EMRFD Message Archive 562

Message Date From Subject
562 2007-03-23 18:03:40 homsleyt Universal QRP MK II
Has anyone successfully completed the Universal QRP MK II from April
2006 QST? My relay is turning on at < 10 volts instead of 12.

Tom, N4WBS
563 2007-03-23 19:08:38 brainerd@wildblue... Re: 60-120MHz VCO
I am looking for an inexpensive low noise circuit for a VCO (or 2) to cover 60 to 120 MHz.
Any ideas. Was thinking of a Hartley using a J310.

Dave - WB6DHW
<http://users.wildblue.net/wb6dhw>
565 2007-03-24 06:56:30 DSNman@comcast.ne... Re: 60-120MHz VCO
Attachments :
    Dave,

    Are MiniCircuits too expensive or do they not have the right freq range?
    --
    Loren Moline
    WA7SKT

    -------------- Original message ----------------------
    From: brainerd@wildblue.net
    > I am looking for an inexpensive low noise circuit for a VCO (or 2) to cover 60
    > to 120 MHz.
    > Any ideas. Was thinking of a Hartley using a J310.
    >
    > Dave - WB6DHW
    > <http://users.wildblue.net/wb6dhw>
    >
    566 2007-03-24 10:49:47 brainerd@wildblue... Re: 60-120MHz VCO
    On 24 Mar 2007 at 13:20, DSNman@comcast.net wrote:

    > Dave,
    >
    > Are MiniCircuits too expensive or do they not have the right freq range?
    > --
    > Loren Moline
    > WA7SKT
    >
    Mini-circuits wold be too expensive. I am trying to design an easy to build
    low cost rig. I did get both a Colpits and a Hartley oscillating last night using
    a J310 and an air coil made from stripped 14 ga house wiring. Stilll need to
    get it on the right freq range and add the varicap(I'm going to try 1n4007's).

    Dave - WB6DHW
    567 2007-03-24 10:54:23 DSNman@comcast.ne... Re: 60-120MHz VCO
    Dave,
     
    Thats great as long as you can lock the turns from moving with temp changes. What freq did you come up with.
     
    --
    Loren Moline
    WA7SKT
     
    -------------- Original message -----------
    568 2007-03-24 11:05:32 cfwa2unn Re: 60-120MHz VCO
    569 2007-03-24 11:11:14 Lasse Re: 60-120MHz VCO
    A low noise VCO with a 2:1 tuning range in not easy to  build! One of my favorites is a constrution from Ham Radio which uses coaxal cable for resonance and having a vari cap on one end the other end shows up as inductive. This oscillator is low nosie and have very low sensitivity to vibrations as there is no inductor that will change value!

    I have not the information on which issue this was published at hand, but can dig it out if you are interested. It might not give a full 2:1 tuing range, you might have to split this into 2 or 3 oscillators....
    Lasse SM5GLC


    On Fri, 23 Mar 2007 19:09:06 -0700
    brainerd@wildblue.net wrote:
    > I am looking for an inexpensive low noise circuit for a
    >VCO (or 2) to cover 60 to 120 MHz.
    > Any ideas. Was thinking of a Hartley using a J310.
    >
    > Dave - WB6DHW
    >
    >
    >
    >
    >
    > Yahoo! Groups Links
    >
    > <*> To visit your group on the web, go to:
    > http://groups.yahoo.com/group/emrfd/
    >
    > <*> Your email settings:
    > Individual Email
    570 2007-03-24 11:43:44 Ed Almos Re: 60-120MHz VCO
    The closest Minicircuits part I can see is the POS100, this covers
    from 45MHz to 110MHz so the top 10MHz will be missing.

    Something tells me the soluti
    571 2007-03-24 12:25:58 brainerd@wildblue... Re: 60-120MHz VCO
    That's what I was thinking. Maybe 3 caps in a binary sequence would give
    8 ranges. 60 - 120 MHz isn't magic. I want a 2 to 1 range somewhere in that
    area.

    Dave - WB6DHW

    On 24 Mar 2007 at 18:41, Ed Almos wrote:

    > The closest Minicircuits part I can see is the POS100, this covers
    > from 45MHz to 110MHz so the top 10MHz will be missing.
    >
    > Something tells me the soluti
    572 2007-03-25 03:27:47 Ed Almos Re: 60-120MHz VCO (An ALternative Circuit)
    This design may be of interest, please scroll down the page until you
    reach the secti
    573 2007-03-25 09:07:05 brainerd@wildblue... Re: 60-120MHz VCO (An ALternative Circuit)
    Thanks. I got both a Colpitts and a Hartley circuit oscillating at 60 - 100
    MHz depending on parallel cap. Unfortunately, the 2 back to back 1N4007's
    only provide about 1 MHz of range. May have to use a real varicap. I also
    found the 1uH chokes I'm using don't appear to work well at that freq.(the
    SRF is supposed to be at least 180 MHz). I replaced the 1uH from the
    tuning diode to ground with a 100K resistor and things started working.

    Dave - WB6DHW

    On 25 Mar 2007 at 10:27, Ed Almos wrote:

    > This design may be of interest, please scroll down the page until you
    > reach the section titled 'CMOS inverter VCO tunes octave to UHF'
    >
    > http://www.edn.com/archives/1998/111998/24di.htm
    >
    > By using this circuit together with a divide by two bistable it will
    > cover the range that you require.
    >
    > Edward Almos HA6SST

    >
    >
    >
    >
    > Yahoo! Groups Links
    >
    >
    >
    574 2007-03-28 04:50:03 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    575 2007-03-28 05:38:34 larry allen Re: 60-120MHz VCO (An ALternative Circuit)
    Thanks for the information....
    Larry ve3fxq


    ----- Original Message -----
    From: "Allis
    576 2007-03-28 06:28:30 Luiz Amaral Re: 60-120MHz VCO (An ALternative Circuit)
    Remember that a serie tuned Colpitts normally presents a much higher ratio
    Fmax/Fmin because the variable capacitance is not swamped by the fixed ones
    (feedback capacitors). Indeed that ratio increases with the fixed
    capacitances.

    Luiz - PY1LL

    ----- Original Message -----
    From: "Allis
    577 2007-03-28 20:34:28 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    578 2007-03-28 20:37:48 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    579 2007-03-28 20:49:35 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    580 2007-03-28 20:58:44 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    581 2007-03-28 21:08:39 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    582 2007-03-28 21:43:58 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    583 2007-03-28 22:29:47 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    584 2007-03-29 00:44:02 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    585 2007-03-29 04:59:22 Luiz Amaral Re: 60-120MHz VCO (An ALternative Circuit)
    I don't like low frequency rectifiers (like 1N4004) as varactors because
    their temperature coefficients are not controlled, and inherent noise is
    rather great. Both factors geopardize high performance PLL's.

    Luiz - PY1LL

    ----- Original Message -----
    586 2007-03-29 05:31:17 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    587 2007-03-29 06:49:10 Luiz Amaral Re: 60-120MHz VCO (An ALternative Circuit)
    The problem is not the temperature coefficient itself, but its spreading. In
    the case of rectifiers, it is not contolled.
    When I designed some very low noise UHF PLL's, I had to use some special
    1NXXXX varicaps from MOTOROLA, said to be the best ones as to intrinsic
    phase noise (unfortunately I don't have their names any more; I'm now
    retired). In certain cases, low phase noise is sometimes a great challenge
    to the designer, specially when some specifications are to be accomplished
    (like fine step and large band to be covered, etc). But I like them! hi hi

    Luiz - PY1LL

    ----- Original Message -----
    591 2007-03-30 08:34:13 Ted Bruce KX4OM Re: 60-120MHz VCO (An ALternative Circuit)
    Allison and group,
    Just wondering where I could find some information on the 1N4007s in
    terms of the capacitance range, say over 1 to 8 Volts. I'm looking
    for a substitute for the MV1662 in Colpitts VFOs, similar to the
    configuration of the Dave Benson "SW" rigs. I imagine the 1N4007s
    would have to be used in the back-to-back configuration to get much range.

    Ted KX4OM

    --- In emrfd@yahoogroups.com, "Allis
    592 2007-03-30 08:59:46 adams Re: 60-120MHz VCO (An ALternative Circuit)
    On Fri, 2007-03-30 at 15:33 +0000, Ted Bruce KX4OM wrote:
    > Allison and group,
    > Just wondering where I could find some information on the 1N4007s in
    > terms of the capacitance range, say over 1 to 8 Volts. I'm looking
    > for a substitute for the MV1662 in Colpitts VFOs, similar to the
    > configuration of the Dave Benson "SW" rigs. I imagine the 1N4007s
    > would have to be used in the back-to-back configuration to get much
    > range.
    >
    > Ted KX4OM
    >
    If you happen to have a copy of "SPICE - Practical Device Modeling"
    by Ron Kielkowski from McGraw-Hill, there is a chapter on Modeling
    Diodes and Zener Diodes. In it it measures the junction capacitance
    for a 1N4002 diode with a reverse voltage from 0.0 to 2.5V.

    You get a non-linear curve from 50.05pF to 26 or so pF. You can
    take the device model for SPICE for the 1N4007 and run it through
    SPICE to get the cap-curve. Ron (I can call him by his first name
    as I have an autographed copy of the book from a course that I took
    in Dallas from him) shows that the simulation and the measurements
    agree exactly for all voltages that he ran.

    FYI


    >
    --
    Chuck Adams, K7QO k7qo@commspeed.net
    http://www.k7qo.net/ personal web page

    Moving to Arizona? Bring your own water.
    593 2007-03-30 17:13:37 Allison Parent Re: 60-120MHz VCO (An ALternative Circuit)
    594 2007-03-31 15:08:24 Ted Bruce KX4OM Re: 60-120MHz VCO (An ALternative Circuit)
    Chuck,

    I have your tutorial on SPICE, and your models set, along with some
    others I found on the web, but I've found only a limited amount of
    information (mostly vendors) on device modeling. I checked Amazon on
    the Ron Kielkowski book, and it's $221, a bit steep for me, as a
    newbie to SPICE. I think I overstepped my capabilities in trying to
    understand how to model power MOSFETs, to translate characteristics
    from RF power MOSFETs to the common switching types we use. No
    success there, yet. I obviously should have started with something
    simpler :)

    I'll look at some data sheets for other diodes and see if i can find
    SPICE models that include the reverse-bias capacitance. On Hans,
    G0UPL's site on common diodes used as varicaps, I found a Schottky
    diode, a 1N5822, that has the large capacitance similar to the MV1662,
    and the data sheets do show the reverse-bias capacitance, so that's a
    start. Unfortunately, it's very nonlinear in the 1 to 8 Volt range.
    Next I'll go to the several vendors' sites that sell the device, and
    see if they have SPICE models for it.

    I've been able to linearize 12 to 13 kHz ranges very nicely around the
    QRP calling frequencies
    595 2007-04-01 13:15:16 Ed Almos Re: 60-120MHz VCO (An ALternative Circuit)
    >I checked Amazon on the Ron Kielkowski book, and it's $221, a bit
    steep for me, as a newbie to SPICE.<

    Am I the only one who thinks that a book on a computer program that
    costs $221 is a little bit crazy?

    Edward Almos HA6SST
    596 2007-04-01 14:58:56 DSNman@comcast.ne... Re: 60-120MHz VCO (An ALternative Circuit)
    Attachments :
      Ed,

      I think the same thing. The price to the amount you will use the program ratio is too high. I also have bought some books in which less that 5% of the info was useful to me.

      --
      Loren Moline
      WA7SKT

      -------------- Original message ----------------------
      From: "Ed Almos" <edwardalmos@gmail.com>
      > >I checked Amazon on the Ron Kielkowski book, and it's $221, a bit
      > steep for me, as a newbie to SPICE.<
      >
      > Am I the only one who thinks that a book on a computer program that
      > costs $221 is a little bit crazy?
      >
      > Edward Almos HA6SST
      >
      >
      597 2007-04-02 10:26:33 Ray Anderson Re: 60-120MHz VCO (An ALternative Circuit)
      EMRFD

       

      Re: 60-120MHz VCO (An ALternative Circuit)

      Posted by: "Ed Almos" edwardalmos@gmail.com   edwardalmos

      Sun Apr 1, 2007 1:15 pm (PST)

      >I checked Amazon on the Ron Kielkowski book, and it's $221, a bit
      steep for me, as a newbie to SPICE.<

      Am I the only one who thinks that a book on a computer program that
      costs $221 is a little bit crazy?

      Edward Almos HA6SST

       

      Checking the following page it looks like the publishers (McGraw Hill) list price is $55.00

      http://doi.contentdirections.com/mr/mgh.jsp?doi=10.1036/0079115241

      It must be out of print as Barnes and Noble doesn’t seem to have stock and Amazon is quoting the ridiculous price for the 1 copy  (most likely used) that they have.

       

      -Ray Anderson   WB6TPU

       

       

      674 2007-04-27 02:29:54 sp9mrn Re: Universal QRP MK II
      My relay is turning on at < 10 volts instead of 12.
      >
      May be it will help you:

      http://www.kangaus.com/universal_qrp_transmitter_-_mkii_files/
      voltages.pdf

      73
      MAc
      mrn