Instruction/ maintenance manual of the product FT146 Ramsey Electronics
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FT146 • 1 2 METER FM 5 W A TT TRANSMITTER KIT Ramsey Electronics Model No. FT146 • Dire ct, tr ue FM for excel lent voice and dat a qual it y. • Both Data a nd mi ke audi o inputs • Solid 5 watt RF ou tput - add our PA -146 for 40 watts • Crystal controlled with 146.
FT146 • 2 RAMSE Y TRANSMI TTER KITS • FM10, FM-25 FM Stereo Tr ansmitters • TV6 Tele vision Transmi tter • Cube TV Tra nsmi tt er s RAMS EY RE CEI VER KI TS • FR1 FM Broadcast Receiver • A.
FT146 • 3 FT146 FM RECEIVER KIT Ramsey Publication No. M FT146 Price $5.00 TABLE OF CONTENTS I ntroduc tion to the FT146 .............. 4 Circ uit Desc ription ......................... 5 Parts List ............................. ........... 6 FT146 Asse mbly Instructio ns .
FT146 • 4 INTRO DU CTION Two meter FM has been around for y ears, but never with the popularity that is enjoyed today. In the old da ys, hams snooped around the local tw o-way radio shop in search of an obsolete ta xi cab or police radio.
FT146 • 5 and IC chip) give the equ ivalen t of ab out 130 or more tran sistors an d diodes. And, in addition to 13 inductors, a crystal and the various plus and jacks, there are over 60 capacitors and resistors.
FT146 • 6 into transm it. There is no need to con trol the voltage to any other tran sistor s since they a ll operate class "C". A class C am plifier draws no current unless it is driven, so there is no need to s wit ch the later stag es on and off .
FT146 • 7 Inductors and ferrite co res: ❒ 2 Shielded can tunable inductor (marked 007007) [L9,13] ❒ 2 Tunable indu ctor (pink plastic body ) [L5,11] ❒ 2 6 hole ferrite bead core [L1,6] ❒ 2 S.
FT146 • 8 RAMSEY Learn-As-You-Build KIT ASSEMBLY: There are over 200 solder connections on the F T146 printed circuit board. Th at means your work could be 99% perfect and you could STILL ha ve 2 or 3 cold solder points or so lder bridges.
FT146 • 9 ❒ 3. Install J2, the subminiature phone jack. Solder all three points. Be gentle and patient in inserting, so as not to damage the solder tabs. ❒ 4. Install R13, 5K trimm er pot. This is the modulation adjustment control. ❒ 5. Install U1, LM358 op-a mp IC chip.
FT146 • 10 ❒ 21. Install R15, 10K ohm (brown-black-orange). ❒ 22. Install C33, .001 uf disc capacito r (marked .001, 1 nf or 102). ❒ 23. Insta ll R16, 10K ohm, (br own-black-orang e).
FT146 • 11 ❒ 41. Install R7, 470 ohm (y ellow-violet-brown). ❒ 42. Identify Q1, a 2N3904 N PN transi stor (m arked 2N3904). I nstall Q1 , observing correct placement of the flat side. ❒ 43. Install Q2, anot her 2N39 04 NPN transistor (marked 2N3904).
FT146 • 12 ❒ 60. Install C21, 4.7 or 5 pf disc capacitor (marked 4.7 or 5 or 4.7K or 5K). ❒ 61. Install L9, slug tune d shielded coil (marked 007007). This coil is part of the first tripler section. It is tuned to the third harm onic of t he crystal oscillator.
FT146 • 13 stages of your transmitter. W e recommend that you get them ready for installation before assemb ling the Driver and Final stages. If you prefer to proceed with those stages, winding coils a s you go, that's f ine, too, as long as you realize th at all coil making details are provided in this section.
FT146 • 14.
FT146 • 15.
FT146 • 16 The "legs" o r leads f or inserting L2 , L7, L3 an d L4 sh ould be abou t " long. These coils should sit about 1/8" maximu m above the PC board w hen soldered. ❒ 80. Install L12, on e of the small 3 turn ferrite bead RF chokes y ou wound.
FT146 • 17 ❒ 97. Install D4, 1N4148 sty le signal diode (glass body with black band). Observe c orrect or ientation of the ba nded end. ❒ 98. Install TP3, the last test point. Se lect a 1K resistor, R29 (bro wn-b lack- red). Trim back one lead w i re to a length of inch.
FT146 • 18 ❒ 112. Install C2, 100 to 220 uf electr olytic capacitor. Be sure to observe polarity - especially with this part since it is directly across th e power supp ly and if reversed, could overheat so fast, so much that it could explode ! ❒ 113.
FT146 • 19 coil drastically whenever it is insert ed into the coil. Y ou may use a metal hex key if you are awar e of this ef f ect and are willing to remove the hex key from the coil after ea ch adjustment. Although not re commended, w ith a little patience and sandpaper, a useable tool may be formed from a piece of wood or plastic rod.
FT146 • 20 ❒ 8. Move your meter probe over to TP2, key the transmitter and adjust L5 and L11 for maximum negative read ing. Once aga in, go back and forth between th e two coils. You should get a reading of at least -120 mV. It is very important to tune for th e best peak as this will ensure proper transmitter operation.
FT146 • 21 transmitter keyi ng in a rece iver is of some help, but even the sim plest crystal oscillator can send a fi ne signal into your neighbor's receiver. Ideally, yo u have a small RF wattmeter, already inserted in the antenna line, capable of accurately measuring low outp ut power in watts.
FT146 • 22 Amateur radio magazines and handbooks provide a variety of circuits for RF wattmeters and relative field -strength indicators, including methods of using your VOM as an indicating device.
FT146 • 23 "hum-m-m-, that's not a .001 uf where a 100 pf should be is it?" If there is a problem in getting the m odulation working, a scope or audio amplifier will allow tracing down any pr oblem in sh ort orde r. The microphone audio is amplifier by about 350 times in U1:B.
FT146 • 24 Here's a handy reference chart for the 5 pin DIN jack PIN # FUNCTION 1 +12 VDC power input 2 Power ground 3 Audio input 4 Audio ground 5 PTT (Push-To-Talk) Audio level required is in the 10 to 50 mV range. PTT requ ires a path to ground of less than 10K ohm s.
FT146 • 25 NOTE ON REP LAC EME N T P ARTS : If you lose or damage parts during assembly or testing, you may, of course, order any needed replacement parts by writing or faxing the Ramsey Electronics, Inc. f actory. Som e of the more common parts m ay also be picked up at Radio Shack or other local parts distributors.
FT146 • 26 FT146 PARTS LAYOUT DIAGRAM.
FT146 • 27 The Ramsey K it Warranty Ple ase read caref ully BEF ORE cal ling or writ ing in about you r kit. Most prob lems can be solv ed w ithou t co ntac ting the fac tory. Notice that thi s is not a " fine print" warranty. W e w ant you to unders ta nd your ri ghts and o urs too ! All Ramsey kits w ill work if assemble d properly .
FT146 • 28 FT146 2 Meter FM Transmitter Kit Quick Reference Page Guide I ntroduc tion to t he FT146 .............. 4 Circuit Descri ption .......................... 5 Parts List ................ ........................ 6 FT146 Assembly Instru ctions .
An important point after buying a device Ramsey Electronics FT146 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Ramsey Electronics FT146 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Ramsey Electronics FT146 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Ramsey Electronics FT146 you will learn all the available features of the product, as well as information on its operation. The information that you get Ramsey Electronics FT146 will certainly help you make a decision on the purchase.
If you already are a holder of Ramsey Electronics FT146, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Ramsey Electronics FT146.
However, one of the most important roles played by the user manual is to help in solving problems with Ramsey Electronics FT146. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Ramsey Electronics FT146 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
