Re: [Elecraft_K3] Re: Powerline Noise reduction
I have three of the Wellbrook loops, one that may no longer be available, the 330S that was for 3 through 30 MHz with extra gain, the 100 with a 40 foot circumferential loop, and a 100M with a 20 foot loop. The larger the loop, the lower the gain and the less the head-amp noise.
To my surprise, I haven't had the expected success on 160 meters, but their broadband pickup on 80 - 17 meters was quite good. The 40 foot loop had too much gain around 22.5 MHz, but since there was nothing around that frequency, it didn't matter. It did have amazing pickup on 15 and 10 meters, unlike the smaller loops.
All the Wellbrook loops were extensively reviewed by Passport to Worldband Radio, which was published for 25 years. The last book came out in 2009. Back issues are often available on Amazon.com.
Having a figure of 8 pattern, a null could be useful on 5 MHz and below if mounted on a rotor. I never did that, and never found them particularly directive on most ham bands. They could never compete with a yagi at a reasonable height, but that isn't their selling point.
The Pixel loop is made in Colorado and seems to have a good following. There is one mounted on a tower in an urban environment by one of our US OEMs, along with a tri-bander. For those with limited space, active loops can be useful with transceivers with an RX input.
I found it best to mount a loop as far away from one's house, (and neighbor's house), since there are so many sources of local RFI from all our electronics and wall wart switching supplies.
On Jan 31, 2016, at 3:28 AM, "mike@... [Elecraft_K3]" <Elecraft_K3@...> wrote: