Hi Ben

Keeping on mind that the data rate going to/from the sensor is very low
compared to the RF I *think* they will co-operate. Some thoughts though;

- Opto systems have the problem that you need a power supply for the
remote end. Using optical fibre is even a more elegant idea than wires
but has a high-ish setup cost. You could of course use a IR
LED/optotransistor config but as stated the power supply becomes an issue.

- You could argue that infrequent TX RF on the antenna even if it
affects the sensor (data) can be ignored . This of course depends on
what you are using the weather data for.

- If the weather data is a DC/AF level only you can allow RF onto the
connection wire. Dont bother to try isolating it from the antenna at
all. Dont even think of using shielded/coax. This way the effect on the
antenna RF use will be small(er). You could get away with a choke/LPF or
two at the antenna base, perhaps even with the use of coaxial stubs.
(I'd start with a 1/4 wave open coaxial stub between each wire and
antenna metalwork ground (ie where the antenna feed coax joins, then a
other two further down)) Running the wire on the inside would of course
be best for aesthetic and weather damage considerations.

- I'd say the effect of a base decoupled wire on the antenna would be
neglible next to that of the aneometer or any box at the antenna tip.
You would be capacitively loading the antenna at the "worst" place.
(assuming a current node like at the tip of a 1/4 wave) ie it would need
a retune.

Cheers Bob VK2YQA

Ben Jackson wrote:
Let's say I have a free-standing vertical HF antenna transmitting about
10wa, and I'd like to run wires to something at the tip.