Author Topic: Ambient WS-2902A External Antenna  (Read 866 times)

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Offline XterraGuy

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Ambient WS-2902A External Antenna
« on: September 13, 2018, 03:21:16 PM »
I just purchased a WS-2902A last week and have been struggling to find a good installation location for the sensor unit that will provide unobstructed wind speed and direction information AND still be within the limited range for a reliable connection to the display unit.  I've pretty much concluded it can't be done in my situation.  With the sensor unit and display about 125' apart and obstructed by just the back wall of the house and a few trees in between, I get very minimal and intermittent connectivity.  I'm wondering, has anyone successfully added an RF connector on the sensor unit and connected an external antenna?  A small, directional 915 MHz antenna pointing back at the house would certainly resolve my situation.

Offline WA4OPQ

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Re: Ambient WS-2902A External Antenna
« Reply #1 on: September 13, 2018, 04:46:55 PM »
I have five 2902 arrays. As soon as they are out of warranty I'll try it and let you know.

Offline galfert

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Re: Ambient WS-2902A External Antenna
« Reply #2 on: September 13, 2018, 10:17:12 PM »
I would recommend you put it on your roof. You can get a tripod like mast for direct roof mounting or you can get a side of the house and then up over the roof type mast.

If you are at least 5 or 6 feet up over the roof you won't really be affected by roof radiation. I have a WS-2902A and my neighbor around the corner also has a WS-2902A. We are 500 feet apart as the bird flies. My station is in my back yard on a 10 ft pole (my 16' flag pole comes tomorrow). My neighbor's station is on his roof 6 feet up. If you compare our data we are spot on even temperature wise. He records higher wind speeds than me because of his added height. I'm hoping to correct my wind speed with my new flag pole.

Compare - over grass vs roof mounting (500 ft apart):
My station over grass: https://www.wunderground.com/personal-weather-station/dashboard?ID=KFLWINTE111
Neighbors station on roof: https://www.wunderground.com/personal-weather-station/dashboard?ID=KFLWINTE849

So consider the roof mount with the various methods available.

« Last Edit: September 13, 2018, 10:20:58 PM by galfert »
WS-2902A | ObserverIP | WeatherBridge (Meteobridge)
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Tele-Pole flag pole is here (not installed yet)

Offline XterraGuy

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Re: Ambient WS-2902A External Antenna
« Reply #3 on: September 14, 2018, 09:14:10 AM »
Unless you're out of warranty this week, I think I might have to ignore the warranty and let YOU know!   ;)  As for installing on the roof, that would normally have been my first choice given our terrain... except that our covenants don't permit rooftop installs.  Aside from that, the roof is concrete tile which is a bit more challenging to seal against moisture, plus it's steep enough that getting up there isn't as much fun as when I was younger.  The only other option I've pondered is mounting to a corner newel post on our bedroom balcony, but I'd have to go up another 16' or so to get close to clearing the roof which means a pretty hefty pole without guying it, and my wife isn't even close to being crazy about this option.

So other than for the range limitation, the remaining option seems to be far enough away from the house out in the back or side yard, which means about 125' away.  As nice a build as the 2902A is, the extra $1 or so for the manufacturer to have designed in a small connector for an external antenna seems like it would have been a nice capability to provide.  I was hoping someone had attempted this as a mod, but maybe I'll be the first...

Offline galfert

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Re: Ambient WS-2902A External Antenna
« Reply #4 on: September 14, 2018, 11:26:04 AM »
If you can't put it on the roof then use the side of the building mount. Something like this (but add some height to it).
https://www.amazon.com/Ambient-Weather-EZ-30-12-100-Mounting-Stations/dp/B01LZN0EZ2/

Mast extension:
https://www.amazon.com/Ambient-Weather-EZ-100-35M-Extension-Stations/dp/B01M19JXTB/

Also regarding the HOA covenants you may be able to fight that. Do you have any neighbors with satellite dishes? Our HOA had the similar covenants years ago regarding satellite dishes. Then someone fought it and won. They got lawyers involved. I didn't cost much with the lawyer either from what I was told (couple hundred).

If you are going to open up the outdoor unit to put a bigger antenna on it be sure to spec out an antenna that is designed for 915 MHz for best performance. I don't know how far you will go with this but know too that you are breaking FCC regulations if you increase power. Depending on the frequency there is an optimum length. Well there are more than one lengths that would work but they would be in multiples based on the wave length. Also it may be possible to do a dipole antenna setup with two lengths instead of one, or maybe a directional yagi. I know enough about this to say this much....but not enough to guide you better. So I hope you know what you are doing or you researched it well. You may want to open up the console and inspect the receiving end and see if that antenna could be made better.

Another option is to forget the console. Get the ObsererIP device and maybe that receives better than the console. Then you can also add a Meteobridge and be publishing to many many more online weather network services. But I don't know if the ObserverIP is better than the console.
If you get the ObserverIP device don't forget to add the WS-1000-BTH.
« Last Edit: September 14, 2018, 11:28:25 AM by galfert »
WS-2902A | ObserverIP | WeatherBridge (Meteobridge)
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Tele-Pole flag pole is here (not installed yet)

Offline WA4OPQ

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Offline XterraGuy

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Re: Ambient WS-2902A External Antenna
« Reply #6 on: September 14, 2018, 03:20:03 PM »
Thanks for the mounting suggestions, but I think installing on the house is just not practical.  First, I have a hip style roof on the main part of the house with about an 18" overhang, and I'd still need a pretty lengthy mast to get near the ridge elevation given the roof slope.  And second, I'm an ex-HOA Board member and currently on the Design Review Committee for new homes and exterior improvements, and legally challenging the rules for this doesn't seem prudent.

As for antennas, I had already found a few yagi's out there for this frequency range, including the one WA4OPQ found for $30 on eBay (my guess is that's a call sign?).  Getting some gain by going directional would be the only rational approach, I think, as an external dipole will continue to throw energy everywhere it isn't needed.  Adding an antenna on the receiving end would provide some help, too, but it would be nowhere near as good as directing the transmission energy.

I'm an electronics tinkerer, not a licensed radio operator, but I'm handy with a soldering iron.  What I don't know is how to best handle the short run to a connector at 915 MHz... maybe in similar fashion to the wifi connections in a laptop.  Since it appears I'll be the guinea pig for this, any expertise out there with wire type (mini coax?) and configuration so as to keep the little transmitter happy would be appreciated!

Offline WA4OPQ

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Re: Ambient WS-2902A External Antenna
« Reply #7 on: September 14, 2018, 08:01:09 PM »
WA4OPQ is indeed my callsign, I worked over 40 years in radio.
I haven't opened up the 2902 array yet, but I do have a photo of the ObserverIP which shows what it uses for an antenna. I will assume the 2902 is similar. I would unsolder the coil antenna and attach the center conductor of RG-174 coax, the outer braid goes to ground. I would run the coax to a bulkhead BNC connector on the bottom of the array. I would use RG-58 coax from the BNC connector to the antenna and waterproof it well

Offline XterraGuy

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Re: Ambient WS-2902A External Antenna
« Reply #8 on: September 15, 2018, 06:56:07 AM »
Many thanks, that sounds like a good plan.  I'm in the middle of refurbishing garage doors at the moment, and heading out on vacation in a couple of days (including Nashville  \:D/ ), so this'll be a little project for when we get back.  I'll definitely post results!

Online davefr

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Re: Ambient WS-2902A External Antenna
« Reply #9 on: September 16, 2018, 09:58:55 AM »
WA4OPQ is indeed my callsign, I worked over 40 years in radio.
I haven't opened up the 2902 array yet, but I do have a photo of the ObserverIP which shows what it uses for an antenna. I will assume the 2902 is similar. I would unsolder the coil antenna and attach the center conductor of RG-174 coax, the outer braid goes to ground. I would run the coax to a bulkhead BNC connector on the bottom of the array. I would use RG-58 coax from the BNC connector to the antenna and waterproof it well

That's exactly what I did with both my Acurite Smart hub and Access hubs after suffering poor connection reliability from each of them at 125' from the sensor. (hubs in the basement)

Based on my research the weak link is the receiving antenna in the hub vs. the sensor's transmitting antenna.

I used a simple half wave dipole antenna and oriented it for best signal strength.  In each case, all my intermittent connection problems went away and signal strength has remained consistently excellent.

I know Ambient uses a higher frequency but I'd still try a modified hub with a simple external dipole antenna matched to the 915 Mhz wavelength before attempting any roof mount sensor options.




« Last Edit: September 16, 2018, 10:03:07 AM by davefr »

Offline XterraGuy

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Re: Ambient WS-2902A External Antenna
« Reply #10 on: September 17, 2018, 01:15:30 PM »
I'm glad this worked well for you.  For the 2902A, a tuned antenna on the receiving end would likely make some improvement, given that the current receiving antenna is a simple length of wire (red wire, upper right in the photo).  But I would think that antenna tuning for receivers is much less critical than with transmitters, and this option might only make a decent improvement if the antenna were physically positioned outside.  Doing that would be problematic for my arrangement.  On the other hand, beaming an extra 9 or 10 dB of signal toward the receiver using a 6-8 element yagi at the sensor unit should be equivalent to moving it to about a third of the actual distance from the display (maybe WA4OPQ can do the math  :shock: ).  I'm hoping that'll be enough signal to move the display into my home office, which is another 40' of distance.  I'm thinking I have to check it out...

Offline WA4OPQ

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Re: Ambient WS-2902A External Antenna
« Reply #11 on: September 17, 2018, 02:13:48 PM »
Here's the math for the 14 dB antenna:
14 dB gain is logarithmic, it is is 25 times increase in power
The radio signal diminishes by the square of the distance.
So a 14dB antenna should give you five times the the distance in free space. In theory.

Offline WA4OPQ

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Re: Ambient WS-2902A External Antenna
« Reply #12 on: September 25, 2018, 05:26:05 PM »
Well, Xterraguy, you got me motivated. I ordered this yagi today.  $17.99 on amazon

https://www.amazon.com/Phonetone-Outdoor-Directional-Antenna-Connector/dp/B00EC804SO




Offline danoh

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Re: Ambient WS-2902A External Antenna
« Reply #13 on: September 30, 2018, 10:33:17 AM »
Interesting thread, I may be facing the same issue.  Subbed to see results.

I've already modified. My 2902 display and replaced the quarter wave red antenna wire with a full wave wire length for 915 mhz, and there is some improvement, but it's still missing packets from the sensor array.

Next step will be a yagi on the sensor array.

Thank you! WD4DAN

Offline galfert

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Re: Ambient WS-2902A External Antenna
« Reply #14 on: September 30, 2018, 10:40:38 AM »
If you have done mods, please post pics!
WS-2902A | ObserverIP | WeatherBridge (Meteobridge)
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Tele-Pole flag pole is here (not installed yet)

Offline danoh

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Re: Ambient WS-2902A External Antenna
« Reply #15 on: September 30, 2018, 10:44:02 AM »
Just ordered the yagi above, an n female bulkhead connector and an n male jumper.

Will be experimenting soon as well.