May want to browse the W8JI website for a lot of interesting information on all phases of ham radio. Here's a link to the Beverage antenna section: https://www.w8ji.com/beverages.htm Have a look at his antenna comparison spreadsheet to get an idea of performance of various receive antennas. https://www.w8ji.com/receiving.htm
Best DX Bill W2PKY On Mon, Nov 13, 2023 at 6:12 PM Neil via wsjt-devel < wsjt-devel@lists.sourceforge.net> wrote: > Hi Glenn, I've only been using Beverages on 160m for 40 years, so this is > a somewhat partial and subjective view, but they certainly increase the S/N > ratio considerably for human ear reception of extremely weak signals *when > terminated correctly*. Usual gain is around -20 dBi, but irrelevant > because I use carefully-designed preamps to increase the signal level back > to the receivers to overwhelm locally-generates noises from my neighbours > properties. > > I found that I could get almost as good results with phased rotatable > terminated loops, using Vactrols and phasing networks to tune the > characteristics, mainly null steering to reduce high-angle local signals, > and reducing human-generated noise and noise from the auroral curtain up > here at 54 degrees north. Those loops have a gain around -32 dBi when > phased, but the gain in S/N is definitely worthwhile. Beverages work > *because* of the lossy dielectric soil beneath them, not despite it. > > E-field probe antennas and small loops also work very well to improve the > S/N on some paths. You need a selection of different antennas to get best > results for all directions. I also use multiple receivers concurrently. > > You also have to detune and terminated any transmit antennas within a few > wavelengths while you are on receive, avoid putting a station near any > large wire arrays such as power grid feeds or electric fences or strained > wire fences. > > I agree that Beverages and other specialist receive antennas are difficult > to model, but luckily folks have been getting excellent results since > FOREVER without worrying about whether they can be modelled. Having a way > to adjust the terminating resistor is helpful, and having the wire elevated > the right distance above ground and having it multiple wavelengths long is > also helpful. but I've used Beverage-on-ground antennas over poor soil with > some success. > > Using my receive antennas often bring signals up that are entirely > invisible and undecodable on the waterfall on transmit antennas. > > -- > Neil G4DBN > https://youtube.com/MachiningandMicrowaves > > On 13/11/2023 21:41, robert evans LAST_NAME via wsjt-devel wrote: > > When they built and installed the beverages they noticed they > had just as much noise as the other antennas if not more. > > I modeled the Beverage and discovered it was a very high > loss antenna. The soil was the lossy element and if you > tried to reduce the loss by tuning the termination and > matching networks you compromised the front to back > ratios and lost directionality. > > The performance of the Beverage was dependent on soil > characteristics and difficult to model and variable to > to due to rain etc. > > We put an oscillator in the undesired direction. > Before a contest the termination and matching was > tweaked to null the oscillator in the park while favoring > European stations. > > The Beverage is a lossy antenna with the least loss > in the desired direction when correctly terminated and > matched for the soil conditions. > > BCNU DE N2LO~> > > > On 11/13/2023 11:45 AM EST Glenn Williams via wsjt-devel > <wsjt-devel@lists.sourceforge.net> <wsjt-devel@lists.sourceforge.net> wrote: > > > This is a theory question. There is a bit of FT8 on 160m. Does use of a > Beverage Antenna to get more signal raise the S/N value? Would that > antenna help with receiving weaker signals (a variation of that S/N > question)? > --73, Glenn, AF8C > > > > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel >
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