[time-nuts] GPS Timing Antenna Failure - Long

Larry McDavid lmcdavid at lmceng.com
Sat May 12 20:38:59 EDT 2018

Thanks, Dave, for reporting your failed GPS antenna; at least, I am not 
alone in having this failure.

It will be interesting to understand what you find when you open your 
failed 58532A. Removing the radome is very easy, just 4 screws and some 
wiggling or gentle prying. If yours does not have the metal shield-can 
over the coax termination, a quick look at the coax solder joints for 
old flux will confirm or refute that as the likely failure cause. If 
your antenna has the shield-can and you see no flux around its soldered 
tabs, there likely is no flux problem.

Perhaps 1-2 years ago Symmetricom offered here a deep discount on this 
antenna, clearing their stock; presumably they have something newer. The 
antennas with the shield-can are from my purchase from Symmetricom of 
several of these antennas. The 58532A that failed is at least 10 years 
old so they must have made an in-line design change without changing the 
part number.

If you do remove the PWB, you will find the RF circuit rather obvious 
and even rectilinear in layout. All the parts are SMT. Two of the three 
amplifier chips are the same, as are two of the three bandpass filters. 
The first amplifier and the first bandpass filter are unique.

My primary goal in writing this narrative was to help someone who also 
had a similar antenna failure. I've heard now from several who have. If 
the fix is as simple as old flux removal, the antennas can probably be 

When I first tested the repaired antenna, I used a 5 vdc GPS device and 
that was successful. Later, I used another GPS device that puts only 3.3 
vdc to the antenna and that worked ok also, with no noticeable 
difference in performance. Note that the Symmetricom spec rates the 
antenna at 5 vdc input.

Larry W6FUB

On 5/12/2018 3:17 PM, Artek Manuals wrote:
> Larry
> Thanks for the analysis... I too have a failed 58532A which died  a year 
> ago . which I had not bothered to disassemble yet..The weather guessers 
> are predicting rain all week net week so maybe I will find an 
> opportunity to comp[are my findings to yours
> Do you have a schematic for the board or is the layout so simple that it 
> is self evident once you look at the board?
> Stay tuned for film at 11
> -DC
> de NR1DX
> manuals at artekmanuals.com
> On 5/12/2018 4:07 PM, Larry McDavid wrote:
>> I recently had an unexpected failure of a white-conical-dome 
>> HP/Symmetricom 58532A GPS antenna......

Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)

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