FM antenna made simple


I have a Rotel RX-975 receiver that cuts in and out when listening to local FM stations in Hartford. I am using the supplied "T" wire antenna simply taped to the wall behind the receiver. How can I improve my reception without getting too complex ? i.e without getting up on the roof or climbing the chimney to install a rotating antenna.
loshinskie0c67

Showing 1 response by sgmlaw

An indoor antenna may or may not help you in this situation. Unlike AM, antenna mounting height will make a large difference both in FM sensitivity and multipath rejection. Another factor to consider is whether you need a directional array to capture these stations. Before investing in any antenna, I would suggest making some walkaround reception observations with a high quality portable monaural FM radio in your listening room. These units, being mono, generally surpass all but the finest stereo units for sensitivity and selectivity. I have used the GE Superadio II for this purpose with very good results. This should give you an initial indication of whether reception is possible for this location, the 'hot spots' in the room for best reception, and what directionality, if any is needed. Don't be upset if you find that you simply cannot get good reception - occasionally an interior room will simply not permit satisfactory reception. My own listening room has very poor FM reception and I am forced to go outdoors. If you are lucky enough to obtain decent interior reception, try to stay with a passive antenna. Believe it or not, the humble 300 ohm "T" is one of the best. Sean's homemade design is very good also. While some have had success, I am not a big fan of the $100 designer interior antenna, and think even less of the Radio Hack models - many having built in amplification that simply mangles any signal. Don't forget to take the "T" right up to the ceiling, the higher, the better. If you cannot obtain a satisfactory signal from the "T", you probably won't get it with any other interior unit and may have no choice but to go higher and perhaps outdoors (if you simply cannot leave the room, then your only possible option is a better tuner, which in virtually all cases represents very poor value per dollar over a better antenna). While this may not require a roof mounted array, you might first consider an attic-mounted or exterior wall mounted omnidirectional unit. The Fanfare omni is quite good - and so is the $20 Radio Hack "X" model. If you have a drop ceiling, you can sometimes fit the "X" above it, with varying results. But these units perform best outdoors. Remember that ANY quality outdoor antenna, properly mounted, will outperform any interior model, period. If you have a multipath issue or require maximum gain, then you may be forced into a directional unit, which may require roof or obstruction free mounting. Radio Hack outdoor antennas are OK, but not great value, IMHO. The better, sensibly priced, outdoor models can be found from Channel Master and Winegard. A couple of other pointers if you're serious about this: First, unless you are prepared to buy the very best (i.e. Blonder-Tongue, Channel Master, etc.), avoid all RF amplification - most do a horrific job and impose unacceptably high levels of noise. A quality, low-noise FM amplifier can run upwards of $200. Unless you really live on the fringe, most folks simply don't need them, and the money spent on amplification is better spent on a larger or better passive outdoor array. Second, if you have a lead in run under 20 feet, you may use 300 ohm twin lead (this has the lowest loss, but is generally unshielded and will pick up noise). Ideally, shielded 300 ohm cable is the very best for this application, but is nearly impossible to find anymore. If you have a longer run, the shielding of 75 ohm coaxial outweighs it's higher loss rate. Remember too to use only RG-6 coax, as RG-59 has a very high loss rate. The good thing about basic radio reception (raw sensitivity and selectivity, not all those other qualities we associate with high end tuners) is that the antenna is 90% of the deal - an average tuner with a great antenna will run rings around the very best tuner with a poor antenna. The latter part of this response admittedly exceeds your question, but may be of some help should you decide to attempt a more complex installation.