Hello Ken,
The thing is, i want to have a very small VFO that consumes almost no
power (say < 50 mA at 12V DC). Also i have a f divide by 4 PA and
would like to have a VFO that shows the frequency from 472...479 kHz,
without the need to divide by 4 in my mind. I like to learn about
simple analog oscillators by building them by myselfe, not using the
VFO of a ready to use HF TRX.
Furthermore it is no necessity for me (as an individual) to do things
that are up to date. Otherwise i would have to decide to stop with the
old fashioned amateur radio hobby and do things that "all" men in my
age (have to) do: Working as much as possible to earn as much
money as possible to consume as many useless things as possible,
marrying, building a house, driving an expensive car (not older than 5
years of course), leaving the house in the morning in darkness to go to
work and coming home again in darkness, AND: Saying " I have no time
because of my job" and later "I have no time because of the
grandchildren" or "My XYL said i have to...". :-)
No, i prefer to build a simple Oscillator and i'm happy when it starts
to oscillate after a few hourse after starting the project. I like the
helpful comments from others and like to see the ongoing optimisation
of that VFO. This will not take 6 months but maybe rather 6 days (say 4
hours per day) and this work is fun. Lastly i am glad to come on the
band with my MF station. It is the same with my PA and the
complete LF stuff that seems to work pretty well, obviously.
73, Stefan/DK7FC
Am 06.07.2012 19:19, schrieb Ken:
Dear all.
I have been
following this thread from the
start, and thought why build an Analog Oscillator when you most likely
have a good
one already i.e. my old FT707, if I tune from 3.776MHz to 3.832MHz,
reduce the
power into a 50 ohm dummy load, tap off some of the output into a
divide by 8,
build two buffered 50 ohm outputs one to the tx the other to a
frequency counter.
It may be Heath Robinson but it beats spending six months trying to
build a
stable oscillator, also you can key the rig, ingenuity and a soldering
iron? Most
of you will have an old transceiver which includes top band so you need
only
divide by 4. As Mal would say that’s amateur radio at is best.
73s
Ken M0KHW
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 !
Sent: Friday,
July 06, 2012 9:41 AM
Subject: Re: Aw:
Re: LF: RE: Analog oscillators
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.
----- 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 !
Sent: Thursday,
July 05, 2012 9:16 PM
Subject: Aw: Re:
LF: RE: Analog oscillators
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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