Not small when you are trying to achieve a -160dBc noise floor. Then even a
small fan can show up as a massive -120dbc or higher spur easily and ruin your
day due to the microphonics of the crystal. Some time ago there was a
discussion here about how entering a room measurably changed an ocxo fr
On Thu, Jul 12, 2012 at 6:56 PM, Said Jackson wrote:
> Sorry guys, but using a fan on a thunderbolt is nuts. Not time nuts.
>
> First you get ADEV humps as discussed here. Then the fan vibrations will
> show up as massive spurs in the phase noise plots. Then the fan's
> commutator emi will go eve
Nope, if implemented properly it works VERY well. No ADEV humps, no
vibration induced spurs, no commutator EMI, no power supply garbage.
Lady Heather's PID PWMs the fan to control the speed. It is not a bang-bang
controller. You should baffle the air flow so that it does not impinge
Sorry guys, but using a fan on a thunderbolt is nuts. Not time nuts.
First you get ADEV humps as discussed here. Then the fan vibrations will show
up as massive spurs in the phase noise plots. Then the fan's commutator emi
will go everywhere. Then the fan may modulate the supply voltage going in
Sorry about the bad URL. I corrected it below.
On 07/12/2012 12:22 AM, Chuck Forsberg WA7KGX N2469R wrote:
I mounted mine in a cabinet along with a power line filter
and power supply. Pics at www.omen.com/wa7kgx/ham.html
The filter is important if you are a ham or SWL.
The temp hangs around 35C
fan designed for variable speed plus finned heatsink plus temp sensor
(sometimes) in a neat package from any old computer cpu cooler...
Don
WarrenS
> Mark
>
> Although Lady Heather's temperature controller can hold the temp at the
> TBolt's sensor constant to delta 0.000x deg over 72 hrs,
> this d
mp...@clanbaker.org said:
> Eventually, I tried putting it in a large picnic sized Styrofoam container.
> This worked much better. The inside temperature did go up, but not so
> much as to be a problem. At some point the size of the container provided
> enough heat loss so as not to overheat
Time-Nutters--
Some years ago I ran some experiments trying to improve
on the temperature control of a circuit board with a reference
oscillator and other heat producing items on it. I quickly
discovered that enclosing it in a small Styrofoam container
jacked the temperature up wy to high.
On 07/12/2012 03:22 PM, Jim Lux wrote:
On 7/11/12 7:00 PM, Mike S wrote:
On 7/11/2012 8:15 PM, Chris Wilson wrote:
Does anyone know if there's a means to log max and min temps for these
things? I was going to make a crude box for mine out of 2 inch cavity
wall
insulation hard foam,
The TB rep
On 7/11/12 7:00 PM, Mike S wrote:
On 7/11/2012 8:15 PM, Chris Wilson wrote:
Does anyone know if there's a means to log max and min temps for these
things? I was going to make a crude box for mine out of 2 inch cavity
wall
insulation hard foam,
The TB reports it's own temperature. Lady Heather
I think that the only action is to wipe out any old setup present (use the
TBolt monitor program), especially a previous position hold setting. You
know, timing receivers have the position hold capability and it is
mandatory to restart the survey for your location.
I have 2 TBolts but (what a shame
On 07/12/2012 05:54 AM, Chris Albertson wrote:
On Wed, Jul 11, 2012 at 6:55 PM, Mark Spencerwrote:
I tried putting my thunderbolt in a styrofoam box. It got hotter than I
liked and didn't seem to perform any better than when I left it in a
cardboard box.
I worry about the long term implicati
When I had my Tbolt running full time, I just had it sitting in the bottom
corner of a bookcase that was hard to get to (Tek 7104 on a cart packed with
other gear too was in the way, along with piles of other things). No drafts, so
the temp stayed pretty constant. It was taken out of full servic
Just thinking outside of the Styrofoam box, wouldn't an analog
controller on the fan be better? That is use a DC fan and adjust the
current to change the speed.
On 7/11/2012 8:54 PM, Chris Albertson wrote:
On Wed, Jul 11, 2012 at 6:55 PM, Mark Spencer wrote:
I tried putting my thunderbolt i
I mounted mine in a cabinet along with a power line filter
and power supply. Pics at www.omen.com/wa7kgx.ham.html
The filter is important if you are a ham or SWL.
The temp hangs around 35C. The cat likes to sit on it as it
is slightly warm.
The Rb oscillator and its 15 volt power supply have b
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