There is a design oversight in all three models - the audio level of AM signals is somewhat below that of NBFM signals, requiring a different setting of the volume control. A trimpot or two in the audio mixer that combines the outputs of both detectors can be added, but a bit more care in the initial design would have precluded that necessity. One popular mod makes the unit portable by removing the power transformer and replacing it with a 12v gell-cell. There are some cosmetic differences like the keyboard layout, but the internal electronics design is very similar across the three receivers.
The major differences were physical packaging and the position of a few diodes in the configuration matrix plus: The The model was introduced in late and nearly 45, were sold until until it was discontinued in early It had a metal case, good internal construction and shielding, but was designed as a table top unit, there no way to add a mobile mounting bracket. It was artifically limited in the number of channels it could listen to and had a slower scanning speed.
You could cut a diode and get the channels of the but the channel numbering on the channel keyboard which was not backlit would be confusing. Cutting another diode got the faster scanning speed of the Adding either a COS or a TS32 PL decoder or both was easy - in fact a Pro was my across-the-garage link receiver or remote base receiver for repeater experimentation for several years.
You can improve the squelch action by replacing R 47K with a K resistor. Anyone have a scan? One common problem with the PRO involves the memory backup battery circuit. The 9v Alkaline is the only thing keepng the memory alive. Sometimes the low battery warning keeps activating even when a fresh battery is installed. Memory loss when the radio is unplugged is also a symptom of the same problem.
Make sure the contacts on the battery connector are tight. The snaps widen and lose contact, and you can squeeze them gently with a pliers to tighten them. Unplug the AC cord from power and remove the battery. After a few minutes, insert a good battery, plug the power cord back in the wall and perform a full reset according to the owners instruction manual. Check the through-board solder joint at connector CN6, pin 3. Check the wires from the battery connector to the printed circuit board for continuity.
If a new battery goes dead after just a few days, it is likely that the memory regulator has gone bad. The regulator is in a TO package and looks like a small transistor with three leads.
It is labeled IC9 on the printed circuit board. The part is made by Seiko, type SHG. The PRO had serious quality problems with its printed circuit boards, especially during the production year. There are copper traces on the top and bottom of the boards. In places where it is necessary to connect top and bottom traces together, a hole was drilled and then plated with copper to make the connection.
This plating was faulty and over time it cracks, breaking connection from top to bottom. The symptoms can range from corrupted memory to the squelch not working. Sometimes the problem comes and goes or may be sensitive to temperature. The only way to permanently fix the problem is to put wires in all the holes and solder the connections on top and bottom. Pop the tops off the shields and repair the connections inside too.
This takes a huge amount of time and many repair shops consider the PRO to be unrepairable. When the unit was in warranty RadioShack just swapped the boards, then crushed the old ones.
Another problem involves the glue GRE used to secure the large power supply capacitors to the main PC board. It's often black in color and you should see it around the base of the capacitors. There is a corrosive element in the glue and given enough time it eats through the copper on the PC board.
The glue can be scraped off the board with a toothpick don't use a metal tool and you can then assess the amount of damage due to corrosion. Repair any broken traces with small lengths of wire soldered down to bridge the gaps. Operation Manual 1. Service Manual The size reduction was accomplished by converting from through-hole to surface mount circuit boards.
The unit had a better keyboard but it was not backlit however the layout was easier to use when mobile. The was a bit more sensitive than the but had a problem where MHz signals leaked into the aircraft band. You could cut another diode and get the faster scanning speed of the Operation A text web page that covers the basic operation. Parts List 22kb The The model was introduced in and was essentially a faster scanning PRO It's probably the best conventional-only scanner made to date.
You can improve the squelch action by replacing R, a 33K resistor, with a K. It is designed to fit a standard DIN slot in a car dashboard. It's a lot better built than the average piece of RS equipment. A viewable text file of the same document can be found here. Nony Mous, but has a RadioAmateur. It's a pretty poor scan, but it's all we have. Of the ones I am familiar with the older unit is the and the newer unit is a , later replaced with the A yes, a numerically lower model number on the newer unit.
The series is made by Metex of Japan. There is also a and a but I do not know where they fit into the marketing sequence. If you are going to be buying any computer-connected meter make sure that the serial port is isolated from the rest of the DMM via an infrared link in the DMM's case - this means there is no connection between the serial data pins and any meter input terminals.
If you are going to use any battery operated serial meter to do some long-term data logging you might want to power it with a 9vDC wall wart transformer with an appropriate battery-snap-clip so that you aren't replacing the meters internal 9v battery on a regular basis.
Or use 9 volts of "D" cells in a length of PVC water pipe. Like most DVMs all of these meters have internal fuses. You might want to keep an extra set in your meter case. It's interesting that Sears sold a similar unit: the "Craftsman Professional, PC interface auto-ranging digital multimeter ".
Click here for a photo. The page has some info - but again no operating manual! The number at the end of the file name is RadioShack's faxback file number. The "Addendum-1" file has the only programming info that I have found. The Addendum-2 file has a very important note on the 9v battery. The test probes in the photo look funny because they have a piece of cardboard wrapped around the tips points.
We have RadioShack's "Meter View" software that shipped with the It came on a CD, the zip contains everything that was on the CD. The software is known to work with XP-SP3. The communications protocol sends 9 bytes at baud, and is documented in the programming notes here. The data sent is essentially the raw display segment info, if you are going to be writing your own software you need to include a translation routine for 7-segments into a BCD digit. The , and have a much better data protocol that sends the avtual value and units as an ASCII string.
The meter has a 2 amp 5x20mm fast-blow glass fuse and a 3AG 20A V ceramic fuse inside. The assembly section of the manual has been eliminated. Thomas Myers N9LHK sent me a very good, well-lit closeup photograph of the schematic sticker that was in the "B" model units they no longer do that.
I played with and cleaned up the image a little using a couple of graphic programs. If you examine the schematic you will notice that the unit has a design flaw due to the fact that it was designed to meet a sales price target. There is no input DC blocking capacitor, it has an input impedance of 5K Ohms, and may load down a high impedance source. The first part I fixed by adding a series cap to the test lead set, the second I will fix if I ever have to replace the input pot.
I'll use a K or K pot, and add the DC blocking cap internally. The next time I get inside mine I'll try it. The cap in my unit was leaking 19 to 20 ma worth Adding the switch and the two parts allows you to monitor receiver discriminator "flat audio" sources properly.
You can build one into an old Motorola mobile speaker housing, and put the volume control and power switch into the side or back wall - or even into the center of the grille.
This unit is a cheap knockoff of Motorola's "Power Voice" mobile speaker with an interesting design twist. It's designed for the situation where the speaker amplifier in a CB doesn't have enough power to be heard, for example in a pickup truck with the windows open.
Obviously it's just as usable on ham radio as on CB. The interesting twist is that the DC power to the audio amplifier is controlled by a VOX-type of circuit. Motorola's design didn't need it. The catalog number and date code are located on the back or bottom of the power supply. The CPSC alert stated that , total units were mis-manufactured. Power supplies with a green dot on the product and the product's packaging were either built correctly or have already been repaired and are not included in the recall.
The production line incorrectly put the black wire on Neutral and the white wire on Line. Interestingly, the bottom of the unit says that the power cord is not replaceable. They lie. Here's the paperwork packed with the 1. Does anybody have a schematic of any revsision of the or the ? As long as you are inside the or power supply you will find there is enough room on the front panel for a set of Anderson Powerpoles. There is also extra space on the rear panel in the corner opposite the power cord to add a second set of PowerPoles.
First, they are a receiver preset to the NOAA Weather Radio NWR services frequencies, and they receive regular, around-the-clock weather status and forecasts information.
Second, the newer ones are designed to respond to geographically-based alert signals sent by the NOAA Weather Radio service. When the weather radio receives an alert signal, it will sound an audible alarm to attract attention. The Weather Receivers come in three flavors: First, there are the plain monitor receivers that listen to the weather channels and has no warning mechanism at all. This is the same functionality as having the local weather channel programmed into an extra memory in your 2m handheld radio.
Secondly there are the simple first generation alert receivers that decode the Hz alert tone. The SAME system divides the United States into geographical weather areas and you program the reciever to respond to the geographic code called a FIPS code for your local area or if you live near a boundary, you program in both codes , or if you want, you can add the codes for the areas surrounding the perimeter of your FIPS area.
Most of the codes are aligned along county lines, but as we all know RF doesn't pay attention to political boundaries. The first weather channel allocated was They added Most second hand receivers that you find will be single channel There is a lot more information on weather radios and the SAME system on this page.
If anyone has info on other RS receivers such as the , , or please send it in. There is an article on interfacing a Reecom brand weather receiver on the Arcom page at this web site. The Reecom is a decent knockoff of the very desirable Radio Shack It is powered by a normal power cord and has a 9v battery pocket in the bottom of the case.
It uses one 9 volt battery or an external 9v wall wart transformer. It is powered by vAC. The external antenna connector on the rear is an RCA jack. We don't have a PDF of the owners manual, does anybody? Some of these radios have firmware that does not recognize the EOM signal. These have a fixed 5 minute message timeout. This unit has an external antenna jack, plus a 2-pin terminal strip accessible from outside the case for an external alarm. These terminals on the radio have a constant 1.
The 7. The voltage is at a low current originally designed to feed an X Encoder, but very useful for other things. Don't plan on powering anything more energy intensive than a Solid State Relay, a switching transistor, or maybe the coil of a reed relay. Here's what the terminal strip was designed for. If you are going to use an RS Weather receiver this is the one to look for the is your second choice. I'm told that there are at least two different revisions of the firmware in this unit, and that one does not respond to an EOM code - but that the built in 5 minute timer does re-mute the audio.
You could replace the motor with a relay coil We have no technical data on this other than the advertisement on the RS web site, which by the way says it has a scan function in case the local weather transmitter goes off the air. The photo shows only one LED indicator. There is no tech info in the owner's manual other than a page of specifications. It also has an external antenna jack, plus a 2-pin terminal strip accessible from outside the case like the for an external alarm.
There is an interfacing article below on this unit. The owners manual calls it the "Skywarn band" and the owners manual says it covers The wall wart is 12vDC at ma and the connector is tip positive. There is a pocket in the unit for six penlight cells "AA" size for backup you can also use Ni-MH rechargeable batteries, but you must remember to flip the switch inside the battery compartment from ALK alkaline to RCH rechargeable.
There is a 2-pin terminal strip accessible from outside the case like the for an external alarm like a pillow shaker. The speakers are small and tinny, the only other complaint I have heard is that the blue display is a little bright at night even at "low" setting there is no OFF selection. Weather Receiver Interfacing Articles These articles cover only the interfacing aspects. At some sites the Weather Radio may suffer from RF overload, which may require other methods to resolve, up to and including repackaging the Weather Radio receiver in a shielded box and feeding it with an outside antenna.
Extreme situations may require a cavity filter between the antenna and the receiver-in-a-box. One acquaintance ended up tracing the circuitry in a RadioShack receiver and completely disconnecting the receiver section and feeding a MICOR receiver into the RS decoder. Depending on your circumstances you may want to have your repeater transmit in response to a "Watch" or to a "Warning" or to both.
The NWS describes the difference as: 1 A watch alerts you to potential severe weather approaching your area. It doesn't mean severe weather will occur, but that the right conditions exist which could lead to severe storms. You should be prepared for deteriorating weather 2 A warning states the severe weather is imminent or present in your vicinity. You should immediately take precautions to protect yourself and your family. Interfacing the Weather Radio to a repeater controller Scott Zimmerman N3XCC connected a Weather Radio to an Arcom repeater controller, but the , and similar receivers like the Reecom would work just as well.
This article describes the hardware interface only. The outputs for Statement, Watch, Warning and COS connect to alarm inputs on the RC, and the receiver reset input is connected to a digital output and is used to acknowledge or clear the Statement, Watch and Warning alerts.
See the "More than three ports? FUNC Button names are printed in this manual in small, bold, capital let- ters such as. The transceiver opens a door for you to the world from almost anywhere! Amateur radio is a great hobby that has enriched the lives of mil- lions of people all over the world. The ARRL would be glad to hear Page Connecting An Antenna 4.
Attach the transceiver to the mounting bracket using the supplied rubber washers and mounting knobs. Each antenna type has its own benefits, so choose the one that best meets your needs. Page 11 Once you choose an antenna, follow its mounting instructions.
Then route the cable to the transceiver and con- nect the cable to the jack on the back of the transceiver. Then fully insert the plug into the jack. Slide the microphone onto the microphone holder. Page Using Vehicle Battery Power To connect the external speaker to the transceiver, insert the speaker's plug into the jack on the back of the transceiver Note: Connecting external speaker disconnects the transceiv- er's internal speaker.
Page Using The Transceiver As A Base Station Caution: Do not connect the black wire to a non-metallic plastic part, or to any part insulated from the vehicle's chassis by a non-metallic part. Connect the single connector end of the power cord to the connector on the back of the transceiver. Page 15 Follow these steps to install the transceiver as a base station. Mount the base station antenna as described in its owner's manual. Warning: Use extreme caution when you install or remove a base station antenna.
If the antenna starts to fall, let it go! It could contact overheard power lines. Rotate fully counterclockwise. Rotate fully clockwise. RF-G 3. The display lights and the frequency appears. The transceiver blocks the weak transmissions. Page Notes On Ssb Reception 3.
To transmit, hold down the push-to-talk button on the micro- phone, hold the microphone 2—3 inches from your mouth, and speak in a normal tone of voice. As you press STEP one of the three frequency digits flashes for about 2 seconds to show which digit is selected. Press to recall the stored frequency at any time. The fre- CALL quency flashes.
Follow these steps to set the frequency shift direction and offset frequency. Select the desired frequency. Press then appears. While appears, press the desired memory channel num- ber. The transceiver stores the frequency you selected into the memory channel you selected.
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