[ARC5] A Heterodyne Sweep Generator

[Bruce Long]

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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