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Thread ID: 50069	2004-10-09 11:24:00	Antennas and Leakage	Growly (6)	Press F1

Post ID	Timestamp	Content	User
279581	2004-10-12 05:18:00	Well, yet another blow - the antenna is massive, @ 1m by 60cm - anyone still think there's a chance?	Growly (6)
279582	2004-10-12 07:02:00	>Well, yet another blow - the antenna is massive, @ 1m by 60cm so whats the problem with that ? its only a mid size aerial ?:| just stick the poles(+stays) in and install it ! ! !	tweak'e (174)
279583	2004-10-12 08:40:00	>so whats the problem with that ? That's exactly what I wanted to hear :D	Growly (6)
279584	2004-10-12 09:45:00	Doesn't the average " Russian Thermonuclear Intercontinental Ballistic Missile Silo" have an attached antenna farm?	R2x1 (4628)
279585	2004-10-12 20:44:00	For an alternative view: It looks a little like you might be able to mount the antenna inside the attic . It depends on whether there is foil-backed building paper lining the inside of the walls, but if not, the path losses through the wall structure might not be significant over that small distance and especially with a hi gain antenna at each end . Provided the attic area is not lined you should be able to see what the paper is like, and even if it is foil backed, the "Man in Charge" may accept removal of a small circle for the dish to fire through if you promise to replace it when the experiment is over . Aligning the antenna might be a bit of a problem, but nothing that a compass, a builders level and a dose of patience won't sort out for you . A preliminary alignment in the room to get the approximate declination, a few minutes outside to get the compass bearing, then setting up the link so that you know it works before you take the antenna inside, and away you go . Of course if the outer cladding is laid over wire mesh or such like, all bets are off . Cheers Billy 8-{)	Billy T (70)
279586	2004-10-13 06:10:00	It seems to me it was just a few weeks ago when I made a stand about the "Indoor Aerial" and got rubbished, It interesting to see that still no one from the PressF1 knows "Jack ****" about aerials . You don't have the coax going from the shortest path from the roof to the hole in the wall or you will have water dripping down, inside your home . You have a "drip loop" that looks like a "j" from the outside, so the coax goes up from the loop to the hole in the wall, then the water will drip off the loop . Also make sure the water will not go inside the coax, as I have heard once . And before any one says a "Indoor Aerial" or rabbit ears is a aerial GO AND STUDY A AERIAL THEORY BOOK, and see if you can find any theory on them, like you will on a standard out side aerial .	Eric Richards (6226)
279587	2004-10-13 07:17:00	Good advice on the drip loops guys, most aerial installations I see only prove that the installers know nothing about weathertightness or the materials they are working with. Growly, avoid like the plague a roof mounting, especially on Decromastic tiles (they are Decromastic not a Gerrard tile) which are fixed to 40x50mm tile battens (not purlins as per iron) with probably one gun fired 90mm nail per truss which then could be up to 1200mm apart but most probably 900mm. Teck screws and a dollop of silicon will not do it (people should be barred from using the stuff unless they're licensed) and, as it looks like your looking into the Pauatahanui Inlet, probably from somewhere near the Crowsnest, the winds will be wicked at times. Fascia mount if you must but, make sure your fixings are into solid by a good 50mm (not counting the 19mm of fascia) and be prepared to pop a gable brace in the roof space. Do use stays, fixed through the front edge of the tile not the top (the tile will simply crush down onto the batten if top mounted, providing a nice funnel for water and a loose mount), use a dab of silicon in the hole with a neoprene washer under the head of the tech screws. Stability will prove to be your friend for both the performance of the aerial and helping to prevent future water ingress. If you mount on the wall, make sure your into solid, 7.5mm thick, textured fibre cement sheet will not hold anything. Again use stays, but this time at the fascia. Look the cable and seal the entry point against both weather and abrasion to the cable, circular PVC flange siliconed to the wall where the ebtry point will add to both. Oh, BTW metal stays are better than guys to secure the lot against wind movement. It's not the big gaping holes that let in the most water, it's the tiny little cracks, splits or delaminated silicon that gets it flowing. Most sealants don't perform well when exposed to the environment and less so when incorrectly applied. Cheers Murray P	Murray P (44)
279588	2004-10-13 08:06:00	Alright,heres the skinny. Mount it in the attic as per BillyT sugestion to remove any building paper,if it still no go then get a hammer,whack a hole through to the outside,Arial is garenteed to work,it will be far easier then getting on the roof........Plus,if your old boy don't like it just tell him to get his own house. gees,the stunts me and my brothers used to pull would make a little hole in the wall look insignificant,Just remember kids...if you don't ask then they can't say no.	metla (154)
279589	2004-10-13 09:58:00	Steady on Eric, nobody is suggesting Growly use rabbit ears or even a half-wave dipole for his wireless link . If you are worried about my suggestion to put his WiFi antenna dish inside their attic, don't be . A short range link with dish antennas will fire through a wall no problems at all . If WiFi signals couldn't get through walls, war-driving & war-chalking wouldn't have taken off . As for the theory for balanced half-wave 300 ohm dipoles or unbalanced half-wave 75 ohm dipoles you need look no further than the ARRL or RSGB antenna handbooks, or any other good book on antenna theory . They don't call them rabbit ears of course, but the principles are exactly the same . Rabbit ears may not be resonant in Band 1, but in Band 3 they can do a creditable job, if a little narrow in bandwidth for TV, and they are a much more tolerant on FM radio signals . For prime signal areas where choices for external antenns are limited by landlords etc they do just fine . Don't get uptight about it, nobody is asking you to like them or even use them . Cheers Billy 8-{)	Billy T (70)
279590	2004-10-13 10:46:00	>probably from somewhere near the Crowsnest Mate, I am the Crowsnest . Well I live in it atleast . . . Yeah thanks very much for the advice - very very very much! (Don't stop though) . My dad himself must be credited at this point, as he believes that in no way should I put it in the roof . This is probably because, although he hasn't told me, there is a large amount of reflective metal in that attic - none of which he will be willing for me to cut - so although feasible, as these are powerful antennae and it's only wood . . . the man will have none of it :'( Therefore, if at all feasible, I am only left with the option of mounting it on a mast . At the other side of the house there is a TV mast with a TV antenna mounted on it in a similar fashion, unfortunately this is a) a bit too short and b) has trees within the line of sight . It appears that Murray P has clearly outlined my Dad's fears . Unfortunately, I cannot see why the same labour cannot be put into mounting a mast for my precious antenna as had been put into mounting the now redundant TV antenna . from looking at it, it looks as if it is using a facia mount and two supporting poles . Unfortunately this is also aided by the fact that some of the more overtly nosey neighbours will not rest at any opportunity to lay claim that my antenna is ------- ugly . But screw them . So let's review (so much technical non-computer related phrasing has confused me, and so if I got the wrong idea, please correct me): I take said antenna and a mast . I get a facia plate . I stick mast to fash the plate, and i secure the mast with poles . While drilling I must be careful to to cause to many cracks . I must fill up with silicon (from in the attic, maybe?) . I will tighten . I take the cable and do some sort of loop (not quite sure where or how) so that the water drips off before going into the house . In doing so, I increase the signal loss (great . ) . I keep the cables dry, presumable with alot of electrical tape, or self-something tape . I align it using diagrams, compass bearings and depression angles, which I figure out using some sort of tool (maybe one of those you point up at the sun and click, and then it tell you the angle? Like in maths?) Then I plug it in and it works . (PLEASE) Sound easy . . . Hmmm - thanks again! Oh, and > Doesn't the average " Russian Thermonuclear Intercontinental Ballistic Missile Silo" have an attached antenna farm? Only on Tuesdays .	Growly (6)
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