On 23.03.12 18:34, Viesturs Lācis wrote: > Is there a place, where I can read, how are such things set up? I am > thinking that such a repeater could be placed on the roof of barn > (very far end of it is not "blocked" by the trees on the hill), which > is not the place, which could be conveniently reached with a coaxial > cable.
This isn't much help: http://en.wikipedia.org/wiki/Passive_repeater though it does mention exactly what I had in mind, and even mentions the Yagis. > Are the Yagi antennas mandatory or could I use "normal" TV antennas (I > think there must be several more smaller antennas lying around)? The "normal" TV antennas we have here are Yagis, i.e. a metal pipe with crossbars decreasing in length toward the end which is pointed at the transmitter. The second-last "crossbar" is comprises two insulated halves of the receiving element, which are connected to 300 Ohm ribbon, or via a Balun to 75 Ohm coax cable. So, if we're using coax, it's just: Transmitter . . . --- | ----- | ------- 300 ohm ribbon, with no Baluns. \ OR Balun 75 Ohm Co-ax Cable \===============================\ Balun Hilltop \ ------- | ----- | --- . . . House Good quality low-loss cable will help, if you need 20 or 30 metres of it to get over the hump of the hill, but the top of the barn sounds good. If there's only a metre or less of cable, then there is more signal to be re-radiated to your house. If one of the antennas is longer, I'd be tempted to point it toward the transmitter, in the hope of picking up an extra microwatt or two of signal. (They should both be of similar width, since that's dictated by the TV band they're built for.) For a short distance, it is easier to interconnect the antennas with a bit of 300 ohm ribbon, than muck with baluns. But if you only have coaxial cable to hand, then the photos here: http://en.wikipedia.org/wiki/Balun show some typical TV baluns. The last image on that page shows some 300 ohm ribbon as well. I hope I haven't overcomplicated what's a simple wiring exercise, so long as it's all 300 ohm from end to end, or the baluns are used to go down to 75 ohm and back up again. > > The set-up might bend local regulations. > > Who cares? Good picture in TV is what matters :)) :-)) It sounds like you have the perfect site for trying it out. I hope it works. Here someone else had a similar issue, at much longer range, but didn't report results: http://www.eng-tips.com/viewthread.cfm?qid=29934 This might help too: http://www.matthewsworkbench.com/passive-tv-repeater/ (Though he used an amplifier, to get perfect reception. That resulted in their authorites shutting it down, if my quick glance got the gist.) Aha! This guy: http://web.archive.org/web/20080328024851/http://www.shol.com/kuggie/cttip/passive.html achieved a "good picture" from "non existent" without an amplifier. It might just work, if there's a decent signal up on top of your barn. :-) Good luck! Erik -- My 4 year old niece offered a helpful suggestion while I was in the middle of resolving a LAN routing problem: "Turn it off and turn it on, Uncle Jack; that always works for me." - Jack Ganssle ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
