What will we do with all the old reduntant VHF aerials?

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Printertech

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Topic # 96482 28-Jan-2012 14:27

Cut them down and make them more tuned to UHF? Most band III, Ch 4-11 aerials pick up UHF reasonably well, they could be polarised the right way for UHF in most cases.
I suspect there will be a lot of hardware being taken off buildings in the near future. Do scrap merchants pay the same price/kg for them as they do for cans?

vinnieg

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Reply # 574410 28-Jan-2012 14:37

I've got a dual, bought 2 years ago, I'll just remove the larger VHF pieces of it and drop the aluminium leftover in my recycling bin

Otherwise take it into a scrap metal dealer, if you really wish. But the current price for aluminium scrap per kg is only $1.13. Not even enough for a coffee, unless you collect a few dozen aerials :)

I only wish they were made of copper

I have moved across the ditch. Now residing in Melbourne as a VOIP/Video Technical Trainer/Engineer.

Printertech

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Reply # 574413 28-Jan-2012 14:42

Yeah, by the time you fiddle about replacing rusted bolts and wingnuts, you could buy a 43 element UHF with better gain.

vinnieg

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Reply # 574415 28-Jan-2012 14:43

Printertech: Yeah, by the time you fiddle about replacing rusted bolts and wingnuts, you could buy a 43 element UHF with better gain.

Yeah, that's exactly what I did originally, but a combined one. The old was was so rusted I just angle grinded it off the roof :)

I have moved across the ditch. Now residing in Melbourne as a VOIP/Video Technical Trainer/Engineer.

geek4me

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Reply # 574450 28-Jan-2012 18:56

Those long rods make great tomato stakes.

johnr

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Reply # 574454 28-Jan-2012 19:17

dump them on @Nate front lawn during the night

richms

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Reply # 574463 28-Jan-2012 20:07

Re-aim to use as an FM antenna?

Richard rich.ms

Printertech

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Reply # 574466 28-Jan-2012 20:17

richms: Re-aim to use as an FM antenna?

Yep, thought of that too, but the CH 1 aerials are a bit big and ugly. They can't hold many ducks or seagulls when horizontal. I suppose on a diagonal the birds slide off.

JimmyH

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Reply # 574468 28-Jan-2012 20:26

I wasn't planning to do anything immediately, and there is no compelling need to get it down quickly as it's only about 5 years old and is in good condition. I was sort contemplating hooking it to the stereo as an FM antenna to see if it improved radio reception.

oxnsox

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Reply # 574484 28-Jan-2012 21:08

richms: Re-aim to use as an FM antenna?

....and re polarize

lonney

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Reply # 574486 28-Jan-2012 21:17

The low band antennas could be cut down for FM.

150 /freq = a half wave length for your elements - tip to tip & use 0.2 wave length spacing between them. Make the reflector (singe one behind the with the coax connected) 5% longer, and the directors infront 5% shorter.

You can use a simple split dipole with a plastic mounting, and wind a dozen turns of coax into tight loop where the braid goes to one side, and the core to the other, this will act like a choke and stop the coax from acting as part of the antenna. Be sure to seal things so water doesnt get down it. Or with a folded dipole use a 4:1 balun.

Problem is TV antennas are cheaply made, after a couple years the steel bolts react with the aluminum and corrode, and eventually go rotten. lanocote will make em last, but use the grease type, not a spray on stuff. Marine shops usually have it.

Failing that, if the antenna is in reasonable condition , especially if it covers the lower channels (1,2,3), find your local ham radio club, they can be cut down for 144 and 430Mhz bands. With analogue being switched off there will be a few hams out there keen to get back on the (amateur allocated) 6m/50MHz band, so stuff to knock up antennas - esp the old channel 1 antennas will come in handy. 6m/50Mhz is known as the magic band, as it'll open with out warning for long range communications, so it can be quite exciting!

lonney

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Reply # 574487 28-Jan-2012 21:19

oxnsox:
richms: Re-aim to use as an FM antenna?

....and re polarize

FM is usually circular polarization - better for car radio reception where you're moving, so it dont matter, just mount it horizontal, easier and looks better.

richms

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Reply # 574493 28-Jan-2012 22:03

I actually got a big-ass FM antenna back when they all shifted to the skytower and there ended up virtually no signal here. Thankfully that got sorted after a while so I dont need it, but I guess now I dont need the VHF I can use the diplexer to combine it in instead of the VHF so I can get better reception on the garage stereo than 2 meteres of wire gives.

Richard rich.ms

mattwnz

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Reply # 574502 28-Jan-2012 22:33

Mine fell apart when I took to down. The connections were all rusty. Don't think they are worth much in scrap either. Looks to be just aluminium. I just put it in the bin.

wmoore

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Reply # 574522 29-Jan-2012 00:39

Turn it into a clothes dryer.

"In the end, it's not the years in your life that count. It's the life in your years." -
-- Abraham lincoln

gareth41

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Reply # 574745 29-Jan-2012 21:35

I made a LPFM transmit dipole out of our old tv antenna, used a bit of RG58 for a balun and seemed to work quite well with the tennatron xmitter I had at the time, given that we are located in a bit of a dip.