See Secure Order Form for prices. Schematic Diagram (39K GIF)
SUPER EXPO
Crystal Oscillator & Mixer
INCLUDES T/R SPLIT CIRCUIT FOR 10-METER REPEATERS!
Our SUPER EXPO frequency modification kit is perfect for all your CB and HF applications. It consists of a local oscillator which can switch up to 4 crystals of your choice, a mixer stage, and an offset circuit for 10-Meter repeater splits or other duplex operation. Each mixing crystal will generate a complete 23- or 40-channel band, and is fully adjustable with trimmers.See the Block Diagrams below. To modify frequencies you no longer have to change the program coding or inject new mixing signals inside a PLL circuit, often with complicated retuning procedures. Instead it's now as easy as 1, 2, 3! First, break the PLL's VCO signal at the output side, where a common PC trace or coupling capacitor in the radio leads to the Receive Mixer and Transmit Mixer stages. Then connect the PLL side of the break to the input of SUPER EXPO. Last, connect the output of the SUPER EXPO to the other side of the break. The crystal oscillator in the SUPER EXPO will mix with the radio's VCO to generate a totally new injection signal. This new signal when applied to the radio's RX and TX mixers will change the transceiver's operating frequency.
The right-hand Block Diagram shows that the SUPER EXPO will also modify crystal-synthesized CBs, without having to change a whole bank of crystals. (Doing that would still give you just 23 new frequencies.) Instead, you'll now get an entire 23-channel band of frequencies for each mixing crystal you choose. This means a possible total of 4 x 23 = 92 channels from these great old high-performance rigs! The reason is because you only need to sample from the composite synthesizer output signal that results from mixing all those crystals. (Just like a PLL's VCO output.)
The SUPER EXPO has no effect on the PLL or crystal synthesizer circuits themselves, and these continue to work normally. This includes the Clarifier circuit; you can modify that just as you normally would if the SUPER EXPO wasn't there. So you can stop worrying about things like out-of-lock conditions, accidentally blowing up an obsolete PLL chip, realignment of the PLL or crystal synthesizer, or upsetting the alignment of the USB/LSB offsets. Why? Because you are connected externally to the synthesizer circuit! This greatly simplifies many installations.
Finally, many popular PLL SSB rigs like the Cobra 138/139XLR use separate mixing crystals, one each for AM, USB, and LSB. Which meant you had to change all three of them if you wanted to keep all modes. The SUPER EXPO solves this problem because each mode's carrier frequency is generated inside the loop, and you never touch the inside of the loop.
EXAMPLE OF PLL MODIFICATION:
Newer radios like the Courier Galaxy V, Galaxy VI, and Midland 79-265 use the LC7131 PLL
chip in a single crystal (10.240 MHz) circuit. Not easily modified until now. The IF
is 10.695 MHz, and the Ch.1 AM VCO is normally 16.270 MHz. By mixing this signal with
a crystal oscillator of say, 22.725 MHz, you get a mixing product of [16.270 MHz + 22.725
MHz] = 38.995 MHz at the output of the SUPER EXPO. When you mix this
product with the 10.695 MHz IF of the radio, the result is a totally new Ch.1 carrier
frequency of [38.995 MHz –10.695 MHz ] = 28.300 MHz in the 10-Meter band. Just
choose the crystals for the frequencies and/or splits you want.
EXAMPLE OF CRYSTAL RADIO MODIFICATION: Johnson Viking 352, Midland 13-893, 13-895, Pace 1000M, 1000B. These excellent old SSB rigs used banks of 8 MHz and 11 MHz crystals in a very complicated synthesizer circuit. That doesn't matter! The IF is 7.8 MHz, and the Ch.1 USB synthesizer output is 34.765 MHz. By mixing this with your local crystal of say, 14.265 MHz, the result is [34.765 MHz – 14.265 MHz] = 20.500 MHz at the output of the SUPER EXPO. Mixing this 20.500 MHz with the 7.8 MHz IF gives you [20.500 MHz + 7.8 MHz] = 28.300 MHz again.
We've designed the SUPER EXPO for
maximum parts and circuit flexibility. You can choose several configurations:
1. Straight 160 (or 92) channels: 40 (or 23) channels per
mixing crystal.
2. 120 (or 69) channels + T/R repeater offset for 10M FM use: 40 (or 23) channels per
crystal in 3 bands, plus one offset band of 40 (or 23) channels.
3. A straight 80 channels for the impossible AM type rigs using the LC7131 or TC9106 PLL
(one crystal needed for each mode, RX and TX, resulting in 40 channels for each of the 2
crystal pairs.)
The SUPER EXPO is powered from a regulated +7–10VDC source in the radio. Current drain is a tiny 13 mA @ 8VDC. There are only four wire connections to the radio: VCO/SYNTH. IN, RF OUT, +DC, –DC. A fifth wire would be connected to a TX-only voltage source if you plan to use the T/R split feature. Dimensions are 2˝" x 3". The quality PC Board has a solder mask and a printed parts legend for easy assembly. Complete kit contains all parts except switch. The 16-page instructions include circuit theory, crystal calculations and suppliers, hookup examples for many popular PLL and crystal CB radios, schematic, parts list and layout, installation and alignment, troubleshooting hints, and more. Just order your crystals, stuff the board, and go! NOTE: Crystals are not included due to the large number of possibilities.
IMPORTANT TECHNICAL NOTES — READ BEFORE
ORDERING!
1. A Frequency Counter, 30 MHz oscilloscope and service manual or SAMS Fotofacts® are
required to properly align and install the SUPER EXPO. An
RF Signal Generator would also be useful for pre-alignment before installation.
2. The SUPER EXPO won't work with any of the following PLL
circuits: C5121, LC7132, LC7136/37, LC7185, LC7232, LC7234, MB8733, PLL03A, PLL08A,
SM5124A, TC9109. These are generally found in the cheaper AM-only rigs, not SSB types. The
SUPER EXPO will work with any PLL circuit using discrete TX
and RX mixer stages, including most of the formerly "impossible" chips like the
LC7131 and TC9106.
3. Radios with frequency displays (Cobra 2000/2010GTL, Courier Galaxy VI, Uniden HR2510,
HR2600, etc.) will not show the modified frequency. The SUPER EXPO
inverts the L.O. mixer injection, from high side to low side or vice versa depending upon
the radio. The radio’s built-in display only works with the existing VCO frequency
and since the SUPER EXPO doesn't affect the VCO, the display won't
be affected either.
4. A few older rigs use separate 19 MHz and 34 MHz VCOs for AM/LSB and USB. You can only
choose one VCO and therefore one mode (such as USB for 10-Meter Novice use), so check your
synthesizer circuit first.
5. The SUPER EXPO may not physically fit inside some of the
smaller mobile CBs, so check all dimensions carefully first.
The SUPER EXPO works with all the same radios that can currently use our EXPANDER 160 or EXPANDER 240 kits, as well as the 23-channel and more difficult PLL models. For many radios our simpler kits will do. When deciding which kit to buy, you should consider things like price, size, ease of construction and installation, available test equipment, technical experience, and your need for T/R splits.
SOLD EITHER AS COMPLETE KIT OR AS PLANS + PC BOARD
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