Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 exptools; site ihu1h.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!ihu1h!parnass From: parnass@ihu1h.UUCP (Bob Parnass, AJ9S) Newsgroups: net.ham-radio Subject: Trick the ICOM R71A below 100 kHz Message-ID: <479@ihu1h.UUCP> Date: Tue, 12-Feb-85 08:44:28 EST Article-I.D.: ihu1h.479 Posted: Tue Feb 12 08:44:28 1985 Date-Received: Wed, 13-Feb-85 03:53:43 EST Distribution: net Organization: AT&T Bell Laboratories Lines: 42 x Tricking the ICOM R71A to Tune Below 100 kHz Bob Parnass, AJ9S The ICOM R71A general coverage receiver is designed for VLF reception down to about 0.097 MHz. The following steps will confuse the microprocessor-based controller sufficiently to permit reception down to 0.0 MHz: 1. If all 32 memory channels contain frequencies, use the FUNC and CLEAR buttons to clear a memory channel. 2. Place VFO/M switch into the M (Memory) position. 3. Using all the manual dexterity you can muster, rock the Main Tuning knob back and forth, while simul- taneously rocking the MEMORY-CH rotary control to switch back and forth between a memory channel with a frequency in it and a clear memory channel. 4. While manipulating both the controls described in the previous step, a frequency of 0.000.0 will appear on the digital display. You can now rotate the Main Tuning knob clockwise to tune up from 0.000 MHz to the frequency you want. Be careful: if you rotate the Main Tuning knob counter- clockwise, the radio will immediately revert to 29.999 MHz. I used a Wavetek 180 sweep/function generator to verify that the R71A is indeed receptive to signals below 100 kHz. To make things easier, store the 0.000 MHz frequency in a memory channel for future use. That way, you don't have to use two hands every time you tune below 100 kHz. -- =============================================================================== Bob Parnass, Bell Telephone Laboratories - ihnp4!ihu1h!parnass - (312)979-5414