Date: Tue, 9 Nov 93 04:30:36 PST From: Ham-Homebrew Mailing List and Newsgroup Errors-To: Ham-Homebrew-Errors@UCSD.Edu Reply-To: Ham-Homebrew@UCSD.Edu Precedence: Bulk Subject: Ham-Homebrew Digest V93 #98 To: Ham-Homebrew Ham-Homebrew Digest Tue, 9 Nov 93 Volume 93 : Issue 98 Today's Topics: Modification of SR210 (150W SSB HF RTX) My home brew.. 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 Ham-Homebrew Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew". 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: 9 Nov 1993 07:43:09 GMT From: olivea!flash!robertov@uunet.uu.net Subject: Modification of SR210 (150W SSB HF RTX) To: ham-homebrew@ucsd.edu Hi there, I have got a SR-210 HF SSB (150W) TRANSCEIVER by SCIENTIFIC RADIO SYSTEM INC. 367 Orchard Street Rocherster, New York This radio is from 1975. It has 10 channels that can be placed into HF frequencies but unfortunatly everything is designed for a fixed configuration. For example the there are 10 output network that are fixed and parts (capacitor) should be changed when you wish to change frequency (changing the crystal) the same is more or less true for the input mixer network . A multisection rotary switch with 10 position select all the 10 different network. Question: Does anybody know the better way to modify this radio and make it working by using a VFO instead of only using the 10 available channels that are standard with the ten xtal that are into it. I have figured out some ways but I am not sure. If somebody already did some modification on this equipment I am asking for hints. I want to move from each channal 100KHZ so that the input and output network should not suffer too much about the modification. Thanks in advance to anybody that will help me. 73 If possible please reply at this addr. robertov@hqlab.ico.olivetti.com ------------------------------ Date: Sun, 7 Nov 1993 17:00:51 GMT From: sdd.hp.com!cs.utexas.edu!swrinde!gatech!usenet.ins.cwru.edu!nshore!fmsystm.telemax.com!andrews@network.ucsd.edu Subject: My home brew.. To: ham-homebrew@ucsd.edu In article <2bivng$ieo@reznor.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes: >In article dfeldman@teal.csn.org (Dave Feldman) writes: >>Well I just sampled the last of my 3 batches of home brew and they all >>came out great (an ale, a bock, and a wheat). I just want to know why >>my homebrew radio projects don't improve with age... 73 - wb0gaz > >On a more interesting note, I got my first international contact with the >$10 Teenage Mutant Ninja Turtle HT, recrystalled for 6M and with an added >amplification stage on the output for almost half a watt of power. Okay, >so it was only Canada, but it's still going to be a lot of fun to fill >out the EQUIPMENT: field on the QSL card. >--scott Come on Scott, youv'e got to send me the schematics and mod's to convert the 'Mutant' walkie to a 6M QRP HT. I've been looking for this mod forever! BTW (for DAVE), I've been drinking alot of micro-brewrey beer. It's all over the place. Of course, you can always send me a bottle and I'll tell ya how it rates... -- Tell Me Something I Don't Know, ! HAM = N8OFS Show Me Something I Can Use, ! ARMY MARS = AAN5HJT Push The Buttons, ! CB = THE NEON KNIGHT Connect The God-Damn Dots!!! - Ministry ! HACKER = TH3 N30N KN16Ht ------------------------------ Date: Sat, 6 Nov 1993 05:01:28 GMT From: elroy.jpl.nasa.gov!swrinde!gatech!news-feed-1.peachnet.edu!umn.edu!csus.edu!netcom.com!wa2ise@ames.arpa To: ham-homebrew@ucsd.edu References <1993Nov3.191337.21649@jupiter.sun.csd.unb.ca>, <2bb029INN93f@news.uwsuper.edu>, <1993Nov5.192134.17150@jupiter.sun.csd.unb.ca> Subject : Re: Rewinding transformers Somebody mentioned how many turns per volt, and such. I wound some transformers back in high school days. Saw an article in a model railroad magazine (of all places!) that had an equasion like: number of turns for 110 volt primary = 800 * square inch area of laminations, plane of which is the plane of the loop of wire that would form a single turn. Measure the height of the stack of all the E's laminations, and the width of the center prong of an E lamination. ____________ \ _________\ |\ \________|_ ___ | \ \ \ width of center prong of E's \ \ _________\ __\ \ \ \________|_ \ \___________\ ___ \ | | | height of lamination stack \|___________| ___| Once you have the number of required turns for the primary, you can easily figure number of turns per volt. pri turns/110 = turns per volt You have to have enough turns to keep the magnetic flux B low enough so the laminations don't saturate. If I remember my electromechanical devices class right, don't go above 1.5 for B. Don't remember what the units were called though. The idle (magnetic charging? current in the primary is kept lower by the permability of the laminations, than if it was air. But that's only good until you saturate the laminations with magnetism. When that happens, the idle current soars, and you get lots of i r heating, and most likely a smokey firey burnout! Go to the library or your double E dept and ask someone. --------------------------------------------------------------------------- Western culture is like a virus that has infected the entire world :-) ------------------------------ Date: 8 Nov 1993 14:08:10 GMT From: news.larc.nasa.gov!grissom.larc.nasa.gov!kludge@ames.arpa To: ham-homebrew@ucsd.edu References , <2bivng$ieo@reznor.larc.nasa.gov>, klu Subject : Re: My home brew.. In article andrews@fms.com (Andrew Sargent N8OFS) writes: >In article <2bivng$ieo@reznor.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes: >> >>On a more interesting note, I got my first international contact with the >>$10 Teenage Mutant Ninja Turtle HT, recrystalled for 6M and with an added >>amplification stage on the output for almost half a watt of power. Okay, >>so it was only Canada, but it's still going to be a lot of fun to fill >>out the EQUIPMENT: field on the QSL card. > >Come on Scott, youv'e got to send me the schematics and mod's to >convert the 'Mutant' walkie to a 6M QRP HT. I've been looking for >this mod forever! On the transmit side, it's really just an VCXO without any tuned amp; you can replace the crystal without making any other circuit changes (although you might want to replace the 220K resistor with a smaller value in order to get a bit more output power). With a 5K resistor in place, you can get enough power to drive a 2N2222 stage class C without any problem. The receive side is a bit harder; it's really just a TRF set with a single tuned circuit. You can just reduce the capacitance on the tank circuit to move the frequency up a bit, and use the adjustable coil to set it exactly. The performance stinks, though. It's no worse on 6M than it is on 49 MHz, but it's almost unusable on 49 MHz. There are some mods for the Radio Shack personal communicator sets, which apparently use that Motorola quick-and-dirty transceiver chip set. Now, that looks like a nice 6M HT. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." ------------------------------ End of Ham-Homebrew Digest V93 #98 ****************************** ******************************