Ramsey electronics model no. Sca1 • tunes entire sca subcarrier band 50 - 100 khz • excellent performance - uses pll decoder • feature both speaker and line-level audio outputs • connects to any fm receiver or simply plugs into our fr-1 fm broadcast receiver • band-pass filtered input for excellent ...
Sca1 • 2 ramsey transmitter kits • fm100b professional fm stereo transmitter • fm25b synthesized stereo transmitter • am1, am25 am transmitters • tv6 television transmitter ramsey receiver kits • fr1 fm broadcast receiver • ar1 aircraft band receiver • sr2 shortwave receiver • aa7 active antenna • s...
Sca1 • 3 ramsey publication no. Msca1 price $5.00 table of contents introduction to the sca .................. 4 fm and subcarrier background ...... 4 circuit description .......................... 6 parts list ......................................... 7 parts layout diagram ...................... 9...
Sca1 • 4 introduction the ramsey subcarrier adapter kit allows you to hear the commercial free background music that is broadcast along with some commercial fm signals. This is accomplished by connecting the sca1 to a standard fm broadcast receiver tuned to the local fm station which is providing th...
Sca1 • 5 fm broadcasting and subcarriers - some background before we explain how the sca decoder works, we first need to know what it is "looking" for in the received fm signal. (a note to newcomers: don't let this description scare you. Rest assured that your sca decoder will perform the desired ta...
Sca1 • 6 well, you may say, that works out nicely, but why not just transmit a separate left and separate right channel, and avoid the math? There are a couple of reasons why: one, to receive on a mono receiver, the receiver would have to detect and demodulate both left and right signals and combine...
Sca1 • 7 sca1 subcarrier demodulator kit parts list resistors 1 2 ohm [red-black-gold] r13 4 1k ohm [brown-black-red] r8,9,10,11 1 2.2k ohm [red-red-red] r3 4 10k ohm [brown-black-orange] r2,5,6,7 1 22k ohm [red-red-orange] r14 1 220k ohm [red-red-yellow] r4 capacitors 3 .001 uf disc [marked .001 or...
Sca1 • 8 sca subcarrier demodulator parts layout diagram.
Sca1 • 9.
Sca1 • 10 ramsey learn-as-you-build kit assembly: we have a two-fold "strategy" for the order of the following kit assembly steps. First, we install parts in physical relationship to each other, so there’s a minimal chance of inserting wires into wrong holes. Second, whenever possible, we install in...
Sca1 • 11 now let's start building 1. Press s1 firmly into its six holes and solder all six pins. The switch fits the board only one way. 2. Install j1 and j2, the rca-style audio jacks. Solder all 4 points. You'll notice that the mechanical grounding tabs will take longer to solder. This is due to ...
Sca1 • 12 13. Install r4, 220k ohm [red-red-yellow]. 14. Install q1, the 2n3904 transistor. The pc board drawing shows how the flat side of each transistor points in relation to other parts. To install a transistor, press its three leads in place as far as they go without forcing. The wires may be s...
Sca1 • 13 25. Install c1, .01uf disc [marked .01 or 103 or 10nf]. 26. Install c11, .001uf disc [marked .001 or 102]. 27. Install c3, .001uf [marked .001 or 102]. 28. Using a scrap resistor lead, form a jumper wire to insert in the pc board in the jmp1 position. Jumpers act as electronic bridges carr...
Sca1 • 14 42. Install c18, 220 uf electrolytic. Again, check that polarity! 43. Install c19, .1 uf disc [marked .1 or 104]. 44 install c20, .01 uf disc [marked .01 or 103 or 10nf]. 45. Next we'll install u2, the lm 386 audio amplifier ic. Use care when inserting the ic into the circuit board not to ...
Sca1 • 15 1. Install a fresh 9 vdc battery; an alkaline is preferred. 2. Push the power switch to the "on" position. The unit should draw about 20 ma from the 9 vdc source, without a speaker connected. 3. Using a frequency counter or oscilloscope connected to tp1, verify that there is a square wave ...
Sca1 • 16 contained on the received signal. If you have a receiver with such an output jack, you're in luck; simply hook-up the sca-1 to that jack. If your radio does not have a multiplex output jack but you are fortunate enough to have the schematic of your receiver, then look for the point where t...
Sca1 • 17 troubleshooting guide if your sca1 doesn't work, a thorough check of the component placement will usually turn up the problem. Checking your work backwards through the assembly steps is very effective in locating placement errors. If the unit appears to operate correctly, but just doesn't ...
Sca1 • 18 • problem: audio is good from the low level output jack, j2, but no speaker audio. • solution: check all circuitry around u2, the audio amplifier section. • problem: unit has low frequency "growl," squeal or erratic operation when volume is turned up. • solution: it’s nothing more than a d...
Sca1 • 19 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 assembled...
Sca1 • 20 sca1 fm subcarrier decoder kit quick reference page guide fm and subcarrier background .......4 circuit description ...........................6 parts list ..........................................7 parts layout diagram .......................9 schematic diagram .......................10 ...
