On 5/20/2012 7:56 PM, Mark Sims wrote:
An interesting test would be to test a Nortel unit and a Tbolt with the same
oscillator and see if the basic hardware had any difference in performance (I
bet they would be very close)
I had my Nortel running on the bench, in the open, for about 48 Hours,
fed with a pretty good quality Lambda power supply. I suspect that any
perceived diiference between it and the T'bolts may be down to the oven,
which I suspect may be a double oven in the case of the Nortel. Due to
the seller putting a sticky label on it helpfully saying "used" any
identification has gone, but the size of it for it's age would indicate
that it is something like the Morion inside. I don't see the
temperature variation effects on the LH display that both my t'bolts show.
It's performance at the 10,000 Tau level after 24 hours, with only the
quick survey, and no tuning of any parameters was on a par with my
T'bolt / E1938 and a little better than the standard t'bolt, all fed
from the same antenna / splitter. It does, as Mark pointed out, see a
better signal strength than the standard t'bolts, but as there are two
RF amp stages visible on the board, with three filters, that doesn't
surprise.
I suspect the three LEDs grouped on the left of the little board may be
more than just a "power on" indicator. Watching them and the LH 3.1
display with a cold start, I would guess that the red led is a cold oven
/ warm up indicator, and possibly the yellow one is a minor alert flag,
with green being all OK. Only the imminent coming of the leap second
will prove this one way or the other. The other two LEDs are steady
green for phase lock, green flashing for recovery and the other, yellow,
for holdover. These are all a bit delayed compared with the LH display.
So, at the right price, worth getting, if you can live with the physical
size and power supply needs. I'll be looking for a nice 2U case at the
next swap meet.
And many thanks to Mark for his swift LH changes!
Dan
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