HOMEBREW
80 METER CONVERTER
| This is a converter for 3.5 MHz to 3.8 MHz. Output frequency is 1.3 MHz to 1 MHz. LSB at the input frequency comes out at the output frequency as USB. The converter is designed for Mw.E.c and Lw.E.a. All part of the converter is my design. |
Here is the converter ready for operation.
The box is a drawer from IKEA.
This is the first test of the converter. An Mw.E.c
is used.
My new power for Mw.E.c is placed above the
converter.
Here are all parts collected before I start the work.
Power supply.
Power connector, fuse, power-switch, power lamp, transformer,
rectifier and power capacitor.
Power supply.
From left:
Power supply, Tuning capacitor for output, ECH81 and Tuning
capacitors for input filter.
Underside.
Underside.
Input Filter
Here is the filter response curve for the input filter.
The image-frequency is 70 dB down.
This filter is very important for the performance of the
converter.
Here is the filter response curve for the output filter.
This filter is a pi-filter and work as an impedance
converter from the high impedance on the ECH81 anode down to the
low impedance on the receiver input.
| Jeg ønsket å
kunne benytte den utmerkede mottaker Mw.E.c
til noe nyttig. Jeg bestemte meg derfor å lage en
converter for 80 meter ned til frekvensområdet til Mw.E.c.
Målet var å lage den enklest mulig. Jeg ville derfor
benytte et ECH81 rør. Dette er et rør
som benyttes i BC mottakere for oscillator og mixer. Følgende utfordringer måtte løses: En Xtal oscillator som fungerer på triodedelen på ECH81. Et inngangsfilter som undertrykker speilfrekvensen maksimalt. Et filter/impedanseomvandler for ECH81’s anode til Mw.E.c’s antenneinngang. Resultatet kan sees på denne siden. Resultatet ble meget bra. |
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