Hi Larry, There isn't much difference between 70 foot and 130 foot end-fire spacing. If there isn't any other consideration, 130 feet is probably the better choice.
73 Frank W3LPL ---- Original message ---- >Date: Sat, 2 Feb 2013 19:13:22 -0500 >From: "Larry - K1UO" <[email protected]> >Subject: Re: Topband: New 160M high performance receiving antenna at W3LPL >To: <[email protected]> > >Thanks for the tips Frank...This Spring Ill try the 300ft spacing...Also do >you think I should go to 130ft endfire spacings rather than 70? > >I have the space because I have great rural neighbors! quiet ones also. > >73 > > > > >-----Original Message----- >From: [email protected] >Sent: Saturday, February 02, 2013 2:57 PM >To: [email protected] >Cc: Larry - K1UO >Subject: RE: Topband: New 160M high performance receiving antenna at W3LPL > >Hi Larry, > >Your 160 meter CW skimmer is working extremely well, it spotted T6LG last >night. No other U.S. skimmer spotted him! I couldn't hear any trace of >T6LG, I guess I need to move my BSEF receiving array to Maine! > >I use exactly the implementation described at: > >http://pvrc.org/bsef/bsef.html > >Each vertical is 25 feet of aluminum tubing with four 25 foot umbrella wires >and eight 70 foot radials (inexpensive 16 AWG speaker wire) laid on the >ground. The verticals are low impedance at the base, so there are >absolutely no issues with handling very high impedances like in the Hi-Z >array. My insulators are phenolic, but any insulator -- even wood -- will >work fine with low-Z verticals. > >The strong advantage of the low-z BSEF array is that there is no need to >adjust the phasing, the only adjustments are is inductors and resistors at >the base of each vertical. Adjusting them takes five minutes or less. If >you want to steer the sidelobes, you could eliminate the fixed phasing line >in the center of the array and run two RG-6 feedlines to a DX Engineering >NCC-1 Receive Antenna Variable Phasing Controller in your shack. > >The low-Z BSEF receiving array has important disadvantages too: > - it is physically large (300 x 130 ft), > - it needs radials, and > - its strictly a monoband antenna. > >Each vertical is base loaded with a resistor and inductor, adjusted to >resonance (75 + x0) at 1840 kHz. Each base loading enclosure has a BNC >connector that I use only with my MFJ-259 to set the impedance to exactly 50 >ohms resistive and zero ohms reactive at 1840 kHz. A 25 ohm resistor >(measured with a digital ohm meter) runs from the BNC connector to the 75 >ohm F-connector. The RG-6 must be disconnected when connecting the MFJ-259 >to the BNC connector. > >The F-connector connects to a half wavelength (225 feet) of RG-6 that goes >to the RF combiner near the center of the array. > >The RF combiner uses three Minicircuits Labs 75 ohm splitters used as simple >RF combiners. The only phasing line is a 68 foot length of RG-6 and a phase >inversion transformer that sets the relative phase of the rear two broadside >verticals relative to the front two broadside verticals. This phasing >provides minimum sidelobe levels. > >I highly recommend the low-Z BSEF array since you obviously have the space. >You should reduce your broadside spacing to 300 feet rather than 320 feet, >your sidelobes will be minimized as a result. Although 320 feet is a good >choice for a transmitting BSEF array (maximum gain), 300 feet is a better >choice for a receiving BSEF array (minimum sidelobes). > >I'll be pleased to answer any specific questions about my BSEF receiving >array implementation. The three photos pretty well cover everything I could >possibly tell you. > >73 >Frank >W3LPL > > > > > >---- Original message ---- >>Date: Sat, 2 Feb 2013 10:51:52 -0500 >>From: "Larry - K1UO" <[email protected]> >>Subject: BSEF >>To: <[email protected]> >> >> Hi Frank, >> >> I read with interest your comments on the new BSEF array >> there. My experiments with a 70X320 BS/EF array with 20ft >> Hi-Z type verticals was short lived since strong winds toppled >> trees directly on top of 2 of the verticals!! The direction I >> am aimed is favoring Africa one way and the North Pacific the >> other (switchable). >> I will be rebuilding them to 24ft verticals with fiberglass >> rod insulated bases (less pf) and trying it once againSmile >> Initial results were comparable to a small broadside phased >> Beverage array here but that was without any tweaking of the >> phasing and of course directions were not exactly the same. >> What phasing arrangement did you employ? >> >> 73 and congratulations >> >> Larry K1UO > > _________________ Topband Reflector
