Ft146 • 1 2 meter fm 5 watt transmitter kit ramsey electronics model no. Ft146 • direct, true fm for excellent voice and data quality. • both data and mike audio inputs • solid 5 watt rf output - add our pa-146 for 40 watts • crystal controlled with 146.52 mhz crystal included • built-in test points...
Ft146 • 2 ramsey transmitter kits • fm10, fm-25 fm stereo transmitters • tv6 television transmitter • cube tv transmitters ramsey receiver kits • fr1 fm broadcast receiver • ar1 aircraft band receiver • sr2 shortwave receiver • aa7 active antenna • sc1 shortwave converter ramsey hobby kits • rb1 rat...
Ft146 • 3 ft146 fm receiver kit ramsey publication no. Mft146 price $5.00 table of contents i ntroduction to the ft146 .............. 4 circuit description ......................... 5 parts list ........................................ 6 ft146 assembly instructions ........ 8 testing and alignment ....
Ft146 • 4 introduction two meter fm has been around for years, but never with the popularity that is enjoyed today. In the old days, hams snooped around the local two-way radio shop in search of an obsolete taxi cab or police radio. These radios were in the 150 - 174 mhz business band and were easil...
Ft146 • 5 and ic chip) give the equivalent of about 130 or more transistors and diodes. And, in addition to 13 inductors, a crystal and the various plus and jacks, there are over 60 capacitors and resistors. Surely, all that should result in a decent transmitter! You could easily spend twice the mon...
Ft146 • 6 into transmit. There is no need to control the voltage to any other transistors since they a ll operate class "c". A class c amplifier draws no current unless it is driven, so there is no need to switch the later stages on and off. Ft146 2 meter fm transmitter kit parts list capacitors: ❒ ...
Ft146 • 7 inductors and ferrite cores: ❒ 2 shielded can tunable inductor (marked 007007) [l9,13] ❒ 2 tunable inductor (pink plastic body) [l5,11] ❒ 2 6 hole ferrite bead core [l1,6] ❒ 2 small ferrite bead core [l10,12] ❒ 2 aluminum coil shield cans [for l5,11] semiconductor devices: ❒ 1 1n4002 style...
Ft146 • 8 ramsey learn-as-you-build kit assembly: there are over 200 solder connections on the ft146 printed circuit board. That means your work could be 99% perfect and you could still have 2 or 3 cold solder points or solder bridges. Since this circuit is more sophisticated than a direct-conversio...
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 trimmer pot. This is the modulation adjustment control. ❒ 5. Install u1, lm358 op-amp ic chip. In installing the ic, you may ...
Ft146 • 10 ❒ 21. Install r15, 10k ohm (brown-black-orange). ❒ 22. Install c33, .001 uf disc capacitor (marked .001, 1 nf or 102). ❒ 23. Install r16, 10k ohm, (brown-black-orange). Time for a breather and progress check. So far, we've built up the audio section of our transmitter, from microphone amp...
Ft146 • 11 ❒ 41. Install r7, 470 ohm (yellow-violet-brown). ❒ 42. Identify q1, a 2n3904 npn transistor (marked 2n3904). Install q1, observing correct placement of the flat side. ❒ 43. Install q2, another 2n3904 npn transistor (marked 2n3904).Observe correct placement of the flat side. ❒ 44. Install ...
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 tuned shielded coil (marked 007007). This coil is part of the first tripler section. It is tuned to the third harmonic of the crystal oscillator. ❒ 62. Install l13, another slug tuned shi...
Ft146 • 13 stages of your transmitter. We recommend that you get them ready for installation before assembling the driver and final stages. If you prefer to proceed with those stages, winding coils as you go, that's fine, too, as long as you realize that all coil making details are provided in this ...
Ft146 • 14.
Ft146 • 15.
Ft146 • 16 the "legs" or leads for inserting l2, l7, l3 and l4 should be about " long. These coils should sit about 1/8" maximum above the pc board when soldered. ❒ 80. Install l12, one of the small 3 turn ferrite bead rf chokes you wound. Pull it up snug against the pc board and solder. ❒ 81. Insta...
Ft146 • 17 ❒ 97. Install d4, 1n4148 style signal diode (glass body with black band). Observe correct orientation of the banded end. ❒ 98. Install tp3, the last test point. Select a 1k resistor, r29 (brown-black- red). Trim back one lead wire to a length of inch. Bend this wire into a small loop as b...
Ft146 • 18 ❒ 112. Install c2, 100 to 220 uf electrolytic capacitor. Be sure to observe polarity - especially with this part since it is directly across the power supply and if reversed, could overheat so fast, so much that it could explode! ❒ 113. Install d5, 1n4002 style black epoxy diode, observe ...
Ft146 • 19 coil drastically whenever it is inserted into the coil. You may use a metal hex key if you are aware of this effect and are willing to remove the hex key from the coil after each adjustment. Although not recommended, with a little patience and sandpaper, a useable tool may be formed from ...
Ft146 • 20 ❒ 8. Move your meter probe over to tp2, key the transmitter and adjust l5 and l11 for maximum negative reading. Once again, go back and forth between the two coils. You should get a reading of at least -120 mv. It is very important to tune for the best peak as this will ensure proper tran...
Ft146 • 21 transmitter keying in a receiver is of some help, but even the simplest crystal oscillator can send a fine signal into your neighbor's receiver. Ideally, you have a small rf wattmeter, already inserted in the antenna line, capable of accurately measuring low output power in watts. And it ...
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. Cq magazine for march 1990 offers an article by kb4zgc on how to make a highly accurate yet inexpensiv...
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 modulation working, a scope or audio amplifier will allow tracing down any problem in short order. The microphone audio is amplifier by about 350 times in u1:b. You should see at least a ...
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 requires a path to ground of less than 10k ohms. Other enclosure recommendation...
Ft146 • 25 note on replacement parts: 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. Factory. Some of the more common parts may also be picked up at radio shack or other local parts dist...
Ft146 • 26 ft146 parts layout diagram.
Ft146 • 27 the ramsey kit warranty please read carefully before calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All ramsey kits will work if assemble...
Ft146 • 28 ft146 2 meter fm transmitter kit quick reference page guide i ntroduction to the ft146 .............. 4 circuit description .......................... 5 parts list ........................................ 6 ft146 assembly instructions ........ 11 testing and alignment ................... ...
