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NOTE: Limited supply left as of late 2014.  Please email us first before ordering.
See Order Form for prices.
For specific hookup info by model number, see the detailed Installation Instructions & Technical Notes.

Closeup of both CG filter types.

We have The Answer—the CHANNEL GUARD.  A unique active IF filter that wipes out CB radio's most annoying problem once and for all.

Fits all PLL or crystal CB radios using a 7.8 MHz or 10.695 MHz IF frequency.*  Usually installs in minutes with common tools and no special knowledge.  Connect the left & right bare wires to IN & OUT along the I.F. signal path.  (We tell you exactly where.)  Connect the middle bare wire and the long colored wire to the radio's GROUND and +DC power.  That's all there is to it!

                    Works on AM, FM, and SSB.

CB radio is popular. Maybe even too popular. Either the skip cycle is in, with great DX to crowd every channel, and all the Hams converting CBs to 10 Meters. Or the skip is dead, so every local guy in town seems to be busy talking to his neighbor at the same time as you. Many stations are overpowered and overmodulated, and are guaranteed to make your operating miserable with splatter and bleedover. Fed up with hearing the guy down the street ten channels away? The CHANNEL GUARD will stop him cold!

We have two CHANNEL GUARD filters to fit the most common CB IF frequencies, 10.695 MHz and 7.8 MHz.**

These high-frequency filters are specially designed for SSB rigs and most newer AM or AM-FM rigs. Simply unsolder the correct IF coupling capacitor listed in our detailed instructions, install the INPUT/OUTPUT leads and GROUND, and connect the long colored wire to +8-13VDC. You are done!  Complete instructions are included and are also online at the link shown above.

NOTE: The 455 KHz ceramic filter we sold for many years has been discontinued due to the greater use of our sharper crystal filters.  Although it was used in nearly all AM and AM/FM models at the second IF, the first or high IF is typically 10.695 MHz and these AM CBs can use our 10.695 MHz crystal filter with even better results.  That's because crystals are far sharper than ceramic elements.

Graph: I.F. Skirt Selectivity (8794 bytes)

Using the same idea as our original 455 KHz CHANNEL GUARD, the high-frequency SSB filters combine an IF amplifier stage with two high-Q crystal elements. You install our filter at an early IF signal point, before the signal branches off to the separate AM, FM, or SSB detectors. The result—razor-sharp selectivity in every mode. Since the "Q" (Selectivity Factor) of a crystal is many times higher than the normal tuned IF transformers in a CB, the strength of interfering signals even slightly off the center frequency drops off very quickly. Bleedover is greatly reduced. See the Graph.

Provides up to 100 dB adjacent-channel rejection. This is much better than most CBs, which typically specify only –40 dB to –60 dB. A factor of "100 dB" means that any signal outside the normal 10 KHz CB channel spacing is reduced in strength by a factor of 10 billion from channel center. Turn your ordinary rig into a hot performer!
No reduction in receiver sensitivity. In fact, the CHANNEL GUARD adds one stage of amplification at the most critical point—right in between IF filtering stages. You may even hear those weak signals that you missed before.
Every REACT monitor needs one to eliminate Channel 9 bleedover.
Quality components used. Each CHANNEL GUARD is hand-made and thoroughly checked against a powerful 30,000 V modulated test signal.
Just solder it in and forget it!

* Most CBs use these IF frequencies. The dual-conversion SSB rigs with a 455 KHz IF only use that frequency for AM or FM; otherwise nearly all SSB types are 7.8 MHz or 10.695 MHz. The AM-only or AM/FM-only radios almost always use a 455 KHz low IF, and our 10.695 MHz filter will usually work in these at the first IF location. If in doubt, send us an email or a large stamped SASE with the exact radio model and we can advise you what works and how to install it.
** There are also some older SSB radios with an 11.275 MHz high IF.  Models include JC Penney, Lafayette, Sears, and others.  For these CBs we still have a limited supply of 11.275 MHz monolithic (3-lead) crystal filters that greatly improve their selectivity.  If interested send us your mail or email questions or model numbers.

Our 10.695 MHz filter really cleans up all the Uniden, Cybernet, and RCI/Ranger “export” radios, and all the CB &
10-Meter lookalikes (HR2510/HR2600, Cherokee, Connex, Eagle, Galaxy, Ham Int'l, Magnum, Mirage, Northstar, Ranger/RCI, Superstar, TriStar, etc.)
And in every mode!  See Pages 4-6 of the online CG HOOKUP LIST,

Manufactured by:
TEL/FAX: 888-I-FIX-CBs (1-888-434-9227), (520) 298-7980
Electronic Mail:
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