First HF Antenna?

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This topic contains 5 replies, has 2 voices, and was last updated by  K0NR 1 month, 1 week ago.

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  • #9971

    kc8kpx
    Participant

    Hello,

    I’d like suggestions on what I should purchase as my first HF antenna. I’ve never transmitted in HF and do not own any HF equipment. I’m expecting a Yaesue FT-991a for Christmas but no other equipment. As I have no HF experience, I don’t have a band preference but would like to be able to access as many bands as possible.

    Cordially,

    Rob
    kc8kpx

    #9972

    K0NR
    Participant

    Rob,
    Well that is a very open ended question that triggers a bunch of additional questions.
    What kind of antenna restrictions do you have? Can you put up antennas wherever you want?
    Do you have any tall trees that you can string wire antennas to?

    I’d suggest starting out simple with wire antennas, such as a dipole or half-wave end fed.

    73, Bob K0NR

    #9973

    kc8kpx
    Participant

    Hello Bob,

    Thanks for the reply. I am restricted to a fenced yard that’s ~50ft wide by 20ft deep. I do not have any trees nearby. I’ve been primarily looking at dipole antennas (MFJ-1779C hung between my fence posts or an MFJ-1778M as inverted V). I’ve only just earned my General and Extra this fall and have never used any HF gear before. Santa was kind enough to send me a new FT-991a for Christmas but I still need an antenna and maybe an antenna tuner(?).

    I realize that there’s no silver bullet when it comes to anything. Looking at the market there are just a monumental amount of antennas, antenna tuners, antenna analyzers, towers, grounding setups, antenna configurations, etc. I like the idea of making my own antenna but I’m not familiar with balanced vs. unbalanced antennas, baluns, antenna tuning, antenna analyzers, or the performance I can expect from any particular antenna style.

    Thanks in advance,

    Rob
    kc8kpx

    #9974

    K0NR
    Participant

    Rob,
    The FT-991A is a great little radio. I have the original version (not the “A” model), and love it. The FT-991A has an antenna tuner built in, so that should be sufficient.

    The MFJ-1778 is a G5RV Junior design…I have one of those and its a reasonable choice to cover 40m and up. I’d choose it over the MJF-1779C which does not have 40m coverage. I think having 40m would be very useful given where we are in the sunspot cycle. A basic wire antenna like this is a good way to start out…they work pretty well but don’t cost a lot of $$$.

    I wonder how high up you are going to be able to hang this antenna? Higher is generally better but I’d say the minimum on the G5RV Jr is something like 20 feet at the center (inverted vee configuration).

    Bob K0NR

    #9975

    kc8kpx
    Participant

    Hello Bob,

    I ended up purchasing a Radio Oasis 10m dipole from HRO and installed it in the back yard. Unfortunately, I only have two locations I can install the antenna. The first position accommodates an inverted V with the high point connected to the corner of the back porch roof. The other position has the antenna spread horizontally between fence posts. Using an antenna analyzer (RigExpert AA-35 Zoom), I found that the inverted V had a flat-ish SWR of 3 across the 10m band and the horizontal fence connected configuration had a flat SWR of 5. The antenna advertises an SWR of “Less than 2:1”. The inverted V configuration places the high point of the antenna about 10′ off the ground and the fence configuration places the antenna around 6′ off the ground. From what I’ve found online, the antenna should be at least 1/2 wavelength above the ground (16′). I just don’t have any way to get it up that high at the house I’m living in. Seems like I’m stuck with VHF/UFH until we PCS in May…

    Thanks!

    Rob
    kc8kpx

    #9976

    K0NR
    Participant

    The challenge with 10m right now is that it is not open for long distance communication very often. You’ll have to listen a lot.

    With a basic dipole, you should be able to get a decent SWR across at least part of the band, something like an SWR less than 2. Use your antenna analyzer to check the SWR across a broad range of frequencies, outside the ham band, maybe 26 MHz to 30 MHz to see if the antenna has low SWR anywhere at all.

    Yes, it would be better to have the antenna higher but I think it should work at the height you mentioned. Do you have any large metal objects or wires close to the antenna that may be affecting it?

    Bob

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