iROX/Mebus/Honeywell TE923 antenna modification

I want to share with you the first modification I made to my iROX Pro-X USB weather station (a.k.a. the Mebus/Honeywell TE923). The reason being the “deafness” of the main unit when placed close to a PC or when connected with the USB cable. I started thinking about this mod after I received a reply from Hideki Ltd. last November. Part of it read…

According to your inquiry letter for the problem of the TE 923 USB cable connection, we had discussed the problem with our engineers. As our item of TE923 design is not for connecting PC continuously as PC generates too much interference on 433MHz transmission. If the interference over the acceptable range, TE923 cannot receive the sensor

Photo 1: before the modification.


Photo 2: 9 screws to remove from the back with a Phillips screw driver.


Photo 3: opening the case. There is one loose black wire dangling in the case connected to the radio module. I’m going to contact Hideki about the purpose of this wire.


Photo 4: the 433 MHz radio module with antenna is at the top.


Photo 5: de-soldering the antenna.


Photo 6: drilling a hole where the connector will come.


Photo 7: using a 10 mm drill bit to make the hole larger. I drilled slowly more or less scraping the plastic away, so it took me about 5 minutes. For the last bit I used a 10 mm countersink bit.


Photo 8: after sanding it smooth it looks like this.


Photo 9: a look from the outside.


Photo 10: the BNC connector in place, obscuring the rough edge from the hole.


Photo 11: a look at the inside.


Photo 12: a short piece coaxial cable to connect the radio module with the connector.


Photo 13: finished and testing it with the internal antenna connected to the BNC connector.


Very interesting thanks for posting :slight_smile: . As regards the antenna, couldnt you attach a proper airband radio style attena to the bnc?

I did (read in my post about the Aurel and click on the link. You will then see what you mean.), but the last photo was only the testing after the mod. I don’t have a photo of the complete setup yet, but then again, I intend to mount the Aurel outside and this will happen next week. I’ll make more photo’s then.

Oh yes so you did, sorry that’ll teach me for skip reading. Some good DIY skills you have there, that new attena should solve all your problems :slight_smile:

That new antenna won’t solve my last BIG problem with the TE923: a Linux driver so I can hook it up to my server and get realtime info on the web. I haven’t found anybody who can reverse engineer the driver, so I’ll contact Hideki about that too. The Windows program that comes with this unit (Weather Capture) is written in Java, so it shouldn’t be too difficult to port that to Linux (open or closed source).

Here a photo of the AS433 mounted outside. It’s about 4 meters from my nearest PC and reception has been okay sofar even though a temperature sensor and anemometer went blank today.

Regarding the black wire on the radio unit I got the following reply from Hideki:

The black wire is functioned as an antenna. Remove it that can reduce noise reception but the receiving range also reduce.

In a next mail I asked “There is already an antenna connected to the radio unit. So why is there a black wire for second antenna?” to which the answer was:

[quote] It is the characteristic of this radio unit. Add the black wire can increase the sensitivity. As a result, the reception distance will be extended, but just add a cost of a black wire. That


Hello

I’m trying to make a linux driver for this station. But my C programming is not the best. I have a lot of informations about the station, some USB logs and a DLL file for using the station unter windows. (Ok, ist not realy useable for linux, but the description in the documentation shows adresses in the memory and some other informations.) So if you have some ideas or need someone to test a driver, give me a sing. I can give you also informations and some code, if I have more then now. I got in contact to a programmer for embedded systems, maybe he has some good ideas.