MFJ-812 and 810 电路图.pdf

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1、- INTRODUCTION The MFJ-810 and MFJ-812 VHF SWR/WATTMETER are low loss meters primary designed for 2 meter operation. However it w i l l function down to 21 MHz with reduced sensitivity.,hhe MFJ-812 also has a f i e l d strength c i r c u i t b u i l t - i n to monitor RF radiated signals. INSTALLATI

2、ON 1. Connect a coax cable from the transmitter t o the coax connecter on the meter marked TRANSMT. TTER I 2. Connect the antenna cable t o the coax connector i n the meter marked ANTENNA. OPERATION 1. SWR Measurement: A) Set the FS/SWR button to OUT f o r SWR. (For model MFJ-812 only.) B) Set the F

3、WD/REF button OUT. Transmit a continuous carrier and set the SWR/ POWER control f o r f u l l scale deflection. C) Push IN the FWD/REF button and read SWR. NOTE: The SWR sensitivity must be reset when power level i s changed . This w i l l maintain an accurate SWR reading. 2. Power Measurement: A) S

4、et the FS/SWR button OUT (For model MFJ-812 only). B) Set the FWD/REF button OUT. C) Set the SWR/POWER control t o the 30 mark. This scale reads a maximum of - 300 watts. - -NOTE : Tk - . ft i s factory - - cal i l m t h i s control . However, due to component tolerance when precision reading i s de

5、si red, the 300 watt range can be recalibrated as follows: Set the FWD/REF button OUT. (Set the FS/SWR button OUT on the MFJ-812.) Set the SWR/POWER control t o 30, note the power level on the 30 watt scale, then rotate the control to read the same power level on the 300 watt sca?. Mark the control

6、setting f o r the recalibrated 300 watt range. FIELD STRENGTH METER (For MFJ-812 Only) 1. Connect a 1 t o 2 feet length of wire t o the binding post on the rear o f the meter. 2. Set the FS/SWR button t o FS (IN). The FW/REF button can be either I N o r OUT. 3. Adjust the SWWPCWER control for the desired meter sensitivity. TRANSMITTER ANTENNA 5 0 OHM STRIPLINE - - - - 1 UF f 100 uA OUT I REF s w 1 IUF ONLY I sw2 ON MFJ-812 FIELD STRENGTH ANTENNA 1 N34 1 ON MFJ-810 JUMPER A TO B L-_I MFJ-8 12/8 10 SCHEMATIC DIAGRAM RadioFans.CN 收音机爱 好者资料库