|
Each to his own, but we would be giving
questionable technical advice, if building a
LC vfo was put foreword as the preferred path to
500 , Racal's barlow-wadley patent expired round
1970 and was replaced with the digital - phase
locked design in the ra1771/2 , with 10 Hz
stepping, round the same time ...
Non of this is relevant now, with the DDS , plenty
of good ex-equipment 5 MHz
standards about , that gives a 10:1 clock
over head , all that's needed is a 500 band
pass filter and output amp , If a
CW tx is all that's needed , later use the
DDS as the conversion oscillator in a down
converter ..
OP QSO mode , good question , the phantom of
the Opera works in mysterious ways .. its
missing at the moment from the latest version , keep
the old version for later in the year !
73 -G..
Sent: Friday, July 06, 2012 9:41 AM
Subject: Re: Aw: Re: LF: RE: Analog oscillators
Graham
Getting One's Oscillator started seems to be the problem
at present. Perhaps a transverter is the answer.
What has happened to Opera QSO mode. I do not get any
replies, others seem to favour Beacon mode.
G3KEV
----- Original Message -----
Sent: Thursday, July 05, 2012 9:27
PM
Subject: Re: Aw: Re: LF: RE: Analog
oscillators
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 > > >
|
