On 05/25/11 07:39 PM, Chuck Forsberg WA7KGX N2469R wrote:
If the radio's clock can be trimmed with a voltage,
why not divide the radio's 20 MHz clock by two and
feed the result into the GPSDO in place of the GPSDO's
10 MHz oscillator.
It can not be trimmed via a voltage. Also, I'm not keen to
Hi
You also may want to avoid an oscillator with much 10 MHz content in it. All
sorts of odd things can happen with spurs when you have unplanned stuff on the
main reference. Another thing to look closely at is - how much of the radio
tracks the reference? On some radios, they don't really
On 27 May 2011 15:21, Bob Camp li...@rtty.us wrote:
Hi
You also may want to avoid an oscillator with much 10 MHz content in it. All
sorts of odd things can happen with spurs when you have unplanned stuff on
the main reference. Another thing to look closely at is - how much of the
radio
Imho phase noise is probably as important as long term stability in this
application.
On Fri May 27th, 2011 10:51 AM EDT David Kirkby wrote:
On 27 May 2011 15:21, Bob Camp li...@rtty.us wrote:
Hi
You also may want to avoid an oscillator with much 10 MHz content in it. All
sorts of odd
Hi
Looking at this in terms of time nut type stability - you really want to lock
the 20 MHz up to something like a TBolt. At that point you have a wire out the
back of the radio and all that implies. Keeping the ground loops and RF issues
at bay in a transmitter is not trivial. For a timing
On Fri, May 27, 2011 at 6:10 PM, Mark Spencer mspencer12...@yahoo.ca wrote:
Imho phase noise is probably as important as long term stability in this
application.
for real and serious amateur radio dxing it's much more important the
phase noise and IMD3 performance of the RX rather than
List,
How about the LM1496 IC DBM? Simple and cheap.
Regards,
Perrier
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Hi
As mentioned earlier, phase noise is critical. That would be the main issue.
The original suggestion of a diode rectifier doubler has a much lower noise
floor. Done from scratch they don't cost much at all.
Bob
On May 27, 2011, at 12:35 PM, Perry Sandeen wrote:
List,
How about the
Yep. But in this case the original poster was looking to improve stability.
Perhaps a better way to have phrased my comment would have been to ensure that
the phase noise is not degraded vs the original xtal oscilator. I do agree
though that phase noise is very important. As a side note I
I left my Thunderbolt running with Lady Heather started. Returning after a few
hours in the room,
which is at a constant temperature (underground, no heating, no air
conditioning), I found the
following plot on the Lady Heather screen :
http://www.sdradio.eu/images/ladyheather.gif
which shows
Hi Alberto,
On Fri, May 27, 2011 at 8:45 PM, Alberto di Bene dib...@usa.net wrote:
I left my Thunderbolt running with Lady Heather started. Returning after a
few hours in the room,
which is at a constant temperature (underground, no heating, no air
conditioning), I found the
following plot
On 5/27/2011 8:59 PM, francesco messineo wrote:
since the plot has a step jump, seems only a few tens mC, and then it
comes slowly back to the normal track, I'd rule out at least an
external temperature change: the thunderbolt can easily detect an hand
in its proximity even for a few seconds,
Does anybody have a possible explanation for this ?
Ghosts, of course!
Likely an issue with the temp sensor, their conversion isn't necessarily flat.
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Hi
If you watch the thermometer on the TBolt for long enough, you will indeed see
narrow temperature spikes. The gif you posted is a very typical spike. They are
fairly rare and they don't repeat. I believe LH averages the readings it gets,
so they may simply be a noise burst. The initial jump
I have seen it, as a matter of fact two days ago I did see a straight jump
in excess of 1 C. I have seen it before. I do not monitor constantly, but
will keep an eye out.
Bert Kehren
In a message dated 5/27/2011 3:19:46 P.M. Eastern Daylight Time,
dib...@usa.net writes:
On 5/27/2011
I confirm Bob's statement.
Such spikes seem to be normal. I am running T-Bolts already since the
begin of the time nut action initiated by Tom (TvB) and with a temp
resolution of 20m°C. I observed always such spikes up to a few times a
day. I do not see a real practical problem.
Arnold
Am
Does anybody have a possible explanation for this ?
Short answer is the spike is caused by the temperature sensor.
This is very typical on all Tbolts at certain temperatures,
which depend on the temperature's rate of change and direction.
You can change LH's temperature display resolution to
Maybe a nearby cell phone calling home?
Bob Camp wrote:
Hi
If you watch the thermometer on the TBolt for long enough, you will indeed see
narrow temperature spikes. The gif you posted is a very typical spike. They are
fairly rare and they don't repeat. I believe LH averages the readings it
Hi
Could easily be. The spikes seem to be random and that would be a source of
random RF.
Bob
On May 27, 2011, at 7:41 PM, Chuck Harris wrote:
Maybe a nearby cell phone calling home?
Bob Camp wrote:
Hi
If you watch the thermometer on the TBolt for long enough, you will indeed
see
The spikes are due to an artifact in the way the Tbolt firmware reads the
temperature sensor chip. It reads two registers and combine the values to get
a high-res temp reading. But if the firmware accesses the registers in-between
the time that the temp sensor chip updates them it can
Hello
In my case I think it's not a rf problem. I am far away from rf or cell
phone stations and the shack is well protected against rf from outside
and no cell phone nor other transmitters were used in this room at this
time. If it would be an emc problem - why is only the temperature output
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