My antenna self-build

Location : Hemel Hempstead, UK Spotter Watch Member : No

Hi All,

I have been blessed (By an ex Sky TV installer) with loads and loads of Coaxial and shielded line. It has inspired me to build my own antenna and attach it permanently to my chimney. (I have already sought permission from girlfriend, and she actually said yes much to my surprise) I have been looking at several designs and set myself on the simple and what seems easy to build. Please see my plan below. If you have any tips, tricks, info, guidiance etc etc etc... Please let me know... Thanks! Laughing

I hope to 'crack on' by the weekend.

Thanks in anticipation!

Location : Midlands Spotter Watch Member : No

Not sure if i am correct thinking here but is the sky / tv cable 75ohms where radio concern it needs to be 50ohms

chris

Subject: Re: My antenna self-build 2009-07-27, 07:17

Hi.

great idea build your own antennas, don't worry about the
50 /75 ohm business, only really matters when transmitting. Anyway
dipoles are 72 ohms impedance at resonance and off resonance
can get up to the thousands.

Just building a log periodic 200 to 400MHz and when complete
will be coupled up using RG6 satellite coax, great stuff.

cheers have fun

George.

Location : Hemel Hempstead, UK Spotter Watch Member : No

george wrote:: Hi.

great idea build your own antennas, don't worry about the
50 /75 ohm business, only really matters when transmitting. Anyway
dipoles are 72 ohms impedance at resonance and off resonance
can get up to the thousands.

Just building a log periodic 200 to 400MHz and when complete
will be coupled up using RG6 satellite coax, great stuff.

cheers have fun

George.

Cheers for the info, He's got a machine that can measure the impedance/resonance so it should be straight forward to produce. So what do I do, make it larger than it should be and cut it down to meet the reasonance?

Subject: Re: My antenna self-build 2009-07-28, 05:30

Hi ?????

Asuming you want to moniter VHF airband, an aerial
cut for 128. MHz will do the job. I made one 44inches
overall ( 1100m/m ish for you youngsters, Hi? ) ie
22 inches each side the centre.
Works well, also works with UHF frequencies but is
a lot less sensitive.
I also made a multi band dipole, ie one centre with
three wires cut to 44 inches 24 inches 16 inches o/a
this covers VHF and UHF. I secured the wires spaced
around a 40m/m dia. plastic pipe and then put that
inside a 50m/m plastic pipe and made that waterproof.
This also works well. As you can see, making aerials
is great fun and not at all critical in the measurement
department at these frequencies.

Have fun George

Location : Hemel Hempstead, UK Spotter Watch Member : No

Thanks George, you info will prove essential I'm sure.

I shall post pics upon completed masterpiece Laughing

Location : Newport/Chepstow

have a go!!!
I have a home made jobby in my loft,all with satalite cable and it works a treat.
I made one in work,and put it on my cement silo,about 80ft up. Just the ends,cut to length,and cable tied to a piece of wood,then a run of about 100m of satalite cable through ducts to my office. It was only an experiment but it worked fantastic!!

Location : Essex Spotter Watch Member : No

Yes use the cable you have, it won't matter for receiving. I am a radio amateur and have used 75ohm to feed an 2m FM aerial! (144MHz)

Also you will be saving money and can pacify your family etc by telling them you are being "sustainable" How "green" is that? Big Grin