A very good radio, with a good selection of bandwidths and step sizes. Can be computer-controlled and it has a discriminator output on the AUX connector. Also has a 10.7 MHz IF output on the back.

A fairly good performer, although mine could use a speaker mod to eliminate the audio cutting in and out that can occur.

Like many owners, I'm looking for the Service Manual for this rig. So far all I have are the schematics.

Four-channel scanning in the VHF band.

GRE America closed down in 2012 and in September 2013 the intellectual property rights were purchased by the Whistler Group of Bentonville, Arkansas.

ICOM bungled the release of the control protocol, but it's been reverse-engineered and is available on the Internet.

As with any receiver, it's important to have the right antenna for the frequencies you're interested in.

I recently purchased a UT-106 DSP Unit and will install it when I have some time.

After all thesee years the internal battery no longer holds a charge.

I bought a second unit, in the original box, from a thrift shop.

Bought a second unit at the 2018 Hamvention.

The "IF OUT" jack on the back panel outputs a 10.7 MHz IF signal with 9 volts DC for external equipment.

I bought a second full coverage unit at the 2016 Dayton Hamvention.

I'm looking for SAMS Photofact 659-4, which covers this model.

It covers 25 to 520 MHz and 760 to 1300 MHz (less cellular) and can decode CTCSS, DCS and DTMF tones. It can track analog Motorola, EDACS and LTR trunked systems and can scan up to 100 channels per second. For monitoring data systems that use frequency shift keying (FSK), the receiver has a built-in data slicer. The Optocom uses a modified version of the Optoscan OS-535 interface with a documented application programming interface (API).

Unfortunately, it's discontinued. It's a neat design -- a GRE receiver board interfaced to a computer-control board (controlled via a Winbond 8051 microprocessor).

Opto had planned to offer a series of add-ons to the receiver, but eventually had trouble getting boards from GRE in the small quantities that sales numbers dictated.

I purchased one at the 2024 Dayton Hamvention.

Eight memories. Coverage from 30 to 50 MHz, 144 to 174 MHz and 450 to 512 MHz.

I don't have a user manual, but these are from a forum posting back in 2005:

1. Place all the "Memory Channel" toggle switches in the Down/Off position.
2. Rotate the "Tuning Speed" dial so that "Manual Scan" and "Auto Scan" are NOT selected.
3. Tune in the frequency desired using the "Tuning Up/Down" switch. The speed at which you go through frequencies can be adjusted by turning the "Tuning Speed" dial to "Low," "2nd," "3rd," or "Top."
4. When the desired frequency is displayed on the LCD panel, switch the toggle switch corresponding to the "Memory Channel" you wish to program to the On/Up position.
5. Press the "Memory Push" button to save the frequency to the selected "Memory Channel."
6. Repeat for the remaining seven "Memory Channels" (Note: Do not have more than one toggle switch in the Up/On position when you press the "Memory Push" button.)
7. Once your memory channels are programmed, you can turn the tuning dial to "Auto Scan," which will automatically scan through all memory channels that have their toggle switch in the up/on position. Or, you can turn the tuning knob to the "Manual Scan" selection and manually switch through the memory channels that have their toggle switch in the up/on position by using the "Channel Selector" switch. Hint: Be sure to install two 9 volt batteries in the compartment on the bottom so that if you lose power or unplug your scanner, you won't have to reprogram all your memory channels. I learned this the hard way.

Very good sound from this receiver.

This radio is still in the original box.

I have two of these units.

Support documents can be found on Radio Shack's support web site, here.

Support documents, including a manual in Adobe Acrobat (PDF) format, can be found on Radio Shack's support web site, here.

This radio is identical to the Sangean ATS-909.

Missing the smaller backup battery door.

I have a little more information about this scanner here.

I have more information about this scanner here.

Covers 550 kHz to 30 MHz.

For more information and photographs, click here.

You can read more about this model here.

For more information and photographs, click here.

Coverage: 118-136 MHz and 144-148 MHz.

Coverage: 25-520 MHz, 760-823.945 MHz, 851-868.945 MHz, 896-1300 MHz

The gaps in 800 MHz coverage are due to the 1986 Electronic Communications Privacy Act (ECPA) which mandated that the FCC deny certification to scanners that could tune to these (at the time) analog cellular telephone frequencies.

Coverage could be restored by clipping a particular diode.

A quick guide to operations is available here.

Coverage: 29-50 MHz, 144-148 MHz, and 410-512 MHz.

A schematic and manual can be found here.

A local copy of the schematic (click for a larger image):

Click here for more photos.

• Beacons: 175 to 400 kHz
• AM Broadcast: 550 to 1600 kHz
• Marine: 1.6 to 4 MHz

This model originally came out around 1971.

Covers the following bands: 33-47, 118-136, 154-164 and 450-512 MHz.

Full coverage (less cellular) TrunkTracking handheld scanner. Capable of computer control.

I bought this unit at a garage sale. When I plugged it in, instead of channel numbers, the two-digit display showed 'L'. I hit the [WX] button and immediately heard the local NOAA weather radio transmission. Hitting [SCAN] after that caused the scanner to run through all sixteen channels.

Apparently there are folks out there who get the 'L' display and are unable to proceed. If the [WX] doesn't work, try programming one of the 16 channels with a known frequency (NOAA weather frequencies are good for this: try 162.400 and 162.550 first). After receiving a good signal, manually step thorugh each channel - you should hear static if the squelch is set correctly.

Serial number format: YM PPPSSS, where Y is production year in the 1980's (e.g. '4' = 1984), M is the productiom month (e.g. 'E' = May), PPP is the production run and SSS is the individual serial number.

The letter 'M' preceeding the serial number indicates the factory installation of a memory module.

I'm looking for computer control and cloning commands beyond the few CAT messages described in the manual.

I bought a second one at the 2016 Dayton Hamvention.

I need to get a spare set of tubes for this unit.

Does anyone have a good source for tubes, especially the 1L6, that aren't at a ridiculous price?

The worse the weather gets, the better AEA FAX III is. This is because AEA FAX III allows you to colorize your received WeFax images, producing amazing full-color weather displays.

This IBM-compatible software receives HF SSB transmissions. Satellite maps and WeFax images are received in gray-scale and can be displayed in dazzling 256 pseudo-color like the one you see above. In addition to images, you'll be able to receive and decode Morse code, RTTY, and NAVTEX transmissions.

AEA FAX III's color enhancement lets you colorize maps and WeFax images however you want. See cloud formations and weather patterns that just can't be seen in gray-scale. Export your colorized images to PCX or GIF files for use in other applications.

Choose schedules from the fax station database (included) and go do something else. AEA FAX III allows your computer to switch frequencies on your computer controllable receiver, receive transmissions, and save them. When you come back you'll have images waiting for you. View the images you receive in the special slide show-mode.

AEA FAX III is easy to use right out of the box. Simply plug in the demodulator (shown here), install the software, and you're ready to receive highly detailed images. Tuning the signal is easy, AEA FAX III has an on-screen tuning indicator to help you keep the signal coming in clearly.

Don't be left out in the cold when it comes to high-tech weather reception, get AEA FAX III.

Requires PC-compatible XT, AT, or better and a general coverage HF SSB receiver. VGA monitor required for gray-scale fax display and false-color.

Note: Timewave Technology Inc. acquired the AEA data products line in April, 1997.

The KT-2 has two basic modes of operation. You may choose between a keyer and a Morse trainer. Control for each mode is provided from the keypad for full feature programming.

You have a fully programmable trainer with an incredible range of features for learning or teaching Morse code. You also have a programmable keyer with selectable speed, tone, dot-dash ratios and automatic and semi-automatic (bug) capabilities.

The Morse Machine is a full-featured, high performance keyer featuring 2-255 WPM programmable or 2-99 WPM variable speed selection and 8,000 memory characters that can be stored into 20 memories (36,500 characters if 32K RAM is used. See page 4). Seven programmable modes of operation are included: KEYER/MEMO- RY SEND, BEACON (to automatically repeat a Morse or RS-232 ASCII message at a programmed interval of one to 999 seconds), MEMORY LOAD, TRAINER (allows random code group practice at steadily increasing speeds), MORSE TERMINAL, CONTEST SIMULATOR and QSO SIMULATOR.

A computer serial port can be interfaced to The Morse Machine through its RS-232 compatible I/O allowing any front panel function to be programmed from the computer. Loading memories is as simple as typing them on the computer keyboard. Further, your random code, contest or practice sessions can be displayed on your computer screen.

Brief documentation is available from Radio Shack's support web site at here. The September 1998 Hints newsletter from the American Radio Relay League (ARRL) has the following modification:

Louder DSP with the RS 21-543 Box

Michael, N4TMI, has a quick fix for anyone trying to get more volume out of a Radio Shack 21-543 DSP box:
The cure is simple. The gain of the audio amplifier can be doubled by soldering wire jumpers across R54 and R57. These are clearly labeled 100-ohm chip resistors on the underside of the circuit board. According to the manufacturer's data sheet, the KIA7227CP audio amp chip does not require these components. Their only purpose is to reduce gain, apparently a bad idea in this situation. After the mod, it's much easier to get room-filling volume from a speaker. Sound quality is excellent, and digital signal processing is unaffected.
--Michael A. Covington, N4TMI, 285 St George Drive, Athens, GA 30606; e-mail mc@ai.uga.edu