I Want a Davis VP, but... "integrated sensors"!

I’m looking to upgrade from my La Crosse WS2307 and would very
much like to upgrade to a Davis VP. However, the problem I have is
that my location is such that I don’t have a suitable single place for
both Rain and Temp/Hum sensors. All the suitable Temperature locations
are are shaded by trees/pergolas, making them unsuitable for the Rain
sensor. The only place I could put it would be in the middle of the lawn and
the wife aint going to like that! I do have suitable places for the Rain sensor,
but they are in warm radiating spots (like shed roof). So the obvious problem is
that the Davis VP has an integrated Rain/Temp unit, which aint no good for me!

However, i’ve been looking at the Davis manuals and to me it looks as though it
would be quite simple to unscrew the Temp/Hum sensor from under the rain bucket
assembly along with the SIM transmitter, place the Temp/Hum sensor (+SIM tx)
where I need it, and then use a long extension cable (100ft) to extend the Rain sensor
bucket to where I can put it. The Wind I would use with the Anemometer Transmitter.

  1. Does anyone know if this is actually feasible? or even tried it?
  2. Does anyone know if its possible to also plug the Rain sensor into the Anemometer Transmitter
    and get the VP Console to pick the Rain up from there?

Thanks in advance
Andrew (a hopeful new Davis owner!)

You may want to have a look at this page and to read this (long) thread.
And I’m sure FarmingtonWeather will be happy to give you some hints :wink:.

Thanks for the link/info, looks like exactly what I want to do except I need to
extend the bucket/sensor alot further. So the next question is:

  1. What is the maximum cable length that either the Rain bucket sensor or
    the Temp/Hum sensor can be extended from the Transmitter ?


Davis separate rain gauge http://www.davisnet.com/weather/products/weather_product.asp?pnum=07852 comes with 40’ of cable. I suspect 100’ would be OK, but it depends on how much electrical noise you have locally. Please add your location to your profile, helps to answer questions like this that depend on cost/availablity of items.

I looked at the Davis web site and if you look at their table in their
cable extensions info (http://www.davisnet.com/product_documents/weather/spec_sheets/7876_spec_4Con_Rev_D.pdf)
It states that the Rain collector and Temp sensors when connected to the
Wizard consoles can be extended up to 900ft ! Which sounds pretty good to me!
Although as you said, interference will be a governing factor.

Depending on the length of extension required the simplest option could be to unscrew just the Temp/Humidity sensor screen assembly and resite those where most appropriate (a simple bracket may need to be made). All you need do is then run a single extension cable back to the ISS transmitter which remains on the rain collector shelf.
Apart from being the simplest option this also leaves the ISS transmitter where it will probably see more sun for charging and also no extra cabling would be required for the anemometer or if either solar or UV sensors were fitted.

One thing to remember is the Temp/Humidity sensor will need 6 core cable and not the normal 4 core as used for rain collector, anemometer or solar/UV sensors.

The one problem could be that Davis only sell 6 core extension cable in 12 metre lengths.

I’ve resited just my Temp/Humidity assembly like this and it all works just fine.

IMHO Davis really ought to offer a bracket and 6 core extension cable as an authorised accessory to resolve any siting issues. The separate wireless temp/humidity station 6382 comes with just such a bracket so Davis already have something that would be suitable.

Yep, I agree. That suggestion has been made a number of times on here.

Just IMHO, but I would be much more comfortable extending the rain gauge cable, and keeping the temp/hum sensor close to the ISS/transmitter unit, that putting a long cable on the temp/hum.

It was very easy separating the rain bucket from the other parts as you all know I did. Sure, it would be nice if Davis made a bracket for mounting the ISS/temp/humid component but it was very easy to make my own. I made the bracket for the solar sensor and for mounting the rest of the stuff after moving the bracket with the rain bucket. The rain gutter connectors made great “L” brackets and a piece of plex made a nice shelf for the bracket. I think most people who would consider putting in a weather station also tend to be the DIY types who can haul out the bailing wire, duct tape and bubble gum and make about anything.

My PVC monster shows how easy it is to properly site the Davis fairly easily and yet not cause a mowing or snow problem.

My Dad always told me there there was a will, there was a way.


Thanks for all your input.
You’re right in saying if I extend the Temp/Hum from the ISS Tx/Rain sensor, then I can simply attach the Wind enemometer to the ISS without the need for a anemometer transmitter since the rain and wind sensor locations are close to each other.
I didn’t realize the Temp/Hum cable was 6 core, I persume it is a RJ11 6p6c connector on the end then?
What i’ll probably do is take my existing La Crosse Wind extension cable which is a Cat 5e cable and
wire it appropriately. It needs to go about 180ft so hopefully using the Cat 5e cable should achieve that.

Sure, it would be nice if Davis made a bracket for mounting the ISS/temp/humid component but it was very easy to make my own.

I THINK this may be the platform that supports the rain cone and tipping bucket mechanism, that the radiation shield bolts onto from below, and bolts to the pole. If so, it, along with the one that comes with the station, could be used to mount the rainbucket and temperature/humidity housing on two different masts. You would still have to wire them together.



My one concern would be with the length of extension i.e. 180ft.

As previously said I’ve separated the temp/humidity screen assembly from the ISS and it all works fine. However only one 12m length of Davis 6 core cable was required for the sensors to be resited in a more suitable location.

I guess the only way to find out is to monitor the temp/humidity readings without the extension in place and then without moving them add the cable between the sensors and ISS transmitter and see if the readings vary.

I ordered one, we’ll see what arrives :smiley:

I’ll second all of the above.

I ordered one, we'll see what arrives
My fingers are crossed.


Mine too :lol:

Can’t you just go pick one up? #-o

:lol: Well, I could, but they aren’t set up for retail sales (no store) and the UPS cost is about the same as the gas :roll:

I agree testing is the only true way of finding out… however I am hopeful it should be ok
as looking at the Davis website for the wired Temp/Hum sensor it states a maximum cable
length of 300ft (and that’s using the standard cable, not Cat5e). So as long as the VP
Temp/Hum sensor is the same it should be fine. See:

If it fails I can try extending the Rain sensor instead, and if that fails then
they’ll be a Davis VP for sale…!!

I believe the Temp/Humidity sensor on the VP2 is different to the wired sensor, which is much older and was originally for use with the early Davis stations (Weather Monitor, etc).
Still as you already have the cable you’ve nothing to lose by giving it a go and seeing how things pan out.

Up to around Jan 2006 (don’t have the exact date to hand) VP/VP2 stations used an analogue humidity sensor based on a thin film capacitance device AIUI. This was based on the 7859 part and I’ve no reason to think that it behaves any differently, eg re extension cable lengths.

Since Jan 2006, what’s described as a digital T/H board has been introduced. The difference in the humidity sensing element is obvious once you take off the cap though I don’t know exactly how it works and quite what makes it ‘digital’. (The digital - .166 - boards are not backwards compatible with older VP/VP2 stations though the analogue - .029 - parts can be used with any ISS.)

So if it’s not a recent VP2 then a long extension cable can almost certainly be used (though Cat 5 isn’t always a good solution here - I’ve seen problems with long runs of Cat 5 cable to a 7859 part when an ordinary ribbon cable was fine over the same length). With a newer VP2 it’s difficult to say without further enquiries. I’d be surprised if a long cable wasn’t perfectly OK with the digital part but I’m not 100% sure.