dthgpefurm79@corp.supernews.com> Use some of that glass that McAlhoun likes so much. Butch Article: 97104 of rec.radio.amateur.homebrew Message-ID: <4437400F.4B7681C4@earthlink.net> From: "Michael A. Terrell" Subject: Re: ECG736 or NTE736 References: <1144344701.254899.208940@z34g2000cwc.googlegroups.com> Date: Sat, 08 Apr 2006 04:46:37 GMT Fred McKenzie wrote: > > In article <1144344701.254899.208940@z34g2000cwc.googlegroups.com>, > pdrunen@aol.com wrote: > > > I been searching the net for the specification on the ECG/NTE 736 which > > is an FM gain block 8-pin dip. > > > > I have an old ECG catalog which gives me the pin out, I have tried the > > NTE website which does not have a downloadable spec sheet. > > > > If you have a spec sheet, would like to get a copy. > > KJ4UO- > > If you don't find one, I suggest you "reverse look up" the original part > number. (Could it be a Fairchild uA736? A National Semiconductor LM736?) > > In other words, you may have better luck finding a data sheet for the > original manufacturer's part, and trusting that the ECG/NTE part meets the > same specs. > > 73, Fred, K4DII ECG published a set of three databooks about 20 years ago that covered their current product line. My set disappeared about 15 years ago. You might want to keep an eye out for a set of them. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida Article: 97105 of rec.radio.amateur.homebrew From: "Sal M. Onella" References: Subject: Re: How get RF through a sealed window? Message-ID: Date: Fri, 7 Apr 2006 22:19:11 -0700 wrote in message news:e13e9u$q3u@unix1.cc.ksu.edu... > I gave a presentation on "How Ham Radio Can Help You in an Emergency" > to 70 Emergency Management types last week, and the windows in the > building which hosted the meeting were NOT open-able (so I "made do" > with an inside VHF antenna and didn't even try to demonstrate HF). > > But in emergency/expedient situations, it would be really handy if one > could pass at HF, say, 100 watts of RF energy through a window (I > visualize some foil strips and an inductor or two to "tune out" the > capacitance) to an external antenna. > > I've been told that the April, 1989, issue of Ham Radio magazine carried > an article "Easy antenna access for urban apartment dwellers" (for 15 > meters) by Bryan Bergeron, NU1N, starting on page 18. > > I'd sure like to read that article; can anyone send me a copy? > -- > --Myron A. Calhoun. > Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge > PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 > NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) I have drilled a hole in a window frame and passed a piece of RG-58 through it. A 2M rig in my den is that way right now. It's easier to justify doing it to your own home than to a place you're visiting Article: 97106 of rec.radio.amateur.homebrew Message-ID: <4437659c$0$12941$91cee783@newsreader02.highway.telekom.at> From: Heinz Schnait Subject: Re: Plexi, Lexan or ??? Date: Sat, 08 Apr 2006 09:05:02 +0200 References: <123dlf5rudmnu81@corp.supernews.com> john graesser wrote: > I seem to recall someone mentioning in the past that glass can be drilled > if it was kept in a bath of kerosene, and drilled while submerged. > thanks, John. > KC5DWD Keep a fire extinguisher ready, when you do this! I would not dare... 73 Heinz, OE5EEP Article: 97107 of rec.radio.amateur.homebrew From: "John, N9JG" References: <123dlf5rudmnu81@corp.supernews.com> <4437659c$0$12941$91cee783@newsreader02.highway.telekom.at> Subject: Re: Plexi, Lexan or ??? Message-ID: <9kQZf.87872$oL.68530@attbi_s71> Date: Sat, 08 Apr 2006 15:06:45 GMT No, you don't keep it in a "bath" of kerosene. Just take an eyedropper containing kerosene and put a few drops right where the drill contacts the glass. Replenish as needed. "Heinz Schnait" wrote in message news:4437659c$0$12941$91cee783@newsreader02.highway.telekom.at... > john graesser wrote: > >> I seem to recall someone mentioning in the past that glass can be drilled >> if it was kept in a bath of kerosene, and drilled while submerged. >> thanks, John. >> KC5DWD > > Keep a fire extinguisher ready, when you do this! I would not dare... > > 73 Heinz, OE5EEP > Article: 97108 of rec.radio.amateur.homebrew From: TomJ Subject: Re: Plexi, Lexan or ??? Message-ID: <6tpf32hvo19dkhmldpk75t75hj61sb90g6@4ax.com> References: Date: Sat, 08 Apr 2006 11:41:16 -0500 On Fri, 07 Apr 2006 13:26:30 GMT, "Rick Mintz" wrote: >Hi. > >I am building an amp and will be using a clear plastic over the front panel >graphics. > >I could use some help in choosing the material, such as Plexi or Lexan. >Since I will be drilling couple of 2" holes to mount panel meters, I need >some suggestions for which material is the best to work with. A hole saw in >Plexi is prone to crack and maybe there is a better choice. There also may >be a better method for creating the holes than a standard hole saw. >Suggestions??? > >de Rick W1TY > >Email: Rmintz@Rochester.rr.com > Hi Rick, All the Lexan I've seen has been sort of green. Thicker = darker. However, I've done a lot of cutting and drilling Plexi. Do not remove protective covering until all holes are drilled. Not only protects while cutting, but easy to mark on. Mark all holes and write their size next to them to avoid mistakes. Use a DRILL PRESS and clamp the piece in place. Clamp hard so that the piece cannot move. Any chatter and/or binding will cause stress and cracking. Been there, done that. We had bitts sharpened especially for cutting Plexi but for one job and in 2" size.... $$$$ A hole saw should work but put a piece of wood under where the blade will come through. Spray the you know what out of the bitt with Windex or any glass cleaner to lubricate and cool. A lot of heat is generated while cutting/drilling. There is no such thing as "too much." If you have to cut the piece to size, use a table saw with a fence. Once you start a cut, don't stop until the cut is finished. Heat again. If you stop in the middle of a cut, heat will build up and screw up the blade. Nothing like a fine coating of plastic on the blade teeth to screw up your day. BTDT again! Same thing happens with a hand saw. Windex works here. Long sleeve shirt, eye protection are mandatory. Sharp and then hot chips are a bitch. BTDT again!!! If possible, buy the piece cut to size. They might be able to drill the 2" holes for you, or give further advice. If they can't/won't drill the holes, see if you can get a piece of scrap for a trial run. All the Plexi we used was a 1/4 inch thick. You're probably only thinking of 1/8 inch thick. Could be harder or easier to drill. Don' know. That covers the basics. It's been a few years since I've done this but I'll try to answer any ?? you might have. TomJ Article: 97109 of rec.radio.amateur.homebrew From: "sw monitor" Subject: New forum around radio and transmitters Date: Sat, 8 Apr 2006 18:35:15 +0200 Message-ID: <4437e802$0$59034$dbd41001@news.wanadoo.nl> New forum around radio and transmitters http://forum.alfalima.net/ Article: 97110 of rec.radio.amateur.homebrew From: nothermark Subject: Re: Plexi, Lexan or ??? Message-ID: References: Date: Sun, 09 Apr 2006 00:43:08 GMT On Fri, 07 Apr 2006 13:26:30 GMT, "Rick Mintz" wrote: >Hi. > >I am building an amp and will be using a clear plastic over the front panel >graphics. > >I could use some help in choosing the material, such as Plexi or Lexan. >Since I will be drilling couple of 2" holes to mount panel meters, I need >some suggestions for which material is the best to work with. A hole saw in >Plexi is prone to crack and maybe there is a better choice. There also may >be a better method for creating the holes than a standard hole saw. >Suggestions??? > >de Rick W1TY > >Email: Rmintz@Rochester.rr.com > 2 thoughts 1. If you decide to use the plastic water with a bit of detergent makes a good coolant/lubricant. Keep the cut flooded. 2. I made a lot of panel covers inthe past by laying out the panel in Autocad then flipping the drawing layer with the graphics on it to get a reverse image. I then made an overhead transparency of the graphics and used the transparency over the metal panel. The result was a clear plastic cover with the printing sandwiched against the metal panel. It worked quite nicely. You might want to consider it. Article: 97111 of rec.radio.amateur.homebrew Message-ID: <4438ACB0.4040603@nettally.com> From: **THE-RFI-EMI-GUY** Subject: Re: OT: Brain pick References: <443581C1.328877BE@visi.com> Date: Sun, 09 Apr 2006 06:39:35 GMT Whats the context of the question? I doubt there are too many new AM applications, however if you are concerned about the envelope of an emission for EMC concerns, Quadrature Amplitude Modulation (QAM) is a form which includes "AM". Also Time Division Multplex (TDMA) signals rapidly switch from an off to on state. There are also On Off Keying (OOK) schemes used by remote control key fobs and garage door openeres. Bob Liesenfeld wrote: >Hi gang, > I know there are a number of people on this list who work in 2 way and > >other RF fields. I used to, but have been out of the loop for a while >so I need your current expertise. > Specifically, I need to determine what transmitting type services >currently (or may soon) use amplitude modulation of the radiated signal >in the 80MHz to 1GHz range. In my day it was restricted to aircraft >comms in the 108MHz to 138MHz range and the video carrier of broadcast >TV. Is this still the case, or have things changed? I don't need to >know about 'closed circuit' paths such as cable TV and the like, only >services that radiate RF. > Also, if anyone has any knowledge of the general picture of frequency >allocations in the same range quoted above in Europe and Asia, I would >appreciate it. > Thanks a lot and please respond off list. > >Bob WB0POQ >wb0poq@visi.com > > > > > -- Joe Leikhim K4SAT "The RFI-EMI-GUY"© "Treason doth never prosper: what's the reason? For if it prosper, none dare call it treason." "Follow The Money" ;-P Article: 97112 of rec.radio.amateur.homebrew Subject: Any antenna and propagation programs? From: JJ Message-ID: <95955$44398f07$d135c4af$25368@MDI.CA> Date: Sun, 09 Apr 2006 18:47:35 -0400 Anything for HF to UHF propagation programs out there? thx JJ Article: 97113 of rec.radio.amateur.homebrew From: Alfred Green Subject: Re: Plexi, Lexan or ??? References: <123dlf5rudmnu81@corp.supernews.com> Message-ID: Date: Sun, 09 Apr 2006 17:32:48 -0700 john graesser enscribed: > > I seem to recall someone mentioning in the past that glass can be drilled if > it was kept in a bath of kerosene, and drilled while submerged. > thanks, John. Having the sheet of glass submerged while drilling dampens out the shock waves and helps to prevent shattering. However, I don't see what the special attraction would be for using Kerosene. Plain old water works just fine. Just make sure you use the correct type of drill bit and a nice slow cutting speed. Kerosene is not significantly more viscous than water, so if you want to really damp things out I'd use a heavy grade lube oil, maybe a 20-50 grade motor oil. Far less flammable, as well. 73 Alf NU8I Scottsdale AZ DM43an Article: 97114 of rec.radio.amateur.homebrew From: "Caveat Lector" References: <95955$44398f07$d135c4af$25368@MDI.CA> Subject: Re: Any antenna and propagation programs? Message-ID: <9Vh_f.234$bm6.167@fed1read04> Date: Sun, 9 Apr 2006 17:46:02 -0700 Try AC6V's Pages -- see URL's: http://ac6v.com/propagation.htm#PROPS AND http://ac6v.com/antsoftware.htm -- CL -- I doubt, therefore I might be ! "JJ" wrote in message news:95955$44398f07$d135c4af$25368@MDI.CA... > Anything for HF to UHF propagation programs out there? > > thx > > JJ Article: 97115 of rec.radio.amateur.homebrew From: "Bob Headrick" Subject: Re: Plexi, Lexan or ??? Date: Sun, 9 Apr 2006 23:00:36 -0700 Message-ID: <123jt4al3a23ke5@corp.supernews.com> References: <123dlf5rudmnu81@corp.supernews.com> "Alfred Green" wrote in message news:UIh_f.345$zf6.180@fed1read08... > john graesser enscribed: >> >> I seem to recall someone mentioning in the past that glass can be >> drilled if >> it was kept in a bath of kerosene, and drilled while submerged. > However, I don't see what the special attraction would be for using > Kerosene. Plain old water works just fine. Just make sure you use the > correct type of drill bit and a nice slow cutting speed. > Kerosene is not significantly more viscous than water, so if you want > to really damp things out I'd use a heavy grade lube oil, maybe a > 20-50 grade motor oil. My experience with Lexan is that oils and/or solvents will cause it to become very brittle and crack at any machined edges, including drilled holes. - Bob W7OV Article: 97116 of rec.radio.amateur.homebrew From: "Deadman Walking" References: <1144681555.714402.227210@u72g2000cwu.googlegroups.com> Subject: Re: Interested? Become a Healthy Adult Male, ("Ham", M9ZZZ) and not a Coughing Bird ("CB", H5N1) - here's the FAQ for you! Message-ID: Date: Mon, 10 Apr 2006 15:17:45 GMT Definatly lost the plot even as mixed his days up usually get this s+++e on a Friday not Monday. Article: 97117 of rec.radio.amateur.homebrew From: "Mike Andrews" Subject: Re: Plexi, Lexan or ??? Date: Mon, 10 Apr 2006 15:24:16 +0000 (UTC) Message-ID: References: <123dlf5rudmnu81@corp.supernews.com> <123jt4al3a23ke5@corp.supernews.com> Bob Headrick wrote: > "Alfred Green" wrote in message > news:UIh_f.345$zf6.180@fed1read08... >> john graesser enscribed: >>> >>> I seem to recall someone mentioning in the past that glass can be >>> drilled if >>> it was kept in a bath of kerosene, and drilled while submerged. >> However, I don't see what the special attraction would be for using >> Kerosene. Plain old water works just fine. Just make sure you use the >> correct type of drill bit and a nice slow cutting speed. >> Kerosene is not significantly more viscous than water, so if you want >> to really damp things out I'd use a heavy grade lube oil, maybe a >> 20-50 grade motor oil. > My experience with Lexan is that oils and/or solvents will cause it to > become very brittle and crack at any machined edges, including drilled > holes. The _easy_ way to drill glass is to use a piece of copper tubing with hole-size for its OD, some powered carborundum as an abrasive, and just enough water to keep it in a slurry. Use a drill press, low RPMs, and light pressure. -- Mike Andrews, W5EGO mikea@mikea.ath.cx Tired old sysadmin Article: 97118 of rec.radio.amateur.homebrew From: Roy Lewallen Subject: Re: How get RF through a sealed window? Date: Mon, 10 Apr 2006 15:04:27 -0700 Message-ID: <123lljdreeb148a@corp.supernews.com> References: <1144705641.418367.163090@i40g2000cwc.googlegroups.com> n3ox.dan@gmail.com wrote: > . . . > I think your idea with capacitative coupling with inductors to tune out > the reactance would work fine too, but I haven't tried that. > . . . If you do try that, I recommend keeping the Q as low as possible. Otherwise, voltages will get very high, and you might well end up with greater loss as well as other problems. Minimizing the Q means keeping reactance values low which in turn means making C as large as possible. This leaves you with less reactance to compensate for. In other words, don't make the C small and try to compensate for the large amount of resulting reactance. Roy Lewallen, W7EL Article: 97119 of rec.radio.amateur.homebrew From: Alfred Green Subject: Re: Plexi, Lexan or ??? References: <123dlf5rudmnu81@corp.supernews.com> <123jt4al3a23ke5@corp.supernews.com> Message-ID: Date: Mon, 10 Apr 2006 20:03:52 -0700 Bob Headrick enscribed: > >>> I seem to recall someone mentioning in the past that glass can be >>> drilled if >>> it was kept in a bath of kerosene, and drilled while submerged. > > >> However, I don't see what the special attraction would be for using >> Kerosene. Plain old water works just fine. Just make sure you use the >> correct type of drill bit and a nice slow cutting speed. >> Kerosene is not significantly more viscous than water, so if you want >> to really damp things out I'd use a heavy grade lube oil, maybe a >> 20-50 grade motor oil. > > > My experience with Lexan is that oils and/or solvents will cause it to > become very brittle and crack at any machined edges, including drilled > holes. > You could well be correct on this, as the lighter weight solvents will have a detrimental effect on the surface of Plexi, etc. I was referring to the comments related to glass, which is not affected at all by such things. 73 Alf NU8I Article: 97120 of rec.radio.amateur.homebrew Subject: Re: Any antenna and propagation programs? From: JJ References: <95955$44398f07$d135c4af$25368@MDI.CA> Message-ID: Date: Tue, 11 Apr 2006 01:07:38 -0400 > > O yes... > > For Linux? > > Try Splat. > > However, It looks like there are a lot of converted Unix > programs that now run on Linux. > > For Windooze? > It looks like many ( most actually ) are commercial > programs only. > > Cheers > > Dan / M0DFI Looks interesting. How about modelling antenna performance in arrays? JJ Article: 97121 of rec.radio.amateur.homebrew From: Allisonnospam@nouce.bellatlantic.net Subject: Re: More solid state HF amp questions Message-ID: <5n5n321pb9d8vb1fitplbmefhac15ojmgl@4ax.com> References: <1144722906.952730.211040@v46g2000cwv.googlegroups.com> Date: Tue, 11 Apr 2006 12:28:32 GMT On 10 Apr 2006 19:35:07 -0700, KC2PIH@gmail.com wrote: >Hello! > >Alright this is my second post on this subject. I appreciate all the >other responses I got. I don't think I provided enough information >about my problem before. So here it goes with everything I've got. I >picked up a HF amp that has four Motorola MRF-454 transistors in it. > >I've already determined (in theory) to make it run "clean" enough, I'll >have to build a band-switched filter bank for it. It already has a >5-element Chebyshev filter >in it and I am guessing that its tuned for 30Mhz. Also, it shouldn't be >driven over about 300 watts (output). > >Though I do still have a problem with it and this is what this post is >about. When the input power to the amp goes up, so does the SWR. I >wasn't able to test it with access to the amp's components when running >to check for components heating up (as somebody already asked about). >You can see it has some swamping resistors to reduce drive power - keep >in mind these readings are taken with all the resistors bypassed >(meaning input power to amp is not attenuated). It has a receive >pre-amp and a carrier operated relay circuit as well. > >Here is what I see: > >Configuration: >[FT-890] -> [SWR/Power Meter] -> [AMP] -> [Dummy Load] >(Power listed is the output power from the radio, driving the amp) > > >Frequency Power(input) SWR >------------------------------------------------------ >3.900 5 1.8:1 >7.200 5 1.6:1 >14.20 5 1.6:1 >21.20 5 2.7:1 >24.90 5 1.7:1 >29.99 5 1.0:1 > > >Frequency Power(input) SWR >-------------------------------------- >3.900 10 3.0:1 >7.200 10 3.0:1 >14.20 10 >3.0:1 >21.20 10 >3.0:1 >24.90 10 2.9:1 >29.99 10 1.3:1 > > >Frequency Power SWR >-------------------------------------- >3.900 15 >3.0:1 >7.200 15 >3.0:1 >14.20 15 >3.0:1 >21.20 15 >3.0:1 >24.90 15 >3.0:1 >29.99 15 1.5:0 > >SWR between the AMP and the Dummy Load is perfect in all cases (dummy >load rated to 670Mhz). Amp output power goes up as frequency goes down >(with constant drive), so I guess this amp doesn't include anytype of >network to normalize the gain of the amp across the HF band. I >actually tried a couple radios (FT-890 and the FT-100) to make sure the >radio wasn't the cause. > >A picture is worth a thousand words. Pics (1600x1200 High Resolution): > >http://www.chadgatesman.com/scott/P1010078.JPG >http://www.chadgatesman.com/scott/P1010076.JPG >http://www.chadgatesman.com/scott/P1010079.JPG >http://www.chadgatesman.com/scott/P1010080.JPG > >Thanks for reading! > >Scott, KC2PIH Ok , what you have is a 11M (yep CB) "4pill amp". Saturated power will easily hit 300W but for clean SSB stay below 280. Check Motorola EB63 and AN762 (MRF454 applications info). The design is two of the (now) classic MRF454 amp in parallel using 0 degree power splitters and combiners. The high SWR at frequencies other than near 10M refelects the design being optimized for CB (11M). Likely the power divider/combiners and the transformers in the amps them selves do not have enough ferrite in them or enough turns for lower frequency operation. Also this amp if the output mismatch is really bad it will be reflected to the input. In this case when I mean output mismatch I'm referring to the match from the transistors themselves through the transformers to the load (not a swipe at the 50 ohm load). I'd bet if you did a continuos sweep the amp from 3 to 30mhz you see power changes and all manner of bad behavour that improves as you get near or in the 25-30mhz region. The attenuator has to be there for two reasons, to allow higher drive power and also swamp out the high input SWR (design misfeature). At a bare minimum based on the picture the input attenuator will have to be 3Db to swamp the swr down to a reasonable value. While the way it was done was to allow CB power selection a "PI" ot "T" style attenuator would suppress the input SWR problem and also insure the input of the amp is loaded (keeps the amp from oscillating). One potenial reason for high SWR is a blown transistor. The alternate if you need low power drive is to create (a set) input filters (mini antenna tuners) as input matching networks for each band. You can then (for each band) tune out the input mismatch. For the basic 140W amp the max power input is in the 5W so I'd expect 12W or less for the two combined at 28mhz will drive it to near full power. The existing filter has to go if yo using band switched filters, it's likely low pass for around 28-29mhz. I'd suggest remving the output filter while testing into the dummy load and seeing how the input SWR behaves (keep under 15W!!!). If it improves withou t the filter thats a hint. As a foundation you really need to examine the amplifers operation and signal quality on the air (or better into a dummy) to insure the stability is good and there are no spurs being generated. It would also be good to study the IMD, it has the potenital to be clean but the transformers appear too small for use at lower HF. Allison Article: 97122 of rec.radio.amateur.homebrew From: "on4ahf" References: <27AZf.72889$A83.1739689@twister1.libero.it> Subject: Re: IC756/TL922 keying - Any Suggestion? Message-ID: Date: Tue, 11 Apr 2006 13:24:53 GMT "Alex" schreef in bericht news:27AZf.72889$A83.1739689@twister1.libero.it... > Hi, i'm searching a simply amp keying circuit, just to control a Kenwood > TL922 with an ICOM IC 756 Pro III. > What do you suggest to me? > > 73 de Alex ik8xir Use an extern relais , otherwise you burn the very little tx relais (my friend dit it with the tl922 ) because the key voltage is 120v suc6 Article: 97123 of rec.radio.amateur.homebrew From: mzenier@eskimo.com (Mark Zenier) Subject: Re: ECG736 or NTE736 Date: Mon, 10 Apr 2006 21:18:58 GMT Message-ID: References: <1144344701.254899.208940@z34g2000cwc.googlegroups.com> <4437400F.4B7681C4@earthlink.net> In article <4437400F.4B7681C4@earthlink.net>, Michael A. Terrell wrote: >Fred McKenzie wrote: >> >> In article <1144344701.254899.208940@z34g2000cwc.googlegroups.com>, >> pdrunen@aol.com wrote: >> >> > I been searching the net for the specification on the ECG/NTE 736 which >> > is an FM gain block 8-pin dip. >> > >> > I have an old ECG catalog which gives me the pin out, I have tried the >> > NTE website which does not have a downloadable spec sheet. >> > >> > If you have a spec sheet, would like to get a copy. >> >> KJ4UO- >> >> If you don't find one, I suggest you "reverse look up" the original part >> number. (Could it be a Fairchild uA736? A National Semiconductor LM736?) >> >> In other words, you may have better luck finding a data sheet for the >> original manufacturer's part, and trusting that the ECG/NTE part meets the >> same specs. > > ECG published a set of three databooks about 20 years ago that >covered their current product line. My set disappeared about 15 years >ago. You might want to keep an eye out for a set of them. > Found it. (I've got the first two ECG books). BTW, it's really a Sprague ULN-2208M, so ftp://ftp.eskimo.com/u/m/mzenier/uln2208m.pdf Mark Zenier mzenier@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com) Article: 97124 of rec.radio.amateur.homebrew From: mzenier@eskimo.com (Mark Zenier) Subject: Re: Radio-Electronics Sept 89 Date: Mon, 10 Apr 2006 21:24:18 GMT Message-ID: References: <1144344552.349256.25410@e56g2000cwe.googlegroups.com> In article , James Thompson wrote: >On the subject of electronics mags: Does anyone still publish any for the >experimenter or is that all in the past? For the US, there are two. Nuts and Volts (www.nutsvolts.com) and Make. Make is a new magazine from O'Reilly, the computer book publisher. It's only a year or two old. (Saw it at the local Barnes and Noble. A rather expensive quarterly, as I remmember). Circuit Cellar Ink probably could qualify, too, but it's more of a pro embedded microcomputer hardware/software mag. Mark Zenier mzenier@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com) Article: 97125 of rec.radio.amateur.homebrew Date: Tue, 11 Apr 2006 20:20:26 +0100 From: Highland Ham Subject: Re: IC756/TL922 keying - Any Suggestion? References: <27AZf.72889$A83.1739689@twister1.libero.it> Message-ID: >> Hi, i'm searching a simply amp keying circuit, just to control a Kenwood >> TL922 with an ICOM IC 756 Pro III. >> What do you suggest to me? > Use an extern relais , otherwise you burn the very little tx relais (my > friend dit it with the tl922 ) > because the key voltage is 120v ================================= Would a high voltage switching transistor with/without an opto-coupler circuit not be more reliable ? The opto-coupler circuit can be tailored for the transceiver's output and a cheap High Voltage transistor could excite the amplifier. Just a thought. Frank GM0CSZ / KN6WH Article: 97126 of rec.radio.amateur.homebrew From: "Rick Mintz" Subject: Need: Panel Meters Message-ID: Date: Wed, 12 Apr 2006 02:58:24 GMT Hi gang, I need two matching square analog panel meters for an amplifier project. 0-100 Volts DC - 2 1/2" face (or 150 volt) 0-30 Amps DC (with shunt) - 2 1/2 " face (or 0-50 Amp) Rick W1TY W1TY@arrl.net Article: 97127 of rec.radio.amateur.homebrew From: "CA" References: <1142687392.568430.122110@e56g2000cwe.googlegroups.com> <7SLXf.22113$dy4.15868@news-server.bigpond.net.au> Subject: Re: Return Loss Bridge Accuracy Questions Message-ID: Date: Wed, 12 Apr 2006 11:52:44 GMT Paul VK3DIP wrote: > If you are interested I had really good results recently with a > homebrew RLB, in fact so good that I doubted the results and had to... I have read your article with great interest. Do you have a specification for the "balun formers" or maybe a Rockby Electronics stock no.? I suppose it is www.rockby.com.au. The only 2-hole ferrite core I could find is stock no. 10967 but I believe this one is too small. 73 Christer SM6PXJ Article: 97128 of rec.radio.amateur.homebrew From: - exray - Subject: Re: Regen with spider web coils ? Date: Wed, 12 Apr 2006 09:04:18 -0400 Message-ID: <123pumofq556ic8@corp.supernews.com> References: <1144845320.775026.160220@i39g2000cwa.googlegroups.com> jvereker@wp.pl wrote: > Anybody built a regenerative receiver (tube or MOSFET :) using > oldschool spider web coils ? > In theory they have a very low amount of parasitic capacitance, and a > high Q. > Is it worth to use them for amateur bands ? > I've built some some for general coverage use. No problem getting them to work. http://www.sparkbench.com/swsw.jpg If there's a complaint to be found it might be that they wouldn't be as thermally stable as a nice tightly wound coil on a form. In my case I used them in a general coverage (0-100) receiver - for a ham band receiver they might be a little sloppy. You also lack the ability to "fine-tune" them the way you can with a solenoid coil where you can squeeze/strech the turns. -Bill Article: 97129 of rec.radio.amateur.homebrew From: You Subject: Re: Lowering the noise figure in a preamp References: <1144845940.982676.234790@j33g2000cwa.googlegroups.com> Message-ID: Date: Wed, 12 Apr 2006 17:17:39 GMT In article <1144845940.982676.234790@j33g2000cwa.googlegroups.com>, "tucker@conninc.com" wrote: > Does anyone have any idaes on how to lower the nf in a uhf preamp? > 1. Lower then temprature of the device, by dumping it in Liquid Nitrogen. 2. Use a device with a lower Noise Figure, as the active element. Daaa..... Article: 97130 of rec.radio.amateur.homebrew From: - exray - Subject: Re: Regen with spider web coils ? Date: Wed, 12 Apr 2006 13:58:58 -0400 Message-ID: <123qfv7n2242bb9@corp.supernews.com> References: <1144845320.775026.160220@i39g2000cwa.googlegroups.com> <123pumofq556ic8@corp.supernews.com> <1144854845.624672.120090@z34g2000cwc.googlegroups.com> jvereker@wp.pl wrote: > Does your "0-100" mean 0-100 MHz coverage ? :) I wish !....hmmm, no I don't. That would be terribly difficult to tune. > Did you observe increased effect of hand capacity or it has nothing in > common with that kind of coils ? > No. If anything the hand effect is decreased since its not "360 degrees" like a typical vertically mounted solenoid winding. Of course that depends on the placement of the hand, doesn't it? I think you should try it. Its easy enough to do - and looks cool also. I can't think of any other reason to do it that way. At SW freqs I suspect the Q is in the same range as toroids or regular coils. I have some specific uh/turn numbers for the spider size that I used if you are interested. Bill WX4A Article: 97131 of rec.radio.amateur.homebrew From: - exray - Subject: Re: Regen with spider web coils ? Date: Wed, 12 Apr 2006 15:27:00 -0400 Message-ID: <123ql49hqub4368@corp.supernews.com> References: <1144845320.775026.160220@i39g2000cwa.googlegroups.com> <123pumofq556ic8@corp.supernews.com> <1144854845.624672.120090@z34g2000cwc.googlegroups.com> <123qfv7n2242bb9@corp.supernews.com> <1144869558.093043.141280@t31g2000cwb.googlegroups.com> jvereker@wp.pl wrote: > Of course I am. :) > Especially for lower bands (3.5 and 7 MHz), because, as far as I know, > regens arn't very good on the higher ones. > Tell me how many uH you want. -Bill Article: 97132 of rec.radio.amateur.homebrew From: mcalhoun@ksu.edu Subject: Re: Radio-Electronics Sept 89 Date: 12 Apr 2006 21:27:31 -0500 Message-ID: References: <1144344552.349256.25410@e56g2000cwe.googlegroups.com> mzenier@eskimo.com (Mark Zenier) writes: < Subject: Source of info on old transistors Message-ID: Date: Thu, 13 Apr 2006 03:25:44 GMT Hi, Anybody have a library of transistor databooks >from the early 60's? I'm trying to find technical info on the following devices: Power Transistors: Motorola 48S23 in TO3 Steel case Signal Transistors: Motorola 48S45 (624 date code or other marking) Motorola MA900 (Sort of crossed to NTE 102A or ECG 102) Mototola SM1824 (612 date code or other marking) (one schematic I have shows this to be a PNP type) 2N1192 (Schematic shows as PNP type - one hit shows as Germanium) Motorola SM2140 (Schematic shows as PNP type) GA987 (980425 date code or other marking) I'm unsure about the manufacturer of the last device. All the other have the Motorola circle M logo clearly marked, but it is not on that device. The system these devices are in was manufactured in the fall of 1963 so it is likely that the deisgn is from the 1960 to 1962. I'd like to browse through a 1960 to 1963 Motorola data book. I'm suspecting all of these to be PNP type Germanium devices, but that is just a guess. Any help appreciated. Ronnie, N5CSE