[ARC5] A Heterodyne Sweep Generator

[Ian Wilson]

The NE602 has a useful amount of conversion gain - an advantage in
receiver applications (which is what it was designed for) - and often a
disadvantage in frequency-conversion applications, I agree.

73, ian K3IMW



On Wed, Mar 12, 2014 at 11:55 AM, Bruce Long <coolbrucelong at yahoo.com>wrote:

> I agree the ne602-612 is not good with strong signals and therefore at a
> disadvantage in signal generation applications.  Till you attenuate the
> signal- feed it into the 602 and then amplify back up to useful levels a
> DBM looks pretty good in my opinion.  I'm currently working on a simple
> data receiver based on a ne602 at work.  My input signal is rather strong
> at -30 dBm- almost too strong for the 602 to handle.  External osc
> injection does seem overly level sensitive as well....
>
>
>
>
>   On Wednesday, March 12, 2014 2:06 PM, "Fuqua, Bill L" <wlfuqu00 at uky.edu>
> wrote:
>    The main problem I have had with NE602 and SA612 has been when
> overdriving the inputs.
> Particularly the oscillator input when using an external oscillator.
>   If you use something like a NE604 as a detector ,assuming the frequency
> is low enough, you can use
> the SSI which produces a log output. Or you can use one of the new Analog
> Devices parts which have
> loads of bandwidth.
>
> 73
> Bill wa4lav
>
> ________________________________________
> From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on
> behalf of Bruce Long [coolbrucelong at yahoo.com]
> Sent: Wednesday, March 12, 2014 11:09 AM
> To: Ian Wilson; Geoff
> Cc: ARC-5 List
> Subject: Re: [ARC5] A Heterodyne Sweep Generator
>
> Ive recently been using the ne602 and NE612 at work and I find it to be
> somewhat finicky.  For a quanty one home brew hetrodyne signal generator I
> would just bit the bullet and use a double balanced mixed.  You will have
> to increase the lo injection relative to the 1496 to 7 dBm or so but
> amplification is easy and cheap  Let me know if you need a dbm  I think I
> may have one I can spare.
>
>
>
>
>
> On Wednesday, March 12, 2014 10:37 AM, Ian Wilson <ianmwilson73 at gmail.com>
> wrote:
>
> A reasonable alternative to the venerable 1496 would be the NE602 and
> friends. Usually available here: http://www.kitsandparts.com/parts.php
> (W8DIZ).
>
> One of those eBay <$5 DDS generators would be perfect here also (either as
> the 'signal generator' or there is public domain to use it as a 'wobbler'
> in which
> case you won't need the sawtooth generator + VCO + balanced mixer!).
>
> 73, ian K3IMW
>
>
>
> On Wed, Mar 12, 2014 at 6:20 AM, Geoff <geoffrey at jeremy.mv.com> wrote:
>
> > Finding active devices may be a chore, I think the MC 1496 has been
> > obsolete for 20 years or so. NTE might have a sub.
> >
> > That will not be an easy circuit for dead bug construction; FAR may have
> > something similar and there are likely many low cost vintage sweepers
> that
> > are still adequate at low frequencies, I had an Eico that was more than
> > adequate up to 5 mc or so.
> >
> > Carl
> >
> >
> > ----- Original Message ----- From: "Roy Morgan" <k1lky68 at gmail.com>
> > To: "Ken Gordon" <kgordon2006 at frontier.com>
> > Cc: "ARC-5 List" <arc5 at mailman.qth.net>
> > Sent: Wednesday, March 12, 2014 12:28 AM
> > Subject: Re: [ARC5] A Heterodyne Sweep Generator
> >
> >
> >
> >> On Mar 12, 2014, at 12:17 AM, Kenneth G. Gordon <
> kgordon2006 at frontier.com>
> >> wrote:
> >>
> >>  Jeep:
> >>>
> >>> I found this when searching for something else.
> >>>
> >>> It might be just exactly what both of us need.
> >>>
> >>> http://users.tpg.com.au/users/ldbutler/sweepgen.htm
> >>>
> >>
> >> Ken,
> >>
> >> Very interesting!
> >>
> >> I wonder if FAR Circuits or some such supplier has such a gadget.
> >>
> >> Roy
> >>
> >> Roy Morgan
> >> RoyMorgan at alum.mit.edu
> >> K1LKY Since 1958
> >>
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> >> -----
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> >>
> >>
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