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EAntenna VHF and UHF Dual Band Yagi EA270ZB13 Great for Sats

Discussion in 'Amateur Radio Equipment Reviews' started by N0AN, Jun 27, 2019.

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  1. N0AN

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    This is a 2m and 70cm small yagi consisting of 5 Elements on 2m and 8 Elements on 70cm, for a claimed gain of 10 dBi. Boom Length is just about 5 feet and power rating is 500w. There are no active components or transformers/duplexers at the antenna, so I have no idea why the power rating.

    It is an unusual, but not unknown, single element feed designed by DK7ZB. The 2m driven element is also the 70cm driven element. The manual states:

    "Covers 144 to 146 MHz and 420 to 440 MHz, which is the entire band in Europe. In the USA they are suitable for use on SSB, CW, digital and satellite as a horizontally polarized antenna. They will NOT function for the American FM Simplex and Repeater band sections of 146 - 148 MHz and 440 -450 MHz."

    This is a bit misleading. The antenna works fine with either polarization. In fact, I am using it in vertical polarization. What I think they intended to say is it will not work well above 146 MHz or above 440 MHz, period. I amusing 145.700 and 435.1 or so. Basically for the satellite uplink (70cm) nd downlink (2m).

    Mechanical:

    Solid Construction, Easy to Assemble if you have the right tools (7 mm thin socket a big help). Pay close attention to the element lengths, as they DO NOT get smaller back to front on 70 cm side.

    Keep pigtail coax for feed as short as possible (one inch or less of leads), or you will lower the resonant freq of the antenna. I also put 5 ferrite snap-on chokes at the feedpoint and supported the coax about 1/2" above the boom (to keep the ferrites from touching the boom). I used LMR-400 Utra-Flex for the pigtail coax feed. This is not required, but I like a choke feed on an antenna like this.

    Performance:

    SWR in House varied all over the place, but I could find places to point antenna where SWR would be 1.1 to 1 on 2m and 1.5 : 1 on 70 cm.

    On top of tower, fixed 15 deg elevation, vertically polarized on 1.5" diameter fiberglass cross boom. Mounted about 5 feet above a 6M LFA 5 EL Yagi

    2m: 1.5 : 1 at 145.700
    70cm: 1.1 : 1 at 435.500

    Performance:

    Outstanding! 12 to 15 dB stronger receive signals on 2m from the satellites compared to an M2 2m Eggbeater at 7' Keep in mind the differences in the two setups, especially the height avoiding obstructions and vegetation losses.

    Reference Existing Setup:
    EggBeater @ 7' > 2/70cm Duplexer > Common Ouput from Duplexer > 60' of 9913 Coax > 2/70cm Duplexer > ARR 2m Gasfet > FunCube Pro+ SDR

    New Setup with EAntenna 2m 5 EL, 70cm 8 EL @ 65'

    New Yagi > 15' LMR-400 UF > 80' of 1/2" hardline > 2/70cm Duplexer > 2m output port > 2nd Duplexer input (acts as filter to prevent desense/intermod) > 2m 2nd Duplexer output to ARR 2m Gasfet > FunCube Pro+ SDR

    Comparison readings taken in dBm directly from SDR Console v. 3.x software.

    I now hear every bird at 0.1 deg Elevation at AOS. This includes CAS-4A, 4B, XW-2A, 2B, 2C, 2F, AO-91, AO-92

    A big plus: it receives NOAA wx birds at 137.xxx beautifully. I get perfect wx image recordings at any elevation > 3 degrees! (NOAA-15,18,19)

    I am using an ARR 2m Gasfet Preamp in the shack, which also works well on the Wx Sats.

    Transmit on 70cm into Satellite Uplinks:

    I used to have to wait until > 30 deg EL to get a signal into the birds due to vegetation losses which are very bad on 70cm. Now I have a Q5 signal 10 dB out of the noise at 0.1 deg Elevation on all birds.

    Summary:

    This is an EXCELLENT satellite antenna. Be sure to use duplexers to prevent your uplink RF from getting into your 2m downlink. This is NOT an option. In my case I had to stack 2 duplexers back to back to get enough filtering to keep the 70cm uplink from overloading the 2m downlink. Duplexers by Comet work VERY well. Since the antenna has only a single feedpoint for both bands, you WILL need the duplexers in the shack to act as bandpass filters.

    I now have an exceptional satellite setup. 15 degree fixed elevation, vertical polarization and computer controlled Azimuth. Works well for 95% of all passes of all LEO birds and saves the money and wear and tear of an elevation rotor. See Web Article by Bob Bruninga, WB4APR for details of the 15 degree fixed EL approach.


    73, N0AN
     

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