This converter is very sensitive.
You can hear the Waterford repeater, about 160KM away. Reception of weak
signals is superior to most commercial 2M rigs.
and Q2, use a pair of 3SK45 dual gate FET's. Most VHF N-Channel dual
gate mosfets should work fine. You can use 3SK88, BF961, and BF981 FET's
in this circuit. If you decide to use a GaAsFET for Q1, you will
probably need to use a Zener diode to reduce the drain voltage to a safe
level. L1 is 5 turns of 1mm copper wire, tapped at 1 turn,coil diameter
7mm, L2 and L3 are 5 turns each. T1 primary is 9 turns on a Toko 10mm
former (old IF transformer) T1 secondary is 2 turns. The screening can
and outer ferrite cup are not used.
Q3 is a BF256 or similar VHF
JFET. The 116 MHz crystal is a 7th overtone type. This simple oscillator
starts first time, every time, and has an output of several volts. L4 is
5 turns, tapped at 2 turns, 7mm inside diameter. L5 is 5 turns with a
ferrite tuning slug.
This converter is not likely to kill
you, but you could very easily kill it! If you are using a HF
transceiver as the IF, make sure that you don't accidently operate the
transmitter. A few watts of RF into the IF output will almost certainly
Reference : ?
Download the page |
RF /Video |
Circuits | Electronics | Home