[R-390] test equipment question

[Tisha Hayes]

What is really cool is to buy a surplus Efratom, rubidium frequency
reference that has a 10 MHz output (approx $100). All of the HP gear I have
has a frequency reference input to the counter, scope and oscillator are all
using the external reference.

Of course it takes week for the frequency reference to get down to the
part-per-billion stability and you can never turn the thing off (it is on a
battery string to keep it going during power outages).

I do a-lot of microwave and VHF/UHF design professionally and work out of my
home lab (coincidentally my radio room) so the test equipment all supports
that role.

Sigh, maybe someday I can get a vector impedance meter and a HP 8350B if I
win the lottery. Of course IF I won the lottery the lab would be more for
fun than work. By that time if anyone mentioned QAM anything I would run
screaming from the room.

On Fri, Feb 13, 2009 at 12:12 PM, David C. Hallam <dhallam at rapidsys.com>wrote:

> That's the reason I got the 8708A phase lock synchronizer to keep my 606B
> signal generator on frequency.  Of course, they fill up a big spot on the
> bench!
>
> David
> KC2JD/4
>
> Tisha Hayes wrote:
>
>> I know that this is broaching on heresy to mention this;
>>
>> I found the URM-25D to be less than helpful when compared to a good signal
>> generator. It is drifty, the impedance matching module is a joke and it is
>> hard to get repeatable results when trying to chase the performance dragon.
>>
>> But; if you use a good frequency reference (like the 100 KHz calibrator
>> and that is not waay off and WWV) you can get darned close to being on
>> frequency.
>>
>> If you dare to dabble with the compensation screws on the PTO to correct
>> linearity you need a much better frequency counter and signal generator. Of
>> course, gettting used HP/Agilent equipment will cost you more than any one
>> radio would ever sell for. You can find a really decent HP 400 series VTVM
>> or a Boonton that would do an excellent job on measuring RF levels for a
>> song-and-a-dance.
>>
>> The original maintenance manuals were written around the inherent
>> limitations of the test equipment available at the time (URM-25's). While I
>> try to keep the filaments glowing and avoid transistor/IC based radios in my
>> setup I do use more modern test equipment.
>>
>>
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>>
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