The problem most likely is not the raised radials per se. That he does not have space for buried radials most likely means he also doesn't have space for full size, dense and uniform all around raised radials either.
Without details, but after 5 years of hearing about what people have actually done for "raised radials", in the abstract the most probable situation is that the redials are irregular and insufficient, limited to what is possible on a limited property. That in turn creates a significant input impedance to the collection of radials. This in turn makes the feedline coax shield an easier path than the collection of radials. This effectively makes the coax shield the counterpoise. That in turn puts the noise from the house and the power lines into the L feedpoint. Even if a "balun" is used, unless it was specifically manufactured *** with 160 in mind ***, or constructed from something like K9YC's cookbook, *** for 160 meters ***, it's likely to be very poor on 160 and will let in stuff on the coax shield any way. An FCP and an isolation transformer has quieted down a lot of noisy inverted L's. 1) Because the FCP counterpoise is isolated from ground and 2) it's folds make it an extremely poor RX antenna, AND 3) it's isolated from the feedline by the isolation transformer which has NO metallic path between the coax shield and the counterpoise. It has been a common report that converting to an FCP and isolation transformer cut down on noise. My best interpretation on those reports is that the noise was coming from the house using common mode entry from the feed coax shield. Have him take a look at k2av.com where these issues are discussed. Also see w4kaz.com where Kaz documents his migrating his inverted L from "radials of convenience" to an FCP + isolation transformer. 73, Guy. On Tue, Oct 17, 2017 at 3:57 PM, K1FZ-Bruce <k...@myfairpoint.net> wrote: > Have a friend that is getting noise from raised radials connected to his > inverted L antenna. > > He can not bury the radials due to space problems. > > Are there any recent solutions to the problem.? > > Thank you in advance for your input. . > > 73 > Bruce-k1fz > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband