AOR AR-900 Scanner

Handheld Amateur VHF/UHF Scanner / receiver
Police Scanner / Communication Receiver

This radio is a wide range AM and FM mode receiver. It is a discontinued model. There are not a lot of these radios out there, and very little information is available. The manufacturer offers no information on their web site for this model. It is a capable model that covers a wide range of frequencies.

Specifications

Frequency range RX

• 27-54 / 108-174 / 406-512 / 830-950 MHz (USA)

Tuning steps

• 5 / 10 / 12.5 / 25 kHz

Modulations

• AM / FM

Sensitivity

• AM: 1 µV (10 dB S/N @ 118-136 & 220-380 MHz)
• FM: 0.5 µV (12 dB SINAD @ VHF)

Receiver system

• Double conversion

IF-frequencies

• 1st: 21.4/177 MHz
• 2nd: 455 kHz

Image rejection

• 30 dB @ 120 MHz
• 11 dB @ 935 MHz

Other

• Power requirements 4.8~6V DC (4×AA/R6)
• Memory of 100 channels in banks A - E

Quick Start

For those, and that is the vast majority of us, who want to listen to something immediately and read the Instruction Manual later, please carry out the following steps:-

1.Fit the thinner of the two aerials (push on and turn).

2.Turn squelch (SQ) control fully counterclockwise.

3. Turn volume (VOL) control clockwise to a comfortable listening level.

4. Turn squelch clockwise until the background noise stops.

5.Press the following keypad buttons in order

Search Progm. If the letters FM show in the middle right hand edge of the display, move to the next step, but if AM j shows press AMFM until FM shows.

Next step - press 9,3,6,ENT,PRY LUUL, 9, 4, 0, ENT, and then press LOCKOUT/INC until 12.5 shows at the top of the display slightly right of centre, ENT, SEARCH (NOT search progm). TheAR9ooUK should, if the battery is not flat, start searchingpart of the Cellular telephone band and you should hear signals. If the search stops on a signal which is unintelligible, pressing SEARCH (not search progm) will restart the search. If the AR9ooUK does not seem to be working properly, the battery may be flat - charging instructions follow a bit firrth er on, but be absolutely sure you have carried out the above instructions to the letter before giving up in despair.

INTRODUCTION.

The AR-900UK is manufactured by A.O.R. Limited" of Japan whose products, going back a long time, have gained a world-wide reputation for both performance and reliability second to none. It has been carefully engineered and manufactured to a rigid specification capable of giving satisfactory and dependable Operation for many years.

After unpacking, it is as well to keep the packing material in case it should ever be needed for remote operation, maintenance or service, and check that it is supplied with the following accessories:

1 - AC Adaptor/Charger. Input 24oVAC 5oHz 5W. Output 6VDC ZOOmA.

It will be necessary to attach a mains plug to this unit suitable for fitting into a standard domestic power socket.

2 - Flexible helical whip aerials, one slightly thicker than the other.

1 - Instruction Manual.

Before using the charger for the first time we recommend that the battery be fully discharged by switching on the dial light. When this goes out or the “bat low” warning appears on the display, switch it off, plug one end of the charger into the mains, the other end into the AR9ooUK charger socket marked “CHG DC6V”, and charge for 8-10 hours. The reason for this procedure is that

Nickel Cadmium (NiCad) batteries may acquire what has been described as a “memory” which subsequently gives rise to difficulty in charging them fully. This full discharge/charge cycle at the outset minimises this problem and ensures that optimum battery usage is achieved. Note that during the initial discharge you can use the ARQOOUIC but it will, in all probability soon start to die on you as the battery gets flatter and flatter. The same thing applies to the initial charge - it will take several minutes to start coming to life again, but after that there is no reason why you should not use it, but I would be inclined to leave the dial light 017'. One other thing to remember - if you use the AR9ooUK during the charging cycle, then the charging time should be increased to compensate. As overcharging: is not unduly harmful it is not necessary to set the alarm for 3 am. to switch the charger off - up to 16 hours once in a while will not hurt. Repeating this rapid discharge/full charge cycle three or four times is not a bad idea and results in the NiCads reaching their full capacity of 7 to 9 hours normal usage. Subsequently, an overnight charge or a charge while you are at work when the low battery (Bat-Low) warning appears on the display is all that is necessary. As for the total life of the NiCads - hard to say o depends not only on usage but many other factors, but I would be a bit disappointed if they only lasted a year and delighted if they lasted four. Fortunately they do not cost the earth to replace.

Operating modes

The AR9ooUK can be used in three different ways. In the MANUAL mode, any frequency within the tuning range may be entered into any of the 100 memory channels (Ao1 to E20) and,recalled by entering the appropriate channel number. Additionally, repeated pressing of MANUAL goes through the memories sequentially, tuning to the different frequencies in them. The second mode of operation is the SCAN facility whereby up to 100 frequencies are manually put in the memories and then rapidly scanned. Should there be a signal present, the AR9ooUK will stop scanning to permit the signal to be heard. The 100 memories are in 5 (A,B,C,D,and E) banks of 20 and any bank or combination of banks may be scanned. One popular method of use is to have local airfield and airways frequencies in one bank, Radio Amateurs in another, Private Mobile Radio in a third, cellular car' phones in a fourth and so on, scanning the bank. or banks of current interest. Should interest in one or more frequencies temporarily wane, that frequency or frequencies may be temporarily locked out by pressing the LOCKOUT/INC key. Pressing a second time brings the frequency back. into the scan. The SCAN operation presupposes that the user knows firstly what frequencies to put in the memories and secondly whether the transmission is AM or FM. There are several books which list various frequencies and your Dealer will be happy to advise. As to whether a transmission is AM or FM, a good general rule is that all airband, civil and military are AM, anything else is FM, but if in doubt, trying both will determine which is correct. For the beginner who has little or no idea of what frequencies are in general use in his area, the third mode of operation comes into its own. This is the search mode, and in this mode the AR9ooUK will scan between two programmable limits, stopping wherever there is a signal.An example of this mode of operation was given at the start of this manual. A good starting point is to consult the “Band Plan” listed further on and decide what you would like to listen to. Take a small portion of the band and search that portion noting any interesting frequencies or putting them directly into a memory bank by use of the HOLD facility described later. Having exhausted the possibilities of that particular portion, repeat over the next portion, and so on, not attempting to search more than a'1MHz portion at a time, otherwise there is a strong possibility that some transmissions will be missed. After 20 frequencies have been entered into a memory bank, it will, of course, be necessary to start a fresh bank.

CONTROLS

Firstly a description of the various switches and keys.

TOP PANEL.

• VOLUME Controls the volume and is also the Oil/off

switch.

• SQUELCH Mutes the background noise, which,

particularly in the FM mode, tends to be most objectionable. Note that in order for the AR9ooUK to scan or search, it is essential to use the squelch control. The best position for this control is when the noise is just, but only just, . muted, otherwise sensitivity suffers slightly.

• KEY This disables the keyboard to prevent

LOCK accidental errors.

• LAMP This illuminates the diSplay, but also rapidly

discharges the battery.

FRONT PANEL

• SEARCH In the search mode, it initiates the search.

• SEARCH In the search mode it is used to programme

• PROGM the upper and lower limits of the search.

• SCAN In the scan mode it initiates the scan.

• PRY This is a dual function key. used in the search

• LL/UL mode to set lower (LL) or upper (UL) limits

to the search. The other function is, in the. scan mode, to make memory Ao1 :1 priority channel. Every 7 seconds or so Ao1 is examined and if a signal is present that signal takes priority over all others.

• MANUAL The key which enables frequencies to be

entered and permits manual examination of the memories.

• LOCKOUT This is a dual function key which stops the reception of unwanted signals in the scan or manual.,modes. It also selects the frequency steps in the search mode.

• DELAY This is a dual function key. The delay function

• HOLD operates in both the scan and search mode to

hold the frequency of a received signal for aboutWS seconds after the transmission has ended; The hold facility operates in the search mode only and holds the signal frequency as long as desired. This gives the user a chance to make a note of the frequency or put it directly into one of the memories simply by pressing ENT followed by the memory location (e.g.

Co9). Searching resumes on pressing SEARCH.

W This selects AM or FM during initial programming (generally speaking everything outside the Air Band is FM).

THE In the search mode, it is possible to obtain

RED 4 manual operation, stepping up or down by

and 7 repeatedly pressing one of these keys, or altering direction of the search, resuming by pressing the search key.

CLEAR If an error is made when programming a frequency, the clear key may be used to erase it.

0 - 9 Frequency entry keys.

ENT Enters a frequency into the memory from manual, scan, or search programme modes.

A - E Selects from one to five memory banks.

DISPLAY In addition to the frequency, the display shows the memory bank or banks in use (A - E), the search increment (5,10,12.5 or ZSkHz), mode (manual MAN, scan SCAN, search SRCH or search programme PROG), delay (DLY) 01' hold (HLD), priority (PRY),Direct access (DIR-ACC), AM or FM mode, lockout of a scan channel (L/O), low battery indicator (Bat-low), memory bank and channel number.

OPERATION.

SEARCH To look for active frequencies within a chosen

MODE. range press SEARCH PROGM, one of the letters A - E, AMFM to select mode (Usually FM outside the Airband). the lower limit frequency may now be entered (the decimal point may be ignored) followed by pressing the ENT key. To enter the upper limit, press the PRY LL/UL key followed by the frequency and then ENT. The search increment may now be selected by pressing LOCKOUT/IN C followed by ENT then press SEARCH. The AR900 will start searching the selected frequency range. Note that recommended search increments are incorporated in the Band Plan and that it is wise to limit the search to about IMHz to avoid missing anything. Also Note the use of the hold facility - an active frequency may be held and entered into a memory simply by pressing ENT and then a memory channel (e.g. DIZ) pressing SEARCH to restart. 77w only problem is that it will replace anything that is already in D12 which is then lost, so it is essential to keep track of what memories are used. Also Note the use of the red 4 and 7 keys described above. The only other point to remember is always to enter the upper and lower limit frequencies by pressing

O . ENT even if they are already displayed. SCAN Assuming that you have found a few MODE. frequencies or know frequencies which you would like to scan, press MANUAL; select bank and channel by ENT, A,B,C,D, or E, (note that DIR ACC appears on the display because this is how channels are directly accessed in the manual mode) followed by a number 01 - 20. The frequency displayed is that which is already in the memory, so be sure it is no longer needed because it will be lost when a new frequency is entered. If it is needed, simply re-enter a different channel number. If the AR9OOUK is new, the frequencies entered are merely those used for our pre - sales check and are of no significance. Enter the desired frequency by the numeric keys (the decimal point and final 0 or 00 may be ignored), select AM or FM (Airband AM) and press ENT. Repeat this prOcess for other channels. Scanning is started (or restarted) by pressing SCAN. Whilst scanning, banks may be temporarily added or deleted by one or more of the letter keys A B. These act as an on/off switch - press once to switch from on to off, or vice versa, and again-to reverse the process. Channels not of current interest may be locked out by the use of LOCKOUT/INC, and the lockout removed by accessing the channel in the manual mode and again pressing the LOCKOUT/INC key. The DELAY HOLD key, if pressed will activate the delay of about 6 seconds, a second press removing it. For correct operation of SCAN and SEARCH modes, W shoulialmaysbesct. The scan may be stopped by pressing MANUAL, and stepping through the memory channels achieved by repeatedly pressing MANUAL. Ao1 is the priority channel and is switched in or out by the PRY LL/UL key. Remember that the AR9ooUK must be squelched before it will scan but that every synthesized receiver has certain “birdies” which cannot be silenced by the squelch control, and it may be necessary to restart the scan by pressing the SCAN key.

MANUAL Virtually every aspect of this mode has already

MODE. been covered, so nothing can be added. This completes the operating of the AR9ooUK, but the following one or two notes may be of interest.

AERIALS

There are two aerials supplied, the thinner more suitable for frequencies above 4ooMHz and the thicker for below this. If you are scanning a mixture of frequencies, it is a question of trying both aerials to see which performs best. Slightly greater range will result by using an extending whip aerial, trying it at different lengths, but with the snag that it is more prone to damage both itself and anyone close-by. Although connection of an outside aerial system such as a discone or ground plane on the house roof will often produce better signal strengths, such aerials will generally produce bloeking or overloading effects on the AR9ooUK, which is designed to operate with the aerials supplied. Your Dealer will be able to advise and supply suitable aerials, or reading any of the books on scanners (our own little pamphlet makes sound sense) will aid your understanding of the factors involved. Some form of roof aerial is to be recommended when using the AR9ooUK in the car - if you have a favourite band, an aerial for that band is a good idea and again your Dealer can advise.