Hi everyone,
Not really a radio antenna, but hopefully gurus can help me.
I'm not a radio/electronics guy (just a computer one), so my knowledge of antennas is pretty limited.
I have a 433 mhz data acquisition base unit with number of remote wireless temperature sensors. Couple of them are too far from the base + walls + something else. I opened base unit and found a single dipole receiver antenna inside (about 2.5" each side, not helical).
Here is what I'd like to do. Run a 6-10 ft coax cable through the roof and make a simple half-wave antenna (=vertical piece of 12 ga wire, 6.5" long). Roof is metal, so I can attach coax shield to it.
My question is. Before I completely break base unit apart, I'm wondering if this will improve my reception (at least there will be no wall). How long can coax be (standard old TV 75 om cable)? Do I need anything else, for example, to adjust its impedance (well, I don't have anything to measure it, anyway)? There are two connectors on the PCB, does it matter which one will be soldered to coax shield (suspect that it has be ground one, but how to tell)? Do I need to cut original dipole off, or I can leave it?
Any other suggestions (like using old TV antenna). Yagi antenna won't work because I have sensors everywhere, so it has to be omnidirectional.
Thanks in advance,
Mike
Not really a radio antenna, but hopefully gurus can help me.
I'm not a radio/electronics guy (just a computer one), so my knowledge of antennas is pretty limited.
I have a 433 mhz data acquisition base unit with number of remote wireless temperature sensors. Couple of them are too far from the base + walls + something else. I opened base unit and found a single dipole receiver antenna inside (about 2.5" each side, not helical).
Here is what I'd like to do. Run a 6-10 ft coax cable through the roof and make a simple half-wave antenna (=vertical piece of 12 ga wire, 6.5" long). Roof is metal, so I can attach coax shield to it.
My question is. Before I completely break base unit apart, I'm wondering if this will improve my reception (at least there will be no wall). How long can coax be (standard old TV 75 om cable)? Do I need anything else, for example, to adjust its impedance (well, I don't have anything to measure it, anyway)? There are two connectors on the PCB, does it matter which one will be soldered to coax shield (suspect that it has be ground one, but how to tell)? Do I need to cut original dipole off, or I can leave it?
Any other suggestions (like using old TV antenna). Yagi antenna won't work because I have sensors everywhere, so it has to be omnidirectional.
Thanks in advance,
Mike