I have found wireless communication to be unreliable. The wireless links for my Davis Vantage Pro weather station, Radio Shack security system and Motorola telephone and intercom are all intermittent. They are all within the specified range and have no metal to shield the communication. I'm not surprised by the Radio Shack wireless link because it is inexpensive. I plan to replace the Davis wireless link with a wire if possible.
Does anyone know of a method of extending wireless communication range and reliability? Can small antennas be used to improve reliability?
The "specified range" is usually overly optimistic.
The FCC prohibits any changes to the transmitter or its antenna. It's also easy to detune many transmitters by soldering connections to the components that control the frequency.
The FCC doesn't care whether you improve the antenna on the receiver. How you do this depends on the specific receiver, whether there's any shock hazard, and what frequency it uses. In general, a centrally located efficient antenna with a UHF preamp will work wonders, giving range of
150-200'.
Sometime in the next few weeks I'll need to setup another web page for roZetta ( a device under development). I'll include my pages on antenna design for HA purposes.
All of your transmitters should have FCC ID numbers on them. You can determine the frequency from the FCC.
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If they are all >I have found wireless communication to be unreliable. The wireless links
I was wondering if I could use a TV UHF antenna amplifier on a Radio Shack Plug n Power security master unit that has a 12" telescoping antenna? If so, how would I connect the amplfier?
Without seeing the device or a schematic for it I really can't say. With some of the X-10 RF modules there is a possibility of getting 120V on the antenna and creating a life threatening hazard. Plug'n'Power sounds like X-10 but RS has been replacing some X-10 designs with their own.
The "B4S" is X-10's ID. There are no attachments to the B4S61-2609R FCC filing. (About 5 years ago, most of the attachments to X-10's FCC files were removed. I was surprised to find the CM15A filing had a schematic attached.)
The problem with many of X-10's devices is that they use a transformerless power supply and use the hot side of the mains as electronic ground. This is the reason they isolate the antenna on the TM751 and RR501 by using the plastic of the case as the dielectric in a "capacitor" that couples the antenna to the RF input circuitry.
For battery powered devices, for those like the MR26 which is powered from the PC serial port, and for those like the CM15A that have isolated power supplies, it's generally safe to replace the antenna with a coax connector and then connect an amplified antenna to the connector. For other devices without isolation, this could put 120V on the coax shield creating a hazard.
It is possible to isolate the antenna connector by using a 1:1 isolation transformer between the coax connector and the RF input circuit. The transformer must be inside the case and the primary and secondary must be isolated (many 75:300-ohm baluns are not isolated). I have used a small Toko transformer (B7T-456DS-1012) available at Digikey. MiniCircuits also has some SMD isolation transformers that will work. There will be an insertion loss from the transformer but the amplifier more than makes up for it. Without an amplifier the insertion loss may be enough to make adding a more efficient antenna pointless.
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At this point anyone who doesn't understand the information I've given should forget about trying to change their antenna lest they end up floating on a cloud playing a harp.
On Tue, 31 Jan 2006 10:33:11 -0800, "Ken Gibson" wrote (with possible editing):
While it won't help initially, I share the same problem with the Davis. I have two of them - a Davis VP and a Davis VP Pro 2. Both operate in the 900 mhz band, the "2" uses spread spectrum. Both use simple portable radio type antennae. It will be extremely difficult to replace the radios with a wire connection as they are in separate buildings and the conduit connecting them is almost impossible to access.
Both Davis units were intermittent. The "2" was rock solid until yesterday, then the connection was broken and the console said there was no received signal. Using the console's troubleshooter indicated no signal at all. Last night, it started working again. Legally, as Dave said, you can replace the console's receiving antenna with something directional - a small yagi should do the job. as well as a small dish, such as one left over from a Direct TV or Dish Network. You would need to change the feedhorn, but not the positioning since that is the focal point. I may try to do this - if it works, you are welcome to copy it. If there exists a decent 900 mhz preamp and assembly, I hope I'll find one and report back here.
While I haven't tried it at higher frequencies, I suspect the eggbeater design plus a TenTec 1001 preamp will be more than adequate. You'll just have to cut the elements and phasing line for the frequency Davis uses. The loops would be about 12" circumference or a bit over 3" diameter.
Jeff Volp has a copy of my CM15A replacement antenna page at...
There's one other issue first. The console can retransmit on a separate frequency. At least the original VP could do that so that you can use a monitor elsewhere. I have to make certain that the VP2 doesn't do that as a matter of course, or, as you know, poof goes the preamp!
I think what you saw was the "Data Logger". It's a device which plugs into a port on the VP2/+ and records only. It is identical to the one used on the VP. However, the VP repeated on a different frequency. The VP2 apparently does not. Come to think of it, using spread spectrum and a greater power output, it would be very difficult to repeat without collisions and desensitizing.
The bummer in that is that you need to buy a (very expensive)
2d console to display the data in a second location. I use a program "Weather Display" to handle that, but it means a computer anywhere you want to see the output.
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