Larry, You're absolutely right! I've seen entire communications systems made unusable by a single dirty/corroded connection. There's a couple of points that bear stressing. (1) Antennas can look perfect physically, and yet be failed electrically, particularly the fiberglass models. (2) A good clean, non-resistive ground to the airframe is absolutely critical to correct antenna performance. (3) Given two correctly installed antennas, one on top and one on the bottom, the one on the bottom will perform better, giving better range. Good quality RG-58 or RG-400 coax , clean, properly installed connectors, and a properly installed and tuned antenna are all important to good radio performance. Another thing no has mentioned so far, is coax routing. Coax cable depends on the proper shape (round) for correct operation. Coax which has been pinched under a clamp or screw or deformed by being pinched between two panels must be replaced. Worst case, this can completely short the coax. Usually, it just puts an electrical "bump" in the coax which causes most of the transmit power to be reflected from the bump right back to the radio. This phenomenon is called VSWR (Voltage Standing Wave Ratio) which is a ratio between the power the transmitter is putting out and the power that is being reflected back to the transmitter from the "bump". A defective antenna can cause this also. Communications equipment is one area where attention to detail can pay back big rewards in improved performance, as you have noted. Incidentially, having followed this discussion, I am surprised at how many hams have interests in flying and Ercoupes. My call is W7MBH. Hope all this informs, entertains, and ultimately helps someone. Regards, Dave in Alamogordo, NM (W7MBH)
Larry wrote: > I've kept out of this discussion, as I know little about radio or antenna. But, > when I purchased my Coupe, the Nav-Com on her had a range of about 7 miles. Beyond > that, and it was just static. I got the guys here in Salt Lake City, at King > Avionics to go in and clean her up, and see what was wrong. By the time they > finished, the same radio was reaching out over 50 miles on Com. That's as far as I > went that day, so it could likely go farther. The whole problem was bad connections > and grounds. Want your radios to work better? Forget the antenna, clean up the > connections. Chances are you'll gain far more than changing the antenna from one > type to another. > > Larry > > [EMAIL PROTECTED] wrote: > > > I found the discussions on antenna's real interesting. When I bought > > the coupe, it had two antennas of the swept back Antenna Specialists > > design located just behind the rear windows on the top about 12" apart. > > The first one I tested worked fine on the aviation band but I could not > > get the second one to resonate in that spectrum. I used my grid dip > > oscillator and found that it resonated on the CB band. Guess one of the > > 36 previous owners like CB radio. I was also thinking of a bottom > > mounted antenna. As a Ham radio operator, I have always found that > > antenna orientation is more important in most respects than more power, > > especially with frequencies that work line of sight. > > Rich Blair. > > N99997 4J6 > > St. Marys, Ga. > > > > __________________________________________________________________________ ______ > > To unsubscribe from this list please send mailto:[EMAIL PROTECTED] > > _____________________________________________________________ > > Want to find the best email lists? Check out the Topica 20! > > http://www.topica.com/topica20 > > __________________________________________________________________________ ______ > To unsubscribe from this list please send mailto:[EMAIL PROTECTED] > _____________________________________________________________ > Want to find the best email lists? Check out the Topica 20! > http://www.topica.com/topica20 __________________________________________________________________________ ______ To unsubscribe from this list please send mailto:[EMAIL PROTECTED] _____________________________________________________________ Want to find the best email lists? Check out the Topica 20! http://www.topica.com/topica20
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