[time-nuts] power supply for Z3801

[Larry McDavid]

I have three HP Z3801A GPSDO, one of which runs 24/7 and has done so for 
many years. Because I wanted something conservative that would run 
reliably for a long time, I bought a Power One HD48-3-A 48 vdc 3A open 
frame supply.

I modified the supply by adding a finned heat sink 6.5 x 2.5 x 1.3 (fin 
height) inch heat sink to one side for additional cooling. I added some 
fish paper to close the open side of the supply and just set it in a 
safe place, positioned so the fins of the added heat sink are vertical. 
It runs on a 1500 VA UPS. I see this same P/N supply is still available 
many places but it may not be called a PowerOne now.

I did change one resistor in the voltage-setting pot string so that I 
could adjust the output voltage a bit higher, to 50 vdc. I did that at 
the time because the popular website for the Z3801A recommended it.

Whichever one of the three Z3801A units is in use, it runs without issue 
and is always in GPS LOCK and never in HOLDOVER. I use a Spectracom GPS 
timing antenna atop my 2-storey house roof, with clear horizon view, fed 
with Heliax hard line to a GPS Source S14WI 4-way amplified splitter, 
feeding several other kinds of GPS devices. All these GPSDO run on the 
UPS. Recently, I suffered a 3-hour power outage, very unusual here. All 
the GPSDO went down but came back up in LOCK in less than 15 minutes 
when power was restored; it took 24 hours for the APC SmartUPS UPS to 
fully recharge!

I truly despise switching power supplies. For something I want to run 
24/7 with high reliability and trouble-free, I will use an old-fashioned 
linear supply every time.

I have a switching supply that will run all three Z3801A concurrently. 
That supply has failed twice. Nuts to SMPS...

Larry


On 10/28/2020 3:32 PM, jimlux wrote:
> The 48-ish volt power supply for my Z3801 gave up the ghost..
> 
> What's the latest in off-the-shelf power supplies (external is fine, 
> uncased is fine)?
...

-- 
Best wishes,

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