2. tech-talk
  3. 1006234910

Twin lead or coax for downlead from FM antenna?

I have about a 25-30' run from my attic antenna to my tuner. The antenna has twin lead (300 ohm) output and the tuner has a coax only input (75 ohm). I can either use twin lead and a transformer at the tuner end, or put the transformer at the antenna and then run RG-6. Any idea on which would be better in terms of signal loss, noise, and longevity? I understand that these criteria may be mutually exclusive. Tuner is a Yamaha T-85 and antenna is a Winogard X type omnidirectional. I do not want to fuss with a directional/rotor set up.
128x128swampwalker
swampwalker's avatar
swampwalker OP
5,138 posts
 
OK, thanks guys. Since the cable is in my attic which is quite dry, weatherproofing should not be an issue. Now I just have to get my butt up thru the scuttle and switch over to the coax (RG-6).
nexusrlee
6 posts
 
I agree that you should run a quad shield RG-6 coax line. I just though I would mention that directly connecting an antenna or cable connection to your audio/video system could have disastrous results without some kind of surge suppression to protect the components. You may also create a ground loop that will cause an annoying hum. I recommend the Monster Power series from Monster Cable. The HTS1000 or HTS2000 will provide protection for all your equipment. http://www.monstercable.com/product_info/infosheet_mpwr_hts2000.html
j_k
234 posts
 
Use the RG-6... If the antenna in the attic, it doesn't need surge protection; If it is outdoors, surge protection is a really good idea. The issue one should watch is the possibility of added EMI / RFI that can occur when adding a tuner to a system. One time I was troubleshooting this and found when I started disconnecting everything in the house that the downfeed on my FM antenna was picking up some kind of RFI from some local high power CB transmissions. Pounding a copper rod into the ground with a 00 cable attached to the rod and ground bus bar added to my audio ground knocked it out. Everything in my audio system is chassis grounded to this buss in a "star" configuration (which the shield of all my coaxes are also attached to.
More to discover