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Railfan Technology > MFJ-1866 outdoor discone antenna review.Date: 03/08/17 13:24 MFJ-1866 outdoor discone antenna review. Author: K3HX The MFJ-1866 is a discone antenna. Such antennas are vertically polarized and
are noted for wide bandwidth. These antennas have essentially no gain over a 1/4 wavelength whip but the nominal gain they do have is about the same over a wide range of frequencies. For strictly railfan use, a discone offers no advantage over a 1/4 wavelength whip. For a scanner enthusiast or amateur radio operator - railfan, this antenna is a viable option. The antenna is imported from Taiwan and the hardware is metric. Construction is aluminum top plane and skirt rods into a cast, bright metal plated holder. The connector is a standard SO-239 "UHF" socket. VSWR measurements to 450 MHz. 450 MHz.......2.8:1 VSWR 440 MHz.......2.4:1 VSWR ham radio 420 MHz.......2.0:1 VSWR 220 MHz.......1.7:1 VSWR ham radio 200 MHz.......1.7:1 VSWR 180 MHz.......1.5:1 VSWR 160.89 MHz....1.5:1 VSWR center of US railroad frequencies 162.55 MHz....1.7:1 VSWR NOAA weather broadcasts 144 MHz.......1.7:1 VSWR ham radio 120 MHz.......1.3:1 VSWR 110 MHz.......1.7:1 VSWR 080 MHz and lower very high VSWR Notes: The claim of transmit operation down to 50 MHz is "optimistic." My measurements indicate the antenna becomes poor for transmit below 110 MHz. It will receive some signal down to the claimed 25 MHz low end. So will a straightened wire coathanger. Construction is quite robust as the design uses 8 plane and 8 skirt elements. Usually, consumer level discones "get by" with 4 or 6 elements. The popular "Hustler" discone uses 3 elements. Elements are aluminum, not stainless steel as claimed on the package. The interface between the element end and cast metal holder are press-fitted, threaded, bright- plated steel. The mast clamp u-bolt is stainless steel and requires a 10mm wrench to tighten. The clamp will not fit typical 1.25" "TV mast." Slip a stainless-steel 5/16" nut over each threaded end to act as a spacer and the clamp will grip 1.25" tubing. Assembly tips: You will need a 10 mm wrench for the U-bolt nuts and the holder to tube screw, an 8 mm wrench for the clamp to tube screws and a 6 mm open end wrench for the element to holder interface. You may also need a 10mm nutdriver or socket. One of the skirt elements blocks easy access to the tube-to-element holder screw. It is a simple matter to remove the element, tighten the screw with a 10mm nut driver or socket and replace the skirt element. Do not overtighten the elements or other hardware. Tip: Before assembly, wipe down the elements, tube and clamp with 91% isopropyl alcohol to remove dirt and grease and spray these parts with gloss clear paint. Wait until the antenna is assembled and coax connected before cleaning and painting the element holder. Be sure to follow all electrical code requirements in your area. Operation: It works OK for both railfan and amateur radio use and in my view represents a good value for the @$50 price. Be Well, Tim Colbert K3HX Edited 4 time(s). Last edit at 03/09/17 06:09 by K3HX. Date: 03/08/17 19:06 Re: MFJ-1866 outdoor discone antenna review. Author: wa4umr Good review Tim.
For railfans, a standard whip or ground plain would probable be as good or a better antenna, but if you spend time listening to other services (aircraft, police, military, etc...), this would make a great antenna. It would also work great for ATCS. This would be an antenna to consider for you home location. John Date: 03/09/17 21:38 Re: MFJ-1866 outdoor discone antenna review. Author: tinytrains One thing to keep in mind about discones is you get no band selection off noise. If you are in the boonies they work fine and are quite handy, but in a metropolitin area, all sorts of strong signals and inter-mod will blast through your receiver because the discone receives them all equally. We took them off our emergency ham stations for that reason here in LA.
Do what works for you. 73's Scott, AB6YS Scott Schifer Torrance, CA TinyTrains Website Date: 03/13/17 20:45 Re: MFJ-1866 outdoor discone antenna review. Author: Graybeard1942 re ATCS.....unless you have very short low loss coax, the signal loss over a stub antenna will be great.
Date: 03/20/17 03:26 Re: MFJ-1866 outdoor discone antenna review. Author: ctillnc Finding an affordable discone that's effective on 6 meters is not easy.
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