Place of meteobridge pro 2

[alex1989]

Good morning, I have a question

Is it possible to place Meteobridge pro 2 outdoor at the balcony of my home to get best signal? My home has thick walls and sometimes it lost the signal. When the signal is ok is between -75 and -80 db. The anemometer is on the top of the roof and it is connected to another transmitter. The roof is not thick like the wall, so the signal is better. It is about -62/-65 db.
The ISS is in the garden, I can’t put it on the roof because is so danger to do the maintenance.

If I put Meteobridge outdoor it can be ruined by the weather,for example humidity,cold etc???

Thanks

Best regards

[fotogw]

Hi Alex,

Instead of exposing the MB Pro2 to the outdoors, the better option I see would be using an external antenna. The 2 antennas on the back (one for WLAN and one for the reception of the RF- signal from your Davis ISS-station.
I had similar problems, and solved it by using a 433 mhz ground plane antenna If you use Google you'll easily find one. I purchased at an online electronics-shop. The connection was 'plug and play', just unscrew the MBpro 2's RF- antenna and screw in the external antenna. The cable is thin and flexible. As the connector is small, a hole of 8 mm in the wall is all it takes. The antenna cost me around €40,00
This way you can have your MBpro 2 safe and warm indoors

[alex1989]

Hi Alex,

Instead of exposing the MB Pro2 to the outdoors, the better option I see would be using an external antenna. The 2 antennas on the back (one for WLAN and one for the reception of the RF- signal from your Davis ISS-station.
I had similar problems, and solved it by using a 433 mhz ground plane antenna If you use Google you'll easily find one. I purchased at an online electronics-shop. The connection was 'plug and play', just unscrew the MBpro 2's RF- antenna and screw in the external antenna. The cable is thin and flexible. As the connector is small, a hole of 8 mm in the wall is all it takes. The antenna cost me around €40,00
This way you can have your MBpro 2 safe and warm indoors

Can I put the antenna on the floor instead to the wall?

[Mattk]

.... I had similar problems, and solved it by using a 433 mhz ground plane antenna...

How well did that work considering the MBPro2 Davis RF is 900 mHZ?

[AA5H_AX088]

If you really want to do this cheaply you can make your own using a coat hanger or copper wire, a BNC or SO bulkhead connector with a solder lug, four single solder lugs, and a one meter piece of junk pvc pipe for a mast.

I’ve made several dozen for my aircraft ADSB Receivers, they work fine, a discone antenna is a high gain receiver design, I can pick up aircraft 250 miles away, so they should be fine for sensors. The connectors and feed line are a few dollars on line or the local electronics store, and the rest of the stuff u can find at home. For a feed line I would use RG-316 with SMA connectors attached, also cheap online; it’s 50 ohm and relatively low loss, most important its small and flexible, it won’t tip your antenna over and only needs a pencil- sized hole through the roof. RG59, RG6, or RG8 coax is just too bulky for these tiny antennas.

Here’s a YouTube DIY video, there are dozens more if you don’t like this one. https://youtu.be/AaIhp8AuOnw?feature=shared

Just make sure to trim the antenna elements to the proper half wavelength for the frequency, doesn’t have to be perfect, but accuracy provides a better signal. Here’s a chart in pdf to get the proper cut length. https://www.repeater-builder.com/antenn ... charts.pdf. The YouTube video I posted has a link to online calculator to determine the length, much easier than the chart, and the calculator uses metric instead of the antiquated system we use in the US

Hope that helps, not as fancy but it works and is dirt cheap, make a few extra for spares. At 900 mHZ the elements are going to be VERY small, you could probably make two out of one coat hanger or some spare copper wire.

The photo shows a BNC “Bulkhead “ Type connector as the base, while I prefer the SMA it’s often too small to solder all the wires. The best way is to use a SO or the BNC bulkhead as shown to avoid the microsurgery, and then use an BNC or SO adapter to connect to the SMA connector on the feed line.

If you want a parts list just respond and I can post the links to the connectors and coax.

I’ve tried both the commercial version compared side by side with the DIY version, the DIY version is often superior, just less durable. If you open up the commercial version of the antenna, all you will find inside is two pieces of wire that connect at the base, the rest of the antenna is just to support the wires. The DIY discone design is superior over the store bought two wire dipole design, discone antennas are still in operational use by military forces, aviation, and meteorological agencies worldwide.






Brian, AA5H

[Mattk]

Also note when ordering not all SMA connectors are the same.

[AA5H_AX088]

Yup…

That’s why I want to supply him with direct links if he’s interested. Don’t want to buy RP-SMA connectors, made that mistake one time after driving two hours to a remote site. Two hours back to the base, back to the site, back to the base; eight hours to replace a one meter piece of coax, not a good day

Good catch on the frequency difference, the Half wavelength on that commercial vertical dipole antenna is probably 3X too long for 900 mHz.
Additionally, most sensor transmissions are circularly polarized, the discone with its angled reflectors acts as a circular ground plane and catches more signal

Brian B

[fotogw]

.... I had similar problems, and solved it by using a 433 mhz ground plane antenna...

How well did that work considering the MBPro2 Davis RF is 900 mHZ?

It works fine in my situation. I'm no antenna expert, but it did the trick!
I was told the 433 mhz antenna was 1/4th wavelength, and the same for 900 mhz was 1/2 wavelength, so they would work for both frequencies. But maybe i was not informed correct
By the way, I found the same antenna specifically for 868 mhz on Reichelt's website. Maybe this will be even better. This is however with a different connector, so you would need an adapter for this.

[AA5H_AX088]

Your antenna will work, just not efficiently. Yes, the 900mhz freq is a multiple of the resonant 440mhz freq and will work, but it will be very inefficient. Think of a guitar string, you normally pluck the string at tuned mid point to produce an audible freq, but if you pluck it higher or lower the sound is distorted as the string is not vibrating at its intended resonant point. By the musician tuning the string he is effectively changing the resonant frequency to the desired audible frequency he wants.

Another problem, with antennas and not guitars, is the ground plane. The ground plane, which are the angled elements shown on the discone, act somewhat as a second antenna. Half wave vertical antennas do not require an artificial ground plane, the entire wave can be captured on the different polarities, sort of like a two 120v power sources can be tapped to make a 240v outlet. Quarter wave antennas have to have a ground plane, or a second element to capture the whole wave, your antenna should have two wires inside the metal tube that act as a dipole two element vertical dipole, the second element adds a ground plane that’s tuned for a quarter wave signal at the lower freq; it will capture the higher freq, but the signal phase will be off which significantly lowers the antenna gain.

The reason your antenna works is because the distance between your transmit sensor and your antenna is likely to be relatively short, even a poorly tuned antenna would still be effective at that distance. Your probably losing 70% of the signal, but if you have a direct line of site it will work.

If he wants the commercially produced antenna, that’s fine. I just wanted to give him a low cost DIY alternative.


Brian, AA5H

[alex1989]

Hi Alex,

Instead of exposing the MB Pro2 to the outdoors, the better option I see would be using an external antenna. The 2 antennas on the back (one for WLAN and one for the reception of the RF- signal from your Davis ISS-station.
I had similar problems, and solved it by using a 433 mhz ground plane antenna If you use Google you'll easily find one. I purchased at an online electronics-shop. The connection was 'plug and play', just unscrew the MBpro 2's RF- antenna and screw in the external antenna. The cable is thin and flexible. As the connector is small, a hole of 8 mm in the wall is all it takes. The antenna cost me around €40,00
This way you can have your MBpro 2 safe and warm indoors

My ISS transmitter works with 868 MHz, so if I connect an antenna with different frequency(433 mhz) at the Meteobridge, Do they work each other with no problem?

Thanks

[admin]

To reduce interferrence of WiFi and RF you might also use this filter on the RF side.

https://www.mouser.de/ProductDetail/139-VLF-1000

[AA5H_AX088]

Heres one even cheaper in the US, SAW bandpass filter tuned for 868Mhz:

https://www.walmart.com/ip/868Mhz-Rfid- ... =101176259

I didn't mention it before, and while it seems like overkill you need a lightning arrestor for any roof mounted antennas no matter how small.
Here is an arrestor that comes complete with grounding cable and uses SMA connections that are common with weatherstation feedlines.

https://www.waveform.com/products/sma-l ... qOEALw_wcB

You don't have to take a direct lightning hit for damage to occur, the below photo is a BALUN transformer on my ham radio antenna feedline; this was surge from a ground strike 30M away. The flash surge melted the plastic case, the tops of the screws were welded shut

IMG_3170-3.jpg (192.16 KiB) Viewed 276 times

[admin]

Good point! MB PRO needs to secured from static voltages on the antenna. If not doing so you risk frying the MB PRO. It does not need a thunder strike, pure static voltages on certain weather situations can do that if the antenna is positioned outdoor with some meters of cable going upward.