Dale, thank you for the comments. (Also, thanks as well to Neal, Tim & Greg for their comments)
I read over the weekend that the receiver in the Flex 6700 is really good. I don't know how good it really is but that made me think that, at some point, there must be a limiting case where the capability of the receiver so far outweighs the advantage of having a preamp located at the antenna that it would be better to remove the preamp from the receive chain. Wouldn't it be great if this were the case with the 6700? Maybe that's not realistic but I'm curious how close we're getting to this condition being true. On Tue, Apr 23, 2013 at 3:44 PM, [email protected] <[email protected]>wrote: > Hello Rick, > > Although I don't have any experience with these two manufactured products, > I have been playing with homebrew broadband magnetic loops and broadband > voltage probe receiving antennas. Both antennas have very low output > levels, and require significant amplification. In the case of the magnetic > loop, the impedance of the loop itself is a fraction of an ohm, so a > common-base differential amplifier is frequently used. In the case of the > voltage probe, the impedance is very high, and is frequently fed to the > gate of an FET employed as a source follower. I'm certainly no expert, but > I wouldn't think that either of these antennas would be useful without the > appropriate preamplifier physically located right at the antenna. > > I've used the DX Engineering NCC-1 with a pair of voltage probe antennas > to pretty much eliminate some persistent power line noise. The next > experiment is to build a small array of two independently rotatable 48" > magnetic loops to first let their inherent deep nulls reject the noise, > and then further use the NCC-1 for some minimal beam steering, or without > the NCC-1 for diversity reception. I'd expect the AAPS3-1P would give you > even more versatility, but again, I wouldn't think that locating the > amplification away from the antenna would produce satisfactory results. > > Have fun! > > 73, Dale > WA8SRA > > > > > > Does anyone have any thoughts at to whether active receive antennas such > > as > > DX Engineering's Active Antenna Phasing Systems AAPS3-1P ( > > http://www.dxengineering.com/parts/dxe-aaps3-1p) or Pixel Technologies' > > Shortwave Magnetic Loop Antenna RF Pro-1B ( > > http://www.pixelsatradio.com/product/shortwave-magnetic-loop-antenna/) > > will > > perform well with the Flex 6700? I'm curious based on recent comments > > posted here regarding the 6700's very low noise performance receiver. > > These comments make me wonder if the the preamps included with these > > antennas would decrease system performance when used with this receiver. > > _______________________________________________ > > Flexedge mailing list > > [email protected] > > http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz > > This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is > > used for posting topics related to SDR software innovation and other > > technical SDR topics. > > > > > -- Rick McClelland, AA5S Fort Collins, CO _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software innovation and other technical SDR topics.
