[OT] Best orientation of thermometer sender ?

[Roger Hayter]

ok, thanks, that makes sense. So the strongest signal is perpendicular to the axis of the aerial former, with a null along the axis? And horizontally polarised?

[Graham.]

But you know more than anyone here that it's sometimes comforting to cling to the past. There is no Ministry of Transport but tell that to the motor trade or the roadstone aggregate makers.

And one I am just getting to grips with, there is no Inland Revenue but we have IR35.

[Brian Reay]

Null yes.

Signal yes, to a first approximation (earth effects can change the pattern, as with any antenna).

Polarised // to axis. (the photo the axis is horizontal but normally it would be vertical).

It is, essentially, a 'rubber duck' , albeit not vertical going by the photo, and (as I expect you know) a rubber duck is just a short, loaded, whip.

[Graham.]

The woman on the "Crocodile Style" adverts who points the fob over her shoulder at the garage door knows something about propagation that we don't.

[Bill Wright]

Oh yes, them! I was thinking of full size helical antennas as used for satellite tracking etc. I forgot about the broadside ones.

Bill

[Roger Hayter]

Yes, therefore doesn't behave as a loop, more as a shortened monopole.

[pamela]

It's been working happily in a fixed posiiton for a year but recently started to fail intermittently. New batteries all round haven't helped. Pressing various reset buttons doesn't do much to help.

I figured the next thing is to tweak the orientation.

[ARW]

This is an easy one.

Wait for dennis to reply with his answer and then do the opposite.

[Roger Hayter]

Have you acquired any new radio items or moved any nearer the transmitter or receiver? Such as a WifFi router, DECT phone or similar? Could be in a nearby house.

[Roger Hayter]

I should think that is to make it as long as possible to improve efficiency. At least that's another theory.

[SK3.14159Y]

10-4 'ducky'

[pamela]

Hey! I have a new wireless router in the room below the thermometer receiver. It's arrival roughly coincides with the recent thermometer problem.

How would a router affect the thermometer because they're on very different frequencies? 2.5/5 GHz and 433 MHz.

[Roger Hayter]

snip

If the receivier is well designed you are right, but often a strong signal on another frequency can interfere with the operation of electronic devices in general and receivers in particular. If you can move the router temporarily it would possibly answer the question.

[Bill Wright]

The wireless thermometer for the house becomes intermittent when the motorhome (which has a wireless thermometer) is parked in the yard. The one in the motorhome always looses contact with itself at a certain point on the A1, and needs to be re-initialised.

Bill

[Jeff]

Those were the days; when trolloing meant something entirely different.

Jeff

[FranK Turner-Smith G3VKI]

Is the point near Brookmans Park, Herts? There is a high power BBC AM transmitter site there.

[Andrew Gabriel]

It's not really a coil - it's just a way to get a 173mm aerial (if it's 433MHz) into a box which isn't that big.

It might work better if you used a straight piece of wire 173mm long pointing straight up (which is assuming a ground plane), or second best, horizontal at right angles to direction to receiver (although ideally that wants the other half of the dipole pointing in the opposite direction, and you'd have to find somewhere on the circuit to connect it to get a good ground reference point). (Sometimes a wire slightly shorter than 173mm is used to allow for circuit tracks and component leads.)

If you leave it as it is, it's probably slightly better with the 'coil' axis at right angles to the direct line to receiver, but I suspect the coiled up aerial is probably not as directional as a straight one would be.

[Brian Reay]

Does it not have a switch to change the channel? Mine had two channels, the switch was inside under the battery cover. You needed to switch the display/receiver end as well.

It could be as simple as some electronic noise (interference) from something new (not necessarily a transmitter) you have installed or even a close neighbour has.

[pamela]

That might explain why I was able yesterday to rotate the sender through 90 degrees to make the axis of its coiled aerial wire in line with the reciever (also placed so its receiving aerial is in- line) and still get the signal coming through.

The sender is located far enough away to be on the edge of its range to make the receiver sensitive to a reduction in signal.

I wonder if that will reduce the drop outs.

Unfortunately I can't move the new wireless router in the room below directly under the thermometer receiver. I suspect reorienting the router wouldn't make much difference when it's so close by.

[pamela]

There's no channel switch. The casing has marks referring to one but unfortunately there's an empty space where a switch would have been.