70 MHz FM transceiver     Last update 2012-02-18

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JUMA FM70 front view


JUMA FM70 is a compact digitally controlled FM transceiver for the 70 MHz amateur radio band (4 m).

JUMA FM70 provides 15W RF output and the RX sensitivity is excellent. The front-end is designed to withstand the near by high power FM broadcast stations by high selectivity multi pole band-pass filter. Low noise Dual gate MOSFET is used for high sensitivity. The narrow band selectivity is defined by two IF frequencies, the first 10.7 MHz is using XTAL filter and the second IF 455 kHz is using two cascaded ceramic filters.

Smart construction
JUMA FM70 smart contruction is based on one main board which inludes RX, TX, PLL, and microcontroller. Rear panel inludes the connectors and final RF MOSFET. Behind the front panel there is the control board which includes the VOL pot, SQU pot, Power button, Mic connector, LCD display and the encoder with push button for configuration.

JUMA FM70 internal view

- Mic connector with PTT in
- Power supply
- Antenna 50 ohms (BNC
- Line in e.g. for PC sound card and line in PTT

- Line out, ext speaker or phones
- USB connector for software updates and control

JUMA FM70 rear view

- RF output power 15 W (High) 1.5 W (Low)
- Supply voltage nominal 14 VDC (range 10 VDC...15 VDC)
- Typical current RX 100mA, TX 2 A
- Frequency range 65 MHz...75 MHz
- Channel steps 10 kHz, 12.5 kHz, 25 kHz, 50 kHz
- Solid state T/R switching

- Excellent RX sensitivity -125 dBm (125nV) SINAD 10db
- Squelch sensitivity typical better that 100 nV
- 1750 Hz tone encoder
- Small size Width 153 mm, Height 50 mm, Depth 180 mm

Multifunction LCD
- S-meter bar indicator
- Output power, both bar and numerical
- SWR display
- Supply voltage indicator
- Frequency display (6 digits e.g. 70.2625 kHz)
- State indicator (SQ, RX, TX)

Configurable features
- Channel steps 10 kHz, 12.5 kHz, 25 kHz, 50 kHz
- LCD contrast
- LCD backlight

JUMA FM70 internal details

Easy building
- No coils need to be wound
- No wiring hassle

Copyright OH2NLT and OH7SV.
JUMA® is a registered trademark of Juha Niinikoski and Matti Hohtola.