Ramsey fm transmitter manual

Just like the professional units at a fraction of the cost. The end user is responsible for complying with all rules and regulations of their respective governing body. Orders for the FMBWT are processed manually and verified to be export compliant prior to order acceptance. There are no exceptions.

But on rare occasions a sour component can slip through. Defective parts will be replaced promptly at our expense. If you suspect any part to be defective, please mail it to our factory for testing and replacement. Please send only the defective part s , not the entire kit.

The part s MUST be returned to us in suitable condition for testing. Please be aware that testing can usually determine if the part was truly defective or damaged by assembly or usage. Often times, common sense will solve a mysterious missing part problem. If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as supplied with the basic kit by Ramsey, please write or call us with information on the part you need and proof of kit purchase.

Please understand that our technicians are not volunteers and that set-up, testing, diagnosis, repair and repacking and paperwork can take nearly an hour of paid employee time on even a simple kit. Of course, if we find that a part was defective in manufacture, there will be no charge to repair your kit But please realize that our technicians know the difference between a defective part and parts burned out or damaged through improper use or assembly.

You are given ten 10 days to examine our products. The larger tabs secure the shield can to the ground foil connections, while the two thin leads are the coil connections.

Make sure L1 is squarely against the top of the PC board before soldering. Solid installation of L1 is essential to the frequency stability of your transmitter. Install R8, 47K ohms yellow-violet-orange. Install C16,. Install VR2, the 78L02 2. Make sure the flat side is oriented the same way as shown in the parts layout diagram. Install C10, a. Install R13, ohms red-violet-brown. Install C31,. Install C30, 10 pF disc capacitor marked 10 or 10K. Install C32, 10 pF disc capacitor marked 10 or 10K.

Install C13, a. Install Y2, the small silver "can" crystal. Be especially careful when installing this part as its leads are very small. You may elect to put a small "dab" of glue on the part to relieve stress and to keep it firmly attached to the PC board, or use a piece of clipped off lead and form a loop to go around the crystal and through the holes in the board.

Install JMP1, a 2 pin header. A jumper block will be installed on this to enable stereo transmission. Install Q3, the transistor marked C or The flat side must be placed as shown on the PC board, facing away from R Mount Q3 as close to the board as possible without forcing it. Install R20, 10K ohms brown-black-orange.

JMP2 is the high power jumper, made from a spare piece of component lead. For normal operation in the U. Install R17, ohms red-red-brown. Install C24,. Install C29,. Install R19, 2. Install Q2, the other transistor marked C or Again watch the placement of the flat side and mount as flush as possible. Install R18, 10K ohms brown-black-orange. Install R14, ohms red-red-brown. Install C23,.

Install C35, a 47pF ceramic capacitor marked 47 or 47K. Install C27, a. This is a coupling capacitor for preventing DC from being present on the antenna or J4, the external antenna jack. Install L2, one of the small pre-wound spring style inductors. Install L3, the other small pre-wound spring style inductor.

Install C36, a 75pF ceramic capacitor marked 75 or 75K. Install C37, a 47pF ceramic capacitor marked 47 or 47K. Install C26,. Install R12, ohms brown-black-brown. Note this part is a laydown. Install R23, 10K ohms brown-black-orange. Install R24, 10K ohms brown-black-orange. Install R25, 10K ohms brown-black-orange.

Install R26, 10K ohms brown-black-orange. Install D9 - D20, small glass diodes. The banded ends go toward the inside of the board, as shown on the silkscreen. Install S3, a four posistion DIP switch. The DIP switches are used for programming the exact transmitting frequency of your transmitter. Install S4 and S5 in the same manner. Install Y1, the 6. Install R3, 10M ohm brown-black-blue. Install C1, 27 pF disc capacitor marked 27 or 27K.

Install C2, 27 pF disc capacitor marked 27 or 27K. Install C9,. Install R5, 10K ohms brown-black-orange. Install R31, a 1K ohm resistor brown-black-red. Notice this resistor is a laydown component. Install C8,. Install R1, 10K ohms brown-black-orange. Install Q1, the transistor marked 2N The flat side must be placed as shown on the PC board, facing C6. Mount it as close to the board as possible without forcing it. Check polarity! Install R2, ohms yellow-violet-brown. Install R4, 10K ohms brown-black-orange.

Install D1, the LED. The flat side goes toward switch S1. D1 indicates that the frequency is locked. Once the kit is enclosed, your friends will never know that you were new to soldering. Finally, the enclosure will protect your electronics from many possible causes of damage so that you can receive years worth of enjoyment using, talking about, and remembering the fun you had building your kit. This is the part that you and your friends will look at and admire for years!

Lay the front and rear plastic plates over their corresponding labels. Outline the holes that you need to cut using a pen or pencil. Use your hobby knife or paper punch to cut the labels to their outlines. Peel off the sticker backing on each sticker and place the labels over the plastic plates. Make sure that they are aligned correctly before allowing them to touch the plastic plates.

Believe me, when they stick the first time, they really stick! Insert the board into the case with the knobs and LED extending through the holes in the front panel. Raise the rear portion of the PC board and extend the jacks through the rear plastic plate. Insert the plate into the grooves on the base tray. Secure the PC board to the bottom base tray with 4 short Phillips head screws.

It is your responsibility to carefully research what FM stations can be listened to with a good system within the transmitting range of your FM25A. This is especially important in the low end of the FM broadcast band MHz , where there are numerous medium power National Public Radio stations.

You may not be aware of these stations but your neighbors may be receiving them, using a good receiver and outdoor antenna. Interfering with such reception is a direct violation of federal law. The most reliable way of finding a truly open frequency on the FM band is to check the band with a very good FM receiving system using an external antenna.

If you do not have access to such a radio, most modern car radios with exterior antenna are very sensitive and usable to help you know what stations your neighbors really can be receiving on a particular frequency. B In choosing an operating frequency, remember that most "digital-tuning" receivers, whether portable, mobile or hi-fi, are designed to tune in KHz increments and therefore might not receive well a signal operating between these pre-tuned standard broadcasting frequencies.

In order to comply with Part 15 of FCC regulations, it is your responsibility to determine carefully that your operation will not cause interference to broadcast reception. On these switches you add up the closed positions to make to make any number between 0 and 9. No audio input is needed to make this first adjustment, you can simply listen for a "quieting" in the normal background noise "hiss.

TP1 is located at the lead of R10 that is closest to the outside of the board. With an operating frequency of With a frequency of This is a good starting position. The best audio input for both testing and general operation are the stereo "line-level outputs" of a cassette deck or CD player. Most stereo systems have a variety of auxiliary output jacks of which one or more are line-level outputs.

Hooking up an audio source to your FM25A is really quite simple. Make sure you rotate each one about the same amount to maintain proper stereo balance. It will allow you to easily fade, mix and switch between various audio sources.

Stereo balance Adjust R6 for correct stereo balance. If you are transmitting in stereo adjust R6 to its center position. The better your ear for music and your understanding of quality audio devices and interconnections, the better will be the performance of your FM25A. This connection consists of using shielded audio cables to connect the auxiliary "line audio" output of your cassette deck, CD player or other stereo device to the audio inputs of the FM25A. Consult the literature that came with your stereo equipment.

Even if you intend use of the FM25A for your own home and family, it is still your responsibility, in accordance with Part 15 of the FCC Rules, to ensure that this operation does not cause interference to your neighbors. Operation of the transmitter itself consists simply of the following: 1. Correct construction and adjustment. Setting up a suitable antenna. Connecting the audio source to the Left and Right input jacks. Turning on the transmitter while you intend to be "on the air" and turning it off when you are finished.

Explaining how to build a simple audio "mixing" panel or box, which is at the heart of any studio operation, is beyond the purpose of this instruction manual. We do recommend that you build a mixing system, for several reasons: 1. Parts to do so are readily available at Radio Shack. It would be an excellent class, family or Scout project.

Commercially-made stereo mixing consoles, while much less expensive today than a decade ago, will cost much more than did your FM25A kit! The more home-built your complete setup, the more it is in conformity with the spirit of FCC Part 15 regulations. You can greatly add to the versatility and professionalism of your transmitting station by adding one of our audio mixers and processor.

Check out our free catalogue for all the details. Correct dipole lengths for major sections of the MHz band are: 88 MHz, each side: 2. Some antenna designers have the view that an "approximate" dipole such as 2. If the dipole is installed vertically, the end connected to the center conductor of the coax should be the upper higher end.

If young children will be around the set-up, a flexible wire antenna is preferable, rather than rigid tubing. A "ground plane" antenna can be quite effective. A ground plane consists of one vertical element, the same length as one side of a dipole, connected to the center conductor of the coax. Four "radials" are connected to the shielded side of the coax at a 90 to degree angle to the vertical element.

The dipole formula is also used to calculate the length of the radial; since radials should be slightly longer than the main element, use rather than in your calculations. If you are equipped to make the field strength measurements required by Part 15 FCC rules, and if you think it would be best to aim or "focus" your signal in a narrower direction, you can consult an antenna handbook and design a suitable gain antenna.

Also, you may wish to look at Radio Shack book No. It features proper impedance matching for optimum power transfer and range. See our catalog for details. If you know how, then do so - safely. If not, you can show your FM25A and this book to a licensed radio engineer and negotiate with that person for a safe installation which will feed your signal through interior wiring of your home or building.

Most stereo systems have a variety of auxiliary output jacks of which one or more are line-level outputs. Hooking up an audio source to your FM10A is really quite simple. Page Experimental Broadcasting Projects 2. It would be an excellent class, family or Scout project. Commercially-made stereo mixing consoles, while much less expensive today than a decade ago, will cost much more than did your FM10A kit! The more home-built your complete setup, the more it is in conformity with the spirit of FCC Part 15 regulations.

Page Troubleshooting Guide If you know how to do correctly, then do so - safely. If not, you can show your FM10A and this book to a licensed radio engineer and negotiate with that person for a safe installation which will feed your signal through interior wiring of your home or building. Page 20 Part Use our AM-1 AM radio broadcast kit for this use. FCC Rule No. However, this Rule does not, by itself, tell you everything you need to know about using a device of this kind.

Page 21 FM stations, this is a "generous" limitation designed to accommodate cruder FM devices. Properly built and adjusted, the FM10A kit operates well within this limit. In fact, its signal should sound no "wider" than any other FM station when listening on an ordinary FM radio.

Since it is unlikely that you have the equipment to carry out accurate field strength measurements in microvolts, it is useful to understand at least the theory of field strength so that you can understand both what you can expect from such transmitters, and what limits the FCC The main point is that you may not cause any interference whatsoever to licensed broadcast services and that you must be willing to put up with any interference that you may experience. Page 25 The radio-frequency "intentional radiator" device which may be constructed from kit parts supplied by us is intended and designed by Ramsey Electronics, Inc.

The individual kit-builder and all users of this device assume responsibility for lawful uses conforming to FCC Part 15 Rules. Page 26 [1] This device may not cause harmful interference, and [2] this device must accept any interference received, including interference that may cause undesired operation. Final comment A well-informed person will see today's FCC Rules to be evolving and progressively less-restrictive. Even though today's technology is far more complex than what was possible at the time of the Communications Act of , the FCC rules are becoming more relaxed, giving radio experimenters more and more opportunities to explore many frequency bands, using many All our kit parts carry the Ramsey Electronics Warranty that they are free from defects for a full ninety 90 days from the date of purchase.

Defective parts will be replaced promptly at our expense. If you suspect any part to be defective, please mail it to our factory for testing and replacement.