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Thread: Newbie Ham needs help/info with Yaesu FT991a

  1. #1

    Join Date
    Dec 2017
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    Chilliwack, BC
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    Default Newbie Ham needs help/info with Yaesu FT991a

    Hello everyone, just got my HAM licence & of course I'm feeling a bit green... well I bought an off center dipole 10m - 80m strung out across the yard about 30ft up on the short end - about 40ft. connected to the feed line, the long side sloping to about 20 ft. to an old apple tree, than the last 25ft at offset 80 deg. to an old apricot tree. Then built a dual band 2m & 70cm vertical dipole (the 2m-70m is about 1:1 - 1:2 good match.... Now my question I will hopefully articulate correctly. The meter on the unit has a bar graph with shows signal strength & swr reading on "one graph". How do I know if my swr is low enough to transmit below 2 if the signal strength is reading the static/background noise to a 8 or 9 on the meter.... Or is it because of a high swr??? Now I notice with my RF gain set high on 10m the meter graph with S/SWR reading 1:1 when I turn the RF down the SWR/S meter goes up .... On 20m the RF full the SWR/S bar reads2.5SWR/Signal shows 8 on the graph 40mm is a bit higher. A quick touch on Auto tune gives a tune light than off .... the High SWR light doesn't come on. Conclusion, if the High SWR doesn't come I'm OK?
    How do I know what SWR is if the Sinal strength indicatator bar graph reads the same???

    Would appreciate the help if anyone know what I'm trying to say, thanks for any help / advice with this.
    Yes, so far I really like this radio ... lots to learn on it! 73

    David ..... VE7OPL

  2. #2
    Super Moderator 2E0FVL's Avatar
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    Feb 2010
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    Tangmere, Chichester, West Sussex, United Kingdom
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    Welcome David,
    Bottom left corner of the screen touch tab marked METER press to toggle between PO, SWR and I think ALC.
    Enjoy.
    Pete - 2EFVL
    The QRM Formally Known As M6PAP!!
    www.selseylifeboats.co.uk
    www.amberleymuseum.co.uk

  3. #3

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    SWR only shows during transmit. If too high of swr, then just above the meter where it says tuner when you press the tuner button, it will say "High SWR". To use the tuner you quick press the tuner button to turn it on, then you hold the tuner button in for a second or two to activate the tune cycle. You will hear the relays clicking as it tunes. Hope that helps


    Sent from my iPhone using Tapatalk

  4. #4

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    I think that a lot of people gets confused between SWR - Standing Wave Ratio and VSWR - Voltage Standing Wave Ratio.

    All we are concerned with is the VOLTAGE.

    How much power is at the radio end and how much voltage is at the antenna end.

    A person shouldn't even transmit unless they own a good SWR meter...

    Might I suggest that you invest in a Diamond SX600 - that will give you enough headroom to transmit with less than 200 watts from 1.6 Mhz to 500 Mhz.

    To answer your question - when you increase your power, you increase your voltage.
    When the voltage is increased, the apparent VSWR also goes up.
    This is why you should always check VSWR at the lowest power level first.

    If the antenna is resonant - purely resistive, 50 Ohms J -0, then all the power applied at the feed point is absorbed by the load and is radiated.
    Anything not radiated is reflected back towards the source - Generator ( what you call a radio).

    Regardless of how resonant the antenna is - the feed line - ( coax) is always going to be lossy, especially at UHF frequencies.
    As long as the independent meter shows a VSWR of less than 2:1 , then it is safe to transmit into that set up.
    Over 2:1 - a large part of the power generated is wasted - turned into heat.
    Eventually the heat gets to be too much and it burns up something or the ( radio) generator just folds back its power - to protect itself.

    I saw a general mention of your type of antenna, but nothing as to what type of radios you are using or what brand / type of coax you are using!

    It's hard to give good advice when all the variables are unknown...

    Join an amateur radio club, find someone knowledgeable and ask them to be your Elmer.

    It isn't rocket science, but it is Physic's....

  5. #5

    Join Date
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    Chilliwack, BC
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    Thanks everyone for your answers ... cruiser300 thanks for your answer, this is what I needed to know thank you for simple solution. Tried all HF bands up to 80m, all tuned to 1:1

  6. #6

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    Great glad to be of help. I too am very new after a 40 year down period. I also have the FT 991a


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  7. #7

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    Remember that just because your antenna tunes up 1:1, it doesn't necessarily mean it's a good radiator. Even a dummy load will appear to your radio as a 1:1 load.

    Sent from my SM-G950U using Tapatalk

  8. #8

    Join Date
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    Thanks guys for info, got it figured out.

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