SWR

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W9QK, Feb 4, 2021.

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  1. W9QK

    W9QK Platinum Subscriber Platinum Subscriber QRZ Page

    I’m new to the hobby. I’m trying to figure out if I should get a rig expert or a NanoVna to check my antenna. I bought a Wolf River Coils antenna so I would definitely need something to check the SWR as I’m changing bands. I live in an apartment so thats the only vailable option for the limited space. The ceiling in the living room is about 18 feet height so it would be perfect to set up the whip. I know the nano vna has lost of future that I don’t know to use whet but as I develop in the hobby I heard I’ll get more out of the vna once I start getting more active ans learn more. I see there is nano van’s on Amazon for about 60 bucks. Is that the right price for them and any specific brand I need to be looking out for? It’s see there is a big difference in price compare to the rig expert like devices compare to the nano vna. I know nano vna does more stuff but it’s cheaper. I’m confused.
    Thanks in advance for any advice, 73
     
  2. KL7AJ

    KL7AJ Ham Member QRZ Page

    Hi Ozzie...welcome aboard!
    As most of us old geezers believe, if you give a man a fish, you feed him for a day, if you teach a man to fish, you'll feed him for life. So, with that in mind, I'm going to not give you the easy answers, but give you some tantalizing leads that will allow you to figure out the answers for yourself. This way you never forget.
    As Confucius said:
    I hear and I forget
    I see and I remember
    I do and I understand

    With that advice, I'm going to attach just a SMALL excerpt from my article "SWR Meters Make You Stupid", which I trust you will read in its entirety before too long. But to get you started, please ruminate on this excerpt carefully.
    73!
    Eric


    With a few very rare exceptions, the early impoverished radio amateur usually had little if anything that resembled actual test equipment. In fact, most of the diagnostic equipment that modern hams take for granted was not available at any price for much of amateur radio’s existence. This was actually a good thing, for a few reasons:

    1) Amateur radio station performance was based strictly on...well...performance. The only indication that things were working as they should was the fact that one was making a lot of contacts. The lack of test equipment kept the end goal well in sight.

    2) Ham radio was cheaper. Why use an expensive plate current meter when you could check your transmitter’s tuning by seeing how long an R.F. arc you could draw from the final tube’s plate cap to the tip of a lead pencil held in your bare hand? YES! Hams actually DID this...and most lived to tell about it. Cabinet? What cabinet?

    3) You were likely to make a useful accidental discovery from time to time. Theory is great...up to a point. It helps explain what you already discovered by accident, but it doesn’t often lead to new discoveries, at least on its own. You need to get knocked on your keister a few times and singe a few eyebrows to really understand radio. (Don’t tell OSHA I said this, by the way).


    The salient point is that having a lot of “tools” around usually gives you more information than you need to know, and unless you know how to USE that information, it can be worse than ignorance, as we shall shortly see.
     
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  3. WA4SIX

    WA4SIX Ham Member QRZ Page

    There should be an SWR meter built into most modern rigs that should help you find resonance.
    Either of the products you mentioned will help make the job easier.
    Of course, the NANO VNA is the less expensive & will work fine.

    Ed
     
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  4. G8FXC

    G8FXC XML Subscriber QRZ Page

    I don't know the Rig Expert, but I am a NanoVNA user, so here's my take on it...

    The NanoVNA is an amazingly good value device, but it really is not meant to be used in the context you seem to be describing. It is quite a complicated device and a bit tedious to use - it is intended to support the design and initial configuration of a piece of RF equipment (which may include, but is not limited to, antennae). In your post, you say "I would definitely need something to check the SWR as I’m changing bands" - which implies doing this frequently during an operating session. I would not use a NanoVNA in that way - it would simply be too tedious. It is not an "in-line" device that can simply be left in the feeder - you would need to disconnect your antenna from the rig, connect the NanoVNA, check its SWR, make any required adjustments, then remove the NanoVNA and reconnect the rig. Strictly speaking, the NanoVNA should be recalibrated before each measurement to take into account the change in frequency. It really would be a pain to work that way.

    By all means get a NanoVNA to do your initial setup and understand your antennae - they are so cheap that every ham should have one. But for normal day-to-day operation, checking SWR and making minor adjustments, get a reasonably accurate in-line SWR meter.

    Martin (G8FXC)
     
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  5. W9QK

    W9QK Platinum Subscriber Platinum Subscriber QRZ Page

    Well shit!! I’m more confused than it was before. Having too many tools would make me dumber because... I’m learning , I’m not learning by doing or experimenting or something like that...? Thant’s why I never liked Confusius... I’m a simple guy. I’m going to tell you what I told my exwife. All I want is a drink me few beers on Friday, cut the grass on Saturday and watch football on Sundays. The rest it’s just noise. That’s my philosophy in life! All I wanted to know if Im going to benefit more with a nano vna or rig expert on the long run, you know...buy once cry once kinda deal. But thanks for making it a little bit worse. 10-4 good buddy, 73.
     
  6. W9QK

    W9QK Platinum Subscriber Platinum Subscriber QRZ Page

    Thanks for the info. I guess nano would be a better option for what I need and the knowledge I have. All I need is to check SWR when I changed bands with the Wolf River Coil antenna until I start learning where to set up the sleeve for each band for the lowest SWR. I guess as I’m learning and develop in the hobby I can use it for other things but for now SWR is at the top of my ham knowledge.
    Kung fu master over here threw a whole lot of nothing my way, don’t know why, I guess he wanted to be cute. Anyway thanks again for the reply, appreciated, 73.
     
  7. W9QK

    W9QK Platinum Subscriber Platinum Subscriber QRZ Page

    Yeah my radio has a meter but since I’m using it with a Wolf River Coil antenna I would need a way to measure the SWR when I set it up and also when I change bands. Just to make sure I don’t fry the radio when I change bands and what not. Trying to figure out the SWR in those coils without an SWR meter would be really hard, well at least for me since I’m a new ham,73.
     
  8. N1IPU

    N1IPU Ham Member QRZ Page

    I run the comet analyzer with great results. With a big analog meter its simple you get where you need. You can look at some of the remote SWR meters out there also. May come in handy down the road depending on your plans. I tried the nano and it's cheap so my review would be it's cheap.
     
  9. G8FXC

    G8FXC XML Subscriber QRZ Page

    You have not told us what radio you are using, but all modern rigs have protection against high SWR built in. I use a Superantenna MP1 which is very similar in design to your Wolf River and which I use with an ICOM IC-7100 on our boat for maritime mobile operation. I have a broad idea of where it should be set for each band so, when I change bands, I set the coil to the approximate position, drop the output power on the the 7100 and tune using the internal SWR meter. It's a bit tedious the first few times, but it soon becomes easy.

    The NanoVNA is an excellent instrument at an amazingly low price - if your budget will stretch to it, then by all means get one. It probably will pay for itself in a short time since it makes it easy to experiment with DIY antennae rather than pay someone else to cut a piece of wire! But it really is not an appropriate tool to use every time you switch bands.

    Martin (G8FXC)
     
  10. WG7X

    WG7X Platinum Subscriber Platinum Subscriber QRZ Page

    @W9QK

    A couple of points. First, yes, having an antenna analyzer will be very helpful in the initial stages of tuning an antenna.

    Second, Eric @KL7AJ is extremely knowledgeable about ham radio. Take his advice in the spirit in which it is offered.

    Third, Cut the cussing. We've all heard it before and it does not help buttress your arguments!

    Lastly, if you're going to participate here in the discussions you need to grow a bit of thick skin. Don't just fire off a quick nasty gram reply to someone who was just trying to help. That's the surest way to get ignored forever...

    But: I'm sure you already know that, right?
     
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