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Foundations of Amateur Radio - Episode 117

Discussion in 'Amateur Radio News' started by VK6FLAB, Aug 31, 2017.

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  1. VK6FLAB

    VK6FLAB Ham Member QRZ Page

    foundations-of-amateur-radio_300.jpg
    Which antenna should I get first?

    Building an antenna can be very rewarding but also very frustrating. Similarly, buying an antenna is no guarantee for success. This happens because every environment is different and many combinations of antenna and location are doomed before you start.

    Foundations of Amateur Radio is a weekly podcast about the 1000 hobbies that make our community. You can listen on-air, on-line or on-demand. Get your own personal copy from the website at http://podcasts.itmaze.com.au/foundations/, or search for my callsign VK6FLAB on iTunes, Google, or your personal podcast directory for your weekly fix.

    Onno VK6FLAB
     
    KF0G and KK6JKC like this.
  2. KE0EYJ

    KE0EYJ Ham Member QRZ Page

    Best advice I can give new ops:

    1. Get as high as you can, and above everything else around you
    2. If you cannot get higher, BUY higher -- purchase a tall vertical, or something like a 12mHD Spiderbeam fiberglass pole (if you're making your own antennas). A tower is better, but... yeah..
    3. Stick to resonant antennas, when possible
    4. Ladder line all of the way, from feedpoint to the tuner, turns non-resonant dipoles into doublets -- something much more useful, at very low loss, and on multiple bands.
    5. Avoid compromise antennas, unless you have no other choice. Examples: Endfeds, thin-radiator Mag Loops, very short verticals with coils.
    6. Stop arguing about G5RV, OCF Dipoles, Bazookas, etc... they all pale in comparison to a 2-el beam, which is surprisingly simple to build, and is 80% of the way to a 3-el beam costing a lot of money. If you want simple wire design ideas, I'd be glad to help. Nothing... NOTHING has made my radio hobby more fun than building my own 2-el wire beams out of cheap wire, PVC joints, and some $10 each fiberglass crappie poles.

    8. Ask questions in the QRZ antenna forum.
    9. Learn about "greyline propagation" and how to use VOACAP. You can't enjoy DX if you're not on the air when the DX is coming in.

    Combine a few of these basic things, and you'll do well.
     
    Last edited: Sep 2, 2017
    KK5R, VE2CYV, VK4SDD and 1 other person like this.
  3. KG5THG

    KG5THG XML Subscriber QRZ Page

    I'm new to the hobby and one thing I recommend before you do anything with antennas is get a good antenna analyzer that fits the bands you will use. I only use HF so I have an aa-54. Best money I spent outside of a spool of home depot 12 awg wire to make antennas with. You can look at my qrz log to see how far little dipole(s) 21 feet off the ground will take you. You don't even have to have space to to spread them out properly. My 30, 40 and 80 are bent from horizontal to vertical (looks like a big staple hanging there) as that's all the room I have. The 80 has loaded coils (14 awg wrapped around 1 1/2 inch pvc) stuck 10 feet from either side of the dipole balun) just to bring its length down so it hangs about the same as the 30 meter. If you don't have a lot of room, don't worry. In the end, no matter what you do, have fun! (I'm going to have to look at this home made 2-el beam that KE0EYJ mentioned. Sounds like fun to build!)
     
    KE0EYJ, AF4RK, VE3LDJ and 1 other person like this.
  4. ON3VC

    ON3VC Ham Member QRZ Page

    funny you mention the antenna analyser: this week I realised that that was what really is missing in my shack
    Building antennas really is fun and rewarding!
     
    KE0EYJ, KF0G and KK5JY like this.
  5. DU3LA

    DU3LA Ham Member QRZ Page

    You cannot beat a 1/2wave dipole up 1/2 wave!
    It is the best bang for the buck, hears better and has gain over a 1/4 wave vertical!
    A 2EL yagi is the best bang for the buck for Yagi antennas.
    DK7ZB has outstanding info on 2el yagis.
    http://www.qsl.net/dk7zb/2-Ele-Kurzwelle/2-Ele-details.htm
     
    Last edited: Sep 3, 2017
    AF4RK, KE0EYJ, VK4SDD and 1 other person like this.
  6. OH2FFY

    OH2FFY Subscriber QRZ Page

    For the most part the podcast was good .. but then there was this statement ...''there really isn't a substitute for trial and error.''

    Actually this isn't so.
    This is a statement that is often said when a Ham fails at something , usually accompanied by ,, ''its all part of the fun'', or ''its all about experimenting'' , or ''its just Ham Radio''.

    Professional broadcast antenna engineers don't install a mast or transmitter site , then stand back and say - ''there really isn't a substitute for trial and error.''
    This is something that WE say to sooth the pain of failure.

    The problem is that many Hams do not understand the way that antennas work and the requirements that they have in order to work correctly.
    In turn they do stupid things ,, like placing verticals in their backyard at ground level , and wonder , why am I QRMing my neighbor , and why is his damn TV giving me so much noise.
    Or we put a 40 meter band dipole up at several meters in a tree and wonder why we only get short range local contacts - - that is when Hams blame the bad propagation.

    The first step in selecting the right antenna is to honestly evaluate our install location.
    The fact is that on HF most suburban Hams will never make a decent signal without a tower and a beam to get above to local noise and obstacles.
    In some places it may be impossible to erect a antenna that is effective - if Hams don't like that reality - MOVE , or forget about HF and go with bands that allows smaller antennas that are easier to fit into a small yard or rooftop locations.

    One danger new Ham's can make is spending too much time reading stuff on the Internet as most source of what we think it technical information , is merely opinion.

    Take a look at commercial antenna installations and see how and why they have done what they have.
    They will give you more useful information than 100 web pages of other Hams that too are making mistakes one after another , and then saying - ''there really isn't a substitute for trial and error.''


    gregw:) OH2FFY
     
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  7. MD6YAU

    MD6YAU XML Subscriber QRZ Page

    Sometimes you get lucky without a tower or beam, I live in a semi-suburban area and have only a small yard. My resonant wire dipole is only about 1/4 wavelength above the ground on a makeshift pole guyed by ratchet straps, but the noise floor is low and I've been making transatlantic contacts on 10 watts on 20 meters.
     
    KK5R likes this.
  8. VK6APZ

    VK6APZ Premium Subscriber QRZ Page

    Yes its amazing what you can do with very simple antennas, like tonight i worked KK6ZM 0n 80 mtrs in my mobile using a 9 ft stainless steel vertical on my
    Codan 9350 Auto tune antenna.
    Distance short path 927o miles or 14918 km. For digital modes you don't need big antennas like you need for low band ssb DX.

    VK6APZ Peter.
     
    VK6NSB likes this.
  9. KM4DYX

    KM4DYX XML Subscriber QRZ Page

    Good call on the analyzer; best money I spent in the hobby so far. I have as much fun with that thing as I do my rig.

    I recently constructed a wire Inverted V with reflector. Could really tell the difference in gain.

    A center insulator, a piece of coax, a spool of wire from the hardware store, a wire cutter/stripper tool, some cordage, and an antenna analyzer and you can play antenna forever.

    (You don't "need" a center insulator - but if you want to maximize the fun and try mucho different antennas then you sure will want one.)

    73,
    Al
     
  10. OH2FFY

    OH2FFY Subscriber QRZ Page


    An antenna analyzer is a tool , much like a screwdriver is a tool.
    Having a screwdriver doesn't make a person a carpenter and having an antenna analyzer doesn't make a person an antenna expert.


    It is the person using the tool what makes the difference and is where most of the skill is involved.

    An antenna analyzer CAN help , but it can also be of no help.
    Antenna analyzers give no direct indication as to the efficiency of an antenna , and certainly , it is possible to build an antenna that looks perfect on the analyzer , yet be completely useless.

    Without understanding the requirements of an antenna , a Ham will find an analyzer of little help , and may even lead him to false conclusions and in turn disappointment.

    Education first , analyzer second.


    gregW:) OH2FFY
     

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