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In Reply to: Antennas Poll posted by Timbo in Oz on June 11, 2004 at 15:20:43:
The 10 foot pole is a good idea. Use 2 5' sections, assemble everything then plug them together.
Dont forget that some TV antennas have a built in FM trap and might not be too good for FM.Bill
It is some 30 or so feet high made of several bits of galvanised pipe, sleeved inside to make joints, together and bolted, there are two joints / three sections visible, plus two inside. It is more like > 30 foot long /high, two wall mounts, and one eave mount, and I still haven't guyed it. (Scrounged bits? you betcha!)There are closed ring bolts at top and middle, to retain the rope I use to raise and lower the AM Wire antenna, and a deck lashing ( -.- ) near the mast's base.
The end at the bottom has a welded T-piece of pipe bolted into its bottom, to let me rotate the mast for aim. I use another very stiff pieceo'pipe, so it's rather like the top of a post-hole digger, but upside down.
Not that aiming needs doing very often. [ONE very high telecom tower and restaurant / tourist trap / thing on one big hill.] Even commercial FM stations have to use it!
The mast my be lowered into a 6 ft section of 4inch PVC pipe, set into the ground vertically, with a cap on each end, so I can just reach the top.
There are three ground rods of copper plated steel banged in, one of 12 ft, two 8 ft. My forearms were numb for a week.
IME Antennas really matter, as do down-leads and feed lines, and earthing. One day I really will run a ground plane of wires, under the soil, to help the AM wire.
The only thing I need to add is a hand-winch, with a ratchet, to raise it, and lower it under control, with the knife edge clamps undone so they don't snatch at the mast / the bolts. Bloody thing is HEAVY, 3 antennas plus mast plus 50 ft of RG6 and RG11 cable.
JBTW there's a post by me in 'vintage' I think by me about TVI and RFI. A real saga.
Warmest,
Timbo in Oz
The Skyptical Mensurer and Audio Scrounger
Peace
Nice job. A strong wind would flip your house on it's side.Do you DX/
Bill
I do try with AM on the SW and MW bands the 'tuner' has, but I think I would need a proper directional (tunable loop) antenna for that! My main reason for wanting hi-fi mono AM is the ABC's two services local and national both of which I value highly.I am an ex-grunt (AOT!?) who was a Coy signaller, to Cpl for a time, and later went over to B'n Int, from Sgt up to WO2 / SgtMajor. So I do know the issues and the tech side, a bit, mostly I carried an ANPRC 9, 9A or 25 back pack set.
At other times I was responsible for installing and maintaining the Battalion's G, A, and Q nets, usually run on the Australian designed A510. Tuned by crystals and each often need a vertical end-fed or a tuned long wire antenna. I was glad that as a kid climbing trees was a passion!
http://www.qsl.net/vk4czt/a510.htm
I know that even at HF or lower, antennas and their position matter, why is the good spot always 'out of cover' but, eh!
In Canberra in the ACT (+ Queenbeyan NSW) in Oz, we have the (public) ABC's 2 X FM stations (national networks) and the 'classical and jazz' one doesn't use any compression, except during 'drive times'. It is akin to the BEEB's Radio 3, and a VERY strong signal, by laws about coverage. It, and Canberra's local community arts and music station are what I listen to. I have always hated commercial radio, even when it was just AM, so the rest are of just > zero interest to me.
Most of the other local FM stations, incl. my no. 2 above, also transmit from that one big tower. Don't need a rotator.
But, we are right smack in the middle of the Great Dividing range running down the entire east coast of Australia. Canberra is VERY spread out in and among these hills, bowls and valleys. Lots of hills and Multipath, hence the long / large antennas and tall mast. We have hills over 1000 metres ASL, all around us within 2-3 miles.
The nearest FM sources outside the local region, are > 100km away in all directions and are mostly commercial stations, or low powered rural repeaters for the ABC which I don't need. Further, the mountains make DXing extremely difficult.
Tube front end means low sensitivity, it uses a Foster-Seeley detector! and needs hard driving, but geez is it quiet if you do.
The tube IF stage, when in full limiting, produces a range of harmonics right up into VHF III and UHF IV and V, which goes out up the cable. I posted here at AA about the TVI / RFI saga this caused me. The thing I learned is that even qualified technical advisors have to 'GET the context', before they will give you practical and sensible advice.
You may enjoy the story, do a search under my moniker as Author and TVI and RFI.
One other thing about tube tuners is the 'magic eyes'. I just love 'em, silly old me!?
I would love to use a pr for level meters!
Timbo in Oz
The Skyptical Mensurer and Audio Scrounger
Peace
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