[time-nuts] Wanted: Expert opinion of HP 58503A GPS time and frequency receiver.

Charles Steinmetz csteinmetz at yandex.com
Fri Dec 12 12:47:37 EST 2014

Dave wrote:

>As you will have gathered from my posts on this mailing list, I bought
>something from eBay that was supposed to be an HP 58503A:
>But I have every reason to believe has a new case and serial number
>label fitted to the old chassis. The serial number just fell off in
>fact, but I managed to find it on the floor! I can't imagine HP serial
>numbers falling off, but this one did!!

Back in 2012, in response to a couple of posts from a list member 
about how wonderful the seller was and how great his 58503As were, I posted:

>Looking at the current and completed eBay listings for the 58503As 
>from Hong Kong, I notice that the seller seems to have conversion 
>units based on the Z3801 and on the Z3805, and some that may be 
>factory 58503As.  The listing text for all of them says they have 
>6-channel receivers.  Some have no PPS outputs, some have one, and 
>some have two.  Some have internal AC power supplies, some have 
>external supplies.  There appear to be at least two different 
>rear-panel layouts.  They are priced from $260 to $999, and it does 
>not seem obvious what justifies the radically different prices 
>(aside from different antennas).  Based on these confusing listings, 
>I'd be very reluctant to count on finding anything specific inside 
>the housing (e.g, a particular OCXO) if I bought one, except 
>possibly the $999 units that may be factory 58503As.

I didn't say at the time, but I had, myself, bought one of the 
[then-$230] units the year before.  I recently described how the 
listing promised an HP 10811 double-oven oscillator, but the unit I 
received came with the doubled, 5MHz Symmetricom oscillator 
instead.  I complained to the seller, and he offered to exchange the 
unit or refund $150, which is what I figured I would have to pay for 
the correct 10811.  Because of the cost of a return, I took the 
refund.  Then, as it turned out, the Symmetricom gradually (VERY 
gradually) settled into being one of my very best quartz oscillators, 
and still is.  The insides of mine are very clean -- I'd even say, 
pristine.  The PC cards are all genuine, but I can't say about the 
enclosure.  The front and rear panels look original to me, but I'm 
not sure I could tell the difference from a good fake.

I left neutral feedback -- it should have had the advertised DO 
10811, but then the seller did make what seemed to be a fair 
accommodation when I called him on it, and I couldn't fairly infer an 
intent to deceive from what could have been an honest mistake.  I 
tried to explain that as best as I could in ebay's abbreviated feedback form.

The listing for the one you bought is interesting.  It shows a 
rear-panel serial-number tag that says "Made in USA" but does not 
even pretend to look like any US-made HP serial-number sticker I've 
ever seen, and is too large to really fit the available space (unlike 
the label on the one you received, which at least looks legit at 
first glance if you discount the misalignment).  The s/n prefix is 
"3710A" -- it would be interesting to know if that is a legitimate 
58503A prefix (same with the prefix on the one you received, 3502A).

Good luck,


More information about the time-nuts mailing list