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Re: LF: RE: Analog oscillators

To: [email protected]
Subject: Re: LF: RE: Analog oscillators
From: Stefan Schäfer <[email protected]>
Date: Fri, 06 Jul 2012 22:49:03 +0200
In-reply-to: <18EDA97B55804092940864CAA40C8C50@lindavideo>
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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

 

 


From: owner-[email protected] [mailto:owner-[email protected]] On Behalf Of Graham
Sent: 06 July 2012 12:04
To: [email protected]
Subject: Re: Aw: Re: LF: RE: Analog oscillators

 

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..

 

From: mal hamilton

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 -----

From: Graham

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

 

 

Gesendet: Donnerstag, 05. Juli 2012 um 21:30 Uhr
Von: "Stefan Schäfer" <[email protected]>
An: [email protected]
Betreff: Re: LF: RE: Analog oscillators

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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