Subject: PRO51 MOD There is an interesting test mode in the PRO-51 that, combined with the direct search feature of the scanner, lets you pick up out-of-band frequencies. You will have full access to the 66-88 Mhz ranges as well as the cellular base range of 869-896 Mhz. Actually, there are several test modes in the PRO-51 (most of these comments should be true for any Uniden-made Radio Shack scanner, such as the PRO-46). I'll describe them first and then how to take advantage of one of them to get the restricted frequencies. There are three data test modes. These modes completely destroy any frequencies you had programmed into your scanner, so it's best to use these techniques before you program your scanner. If you have already programmed it, you'll have to decide if these new capabilities are worth reprogramming. TEST MODE 0. Clear the scanner. -------------------------------- A well-known method of clearing the scanner to all zeros is to hold down the 2 key, the 9 key, and turn on the scanner. All frequencies will be lost. TEST MODE 1. Fill channels 1-25 with test frequencies. ------------------------------------------------------- Press the 2 key, the 9 key, the L/Out key, and turn on the scanner. This fills channels 1-25 with these frequencies: 1 30.050 2 40.840 3 49.900 4 138.150 5 162.400 6 173.225 7 406.875 8 453.250 9 511.9125 10 108.500 11 118.800 12 127.175 13 135.500 14 66.450* 15 76.825* 16 87.425* 17 157.800 18 482.3625 19 29.000 20 54.000 21 806.000 22 857.200 23 888.96* 24 911.500 25 954.9125 * indicates not within the PRO-51's normal coverage. More on how to use these in a minute. TEST MODE 2. Fill channels 1-17 with test frequencies. ------------------------------------------------------- Press 2, 9, Manual Fills channels 1-17 with these frequencies: 30.00, 40.00, 50.00, 140.00, 155.00, 170.00, 410.00, 460.00, 510.00, 54.00, 109.00, 118.00, 127.00, 135.00, 810.00, 860.00, 950.00. There is also a display diagnotic mode. TEST MODE 3. Display Test. ------------------------------- Press 2, 9, BAND or 2, 9, MONI. This put the display in test mode. Every annunciator and every digit element is turned on in a scan from the left side of the display to the right. To keep this test mode continuous, release the buttons before the first scan finishes. This mode does not affect stored memory. Press any key to exit this display mode. Now, if you've decided to try test mode 1, you will find several out-of-band frequencies stored in your memory channels. Channels 14-16 hold frequencies in the blocked-out 66-88 Mhz range, and channel 23 holds a frequency in the blocked-out cellular base range. Once you have these frequencies stored in a memory channel, the PRO-51's direct search feature will let you search though these ranges. In the cellular band, the scanner searches in the correct 30 Khz steps. You don't have to keep these frequencies in the channels they were stored by the test mode. You can move them to any channel in the scanner. HereUs how. First move the frequency to a monitor channel: While on a channel with one of these frequencies, open squelch completely. Press direct search button, either up or down. The direct search button puts the scanner into search mode and the open squelch holds the frequency. Then press the Monitor button. The frequency is now in the monitor channel indicated in the display. Now you can move it to any regular memory channel in the scanner: Enter the channel number Press PROG Press MONI Press the number of the monitor channel if the proper channel is not displayed Press E(nter) The frequency is now permanently stored in the memory channel. You can do a direct search from this memory channel at any time. The 66-88 Mhz range mainly covers TV audio. However, there is a strange phenomenon concerning TV audio and the PRO-51. Channels 4, 5, and 6 fall within the 66-88 Mhz range (71.75 Mhz, 81.75 Mhz, and 87.75 Mhz respectively), yet the PRO-51 will not pick up the audio frequency while searching in this range. However, TV channel 2 audio is at 59.75 Mhz. When you add the intermediate frequency of 21.6 Mhz, you get an image of the TV channel 2 audio appearing at 81.35 Mhz. This does come in, although raspy, since the PRO-51 is receiving in narrow FM mode while TV audio requires wide-band FM mode for proper reception. I'd be interested if anyone can verify that any of these test modes work on the PRO-46 or any other Uniden-made Radio Shack scanner. Howard Bornstein CompuServe 76174,637 Internet: 76174.637@compuserve.com -------------------------------------------------------------------- Piran Mohazzabi piran@freenet.fsu.edu From: moy@xp.psych.nyu.edu Newsgroups: rec.radio.scanner Subject: PRO-51 Mod: Shorten squelch tail Date: 20 Sep 1994 20:34:06 -0500 Organization: UTexas Mail-to-News Gateway Lines: 89 Sender: nobody@cs.utexas.edu Message-ID: <9409210139.AA07611@xp.psych.nyu.edu> NNTP-Posting-Host: news.cs.utexas.edu Hello fellow scanbots, Radio Shack PRO-51: Modification to shorton squelch tail This change was performed successfully on a unit coded "11A3." The CPU in this unit was marked "Uniden UC1581." Use the following information at your own risk! Neither I nor my employer are responsible for any damages you may incur from this information! Orientations are with the set flat on a work surface, LCD display facing down, with antenna BNC and knobs facing away from yourself. As with any electronic instrumentation, remove all power and take all necessary precautions to prevent damage from electrostatic discharge (ESD). This modification requires fine soldering and familiarity with surface mount devices. CAUTION: Be aware that parts of the circuitry will *still* be powered! There is a capacitor on the digital board that keeps the channel memory alive. This capacitor may contain enough energy to damage the electronics should a short occur. Parts required: One 1/10th watt carbon resistor, 100K to 220K. Value is not critical. A lower value shortens the time the squelch remains open after incoming signal stops. The resistor should physically as small as possible. Opening Case Fortunately, this set is very easy to open. Open battery compartment and remove batteries. Remove four screws: two straddle the sticker on the back of the cabinet, two others at the upper part of the battery compartment. There are two small plastic detents at the floor of the battery compartment. They are directly downwards from the "-" and "+" legends, which are molded on an extension of the removable back. These detents will need to be unhitched to allow the back to separate from the front. Pull back off gently. Remove RF board The RF board is attached to the top panel, which contains the volume and squelch controls and the antenna connector. At this point, the board is essentially free and will separate from the rest of the set when the header connector at the lower right is pulled apart. This header provides electrical connections between the two boards. Lift the RF board straight out, and set the rest of the radio aside. Flip RF board over, keeping BNC pointing away from yourself. Add resistor Refer to the ASCII diagram below. Bend one of the resistor leads close to the body of the resistor so that the resistor forms a hairpin shape. Trim leads and solder the new resistor in parallel with the chip resistor marked "105." The latter is positioned between the two surface-mount IC's towards the bottom of the RF board. Press the new resistor parallel to the circuit board, making sure there are no shorts. +------------+ [101] | | | | [684] | NJM2090V | | | [224] | | +------------+ [ ] [ ] [ || ] [225] [105] [123] | | | +-+ | |R| <---add resistor: 100K - 220K | +-+ \_/ +------------+ | | | | | TK11900M | | | | | +------------+ Thanks to Bob Parnass for clarifying the nature of the "squelch tail" problem and for inspiring me to figure out this modification. Moy Wong (moy@xp.psych.nyu.edu) Dept. of Psychology, New York University