I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.

Overall they seem like outright junk but are close to the mark of being
reliable to me. I have one made by LaCrosse I picked up from Fry's a couple
years ago, although I can't say it ever worked 100%, it seems to have a
stability problem with summer temps, more or less when it goes over 75F or
so.

Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.

What is interesting is, if you put fresh batteries in both units, it does
seem to work around the clock for several days. But then it starts to peter
out, slowly. Like readings above 90F blank, then in a couple days, readings
above 85F, then 80F and finally in a couple weeks, around 70-75F is tops.

Odd thing, fall and winter doesn't seem to have a problem. Installing a
fresh set of batteries last October keep it running fine until a month or so
ago. Even got down to below zero, never missed a beat.

I'm not losing any sleep over it but the thing stumps me on what the fault
or design problem is. Last night while looking at Radio Shacks website for a
replacement (figured it was a good place to start at), now that they allow
customer comments for their products, it doesn't take much reading to see
that nearly all of them have basically the same problem. Doesn't matter if
it's the $20 model or the $120 one, various comments include "junk",
"trash", "returned it" and "disappointed with reliablity".

What I was wondering about is if anyone knows about the mating ritual these
things need to initialize the operation. According to the instructions you
need to place both the indoor unit and outside sensor near each other, put
the batteries in the outdoor unit, then batteries in the indoor unit. After
the indoor unit gets a reading (changes from --- to actual temp), you set
the time on the indoor unit and place the outdoor unit where you want it to
go.

So it seems like when the batteries are placed in the outdoor unit, it may
be transmitting some kind of id signal the indoor unit starts listening for
when batteries are installed in it. Either that or that ritual just starts a
timing sequence.

What I do know is, even with the two units in close range of each other
(couple of feet), pulling and replacing the batts in the indoor unit only
will never get a reading from the outside sensor anymore. So you do have to
follow that proceedure they outline in the manual and back of both units.

Now I already thought of some kneejerk opinions like there may be a thermal
problem with the outside unit or it's simply a range problem, but I don't
think either is correct.

When I first noted the problem I brought the outside sensor back in, did the
batt replacement ritual then stuck a hair dryer aimed at it for quite some
time (over an hour). It was constantly above 120F, even using the same
batteries as it was outside which seemed to have dropped down to the "can't
read anything above 75F point". Putting the unit back (same batts again)
gave another couple days of use until it started to fade out again with
warmer temps.

The range doesn't seem to be it either, I originally bought the thing to
keep an eye on the attic temp, the indoor unit was on a wall and only about
5 feet (or less) directly under the sensor which I placed above it,
basically right above the ceiling on the attic floor. The numbers were
different but the behavior was exactly the same, it initially got readings
peaking out in the 128-135F range, then after a few days would "blank" out
at readings above 125F, then around 110F then within a week wouldn't provide
a reading unless it was around 80F or below.

Not really any different from the 30 or so feet where I relocated the
outside unit to read outside air temps (I went to a wired thermistor type
for the attic).

Long winded story but the question remains, does anyone know how these units
communicate with each other?

It appears that the inside unit does something every 10 minutes, there is an
undocumented icon on the display of like a satellite dish that turns on at
10 minute intervals for about 90 seconds. A shorter one occurs at the 7
minute mark, but only for about 30 seconds.

My guess is the inside unit doesn't transmit anything to the outdoor unit
but when that icon is on, it's listening for something from the outdoor
unit. Another words when it's working normally, there isn't any temp updates
for 10 minute intervals.

It's just that by not changing batts in either unit (but getting the two
close to each other, either inside to out or outside to in) then doing that
restart initialization makes things work again, but only for a while.

So could there really be an id tag that is getting munged somehow after the
battery gets low or something and the indoor unit is ignoring the output
from the external sensor even though it's "hearing" it?

I haven't ran across much data on these types of units, guess they are all
cranked out from China and generally aren't worth bothering with but the
fault seems to be common with most of the models. Is there like a known
protocol for them? They all seem to work on 433.92mHz.

If anyone has ever spotted any technical info, would love to get pointed in
the right direction. It's not really a matter of repairing it but would like
to know how it's supposed to work in the first place.

-bruce

In article , Bruce Esquibel wrote:

I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.

Overall they seem like outright junk but are close to the mark of being
reliable to me. I have one made by LaCrosse I picked up from Fry's a couple
years ago, although I can't say it ever worked 100%, it seems to have a
stability problem with summer temps, more or less when it goes over 75F or
so.

Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.

What is interesting is, if you put fresh batteries in both units, it does
seem to work around the clock for several days. But then it starts to peter
out, slowly. Like readings above 90F blank, then in a couple days, readings
above 85F, then 80F and finally in a couple weeks, around 70-75F is tops.

Odd thing, fall and winter doesn't seem to have a problem. Installing a
fresh set of batteries last October keep it running fine until a month or so
ago. Even got down to below zero, never missed a beat.

I'm not losing any sleep over it but the thing stumps me on what the fault
or design problem is. Last night while looking at Radio Shacks website for a
replacement (figured it was a good place to start at), now that they allow
customer comments for their products, it doesn't take much reading to see
that nearly all of them have basically the same problem. Doesn't matter if
it's the $20 model or the $120 one, various comments include "junk",
"trash", "returned it" and "disappointed with reliablity".

What I was wondering about is if anyone knows about the mating ritual these
things need to initialize the operation. According to the instructions you
need to place both the indoor unit and outside sensor near each other, put
the batteries in the outdoor unit, then batteries in the indoor unit. After
the indoor unit gets a reading (changes from --- to actual temp), you set
the time on the indoor unit and place the outdoor unit where you want it to
go.

So it seems like when the batteries are placed in the outdoor unit, it may
be transmitting some kind of id signal the indoor unit starts listening for
when batteries are installed in it. Either that or that ritual just starts a
timing sequence.

What I do know is, even with the two units in close range of each other
(couple of feet), pulling and replacing the batts in the indoor unit only
will never get a reading from the outside sensor anymore. So you do have to
follow that proceedure they outline in the manual and back of both units.

Now I already thought of some kneejerk opinions like there may be a thermal
problem with the outside unit or it's simply a range problem, but I don't
think either is correct.

When I first noted the problem I brought the outside sensor back in, did the
batt replacement ritual then stuck a hair dryer aimed at it for quite some
time (over an hour). It was constantly above 120F, even using the same
batteries as it was outside which seemed to have dropped down to the "can't
read anything above 75F point". Putting the unit back (same batts again)
gave another couple days of use until it started to fade out again with
warmer temps.

The range doesn't seem to be it either, I originally bought the thing to
keep an eye on the attic temp, the indoor unit was on a wall and only about
5 feet (or less) directly under the sensor which I placed above it,
basically right above the ceiling on the attic floor. The numbers were
different but the behavior was exactly the same, it initially got readings
peaking out in the 128-135F range, then after a few days would "blank" out
at readings above 125F, then around 110F then within a week wouldn't provide
a reading unless it was around 80F or below.

Not really any different from the 30 or so feet where I relocated the
outside unit to read outside air temps (I went to a wired thermistor type
for the attic).

Long winded story but the question remains, does anyone know how these units
communicate with each other?

It appears that the inside unit does something every 10 minutes, there is an
undocumented icon on the display of like a satellite dish that turns on at
10 minute intervals for about 90 seconds. A shorter one occurs at the 7
minute mark, but only for about 30 seconds.

My guess is the inside unit doesn't transmit anything to the outdoor unit
but when that icon is on, it's listening for something from the outdoor
unit. Another words when it's working normally, there isn't any temp updates
for 10 minute intervals.

It's just that by not changing batts in either unit (but getting the two
close to each other, either inside to out or outside to in) then doing that
restart initialization makes things work again, but only for a while.

So could there really be an id tag that is getting munged somehow after the
battery gets low or something and the indoor unit is ignoring the output
from the external sensor even though it's "hearing" it?

I haven't ran across much data on these types of units, guess they are all
cranked out from China and generally aren't worth bothering with but the
fault seems to be common with most of the models. Is there like a known
protocol for them? They all seem to work on 433.92mHz.

If anyone has ever spotted any technical info, would love to get pointed in
the right direction. It's not really a matter of repairing it but would like
to know how it's supposed to work in the first place.

I like to think I was the one responsible for getting these things on the market
after my requests that such a device be made.

Most units do not communicate with each other. Its a one way signal.
I have had problems. The first unit I have had for at least 8 years still works, but it never
had much range. This unit would not transmit unless a change in temperature
occurs. You can usually do that by holding. And, this unit had a perfectly seald transmitter
like all good ones should have for outdoors. It also could monitor 3 locations.
I have bought two of the recent cheapies from Wal-Mart and both failed after a short time. I have another by the same
company except it the delux model, and works well, but I have not tested its range. That
first unit I have was always hard to understant the sequence of battery insertion
to get it working. Whatever works seems to be OK.
I have also taped a 1/4 wave 420 mHz capacitively couple antenna to the case where
the internal loop is on th etransmitter. Seems to help range.

greg

On Jul 9, 11:41 am, (GregS) wrote:
In article , Bruce Esquibel wrote:

I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.

Overall they seem like outright junk but are close to the mark of being
reliable to me. I have one made by LaCrosse I picked up from Fry's a couple
years ago, although I can't say it ever worked 100%, it seems to have a
stability problem with summer temps, more or less when it goes over 75F or
so.

Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.

What is interesting is, if you put fresh batteries in both units, it does
seem to work around the clock for several days. But then it starts to peter
out, slowly. Like readings above 90F blank, then in a couple days, readings
above 85F, then 80F and finally in a couple weeks, around 70-75F is tops.

Odd thing, fall and winter doesn't seem to have a problem. Installing a
fresh set of batteries last October keep it running fine until a month or so
ago. Even got down to below zero, never missed a beat.

I'm not losing any sleep over it but the thing stumps me on what the fault
or design problem is. Last night while looking at Radio Shacks website for a
replacement (figured it was a good place to start at), now that they allow
customer comments for their products, it doesn't take much reading to see
that nearly all of them have basically the same problem. Doesn't matter if
it's the $20 model or the $120 one, various comments include "junk",
"trash", "returned it" and "disappointed with reliablity".

What I was wondering about is if anyone knows about the mating ritual these
things need to initialize the operation. According to the instructions you
need to place both the indoor unit and outside sensor near each other, put
the batteries in the outdoor unit, then batteries in the indoor unit. After
the indoor unit gets a reading (changes from --- to actual temp), you set
the time on the indoor unit and place the outdoor unit where you want it to
go.

So it seems like when the batteries are placed in the outdoor unit, it may
be transmitting some kind of id signal the indoor unit starts listening for
when batteries are installed in it. Either that or that ritual just starts a
timing sequence.

What I do know is, even with the two units in close range of each other
(couple of feet), pulling and replacing the batts in the indoor unit only
will never get a reading from the outside sensor anymore. So you do have to
follow that proceedure they outline in the manual and back of both units.

Now I already thought of some kneejerk opinions like there may be a thermal
problem with the outside unit or it's simply a range problem, but I don't
think either is correct.

When I first noted the problem I brought the outside sensor back in, did the
batt replacement ritual then stuck a hair dryer aimed at it for quite some
time (over an hour). It was constantly above 120F, even using the same
batteries as it was outside which seemed to have dropped down to the "can't
read anything above 75F point". Putting the unit back (same batts again)
gave another couple days of use until it started to fade out again with
warmer temps.

The range doesn't seem to be it either, I originally bought the thing to
keep an eye on the attic temp, the indoor unit was on a wall and only about
5 feet (or less) directly under the sensor which I placed above it,
basically right above the ceiling on the attic floor. The numbers were
different but the behavior was exactly the same, it initially got readings
peaking out in the 128-135F range, then after a few days would "blank" out
at readings above 125F, then around 110F then within a week wouldn't provide
a reading unless it was around 80F or below.

Not really any different from the 30 or so feet where I relocated the
outside unit to read outside air temps (I went to a wired thermistor type
for the attic).

Long winded story but the question remains, does anyone know how these units
communicate with each other?

It appears that the inside unit does something every 10 minutes, there is an
undocumented icon on the display of like a satellite dish that turns on at
10 minute intervals for about 90 seconds. A shorter one occurs at the 7
minute mark, but only for about 30 seconds.

My guess is the inside unit doesn't transmit anything to the outdoor unit
but when that icon is on, it's listening for something from the outdoor
unit. Another words when it's working normally, there isn't any temp updates
for 10 minute intervals.

It's just that by not changing batts in either unit (but getting the two
close to each other, either inside to out or outside to in) then doing that
restart initialization makes things work again, but only for a while.

So could there really be an id tag that is getting munged somehow after the
battery gets low or something and the indoor unit is ignoring the output
from the external sensor even though it's "hearing" it?

I haven't ran across much data on these types of units, guess they are all
cranked out from China and generally aren't worth bothering with but the
fault seems to be common with most of the models. Is there like a known
protocol for them? They all seem to work on 433.92mHz.

If anyone has ever spotted any technical info, would love to get pointed in
the right direction. It's not really a matter of repairing it but would like
to know how it's supposed to work in the first place.

I like to think I was the one responsible for getting these things on the market
after my requests that such a device be made.

Most units do not communicate with each other. Its a one way signal.
I have had problems. The first unit I have had for at least 8 years still works, but it never
had much range. This unit would not transmit unless a change in temperature
occurs. You can usually do that by holding. And, this unit had a perfectly seald transmitter
like all good ones should have for outdoors. It also could monitor 3 locations.
I have bought two of the recent cheapies from Wal-Mart and both failed after a short time. I have another by the same
company except it the delux model, and works well, but I have not tested its range. That
first unit I have was always hard to understant the sequence of battery insertion
to get it working. Whatever works seems to be OK.
I have also taped a 1/4 wave 420 mHz capacitively couple antenna to the case where
the internal loop is on th etransmitter. Seems to help range.

greg- Hide quoted text -

- Show quoted text -

I have also taped a 1/4 wave 420 mHz capacitively couple antenna to the case where
the internal loop is on th etransmitter. Seems to help range.


Could you give us more info on this?

Thanks

TMT

On Jul 9, 11:12 am, Bruce Esquibel wrote:
I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.

Overall they seem like outright junk but are close to the mark of being
reliable to me. I have one made by LaCrosse I picked up from Fry's a couple
years ago, although I can't say it ever worked 100%, it seems to have a
stability problem with summer temps, more or less when it goes over 75F or
so.

Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.

What is interesting is, if you put fresh batteries in both units, it does
seem to work around the clock for several days. But then it starts to peter
out, slowly. Like readings above 90F blank, then in a couple days, readings
above 85F, then 80F and finally in a couple weeks, around 70-75F is tops.

Odd thing, fall and winter doesn't seem to have a problem. Installing a
fresh set of batteries last October keep it running fine until a month or so
ago. Even got down to below zero, never missed a beat.

I'm not losing any sleep over it but the thing stumps me on what the fault
or design problem is. Last night while looking at Radio Shacks website for a
replacement (figured it was a good place to start at), now that they allow
customer comments for their products, it doesn't take much reading to see
that nearly all of them have basically the same problem. Doesn't matter if
it's the $20 model or the $120 one, various comments include "junk",
"trash", "returned it" and "disappointed with reliablity".

What I was wondering about is if anyone knows about the mating ritual these
things need to initialize the operation. According to the instructions you
need to place both the indoor unit and outside sensor near each other, put
the batteries in the outdoor unit, then batteries in the indoor unit. After
the indoor unit gets a reading (changes from --- to actual temp), you set
the time on the indoor unit and place the outdoor unit where you want it to
go.

So it seems like when the batteries are placed in the outdoor unit, it may
be transmitting some kind of id signal the indoor unit starts listening for
when batteries are installed in it. Either that or that ritual just starts a
timing sequence.

What I do know is, even with the two units in close range of each other
(couple of feet), pulling and replacing the batts in the indoor unit only
will never get a reading from the outside sensor anymore. So you do have to
follow that proceedure they outline in the manual and back of both units.

Now I already thought of some kneejerk opinions like there may be a thermal
problem with the outside unit or it's simply a range problem, but I don't
think either is correct.

When I first noted the problem I brought the outside sensor back in, did the
batt replacement ritual then stuck a hair dryer aimed at it for quite some
time (over an hour). It was constantly above 120F, even using the same
batteries as it was outside which seemed to have dropped down to the "can't
read anything above 75F point". Putting the unit back (same batts again)
gave another couple days of use until it started to fade out again with
warmer temps.

The range doesn't seem to be it either, I originally bought the thing to
keep an eye on the attic temp, the indoor unit was on a wall and only about
5 feet (or less) directly under the sensor which I placed above it,
basically right above the ceiling on the attic floor. The numbers were
different but the behavior was exactly the same, it initially got readings
peaking out in the 128-135F range, then after a few days would "blank" out
at readings above 125F, then around 110F then within a week wouldn't provide
a reading unless it was around 80F or below.

Not really any different from the 30 or so feet where I relocated the
outside unit to read outside air temps (I went to a wired thermistor type
for the attic).

Long winded story but the question remains, does anyone know how these units
communicate with each other?

It appears that the inside unit does something every 10 minutes, there is an
undocumented icon on the display of like a satellite dish that turns on at
10 minute intervals for about 90 seconds. A shorter one occurs at the 7
minute mark, but only for about 30 seconds.

My guess is the inside unit doesn't transmit anything to the outdoor unit
but when that icon is on, it's listening for something from the outdoor
unit. Another words when it's working normally, there isn't any temp updates
for 10 minute intervals.

It's just that by not changing batts in either unit (but getting the two
close to each other, either inside to out or outside to in) then doing that
restart initialization makes things work again, but only for a while.

So could there really be an id tag that is getting munged somehow after the
battery gets low or something and the indoor unit is ignoring the output
from the external sensor even though it's "hearing" it?

I haven't ran across much data on these types of units, guess they are all
cranked out from China and generally aren't worth bothering with but the
fault seems to be common with most of the models. Is there like a known
protocol for them? They all seem to work on 433.92mHz.

If anyone has ever spotted any technical info, would love to get pointed in
the right direction. It's not really a matter of repairing it but would like
to know how it's supposed to work in the first place.

-bruce


Some comments....

The units are all based on a common chip set...communication is one
way...transmitter to receiver. It is a digital data stream and I
*think* without error correction. The transmissions are directional
and suspectible to RF noise and to unintentional shielding due to
metal.

To determine whether you have a good set, set the outside transmitters
next to the indoor readout....if they all show the same temperature
(which is not always the case), then you have a good calibriated
system. Any offset represents a calibriation error...it is too great
for your tastes return the system. Bear in mind with the low cost, you
are the alpha tester for the system.

Some of your comments concerning problems with high temps indicate a
possible battery/circuit problem...change the brand of batteries and
if the problem continues return the unit.

More often one will see problems with low temperatures with the
accompanying diminished battery performance. In this case one should
use lithium batteries.

I have a number of different brands and have had no problems once the
system is setup.

I too would love to experiment with these RF thermometers.

TMT

Bruce Esquibel wrote:
Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.

I have one LaCrosse unit, one Radio Shack which I'm pretty sure is not
made by LaCrosse, and one Taylor unit. They all work fine at all times
IF the receiving unit is within ten feet of the sending unit. When
battery change time comes around, they can be *very* finicky about
whether the sender or receiver is powered up first; I don't remember
well but I think it likes sender powered up before receiver.

--
Postulate a group whose intent is to destroy the United States from within
via anarchy and bankruptcy. The actions of the United States Congress are
completely consistent with the actions one would predict from such a group.

Hi!

I have a few different brands of these units...most are Radio Shack, one is
an "EnviraStation" and the last one is a simplistic promotional freebie from
DeKalb seed corn (!!!) that doesn't have an outdoor sensor.

I've been pretty happy with all of the units and haven't had the problems
that you've reported. I have noticed that the outdoor modules with displays
tend to have the display damaged by the sun or extreme cold very quickly.
The displays usually end up turning very dark or appear to have all the
elements on at once.

As far as the outdoor units go, extreme heat and cold are tough on the
average alkaline battery. The same is probably true for rechargeables and
carbon-zinc types as well. I have found that high quality, name brand
alkaline batteries last much longer than cheaper ones. In most cases the
outdoor sensors will run for several months before I have to replace the
batteries. I try to place the sensors in trees, so they are not in the path
of direct sunlight. I suppose this might affect the temperature reading by a
few degrees, but the figures should still be in the ballpark.

Interestingly enough, the "freebie" DeKalb unit has both the highest and
lowest operating ranges, as it has a button to shift the scale of the
thermometer portion around. It is not otherwise very fancy, as it has only a
manually set clock and measures indoor temperature/humidity only, but it
will reliably run up to 140 and down to at least -10 on the Fahrenheit
scale. It also uses the least amount of electrical power, as it has only two
AAA batteries wired in parallel.

As far as operation principles go, I think these devices all pretty much
communicate somewhere in the 300MHz band. The synchronization process is
needed because there may be many of these in a given neighborhood. Even if
they aren't all from the same maker, the frequencies used are similar. When
the pairing process happens, both units agree upon a (hopefully unique) code
between the two. If one piece loses power, the code is forgotten by that
piece and re-pairing of the units is necessary.

As for the purpose of the "satellite dish" icon, my guess would be that it
is used to indicate the onboard clock is synchronizing itself...that is, if
these units have a clock.

William

Too_Many_Tools wrote:

: Some of your comments concerning problems with high temps indicate a
: possible battery/circuit problem...change the brand of batteries and
: if the problem continues return the unit.

: More often one will see problems with low temperatures with the
: accompanying diminished battery performance. In this case one should
: use lithium batteries.

I have tried different brands of batteries, anything over-the-shelf,
Duracell, Energizer and even the Costco housebrand, Kirkland.

None of these seem to make any difference, they all allow the units to work
flawlessly for about a week, then it develops the --- problem with readings
over 75F or so from the outside unit.

And it just doesn't seem to be a battery problem anyway, if you haul in the
outside sensor, pull the batteries out then put the same ones back in on
both units, they'll work again for some period of time, at least 2 or 3
days.

As someone else mentioned, it does look like other models can have multiple
remote sensors. So it still comes down to the question if there is like a
digital preamble sent that is unique to each remote sensor which is learned
by the base unit during that initialization process.

Thats about the only thing that makes sense to me where the fault could be.
Maybe that satellite icon on the display activates when it hears one of the
remotes but isn't matching the id tag it learned.

http://www.lacrossetechnology.com/7013/index.php#specs

That link seems to be the same unit, although the manual is missing on the
website, the undocumented satellite icon is just under the number 6 on the
display along the bottom. I think mine is a 7010 or 11, it's single channel.

Anyway, it's not anything to lose sleep over, just seems like a curious
operation and widespread fault which is an inch away from being solved.

-bruce

Bruce Esquibel wrote:
I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.
snip

It continues to sound like a battery sag problem to me. If you don't
mind a little risk, how about wiring an extra AAA battery in series with
the two that are in there? This would raise the nominal voltage from 3.0
volts to 4.5 volts. I suppose this might damage the unit, but I doubt
it. In any event, if "something" is marginal at the nominal operating
voltage of fresh batteries, and dies when the battery sags a bit, this
might demonstrate the hypothesis.

Bill

On Mon, 9 Jul 2007 16:12:34 +0000 (UTC), Bruce Esquibel
wrote:


I was wondering if anyone ever tinkered with these low-end wireless
indoor/outdoor thermometers made by like LaCrosse and Oregon Scientific.

Overall they seem like outright junk but are close to the mark of being
reliable to me. I have one made by LaCrosse I picked up from Fry's a couple
years ago, although I can't say it ever worked 100%, it seems to have a
stability problem with summer temps, more or less when it goes over 75F or
so.

Basically what happens is, the display on the inside unit for the outdoor
temp reads "- - -" all day until it cools off outside. Like this morning,
last temp I noted was around 81F, now it's just ---.


Is the unit in the sun or the shade? If it's in the sun, the internal
temperature may rise high enough to affect the operation of the
hardware.

I've had a GE (option of 3 remotes) that worked well until ants
invaded the remote unit.

I currently have an Oregon Scientific unit (with VLF time receiver and
option of 3 remotes) that has been working well for a couple of years.
The remote is hung from a tree limb (for shade) and has a rain shield
made from the bottom of a 2 liter soda bottle.

And we do have temperatures above 90F in Atlanta during the summer...

John

"William R. Walsh" m
wrote in news:ApAki.6735$Xa3.3719@attbi_s22:

As far as operation principles go, I think these devices all pretty
much communicate somewhere in the 300MHz band.

Around there. Mine (a UPM WS410L) operates at 433 Mhz. A particular
"set" will operate on only one frequency.

The synchronization
process is needed because there may be many of these in a given
neighborhood. Even if they aren't all from the same maker, the
frequencies used are similar.

It just needs to discern from units from other manufacturers on the same
frequency first (the RF frequency is hard built into the trasnmitter and
receiver), then from the house and unit codes (at least mine does).

When the pairing process happens, both
units agree upon a (hopefully unique) code between the two.

It is only one way. You set a hous code on the trasnmitter and receiver,
and a separate unit code for each trasnmitter.

If one
piece loses power, the code is forgotten by that piece and re-pairing
of the units is necessary.

Not if you set HC to 1, and UC to 1.

As for the purpose of the "satellite dish" icon, my guess would be
that it is used to indicate the onboard clock is synchronizing
itself...that is, if these units have a clock.

That is possible, if equipped.