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I would say the most useful thing to make
would be a linear transmit HF > 500
convertor .. then all modes are possible , this is
not 137 , ultra stable long qrss will not work ,
due to the short qsb and varying skip
distance, this can be observed in qso or beacon mode ,
propagation will fail before the call is sent
!
G..
Sent: Thursday, July 05, 2012 9:16 PM
Subject: Aw: Re: LF: RE: Analog oscillators
Dear Stefan,
building stable oscillators was a topic in the eighties, and it depeded all
on getting stable components. Later developing OMs reported, that the oscillator
for the qrp-TRX was the most difficult and time consuming part in development.
My recomendation: Buy aready built up DDS-oscillator, available at
Funkamateur.de (herre with IQ-sigs) or ELV-Elektronik. It is stable,
shows little noise on LF/MF. Must just be built into a enclosure. It
is a time saving solution. But: DFCW is not possible, and a keyed frequency
divider must be added; I divide by factor ten with CMOS-ICs. More
details on request.
55, Hans-Albrecht, DK 8 ND
Hello Ha-Jo, Can you pull one of the xtals to
cover the whole band? 73, Stefan Am 05.07.2012 20:57, schrieb
[email protected]: > Dear all, > > the only parts
I have bought so far for MF (still beeing engaged in > other developments)
are two crystals: 6,5536 MHz and 7,0200 MHz, to be > mixed with each
other. The mixer is another bipolar transistor, and its > emitter current
is being keyed. A final source follower after the > low-pass filter will
deliver the output to 50 ohms. > > The same solution I have also
used on LF. > > 73 Ha-Jo, DJ1ZB > >
>
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