GPS? Antenna
On 9/5/16 7:48 PM, Richard (Rick) Karlquist wrote:
As we all know, step #1 in making a clock is NOT
to build a thermometer :-)
I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design. I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature. I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application). I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability. Looking for any ideas,
maybe in the "maker" spirit. I think the
size I need would be perhaps 1/2 the size
of a shoebox.
You might look at inexpensive thermoelectric cooler/heaters - depending
on what temp range you want.
You could get a small electric icechest/heater and cobble up a
controller. They make ones that are designed to heat/cool something the
size of a 1 liter coke bottle..
TE technology has a wide variety of TE coolers and
controllers..Basically it's all about DC power supplies or power op amps
in one form or another.
You can buy inexpensive 1/8 DIN PID controllers for about $20 online..
They will take all manner of input sensor, thermocouple, PRT,
thermistor, etc.
Look at the "homebuilt sous vide" folks.
On 9/5/16 8:52 PM, Scott Stobbe wrote:
The bargain price mini coolers are often peltier cooled, they appear to
fall under the marketing term "thermoelectric mini-fridge". I can't think
of a project name, but I'm sure I've seen this done before using a mini
fridge.
https://www.amazon.com/AGPtek%C2%AE-Digital-Temperature-Controller-Alarm/dp/B005NGL5AK
Not used this particular one, but i have some that look quite similar,
and work well.
There are cheap GC (gas chromatograph) ovens on eBay. They are
well-insulated and give you fast, precise temperature control. Some of
them are designed with a liquid nitrogen input for cooling. Otherwise,
you can use dry ice. I saw one mentioned on one of the mailing lists I
read, maybe this one, a few months ago. I meant to buy one, but got
side-tracked. Unfortunately, I can no longer recall the brand.
Brent
On 9/5/2016 8:48 PM, Richard (Rick) Karlquist wrote:
As we all know, step #1 in making a clock is NOT
to build a thermometer :-)
I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design. I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature. I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application). I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability. Looking for any ideas,
maybe in the "maker" spirit. I think the
size I need would be perhaps 1/2 the size
of a shoebox.
BTW, in case someone has a chamber to sell,
let me know...
Rick Karlquist N6RK
You don't need exact control of the temperature. You just need a slow rate
of change and the ability to measure the temperature accurately.
I have used a picnic cooler with some water in the bottom and a very small
fish tank heater. But this was for an experiment in a home biology lab not
an electronic lab. Any insulated box with a largish thermal mass inside
will do. Try sand in place of the water. The neat thing about aquarium
heaters is their built in thermostat.
Or simp[lly place the DUT in an attic and let the day/night temperature
swing do the work for you. My attic get blazing hot in the day and cool at
night, the rate of change is not to fast
On Mon, Sep 5, 2016 at 7:48 PM, Richard (Rick) Karlquist <
richard@karlquist.com> wrote:
As we all know, step #1 in making a clock is NOT
to build a thermometer :-)
I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design. I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature. I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application). I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability. Looking for any ideas,
maybe in the "maker" spirit. I think the
size I need would be perhaps 1/2 the size
of a shoebox.
BTW, in case someone has a chamber to sell,
let me know...
Rick Karlquist N6RK
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--
Chris Albertson
Redondo Beach, California
Constant temperature chambers are not hard to build.
I assume you want stability in the range 0.001 to 0.01 degC.
I have made a few of these chambers, about 1 cubic feet, out of 3/4 inch particle board,
it is not a brilliant insulator, but you want some heat loss.
Make a partition at one end with both ends open as a radiation wall.
Behind the radiation wall instal one or two tungsten filament lamps,
about 50 watts for heaters, these have low thermal mass and fast response.
Instal a computer sized fan, behind the wall to reduce any radiant output to circulate the air in the box.
You want a small hurricane. On the far side of the box from the partition place a small bead thermistor,
glass encapsulated are good. In the air flow this should have a response time of a second.
A proportional controller sets the temperature. Air velocity of up to 1m/s will not disturb items being tested
but ensures low temperature gradients.
The trick is to have fast response in heater and measurement and no hysteresis in the controller.
cheers,
Neville Michie
On 6 Sep 2016, at 12:48 PM, Richard (Rick) Karlquist richard@karlquist.com wrote:
As we all know, step #1 in making a clock is NOT
to build a thermometer :-)
I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design. I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature. I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application). I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability. Looking for any ideas,
maybe in the "maker" spirit. I think the
size I need would be perhaps 1/2 the size
of a shoebox.
BTW, in case someone has a chamber to sell,
let me know...
Rick Karlquist N6RK
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington rdarlington@gmail.com
wrote:
Rick,
I'm going from memory here. My former business partner (now deceased) had
a "beer fridge" setup as an environmental chamber for our instruments. The
trick for stability was to run the AC compressor all the time, and push
against it with heat lamps.
I had a commercial environmental chamber : it did exactly this. The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.
Yes its H-S model, and it must be a GPS antenna...
http://www.cafr.ebay.ca/itm/Ericsson-KRE-1012082-1-GPS-Antenna-26dBi-For-HUBER-SUHNER-84097323-/182012930579?hash=item2a60d0ea13:g:MAMAAOSwZd1Vdn6-
Regards
Karl
2016-09-06 5:12 GMT+02:00 Chris Waldrup kd4pbj@gmail.com:
It's a Huber Suhner.
Chris
On Sep 5, 2016, at 21:26, Glenn Little WB4UIV <
glennmaillist@bellsouth.net> wrote:
Pete,
I do not know if I can send a picture to the mailing list.
I am sending this to you and the list.
The antenna is 4 inches from tip of cone to bottom of type-N connector.
It is 2 5/8" in diameter.
Thanks
Glenn
On 9/5/2016 8:25 PM, Pete Lancashire wrote:
Nemko is the Norwegian "UL", my guess is the numbers are the
test/certification numbers. A picture would help
-pete
On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV
<glennmaillist@bellsouth.net mailto:glennmaillist@bellsouth.net>
wrote:
At the last hamfest that I attended, I bought an antenna that looks
like a GPS antenna.
The price was right.
This is a Nemko Article number: 84097323, Type number 1315.17.0018.
It has a manufacturing date of 09/2012.
Can anyone tell me if this is in fact a GPS antenna and what voltage
wold be required.
I would suspect that it would be either 5VDC or 3.3 VDC based on the
date.
Any help appreciated.
Thanks
73
Glenn
WB4UIV
--
------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM
28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net
<mailto:wb4uiv@arrl.net> AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
------------------------------------------------------------
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Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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On 9/6/16 1:19 AM, Adrian Godwin wrote:
On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington rdarlington@gmail.com
wrote:
Rick,
I'm going from memory here. My former business partner (now deceased) had
a "beer fridge" setup as an environmental chamber for our instruments. The
trick for stability was to run the AC compressor all the time, and push
against it with heat lamps.
I had a commercial environmental chamber : it did exactly this. The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.
One thing we just found when using a Peltier type device is that the
stock controller typically PWM modulates the 12-24V supply voltage going
to the TE device. This produces enormous current/voltage transients
(many amps at 24V slamming on and off) at some audio frequency which is
sufficient to disrupt your carefully designed quiet device....
On our controllers (from TE Tech) you can use an external DC power
supply that has a remote programming input (e.g. a unipolar power
amplifier) and it just uses the H bridge to switch polarity to the
Peltier. This is MUCH quieter EMI/EMC wise.
The other issue is the condensation/frost when you go cold.
On 9/5/2016 9:48 PM, Richard (Rick) Karlquist wrote:
As we all know, step #1 in making a clock is NOT
to build a thermometer :-)
I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design.
Rick Karlquist N6RK
Another thing I've done in the (distant) past is two cheap foam coolers
with a muffin fan between them. fill one with dry ice and control the
fan for cooling. This was the essence of the bench coolers when I
worked for Collins Radio in the late 70's. In that case they were
aluminum boxes with foam walls. They had Edison based wire heaters with
porcelain forms. OSHA nightmare, but worked for the task at hand. Used
simple bang-bang controllers.
There are cheap (~$25) Chinese PID controllers, but as I said, I use the
Pico-reflow controller. Almost as cheap and a /lot/ more flexible.
Oz (N1OZ, in DFW)
--
mailto:oz@ozindfw.net
Oz
POB 93167
Southlake, TX 76092 (Near DFW Airport)
Also avoids thermomechanical fatigue failure in the Peltier device.
On Wednesday, 7 September 2016 12:14 AM, jimlux <jimlux@earthlink.net> wrote:
On 9/6/16 1:19 AM, Adrian Godwin wrote:
On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington rdarlington@gmail.com
wrote:
Rick,
I'm going from memory here. My former business partner (now deceased) had
a "beer fridge" setup as an environmental chamber for our instruments. The
trick for stability was to run the AC compressor all the time, and push
against it with heat lamps.
I had a commercial environmental chamber : it did exactly this. The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.
One thing we just found when using a Peltier type device is that the
stock controller typically PWM modulates the 12-24V supply voltage going
to the TE device. This produces enormous current/voltage transients
(many amps at 24V slamming on and off) at some audio frequency which is
sufficient to disrupt your carefully designed quiet device....
On our controllers (from TE Tech) you can use an external DC power
supply that has a remote programming input (e.g. a unipolar power
amplifier) and it just uses the H bridge to switch polarity to the
Peltier. This is MUCH quieter EMI/EMC wise.
The other issue is the condensation/frost when you go cold.
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