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I've had some good input about some of the info in this FAQ, the following contains some updates on filtering and PA-1 conversion that needed to be corrected. New sections are leaded by ">". Thanx to all those who've helped out, but would rather stay anon. mycal --------------cut----------- Ramsey FM-10 Info by mycal@netacsys.com 10th Edition ----------- Here is a rough compilation of information about the Ramsey FM-10, and other BA1404 Stereo FM broadcasters. Some of the modifications may make your BA1404 based broadcaster illegal to use on the open airwaves in the US and Canada. Also it has been brought up that the stock Ramsey FM-10 kit may exceed FCC power limits when used with a proper antenna. The information contained in the file is in no way complete, nor do I take any responsibility for its accuracy. With that in mind, along with the above paragraph I must say : "This file for informational purposes only." About This File --------------- When I first started hacking on my FM-10, a few of us on alt.radio.pirate were exchanging information on mods to improve the range, stability and audio quality of the FM-10. After a couple of posts about filters and amps, my mailbox was swamped with requests for copies of previously posted information and other questions about the FM-10. So rather than drive myself crazy with sending a piece of info here and there, I decided to dig through my mailbox an notes and compile this file. I hope it helps. Also if anyone has more information about the FM-10 or FM transmitters, antennas, mixing equipment, programming information, stories about pirates, or anything else that falls into this realm, please send it to mycal@netacsys.com. I will try to update this file as new information becomes available. Also I am working on a some Postscript files that will contain instructions on how to build some equipment that is to complex for ASCII art. You might want to check the FTPable archives every month or so. I would like to say thanx to all the people that contributed to the information in this file. The list has grown quite long, and some of the contributors would like to remain anonymous. So for now I am going to forgo all the names, if this is not up to your liking please let me know. FM-10 Mailing List ------------------ First Things First. There is now a mailing list that deals with the topic of the Ramsey FM-10 and other BA1404 based FM Stereo Transmitters. Feel free to join up and contribute. To send a message to the mailing list, send your question, reply, comment, or contribution to : fm-10@dg-rtp.dg.com To add or delete yourself from the list, send a short message with the function (add/delete/change address) along with the relevant e-mail address to: fm-10-request@dg-rtp.dg.com If you have any questions I can be reached at myca@netacsys.com. FM-10 Archives -------------- Yes it is finally here, message archives of the FM10 mailing list and a place to put/find schematics, reviews, stories, etc. related to the FM-10 and other BA1404 based FM transmitters. Currently a 350mw amp plan, 800mw amp plans, "Radio is my bomb" text, slim jim plans/info and the BA1404 spec sheet are located there. People can FTP into dg-rtp.dg.com with user "anonymous" and password "<your EMail address>". In the fm10 directory you'll currently find two sub-directories: incoming This is writable by everyone and this is where people should upload new stuff. msg-archives This directory will have files named according to the date they were last "sealed". The file "Current" is a running log of all EMail messages from the last "seal" date of the archives. Snail Mail Info Packet (or Pirates Guide to FM Stereo) ------------------------------------------------------ The info packet has evolved yet again, it is now 44 pages. It includes plans for 4 amps, a 200mw, 350mw, 800mw, and 5watt. Instructions for modifying the Ramsey PA-1 for FM broadcast band operation. A section on how to design and build your own antenna. Plans for a power meter, regulated power supply, and dummy load. A block diagram showing a typical station. Spec sheet for the BA1404. FM-10 modifications. Sources for parts and info. And a more up to date design of my digitally synthesized transmitter. Loaded with schematics, board-layouts and diagrams. Plus, schematics and construction details of the FRB 5 watt transmitter. And now compressor and limitor plans, FCC facts and reality, DIY media article. The price for this packet is $10 in the US and $12 overseas. Address to send the $$ to is: mycal PO Box 750381 Petaluma, CA 94975-0381 You can also use this address to send me any info that would be hard to send by email. I will trade info packets for hard copy information, email me for details. Note : this packet is in a constant state of change, more info could be added at any time. Other Places to Look in Cyberspace ---------------------------------- alt.radio.pirate is another good forum to find or post information on FM radio transmitter. Although you may not have pirate aspirations, many of the things talked about can benefit everyone. Other places to scan, sci.electronics and the amateur radio groups. The American Radio Relay League (ARRL) has a useful service -- the ARRL Information Mail Server. This is an automated mail server that let's you access many of our information files, containing information about various facets of Amateur Radio. Some of the information has technical value that is related to all radio services. To use it, mail messages to: info@arrl.org With the message : help This will give you all the information you need to use this service. Radio Resistors Bulliten ------------------------ A little zine that somtimes discusses pirate/micropower radio along with public radio stuph. Send frank a buck to help out with the copying and stamps. Frank Haulgren RRB PO Box 3038 Bellingham, WA 98227-3038 Recommended Test Equipment -------------------------- An SWR/Power meter is a giant help, a CB to 2 meter one will suffice. Power readings will not be accurate, but can be useful for peaking. The most important part is the SWR meter, this is very important when making an antenna. A note on power meters. I recommeded the above power meters because they are inexpensive and most people that are interested in hacking a FM-10 have very limited funds. These are by no means accurate, but they will give you some idea what is going on. If you can spend the money you can get an accurate power meter that is designed for this band, but the cost is 10-15 times more. A rf probe could also be used as a replacement for a powermeter, construction details below. A 50ohm non inductive load is also very helpful, for low power applications a 50ohm 1/4 or 1/2 watt carbon resistor works well. This can be used to tune up your kit and amp without interfearing with anyone. Also note that you can run as much power you want, legally, as long is it doesn't radiate. A VOM is also very helpful. High I would put out the extra bucks and buy one with a freq counter (if you shop around, about $60-$70). Buy the one that covers audio to 20MHz(or more). If you are serious about electronics you need one of these! Dummy load ---------- Dummy loads are great for testing, without radiating a signal. In fact you can run as much power as you want into one of these things legally! Basically you want to create a non-inductive 50-ohm load. This can be done with regular carbon resistors, or by buying pre built Amateur or CB radio loads. For low power ( <.5 watt ) an ethernet terminator works well (check temp when using if it gets very hot lower input power, if it is still cool you may be able to go up to .75 watt.) Most CB loads use a 2-watt carbon 50-ohm resistor. You can build your own, as wimpy or as studly as you want by running resistors in parallel to create 50-ohms. ie, 2 100 ohm 1/4 watt resistors will create a 1/2 watt 50 ohm load... Do not use 50 ohm wire wound resistors, they are not 50 ohms at radio frequencies. ----- ---------\ Sample Dummy Load where -****- = 50 ohm ---|--****-- / mounted in UHF connector. carbon --------- resistor ----- RF Probe -------- For those of you (like me) who are in constant Starving Student mode, and DONT have a good Scope, you can use a good DMM for RF power calcualtions. All you need to do is build a RF probe. Here's the schematic: (Yes, taken from 1989 ARRL Handbook) --probe tip-----||-----/\/\/\-------to center of 50 ohm coax. .01uf | 4.7M -------to braid __ | \/ | ---- | | | cliplead for gnd-------------------- Anyway, the Diode ( arrow-points to ground) should ideally be a Schottky diode (low rf capacitance). Although a 1n914 will work. To use, just hook up to your digital Meter, set on DC voltage. You will get very close to RMS RF Voltage. (this probe was specified for a 10Meg Ohm meter). To calculate power into a KNOWN purely resistive load (a.k.a. a dummy) use: e^2/R where e is the RMS RF voltage, R is resistance :-) This is also useful for checking inputs and outputs of low power RF units, since the inexpensive power meters don't seem to do real well below 1watt. jsawyer@crash.cts.com Paranoid? --------- I've been talking to a few ppl that are worried about there "voice" being on the air, since they are afraid of being recognized. So I dusted off the old stacks of Radio-Electronics and found two articles that may be of intrest. In the January 1993 issue they have a "build your own digital voice changer" using a simple Real time digital signal processor. I think that this design is very simalar to the voice changing telephones. It basically raises or lowers your voice pitch. A place called LNS Technologies @ 1-800 -886-7150 sells the kits for $59. In there September 1992 issues they have a "build this dsp voice-effects board" using a little more complex, programmable, real time digital signal processor. The software they include contains a harmonizer, echo, reverb, and pitch. The kit is sold by American Disributors Inc for $105 @ 1-800-877-0510. You can also write your won software but the programmer is several hundred $$. DC electronics has a Robot Voice Kit for $15. I don't know how well this works or what it sounds like, but it clames to be adjustable for many different effects. Ramsey's Address ---------------- If your looking to purchase a FM-10 kit and can't find one locally try : Ramsey Electronics, Inc. 793 Canning Parkway Victor, New York 14564 Phone (716) 924-4560 FAX (716) 924-4555 Ramsey FM-10 70mw output amplifier ---------------------------------- Provides almost 9db gain to bring the output power of the Ramsey FM-10 Stereo transmitter from 8mw to 70mw. Not the best design, but all parts can be found at Radio Shack! Much better designs are available at the archive site. +12v | / \ R1 *220 ohms(1/2 watt) / \ R2 9k | C2 -/\/\/\/-----------||-----> output | / | / | | / C1 | |/ <----------MPS2222A (276-2009) in --||------|\ -or- 2N4401 ^ | -> -- | | | GND currently on board * you can also use 2 440 ohm 1/4 watt resistors run in parallel I built this thing right on the underside of the FM-10 kit, C1 is the cap that currently goes to the RCA ant jack, the 9k and the 220 ohm resistor have to be bought, note that if you cannot find 220 ohms you can make one by using 2 440 ohm resistors in parallel, and that a 10k will work in place of the 9k but yields poorer performance (-5%). The MPS2222A is from Radio Shack part number 276-2009, use this part! if you substitute it for a 2N2222A you will get only half the gain. Be very careful to get the leads in the correct orientation! I have found that a 2N4401 can be used in place of the MPS2222A with a little better performance, about 5mw more. I think the 2N4401 can be found at Radio Shack too. C2 is of the same value of C1, I took the one that goes to the on board antenna pad. Important! the value for R1 that seems to be optimal is 220 ohms, but it is very close to the sat point, If the amp. seems noisy (interferes with the TV etc.) back this value off to 240 ohms. If you lower this value below 205 ohms the power meter may read higher power but this will not be true, the transistor will be spewing all kinds of junk and the power meter will mistake this for higher output (in reality the signal we want will drop considerably.) Well that's it, effective range with a good antenna should be a little over double. > Ramsey PA-1 2-meter to 3-meter conversion mod > --------------------------------------------- > The Ramsey 2-meter amp (PA-1) can be converted for use on the FM > broadcast band. The following changes need to be made: > > L1 - should be replaced with a 1-turn 1/4" diamater coil, identical > to the stock L2 shown in the PA-1 manual. > > L2 - no change required > > C1 - no change required > > C2 - should be replaced with a larger trimmer capacitor. Use a trimmer > that will go up to at least 125pF. > > C3 - no change required (*) > > C4 - should be replaced with a larger trimmer capacitor. Use a trimmer > that will go up to at least 125pF. > > * - at higher power levels (>15 watts), this capacitor should be > replaced with a trimmer at goes up to at least 200pF. > > Tuning: > > Tuning the amp for proper operation on 3-meters can be tricky. I > suggest the following setup: > > FM xmitter --- SWR Meter --- PA-1 --- Power Meter --- 50 ohm dummy load > > Starting with C1 and C3 about 1/2 turn from closed, tune C2 and then C4 > for maximum power output. If the SWR is much over 2:1, you will need > to adjust C1, C2, and C4 to reduce it to an acceptable level. Watch > the output power while you do this. Sometimes, tuning the trimmers for > minimum SWR will peak the power output, whereas other times the power > output will drop markedly. Avoid trimming the capacitors that have a > large negative effect on the power output. After several iterations of > adjustment, you should have decent power gain and low input SWR. > > Note: Watch for sudden jumps in power output that you can't linearly > tune through. If you encounter this happening, chances are your > SWR between the transmitter and amplifier will go way up, too. > This is a sign that your amplifier is oscillating and you will > need to tune it out of this region for proper operation. ANTENNAS -- read, read, read, read, most important! -------- Do you have a good antenna? I think that is the most important thing that you can do for extended range. I built a 1/4 wave ground plane using a UHF connector and 5 lengths of copper plated brazing rod (found at the local welding shop). Works great and only cost $3 dollars to make. Remember good antenna will improve you range much further than a good amp into a bad antenna. So this should be your 1st project to increase your range. use the formulas out of your FM-10 manual 234/freq=length of rod. Example : 234/88Mhz = 2.66 feet * 12 in/feet = 31.9" -or- 234/108Mhz= 2.17 feet * 12 in/feet = 26" insert the 4 ground plane rods in the 4 holes of the UHF connector, stick them through about 1/4 inch and solder. Solder the radiator in the top of the UHF connector (you may have to grind it a bit to fit.) Then bend the ground plane rods to a 45 degree angle to the radiator. There you have it a very effective antenna, just connect with a 50 ohm CB cable to your amplified Ramsey, stick the antenna in a tree or in another high place and you should have 1 miles of solid coverage (when using the above amp.). Also If you have an SWR meter you can cut the rods a little longer and start clipping the ends off a little until you get the best SWR reading. | | | | = brazing rod | | | | | ----- ----- ----- = UHF connector | - | / - \ - | | / \ | | / \ The final antenna should look like this: | ^ | | // \\ sky ground --horizon-- | v That is 1 radiator pointing strait up and 4 ground plane radials. (sorry for this extreme description, but there has been some confusion.) Be careful when you bend the brazing rod, don't break the connector. Grab the rod right below the connector with a pair of vice-grips (or the likes) and bend the brazing rod at that point. Try not to have anything metal near the radiator, this will effect the radiation pattern. The radiation pattern should look a lot like a doughnut surrounding the radiator, though deformed a bit. I have been told that you can shorten the radiator and make the ground radials longer to lower your radiation angle, but I haven't tried this, nor do I know what this would do to the antenna impedance. On The Road ----------- Old magnet mount CB antennas can make great mobile antennas, just take all of the base load out of them and cut the radiator to 1/4 wave length. If you need a longer radiator than the one that comes with the antenna use the above mentioned brazing rod. I've tried this antenna and it works great! It is better than my di-pole at home and you can drive to a high, optimal location for your broadcasts. Also with this setup you need very little coax cable. Line loss using RU-58u can be killer @ 100MHz. You could also try a 5/8 wave length antenna, this would give you 2+db gain, or almost 2x power gain on transmit. Filter design for FM Radio Transmitters. ---------------------------------------- It is very important to have a clean signal, the way 99% of all people who get busted for illegal transmitting is that the people that live around them complain about interference. Most of this interference is caused by harmonics. Filters cut down these nasties. So don't draw attention to yourself, keep everyone happy, including yourself, be clean, use a filter. When you amplify a signal, you get unwanted byproducts these are called harmonics. The show up at multiples of your starting frequency. For example if you amplify a 50MHz signal you may get echo's on 100MHz, 150MHz 200MHz, 250MHz... If you interfear with your neighbors TV, the local fire department, or anyone else, you are just asking for trouble. If you are only on the FM Band, you will hardly be noticed. ... Filter Designs -------------- (basically scaled from the charts in the ARRL handbook). Filter Design: 7 element Chebyshev I run @ 88.1 so my 1st harmonic is 176.2 This filter seems ideal. Fc 3db 20db 40db 85.8MHz 95.9MHz 116MHz 148MHz .132uh .150uh .132uh -----()()()-----()()()-----()()()----- | | | | <-50ohm - 33pF - 68pF - 68pF - 33pF 50ohm-> - - - - | | | | -------------------------------------- | --- - lowering the 33pF caps to 30pF and the 68pF caps to 62pF would make this filter sutible for higher frequencies like 100MHz. Filter Design: 5 element Chebyshev Not as good as above. Fc 3db 20db 40db 81.8MHz 105MHz 147MHz 222MHz .128uh .128uh -----()()()-----()()()----- | | | <-50ohm - 30pF - 62pF - 30pF 50ohm-> - - - | | | --------------------------- | --- - The tuff part in the above is winding the coils. 3t of #12 wire 1/2" diam should be about .12 uh. 4t is .17 uh. (but ugh, #12 wire is big stuff). You could just use molded inductors, I have found these work well. Try to use fixed value caps, or fixed value with small 5pF trimmers. The latter works well when you have a spectrum analizer to tune there babies. I just pulled a program of a BBS that tells you how to wind inductors. Give it the value and wire size you have and it will tell you how many turns and what size. Way cool. More on this later. > *** SIMPLE *** FILTERS *** SIMPLE *** FILTERS *** > > Many FM transmitters are designed without adequate filtering on the > output. Add to this the fact that most pirate radio operators lack > spectrum analyzers with which to tune up their equipment, and it is > easy to see that many stations are likely to be full of spurious > outputs. You're a lot more likely to attract the attention of the > FCC if you wind up interfering with all your neighbors television > sets because of spurious emissions than you are if you emit a clean > signal. While more elaborate 5- and 7-element filters offer greater > attenuation of harmonics, I have found the following design to be > simple and very useful. Furthermore, several of these filters may > be chained together in series to produce even better filtering. > > If you make L1 with the 18 gauge wire as indicated and use capacitors > rated at 50 volts, the power handling capability of this filter will > be around 20 watts. If you use 100 volt capacitors, it should be > able to handle 50 watts or more. The insertion loss of the filter > is generally less than 1dB if you stay below the F(0db) point. > > Here is a schematic for a 3-element lowpass filter: > > > input o---+---uuu---+---o output > | L1 | > C1- -C2 > - - > | | > gnd o---+---------+---o gnd > > > The following table summarizes 5 different variations of the 3-element > lowpass filter. I have constructed and tested some of these myself and > find that they work as advertised. The attenuation figures shown below > were produced by spice. > > 3-element Lowpass with ~50 ohms input/output impedance > ====================================================== > > C1 C2 L1 F(0db) F(3db) F(6db) F(10db) F(20db) > --------------------------------------------------------------- > 33pF 33pF *(1) 113MHZ 138MHZ 163MHZ 200MHZ 320MHZ > 39pF 39pF *(2) 98MHZ 119MHZ 140MHZ 173MHZ 293MHZ > 47pF 47pF *(2) 95MHZ 112MHZ 130MHZ 160MHZ 270MHZ > 52pF 52pF *(2) 92MHZ 107MHZ 125MHZ 152MHZ 255MHZ > 56pF 56pF *(2) 90MHZ 105MHZ 121MHZ 147MHZ 246MHZ > 62pF 62pF *(2) 87MHZ 101MHZ 116MHZ 140MHZ 235MHZ > > > *(1) - 2 turns #18 wire with a 5/16 inch inner diameter. Wind snugly > at first. If SWR is objectionable, increase spacing between > coils a little bit at a time. > > *(2) - 2 turns #18 wire with a 3/8 inch inner diameter. Wind snugly > at first. If SWR is objectionable, increase spacing between > coils a little bit at a time. > > I constructed my filter in a tiny aluminum enclosure with female > chassis mount BNC connectors mounted for the input/output. I soldered > C1 and C2 between the center connector and ground on each BNC connector > and soldered L1 between the two center pins on the BNC connectors. [Also of interest is that the FM-10 puts out about 8-9mw and the 2nd harmonic is -25db off the fundamental (frequency we are broadcasting on). The FM-4 Kit by Ramsey puts out 130mw and the 2nd harmonic is only -12db off the fundamental, which means the 2nd harmonic of the FM-4 is about as powerful as the FM-10. db is log10, ie 3db is 2 times 6db is 4 times...] FM-10 Myths ----------- There have been several myths about the FM-10 kit, the most prevalent are : 1) The FM-10 puts out 100mw of power. This is not true, or at least not true for the Ramsey FM-10's that I have tested. They put out about 8mw when driven with a 12volt supply. (note: there has been several revisions of the FM-10, it is possible that the original version put out more power, but I find even that highly unlikely since it would require another amplifier stage.) Also the FM-10 is the only low cost kit, that I have seen, with an amplifier stage. Most others have power outputs in the fraction of a mw area. 2) The FM-10's output can be cranked up by reducing the value of R9. This like the above is not true. R9 and R10 are optimized for maximum output and greatest harmonic suppression at 12volts. There are much better ways of getting more output power than to mess with this output stage. Lowering the value of R9 will most likely degrade the FM-10's performance and cause lots of interference. ============================================================================= FM-10 Improvements - -------------------- Note : I sent this file and a list of other modifications to John Ramsey. Low and behold 4 monthes later the FM-10a is released. The new FM-10a incorporates the following mods marked with an '*'. Stereo Pilot Mod ---------------- One of the first problems experienced with the FM-10 is difficulty in getting the stereo pilot to operate correctly. One solution is to replace C7 and C8 with a 38KHz crystal, this works the best and is recommended. If you cannot find a 38KHz crystal, you can make your life a whole lot easier with a couple part changes. As indicated on the Ramsey schematic, about 110pF is necessary to tune the oscillator. The components supplied to achieve this are a small fixed value capacitor (C7) and a slightly larger value trimmer (C8). Since proper setting of the trimmer occurs within a very small 'window' (about 5% of the trimmers range), it can bet difficult or impossible to adjust the pilot to 19KHz and have it stay put. This can be cured by increasing the value of c7 to 100pF and replacing c8 with a 6-50pF trimmer (Radio Shack #272-1340); a 5-30pF trimmer will do the trick. The RS trimmer will not fit the holes in the pc board; one needs to cut the leads off a spare resistor and solder them to the legs of the trimmer (just use bits of wire) to mount it on the component side of the board. On a 2nd note: I replaced c7 with a 68pF cap and found it much easyer to tune a rock solid 19KHz at the test point. Crystal Mod * ------------- Better than the above mod : old set up new setup c8 c1 xtl where c1=10pF and xtl=38KHz |-||-| |-||-|\|-| | c7 | | | v8=var cap |-||-| | | c7=cap | | | | Remove C7 and C8, replace with 38KHz crystal and 10pF cap. Note that the 10pF cap and the crystal are running series and the old cap setup is running in parallel. *** Note : If you have an FM-10 you can call Ramsey and get this mod for free! Treble Boost Mod * ------------------ Treble boost (pre-emphasis) improvement. The FM-10 appears to have been designed by someone outside the United States since it operates at the European audio standard of 50 microseconds. Receivers in the US are set up for 75 microsecond de-emphasis. R3 and R6 determine the time constant for the pre-emphasis curve. Replacing them with 75K ohm resistors (standard value 68K ohm is close enough) will result in improved audio response. A much better pre-emphasis/input circuit is shown in the July 1992 issue of "Radio Electronics". Not only do they use 75K ohm resisters in there pre-emphasis, but they filter stray RF signals by inserting a .001 cap between pin 1 (of the BA1404) and ground, and pin 18 and ground. It has been noted that the above mod may actually cause distortion on cheaper stereo receivers, since they were mass produced for the world market, they were designed for the European audio standard, which Japan and other Asian nations use too. Try it out, let me know what works for you. *** Note : the FM-10a kit comes with both sets of parts so you can select European or American audio standard. Anti-Drift Mod 1 ---------------- There has been quite a bit of discussion on the FM-10's frequency stability. Complaints that digital receivers cannot lock onto the FM-10's signal for any great length of time. I have used the below mod with good results (I used an N750 negative temperature compensated disc), but I have been told that Mylar or Polystyrene caps are even better. The FM-10 was designed to be inexpensive and cost-saving measures with components are inevitable. Disc ceramic capacitors are less expensive than silver-mica caps, and also much less stable. Simply replace c16 with a silver-mica, tantalum or negative temperature compensated disc (say anywhere from N150 to N750) cap of the same value. Even better is to cut the leads of the capacitor as short as possible and mount it directly on the bottom of the circut board. Anti-Drift Mod 2 ---------------- The FM-10 has two power grids, one is a low voltage grid to feed the BA1404. This low power grid uses three diodes to drop the input voltage to a safe level for the BA1404 which can only handle about 3.5 volts. Since the BA1404 contains the oscillator, and the frequency it oscillates on is dependant on the voltage that is feed to it, we can make the xmitter much more stable by replaceing the three diodes with a zener type diode. Select a zener diode with a voltage value of 1.5 to 3. Remove the three diodes that are in series. Insert the zener diode with the banded end going to the low voltage + line and the other end going to the system ground. Power Filter Mod ---------------- Another flaw of the FM-10 is that they don't stop the RF from feeding back into the power supply grid. There are two 270 ohm resistors feeding the RF outputs, one R13 feeds the output of the BA1404, the other R9 feeds the ouput of the amplifier. Inserting 1 to 10 uf chokes in series with these resistors will help clean up the FM-10's output and in the case of R13, boost the power output by about 4mw. ============================================================================ Sources ------- The following is a list of sources for items used for modifications, replacement parts, or other kits and equipment used in FM radio transmitting: -- BA1404s and other FM Broadcaster kits can be found at : D.C. Electronics phone: 1-800-467-7736 & 1-800-423-0070 fax:1-602-994-1707 They sell BA1404s for $2 a piece, seems to be the best deal going. Also they Sell 38KHz crystals for $5.99, which is also a fair deal, the crystals are tiny ones like the digi-key ones, but a different brand and work without problems or the Digi-Key ones. -- -- 38KHz Crystals can be obtained by calling : Digi-Key at 1-800-DIGI-KEY. 38.000 KHz by Epson America, Digi-Key part No. is SE3314 (see notes on crystal mod on using this crystal, also note that this is a cylinder type crystal and kinda delicate. you are probably better off getting the 38KHz crystals from D.C. Electronics.) -- -- Mouser Electronics (800)346-6873 (817)483-9384 fax Giant Catalog! 239pages of parts! Just about everything. No min order for north america. $100 min for overseas. -- -- RF Parts (transistors) 1320-16 Grand Ave San Marcos, CA 92061 Just about any RF transistor! -- -- Dalbani 2733 Carrier Ave. Los Angeles, CA 90040 (800)325-2264 USA (213)727-0054 WORLD (213)727-6032 FAX RF transistors and other semiconductors + more catalog= 178pgs $20 min order -- -- Panaxis Productions makes some very high quality FM transmitters. The last word in Transmitting, tons of kits. Panaxis Productions PO Box 130 (right next to my old place of study Paradise, CA 95967-0130. Chico State! ) (916)534-0417 Catalogs are $2, well worth it, a must have item. A little taste of there catalog : MMC1 Macromod Compander for 2:1 compression Plans $12, PCB $18, P+P 26.50, Full kit $87 SG High performance stereo generator Plans $15, PCB $13.5, P+P 26.50, Full kit $105 FME PLL FM exciter Plans $17.5, PCB $15, P+P 24.50, Full kit $129 More expensive than a FM-10 but much higher performance. -- -- A company called Progressive Concepts sells plans for a 88MHz to 108MHz amp. The power curves show that 12mw in will yield 2.5 watts, but can be driven harder for up to 12 watts. (I have not seen these plans) Plans only in U.S., $16 (a bit spendy, ouch!) Progressive Concepts 1313 N. Grand Ave. #291 Walnut, CA. 91789 -- -- If your looking to purchase a FM-10 kit (or a PA-1 kit) and can't find one locally try : Ramsey Electronics, Inc. 793 Canning Parkway Victor, New York 14564 Phone (716) 924-4560 FAX (716) 924-4555 Should be $29 -- -- The makers of the infamous BA1404 : Rohm Corporation Rohm Electronics Division 3034 Owen DR Jackson Business Park Antioch, TN 37013 PH: (615)-641-2020 (ask for someone who deals with the BA1404) FAX: (615)-641-2022 Also they have: PO Box 1399 Antioch, TN 37011-1399 ============================================================================= -- ============== ============== ============== Other Raw Info ============== ============== ============== the 2SC2570 is supposedly replaceable with an ECG10. Also I have used an MRF901 for a replacement, though tough to mount, try bottom of the pc board and connecting the whip antenna pad to ground plane. MPS901s seem to replace the 2SC2570 directly, same case too, check the pinouts though. I have also been told that MPS918s work well also. The MRF239 can be used as direct replacement for the Ramsey 2 meter PA-1 kit. Cost is around $14 bucks. Newark also has the 38KHz crystals for $2.90 ( I don't know Newark's address, this was sent to me in the mail, will try to find it though.) ------------------ Copyright Info - This file is Copyright 1993,94 by Mycal - mycal@netacsys.com I grant free copying rights in electronic or printed media, in whole or in part, so long as this notice, or footnote refrence to this file is included. ------------------ Once more If you have any info, I stress "ANY", about this subject please drop me a byte or two. have fun, mycal@netacsys.com -- ---------------------------------------------------------------------------- mycal@netacsys.com I can't say "no" 'cause I'm to busy saying "Yea"