A Simple 80 Metre DSB Minitransceiver
VK3AJG
The receiver is quite sensitive and tunes about 80-90Khz, tx output is ~300-500mW
C26 is small plastic tuning capacitor (100pf)
Q4 is 3.58Mhz ceramic resonator.
Coil L1 is 10 turns trifilar wound on ferrite bead.
Coil L6 is 10 turns bifilar wound on ferrite bead.
Coil L7 is 14 turns on old 10mm 455Khz IF Can.
All other coils are RF chokes.
Tx/Rx switching is done with a DPDT switch connected to
JP3 and JP5.
Adjust preset pots for best carrier balance on tx, and tune
L7 for best reception.
NOTE: Must use double sided pc board, with the top layer as a ground plane,
using single sided board the receiver will not work very well.
It seems a bit too complicated as for the start, also I wouldn't be able to manufacture such a quality twosided PCB at home...A 80m Transceiver
http://www.ozqrp.com/docs/MST2_80M_manual_V1.pdf
Are you talkingn about that circuit on the schematic:3. It can be used 'walkie talkie' mode but because of the limited antenna length if you are carrying it, the range will be quite short. When 80m is used in mobile communications, a loading coil is used to make the antenna appear longer than it really is, it makes the transmitter more efficient so it increases the range a little but the coil itself would be big enough to make it awkward to carry by hand.
4. The alternative would be a quartz crystal. As the tuning is achieved by 'pulling' the resonant frequency, quartz would limit the tuning range to maybe less than 1KHz. Ceramic is less stable but can be pulled more than quartz.
3.575611MHz PAL PAL M color subcarrier
3.579545MHz NTSC NTSC M color subcarrier; see colorburst. More specifically, 315/88 = 3.57954 MHz. Because these are very common and inexpensive they are used in many other applications, for example DTMF generators
3.582056MHz PAL PAL-N color subcarrier
3.595295MHz NTSC NTSC M color subcarrier, plus horizontal scan rate (15,750). Used for a rainbow color test, produces color through the entire 360 degrees of phase shift. Unusual.[2]
Similar but not quite the same. Note the length 'l' is still 41m so for a walkie-talkie you would need a helium balloon on the top end or it would be difficult to hold upright :-DAre you talkingn about that circuit on the schematic:
As long as you use the same in the transmitter and receiver it should be OK but such precise frequencies usually mean they are made of quartz so they will suffer the same limited 'pull' range. A single 3.579MHz ceramic will probably cover all those frequencies with the existing tuning circuit.Would I be at least able to make two transceivers on the same frequency with those crystals? I wonder if those crystals have accurate frequency up to 1kHz...
JP5 couples the antenna signal to the mixer (through C25 / J2) so the top two pins as shown on the schematic must be linked for it to work.Now I wonder, the IF Can on the schematic (L7) is connected to ground by JP5 in one case. Does it mean that I don't need to solder L7 (IF can) when I only want to receive?
It should do, but obviously you wont receive anything.Also, should VFO (3.58 oscillator) work without L6 soldered?
I have 1.3V on the base, and 0.6V on emitter and collector.If you have 1.3V on the base, which seems reasonable, you should have around 0.6V on the emitter and something a bit higher, maybe 4V on it's collector.
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