Topic: Barani pro passive shield

[hwcorder]

I do need to add when looking at my graph my instruments are in the shade until about 1130am. 

[ValentineWeather]

FARS cooler by .4F.

Is this one still the stock fan?

Yes it's located over grass 5', pulling air from bottom. 
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. 

[CW2274]

FARS cooler by .4F.

Is this one still the stock fan?

Yes it's located over grass 5', pulling air from bottom. 
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. 

Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better.

[ValentineWeather]

FARS cooler by .4F.

Is this one still the stock fan?

Yes it's located over grass 5', pulling air from bottom. 
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. 

Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better.

I've done that for years over grass very little if any difference. Maybe over hot sand you might see a slight increase but it may be opposite what you think.

[CW2274]

FARS cooler by .4F.

Is this one still the stock fan?

Yes it's located over grass 5', pulling air from bottom. 
It took me awhile to realize why the airport ASOS also pulling air from bottom with much stronger suction over mainly sand runs 1-2° warmer. 

Certainly makes sense.
I know you're doing a boat load of comparisons, but if you get bored (right....), I'd like to see you do stock fan vs a/c. The sunnier, hotter, and calmer, the better.

I've done that for years over grass very little if any difference. Maybe over hot sand you might see a slight increase but it may be opposite what you think.

Yeah, I guess you have. Regardless, I would never consider going back to stock, just curious.
Back to your regularly scheduled program...

[ValentineWeather]

Doing something different today. Almost zero wind again  at 30'.  Its 11am with sunny but some smoke haze from all the fires. Haze scheduled to clear out after 1pm they are saying so maybe winds will pick up.

Anyway I moved the FARS to the one area of bare ground on my 1/4 acre of paradise (just a patch) but still surrounded by lush grass all directions. to see if fars drawing cooler rising air vs horizontal air sample the passive shields are sampling pans out. This patch of bare ground may not be significant enough to make much difference but will see.
Fars currently .4f cooler than pro.

[DaleReid]

ValentineWeather:
What software do you use to create the graphs you are sharing?

Does it read from a database or do you have to extract from one that has all the values in it before sending it to the graphing routine?
Dale

[DaleReid]

hwcorder:
Same question for you as ValentineWeather:
To be able to graph stuff on demand rather than continuously all values is a nice possibility.

If you and he have documented what you're using, I apologize for asking again.

Your shade fills and other tweaks seem to indicate a different graphing routine than what he uses.
Dale

[ValentineWeather]

ValentineWeather:
What software do you use to create the graphs you are sharing?

Does it read from a database or do you have to extract from one that has all the values in it before sending it to the graphing routine?
Dale

I'm using the WTU software that comes with Envoy8x. It saves everything to database either windows or Mysql, it has a export function into Excel where I make the graphs.

[dendrite]

Doing something different today. Almost zero wind again  at 30'.  Its 11am with sunny but some smoke haze from all the fires. Haze scheduled to clear out after 1pm they are saying so maybe winds will pick up.

Anyway I moved the FARS to the one area of bare ground on my 1/4 acre of paradise (just a patch) but still surrounded by lush grass all directions. to see if fars drawing cooler rising air vs horizontal air sample the passive shields are sampling pans out. This patch of bare ground may not be significant enough to make much difference but will see.
Fars currently .4f cooler than pro.

None of that makes sense to me, but I already posted my thoughts on it. Even if the immediate skin sfc was a little cool under the shade of the grass blades, you're going to be running superadiabatic from the grass blades to 2m range. If you're measuring over full sun, 1ft AGL should not be cooler than 6ft AGL.

Try mounting your FARS at 1-2ft over the grass and see what happens. Heck, maybe I'll be wrong.

[hwcorder]

hwcorder:
Same question for you as ValentineWeather:
To be able to graph stuff on demand rather than continuously all values is a nice possibility.

If you and he have documented what you're using, I apologize for asking again.

Your shade fills and other tweaks seem to indicate a different graphing routine than what he uses.
Dale

I use the advanced graphs function in Weather Display.

[hwcorder]

Here is my graph for today. I added solar since I had a few clouds.  Winds were very light today with some periods of calm of near calm conditions.  I noticed during these times the Meteo Pro did run a little warmer 0.5-1.0+F than the FARS with a larger spike visible right before I posted this.  Once the winds picked it cam back down.  Thats where I think FARS really shines, when things get dead still. Highs and Lows, Meteo Pro 60.1 / 86.6    FARS 60.2 / 85.2.

[jerryg]

Update skies partly cloudy winds light in am to breezy in afternoon with seabreeaze   pro 73.0/97.2  fars 72,9/98.0  standard 72.8/98.2

[jerryg]

Well i made a change this am i changed out the Davis fars with the RM Young fars which is the industry standard shield everyone compares to. See specs here http://www.youngusa.com/products/2/16.html  Now will see how pro does against a professional shield.

[DaleReid]

Jerry,
thanks for the variety of tests and units.

I'm interested in how the RMYoung does, so run it awhile and if you can on sunny vs. cloudy days. 

thanks for doing the work.  Nice unit, I followed the link, and seems as good as it can get.  I wonder if their fans burn out as fast as the Davis ones do?

Did Campbell Scientific make a funny looking thing that had a big bulge on one end and a horizontal white tube with a 45 degree angle cut on one end?  The 'Big Boys' have the bucks to do the engineering and research, so I'm wondering how well they work compared to the amateur and low end pro stuff we use, and you are the only one who I recall has tested this so please graph and publish and discuss, just so we know.  Dale

[jerryg]

Well i don't know how to graph but i can tell you how i see it performing, and it will be a while to get a good read but i have already seen something that i long suspected about the Davis fars in high humidity areas and that is in the am the fars readings barely changed with the sun coming up and took about an hour to start showing the correct temp and humidity readings compared to the pro or standard shield. The rmy fars and the pro are tracking pretty well with the temp and humidity of the fars immediately starting to change, no lag time at all. Right now there is no wind and the fars and pro both show 80.8 degrees. I need to add that i took the sht75 out of the Davis and it is now in the rmy so should be pretty good comparison to earlier readings.

[ValentineWeather]

Well i don't know how to graph but i can tell you how i see it performing, and it will be a while to get a good read but i have already seen something that i long suspected about the Davis fars in high humidity areas and that is in the am the fars readings barely changed with the sun coming up and took about an hour to start showing the correct temp and humidity readings compared to the pro or standard shield. The rmy fars and the pro are tracking pretty well with the temp and humidity of the fars immediately starting to change, no lag time at all. Right now there is no wind and the fars and pro both show 80.8 degrees. I need to add that i took the sht75 out of the Davis and it is now in the rmy so should be pretty good comparison to earlier readings.

This will clear up for sure if the Davis FARS wasn't working correctly. I suspect something was wrong especially since you mentioned the humidity lag on the davis unit. You wouldn't expect to see it unless the fan's not working, turning the shield into a bad passive unit.

[jerryg]

In response to the fan, it rates at 80,000 hrs of run time. It is a squirrel cage type fan. Suck a golf ball through a garden hose 

[CW2274]

It is a squirrel cage type fan. Suck a golf ball through a garden hose

Exactly. Put a decent fan in your VP2 and I'll bet that lag will go bye-bye.
As a matter of fact, I just took my new 40CFM out and replaced it with my newer 60CFM fan just so I can hear it working out in the desert, the 40 was too quiet. Works beautifully!

[hwcorder]

Here is todays graph.

Todays Hi and Lo.

Met Pro 90.6 / 64.3
FARS    89.6 / 64.5

[ValentineWeather]

Today, notice what happened when what breeze we had stopped during peak heat of day. Bad timing, I was higher than airport with pro which never happens.
Pro:    97.9-56.4
Fars:  96.4-56.4

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[CW2274]

Today, notice what happened when what breeze we had stopped during peak heat of day. Bad timing, I was higher than airport with pro which never happens.
Pro:    97.9-56.4
Fars:  96.4-56.4

Bad timing? Is this not exactly what you're trying to accomplish, to see if the Pro can handle a no wind, full sun scenario as well as a good FARS?
The only person on here as far as I've noticed that the Pro is always lower than the FARS is "jerryg", and he lives where a breeze is almost always a constant, and that's with the stock fan.
I think it's becoming quite obvious that the Pro is truly an exceptional passive shield, but it's not a FARS, certainly not a good one.

[ValentineWeather]

Okay changed Pro shield around because of limited room inside sensor chamber, now have just the 1-sensor SHT75 inside.

With the 75 DIY longer sensor cable I'm able to raise sensor from shield lower section to middle of sensor chamber allowing the airflow design to work as intended. Being on very bottom may not take advantage of shields helical design.
If using 31 they do make the 30' SHT31 where you can position shield where you want (away from ISS).

[ValentineWeather]

Here is look after changes made with pro shield as of 2pm central full sun no clouds currently. Not bad with light winds averaging under 2 mph sometimes dead still. Late afternoon sun still coming.
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[dendrite]

Keep in mind we’re quickly approaching an equinoctial sun angle too. I wonder if these would perform similarly at the summer solstice.