VHF aerial orientation mystery

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linw

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#289061 10-Aug-2021 10:14

I am curious about why my radio receiver vhf wire aerial lead needs re-orienting twice a year. The radio/cd/dvd player is housed below the TV so has a fixed location.

I am in Aotea, Porirua, and assume my feed comes from Mt Kaukau in Wgtn. The signal line-of-sight is through the house to the far wall where the radio is. Sometimes walking through the line masks the signal, so the signal is weak and directional.

About half the year I have to lay the aerial wire horizontal and the other half, vertical. Yesterday was move-to-vertical day - yes, amazingly, it was that clear cut. And, today, it was still fine in its new vertical alignment.

I am not asking how to fix the weak signal problem but I am just intellectually curious about the orientation change requirement twice a year! Maybe the stars re-align!!

Any technical insights?

mkissin

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#2757817 10-Aug-2021 11:21

If you have a weak signal, it's possible that you're actually receiving two weak signals from different transmitters; one vertically polarised and the other horizontally. During different weather conditions (or times of the year) one may be stronger than the other. Just a guess though.

nztim

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#2757897 10-Aug-2021 12:03

Aotea comes from Baxters Knob not Kaukau

Any views expressed on these forums are my own and don't necessarily reflect those of my employer.

linw

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#2757990 10-Aug-2021 14:45

Interesting, theory re twin sites but, now, knowing it would be coming from the nearby Baxters Knob site, one would think the signal would be strong. Mmmm, who knows?

Oh, well, there have to be mysteries to keep my mind working!

Cheers.

alasta

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#2757998 10-Aug-2021 14:59

Are we sure that Baxters Knob does radio? I thought it was TV only and that Haywards hill had an FM radio transmitter? Or are they the same site going by different names?

frankv

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#2758034 10-Aug-2021 15:34

linw:

I am not asking how to fix the weak signal problem but I am just intellectually curious about the orientation change requirement twice a year!

Every 6 months a technician goes up to Mt Kaukau and Baxter's Knob and cleans the birdshit off the transmitter antenna. To get the last bit clean he turns it 90 degrees.

Your neighbour uses a flux capacitor to heat his basement in winter.

In winter, there's a big puddle where your neighbour usually parks, so he parks bit further up the road/drive. His normal park is on a straight line between your antenna and the transmitter, and the car roof forms a reflector that horizontally polarises the signal.

Oblivian

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#2758042 10-Aug-2021 15:53

https://en.wikipedia.org/wiki/Mount_Kaukau if it helps

Can't find the other transmitter under Kordias list however.

wellygary

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#2758044 10-Aug-2021 15:56

What stations/frequencies are you listening to?? not all of them will be replicated between the two sites....

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neb

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#2758085 10-Aug-2021 17:08

frankv:
Every 6 months a technician goes up to Mt Kaukau and Baxter's Knob and cleans the birdshit off the transmitter antenna. To get the last bit clean he turns it 90 degrees.

Your neighbour uses a flux capacitor to heat his basement in winter.

In winter, there's a big puddle where your neighbour usually parks, so he parks bit further up the road/drive. His normal park is on a straight line between your antenna and the transmitter, and the car roof forms a reflector that horizontally polarises the signal.

You forgot:

Brunzy

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#2758301 11-Aug-2021 07:39

Assuming you’re talking about FM it’s neither horizontal or vertical, it’s at 45°

nztim

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#2758344 11-Aug-2021 08:39

Oblivian:

https://en.wikipedia.org/wiki/Mount_Kaukau if it helps

Can't find the other transmitter under Kordias list however.

baxters_knob_standalone_freeview.pdf (freeviewnz.tv)

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nztim

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#2758346 11-Aug-2021 08:43

Brunzy: Assuming you’re talking about FM it’s neither horizontal or vertical, it’s at 45°

If you are talking about FM some of those stations come from colonial knob and fitzherbit and not kaukau - An exampe of this is The Breeze which has a hutt and north wellington frequency

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alasta

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#2758348 11-Aug-2021 08:56

nztim:

If you are talking about FM some of those stations come from colonial knob and fitzherbit and not kaukau - An exampe of this is The Breeze which has a hutt and north wellington frequency

My understanding is that all of the Mediaworks stations, including The Breeze, transmit from Mt Kaukau with secondary frequencies transmitting from either Fitzherbert or Mt Climie. I think some have a tertiary broadcast from Haywards on the same frequency as the Mt Kaukau transmission.

linw

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#2758598 11-Aug-2021 13:55

Tuned in to FM 89.3. Wikipedia says that freq comes from Kaukau.