Great idea Pete but I also may run head long into false positive results with so many Beverages (12) and each with a different possible indications. Here with the masking over of any subtle changes by strong ever present boiling tropical QRN yielding a possible infinite number of variables, each by themselves variable may not quickly yield any discernible results. If there was any time day or night when QRN did not run S-9 in almost every direction I would give it a try but I fear that with what i have I may be just peeing up a rope.
Herb, KV4FZ On 6/20/2012 4:45 PM, Pete Smith N4ZR wrote: > Doesn't this suggest that there is a role here for cut and try? Take a > set of clip leads to the base of the tower and experiment? > > 73, Pete N4ZR > The World Contest Station Database, at www.conteststations.com > The Reverse Beacon Network at http://reversebeacon.net, blog at > reversebeacon.blogspot.com, > spots at telnet.reversebeacon.net, port 7000 and > arcluster.reversebeacon.net, port 7000 > > On 6/20/2012 3:45 PM, Herb Schoenbohm wrote: >> Tom, >> >> This is not encouraging news for those of us with towers already ground >> and are either shunt fed or cage fed. Even though they are not >> resonate, although top loaded and approaching resonance, it seems that >> even with some elaborate decoupling arrangements, and I hope I am wrong, >> not to much can be gained by even trying to get them "detuned". This is >> crucial for me to know, and I would assume many others that have >> Beverage terminations or feed points 100 feet away, >> >> Thanks for the warning as this summer I was going to install a HV relay >> on the shunt cage to ground....but as you point out it may not help as >> the grounded shunt or cage fed tower is already a noise source for close >> proximity RX antennas. >> >> >> >> >> On 6/20/2012 2:09 PM, Tom W8JI wrote: >>> There are two potential problems with this. As general rules: >>> >>> 1.) Grounding any antenna which is dependent on a ground system to be >>> resonant will maximize reradiation. >>> >>> 2.) Resonant elevated radials, even without an antenna connected, are >>> resonant and re-radiate. >>> >>> 3.) Things that are not resonant can still re-radiate. >>> >>> To minimize coupling from a resonant radial, the radial has to be >>> disconnected from ground and from other radials. >>> >>> Different systems can be different, and in some cases re-radiation can >>> actually cause a null that reduces noise, but the general rule is >>> self-resonant antennas with a ground (Marconi), or nearly self-resonant >>> antennas when grounded, should be floated. Other antennas can be terminated >>> in an inductor, capacitor, or opened, depending on the system. >>> >>> My 220 ft insulated tower, in the center of a four square, is "opened" by >>> shorting a specific length of coax to the "L" matching network. It has much >>> more radiation when open or grounded. radiation is minimal when detuned by a >>> proper impedance. >>> >>> 73 Tom >>> >>> >>> >>> >> _______________________________________________ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
