[time-nuts] HP5090A Off Air Standard Receiver

Bob kb8tq kb8tq at n1k.org
Mon Jun 19 10:08:49 EDT 2017


If it’s an off the air receiver, it’s got front end filtering and all the rejection
you would want to lock on to a single carrier. 200 KHz and 2 KHz fed into
an XOR would give you what you likely need. A PICDiv should be able to 
generate both those “tones” without a lot of crazy effort. There are a lot
of combinations that could be used. A bit of play time with a spread sheet 
is likely called for here. 

If the carrier needs modulation, then that would take a bit more effort. It’s still
not outside the range of what could be done with a fairly simple board. We have
tossed up the names of a couple dozen candidates over the last year or so.


> On Jun 19, 2017, at 9:46 AM, Clint Jay <cjaysharp at gmail.com> wrote:
> If it's just locking to the carrier I wonder if it'd be possible to use a
> suitably modified PICDiv clocked from a 'standard' 10MHz GPS locked device
> like the Lucent?
> On 19 June 2017 at 14:19, GandalfG8--- via time-nuts <time-nuts at febo.com>
> wrote:
>> I suppose a converter from 198KHz could be an option but I know of at
>> least one other experimenter who's run into problems with the Teleswitch
>> modulation on the Droitwich signal when trying something similar with a
>> 5090A.
>> Although, from one point of view, running it from the present 198KHz
>> signal might be considered the ultimate goal it's the operation of the
>> hardware
>> itself that's of more interest to me in this instance, so I'm  quite happy
>> just to feed it with an accurate 200KHz signal from  whatever other sources
>> are available.
>> Nigel, GM8PZR
>> How about building a frequency converter to produce 200KHz; mixing  the
>> incoming RF (198KHz) with 2KHz derived from the output of the  unit,
>> On 18/06/2017 21:17, GandalfG8--- via time-nuts wrote:
>>> Hi  Pete
>> That's quite good timing, if you'll pardon the expression:-), as I
>> uploaded  a pdf version of the 5090A manual to mediafire a couple of
>> months
>> ago.... http://www.mediafire.com/file/u0bf1eips89uo3h/HP_5090A_Ops_
>> and_Service.pdf
>> I know a few others have considered converting the 5090A to 198KHz but
>> it's  not straightforward and I believe the general consensus has been that
>> it's  not  really worth the effort.
>> I have a 5090B which I'm hoping  to get up and running when it finally
>> reaches the top of the to do list and my  view is that it would be much
>> better
>> to leave the original electronics  undisturbed and to drive it with a  200
>> KHz signal divided down from a from  a GPSDO or a rubidium  module,
>> although
>> having one of the latter already  running at 800KHz  does leave me a bit
>> biased:-)
>> Regards
>> Nigel,  GM8PZR
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> -- 
> Clint.
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
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