aor_ar3000a.pdf

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1、AOR AR3000/3000A receiver modifications. AOR (UK) LTD 1994 - 1999 - Page 1 No responsibility is accepted for damage caused by customers carrying out these modifications. AOR AR3000A PLUS Modifications Introduction The following modifications were originally developed by AOR (UK) Ltd as a result of p

2、opular requests by enthusiasts. They are described individually and can be carried out on that basis but when all modifications are done together they are collectively known as the “AR3000A PLUS” modifications. The degree of difficulty in carrying out the modifications varies considerably. The discr

3、iminator modification simply involves the addition of one wire whereas the narrow AM filter uses very delicate surface mount components, fine wiring and the drilling of a hole in the main PCB. We therefore recommend that the instruc- tion are read very carefully and tool kits inspected for suitabili

4、ty before attempting any modification. No test equipment should be needed for carrying out the modifications but a basic DVM is useful for fault finding. All modifications can be checked using off air signals and where applicable the SDU5000. It is assumed before starting a modification that the AR3

5、000 / AR3000A is in full working order and that no previous modifications have been carried out. All description are based on the fact that the IF board has been removed from the set; this however is not necessary for some of the simpler modifications and partial removal is recommended by removing t

6、he five coaxial connectors on the front of the board and hinging the board on its remaining wiring loom over the back of the set. In all the descriptions it is assumed that the front panel is facing towards you and is known as the “front” and the rear panel away from you and known as the “rear”. Whe

7、re colour of additional wires is given it is simply for clarity of description and is based on our original development of the modification. Components described are again based on those used in our original development and in most cases can be substituted; we have therefore only given recommended s

8、uppliers where the component is of a more specialised nature. Limited support is offered by our technical department, time being valuable! Written communication is discouraged in respect of these modifications due to the complexity of the subject matter. For answers to quick questions, phone 01773 8

9、80788. AOR (UK) LTD, 4E East Mill, Bridgefoot, Belper, Derbyshire DE56 2UA. England. Thank you. WEFAX SATELLITE narrower switchable filter (1-3000) The WEFAX custom modification has been designed to optimise the receivers passband for reception of orbital weather satellites operating in the VHF band

10、 around 137.500 MHz and geostationary satellites operating in the UHF band around 1691 MHz. Ideally an IF bandwidth of 30-50 kHz is required for reasonable results, unmodified the AR3000 / 3000A is too narrow on NFM and too wide on WFM. A small PCB is mounted on the IF PCB and holds both the origina

11、l WFM filter for BAND2 & TV sound reception plus a new filter offering approximately 50 kHz bandwidth. The WFM filters are switched using an IC via a rear panel mounted slide switch (UP is narrow and DOWN is standard). A small component change is also carried out to ensure the squelch operates with

12、the bandwidth switch in either position. Of course you still require some form of data encoder such as the AOR WX2000 decoder/ printer (no longer available as new) or a computer hardware/software package. For VHF reception a crossed dipole is quite adequate but a dish or yagi is required for UHF alo

13、ng with a LNA (low noise amplifier). The slide switch may be easily reached from the front of the set. The bandwidth is of course NOT selectable via computer control. AOR AR3000/3000A receiver modifications. AOR (UK) LTD 1994 - 1999 - Page 2 No responsibility is accepted for damage caused by custome

14、rs carrying out these modifications. Using the accompanying diagrams and photographs build the small WEFAX PCB, the parts list being as follows 1 x Blank PCB 30.5 mm x 15.5 mm 1 x SMD 4066 IC quad switch 2 x SMD 10k resistors 1 x Murata SFE 10.7 MF filter, bandwidth 55 kHzBonex part no 080125 1 x 30

15、0 mm green wire 1 x 300 mm blue wire 1 x 300 mm yellow wire 3 x 30 mm tinned wire leads 2 x wire links Very carefully remove the existing WFM filter XF1 from the IF board and solder it to the new WEFAX PCB. Our experience tells us this is quite a fragile filter. Add a 30 mm red supply feed wire to t

16、he hole in the IF PCB WEFAX PCB artwork negative AOR AR3000/3000A receiver modifications. AOR (UK) LTD 1994 - 1999 - Page 3 No responsibility is accepted for damage caused by customers carrying out these modifications. alongside the XF1 position (see photograph). Fit new WEFAX PCB to the IF board wh

17、ere the WFM filter XF1 was removed from. The board should lean backwards with the filters towards the rear of the set (see photograph). Solder the 3 wires to the IF board and the left hand edge of the new board to L7 transformer alongside. Trim and solder the red supply wire to pin 14 of the 4066 IC

18、 on the new WEFAX board. Locate and remove R57 4k7 resistor from the IF Board (see photograph) and replace with a 1k0 resistor. Refit the IF board, twist the blue, yellow and green wires together and run them down the right hand edge of the IF board with the main loom. Fol- low the main loom towards

19、 the position of the new slide switch. Using a sharp knife cut out the hole in the rear panel escutcheon next to the antenna socket to allow the fitting of a miniature DPDT slide switch. Drill out the mounting holes and fix the switch using 2 x M2x4 screws. Trim and solder the blue, yellow and green

20、 twisted wires to one set of switch contacts connecting the yellow to the top connection, the blue to the middle connection and the green to the bottom connection. The new switch now selects the standard WFM filter in the down position and the new narrower WEFAX filter in the up position. As a non t

21、echnical test, tune to a WFM broadcast signal and switch in the narrower filter. You should hear slightly distorted reception as the incoming signal is deviated more than the filter bandwidth. Refit the case halves and the modification is complete. NARROW AM switchable filter (2-3000) The narrow AM

22、filter custom modification has been designed to optimise the receivers passband for reception of short wave AM broadcast transmissions. Generally speaking on long and medium wave a 9 kHz channel spacing is used (in Europe) and a 5 kHz channel spacing for short wave. The standard AR3000A AM filter is

23、 12 kHz as this permits reception of “offset” civil airband transmissions, the same filter is also used for NFM. The modification adds a rear panel switchable narrow AM filter (the same switch as used for WEFAX switching - both are switched at the same time if both options are fitted), the filter sp

24、ecification bandwidth is 4.0 kHz but when fitted “in circuit” is actually wider than this. There is still a very worthwhile improvement which helps reduce BLOCKING when listening close-in to a strong transmission, heterodynes may also be reduced or removed AOR AR3000/3000A receiver modifications. AO

25、R (UK) LTD 1994 - 1999 - Page 4 No responsibility is accepted for damage caused by customers carrying out these modifications. when listening to many transmissions. There is also a small increase in sensitivity over the standard filter by a few dB. The additional narrow AM filter is fitted to the IF

26、 PCB with the data lines used to select the filter by diode switching in conjunction with the rear panel switch. The reception of NFM is still routed through the standard filter even when the narrow AM filter is selected. When the narrow AM filter is selected the squelch closing position is affected

27、. Instead of closing around 11 oclock, it closes around 2 oclock. This is not a problem as the squelch is usually left “open” when monitoring short wave broadcast transmissions. The squelch characteristic is normal and unaffected when in the standard filter position. The bandwidth is of course NOT s

28、electable via computer control. The filter used is a CFW455IT, Bonex part no 080079. The filter sits on a blob of hot melt between L29 and the existing AM filter and is prepared in such a way that of its three connections the input and output legs are extended and pass through holes in the PCB and t

29、he earth connection sticks out of the side of the hot melt and solders to the earth plane on the top side of the board. Move the grey loop of wire on the underside of the IF board as far to the right of the PCB as possible and drill a hole 0.8 mm ( through the board next to L29 on the IF PCB and suc

30、k the solder from the second hole if filled (see photograph). Cut the input and output leg of the filter short and solder a 50 mm length of kynar wire vertically to each. Cut the middle leg of the three earth connections short and bend and cut the outer two to meet it. Solder all three together and

31、add a 50 mm kynar earth wire to exit horizontally to the filter towards the front of the set. The overall effect is that the filter should be able to sit low in its blob of hot melt with its top level with the muRata SSB filter CFJ455K, its two vertical wires through the prepared holes and the earth

32、 connection available to be soldered as close as possible to the earth land on the top of the PCB. On the underside of the board add 2 x 1SS268 SMD diodes piggy backed onto 2 existing AOR AR3000/3000A receiver modifications. AOR (UK) LTD 1994 - 1999 - Page 5 No responsibility is accepted for damage

33、caused by customers carrying out these modifications. diodes D15 and D17. The 1SS268 is a double diode package but only one diode in each is used. Solder the front pins only. Add a 22k SMD resistor to the front anode of the diode above D15 and a 5k6 SMD resistor to the rear anode of the diode above

34、D17 Connect the non diode ends of the resistors together with a piece of tinned wire and connect a 0.01uF SMD capacitor between this tinned wire and an earth plane (see photograph) Connect a 300 mm length of yellow wire to aforementioned tinned wire and connect the kynar wires that are protruding th

35、rough the board from the filter to the diode ends of the resistors, one to each. Cut track to pin 6 of IC4 and connect a 300 mm blue wire to the now isolated pin. Connect a 300 mm green wire to the right hand anode of D19. Insulate the delicate surface mount work with hot melt Refit the IF board, tw

36、ist the blue, yellow and green wires together and run them down the right hand edge of the IF board with the main loom. Follow the main loom towards the position of the new slide switch. AOR AR3000/3000A receiver modifications. AOR (UK) LTD 1994 - 1999 - Page 6 No responsibility is accepted for dama

37、ge caused by customers carrying out these modifications. Using a sharp knife cut out the hole in the rear panel escutcheon next to the antenna socket to allow the fitting of a miniature DPDT slide switch. Drill out the mounting holes and fix the switch using 2 x M2x4 screws. Trim and solder the blue

38、, yellow and green twisted wires to one set of switch contacts connecting the yellow to the top connection, the blue to the middle connection and the green to the bottom connection. To test the unit tune to a broadcast AM station and switch the narrower filter in. You should hear a narrowing of tona

39、l quality and a reduction in adjacent channel interference. Refit the case halves and the modification is complete. SDU5000 spectrum display compatibility (3-3000) The SDU5000 is a new spectrum display unit designed to compliment the AR3000A (and other receivers). In order to provide compatibility,

40、a custom modification has to be carried out to ensure the AR3000A will plug in and go! Note: The AR3000 does not provide microprocessor compatibility with the SDU5000 so only basic facilities are available. The modification to the AR3000A/3000 adds a rear panel BNC socket providing the required 10.7

41、 MHz IF signal. The bandwidth is 10 MHz and gain is about 10dB compared to aerial input. A rear panel toggle switch provides AGC / mute for the SDU, normal is UP and active is down. the normal position being used most of the time. Of course the switch is NOT selectable via computer control. Summary

42、of SDU5000: The SDU5000 Spectrum Display Unit adds a variety of features to extend a receivers capabilities, such as visually identifying new active frequencies and taking measurements. The SDU5000 may be used with a number of receivers which have a 10.7 MHz IF output and produces a bandwidth up to

43、5 MHz in 1 kHz increments with a resolution of 5 kHz or 30 kHz. The SDU5000 remains compact due to the use of an internal 3.1 HQM simple matrix 16 colour LCD 192 dot x 210 dot. An external home colour television with video input may also been connected (PAL or NTSC). In particular the AR3000A has be

44、en designed to provide best compatibility by communicating directly via the receivers CPU via the RS232 port / SDU5000 COM1 en- suring the full potential of the SDU may be exploited. Operation is extremely simple as the SDU5000 utilises an on screen menu system. The AR3000A frequency, mode & attenua

45、tor may be controlled from the SDU so that a displayed frequency may be easily monitored. When using the AR3000A, the cursor frequency is equal to the receiving frequency of the AR3000A, by using the cursor in the SDU, frequency and signal level can be read directly. This enables the SDU5000 to be u

46、sed as a wide coverage spectrum monitor between 100 kHz to 2036 MHz with DDS providing an accuracy of 100ppm. Dynamic range is 50 dB with an acceptable input level between -10dBm to -90dBm with selectable gain control. The SDU-5000 has a multiple AOR AR3000/3000A receiver modifications. AOR (UK) LTD

47、 1994 - 1999 - Page 7 No responsibility is accepted for damage caused by customers carrying out these modifications. processing function which displays Average Level, Peak Detection and Maximum Value Hold. These professional features are usually only available from expensive professional class spect

48、rum analysers. The SDU may also be connected to a PC where all controls are accessible and display data can be downloaded for record and later analysis. The SDU5000 operates from 12V DC 1A and a suitable mains power supply is pro- vided along with the necessary connecting leads for the AR3000A. To b

49、egin the modification add a 1N40148 diode to the IF board as shown in the photograph. Connect the cathode to the cathode of D7 and connect a 300 mm black wire to the anode. Connect a 470R, 1/8W resistor between the emitter of Q7 and the junction of C45 and R29 (see photograph). Short the emitter to the collec- tor of Q9 with a small piece of tinned wire (see photograph). Add one end of a 1000pF ceramic capacitor to the junction of L23 and C48. To the other end connect the inner of a 250 mm length of miniature 50R coaxial cable. Connect the braid to the nearest suitable earth