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DX reciprocity?

Discussion in 'General Technical Questions and Answers' started by Pushraft, Nov 20, 2008.

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  1. G3TXQ

    G3TXQ Ham Member QRZ Page

    Push, you pose a very simplistic model, but fundamentally you are right. Let me put it more generally this way - the deficiencies in the station at one end of the link can be compensated by better performance at the other end of the link.

    But there is no "binary" answer to your question. If you'd ever experienced 10m operation at the peak of the sunspot cycle you'd know that you can easily work all round the world with low power and a mediocre antenna to similar stations. Whereas under the worst propagation conditions you may only be able to work "big gun" stations who are "doing most of the work at their end of the link". Using one of the more power-efficient modes like CW, or some other digital mode can help of course.

    So, yes, your setup can work. And you've got about 5 years to get your "ticket" if you want to enjoy the next sunspot maximum ;)

  2. K7MH

    K7MH XML Subscriber QRZ Page

    The "big gun" is doing all the work. You are a peanut. Because of his big antenna and other stuff, he will probably hear you ok and you will certainly hear him given proper conditions anyway. BUT, (and this is a big but) the guy next door to the big gun with an attic antenna like yours may not hear you at all and you wouldn't hear him very likely either unless conditions were very favorable. But it does depend. on several variables.

    Push, you expect a lot from formulas and stuff like that. Looking for exacting answers that are just not there to a large degree. A lot in the amateur radio world "just depends". This is not a concrete world like mathematics. Some of it is based on it, but not much DEPENDS on it. Much like music or painting. I play guitar well but can't read charts, don't know any theory and half the time couldn't tell you what key I am in. In the rock world, that is not uncommon. You would seem to be more for paint by numbers. It's not like building a 350 Chevy engine from stock parts that will only go together and run if put together one way more or less.
    You can want it to be that way all you want but it isn't. To you, knowing ahead of time what to expect is the thing. For many of us, it is not knowing what to expect that is exciting. Kind of like us going fishing while you head for the fish counter at the grocery store.
  3. W8ZNX

    W8ZNX Ham Member QRZ Page


    Pushcraft's questions are a trap

    waiting for anybody
    that wanders past wishing to help

    answer the question
    traps you
    in Pushcrafts " Tar Baby of Logic "

    you answer the question
    the question is changed
    you answer the question
    the question is changed
    you answer the question
    the question is changed

    till entropy causes the universe to grow cold

    read or die
  4. Pushraft

    Pushraft Banned

    I am glad it is this way. Someone who erects a large antenna 100 ft up and spends big $ is effectively tweaking my (free) attic dipole. If the only way I could hear people would be for me to erect a large expensive antenna too, I would have long been gone looking for another hobby.

    Also, how can it be that a band such as 10m can be used to talk around the world then at other times it is dead?

    What if two hams are in the same town and want to talk locally let's say 10 miles. Do they have to switch to antennas that favor ground wave or can they continue using their "big gun" antenna?

    If I cant find a solution to my noise issue for my attic dipole, there isn't much point to me getting licensed because many of the conversations I hear are R4 on one end and R1 or R2 on the other. Will one of those external DSP speakers help me at all?

    Very rarely do I hear both parties. That would mean even if I do get licensed, I would probably only be able to talk to a few "big guns". I actually looked up a few callsigns of people I heard and sure enough, they have some big a** antennas. So far the farthest callsign I was able to grab was in WA from here in FL and that was during the Nov contest weekend. That guy was about R3 with some fading.

    Is there anything I can do to an attic dipole to make it quieter? Does it matter much if it is high in the center and the legs droop a little? Should I try "stretching" it so that all 33 ft if it are in a straight line or close to it? Sometimes it is so noisy my rig actually sounds better if I disconnect one leg of the antenna by removing the shield connection to the rig and only using the center connector. That is how bad it is sometimes.
  5. Pushraft

    Pushraft Banned

    Well put yourself in my "shoes". If all you could erect was a 20m dipole and maybe some lower bands like 15m, 10m by "fanning" the dipole or maybe a 40m attic loop, would you be excited about this hobby or kinda lackluster like me? I like listening in but the noise sometimes is very annoying. I even try turning off everything electrical but that doesnt help. Is there anything I can do? How about those DSP speakers will those help? It is a Yaesu rig. Sometimes when the noise level is low and the condition are right, I can hear WWV in Colorado at almost full quieting on AM. That is about 1500 miles land from me and maybe 2000 miles if you include skip(s). So the antenna is working it is just noisy a lot.

    Thank you.
  6. K7MH

    K7MH XML Subscriber QRZ Page

    Yeah I know. Been obvious for quite sometime now.
    Don't worry Mac. I am just bored.
  7. KJ4AUR

    KJ4AUR Ham Member QRZ Page

    Removed May 07, 2009
    Last edited: May 7, 2009
  8. W8ZNX

    W8ZNX Ham Member QRZ Page

    i know
    its like a car wreck on the side of the road
    you know you should not slow down to look
    but you do anyways

  9. K7MH

    K7MH XML Subscriber QRZ Page

    More like a train wreck with us QRZ'ers laying about!! :D:D:D
    Pretty painful really!
    I guess we are always hopeful that the little grain of wheat bulb
    will come on!! :rolleyes:
  10. M3KXZ

    M3KXZ Ham Member QRZ Page

    My confusion. I was looking at a vertical over a single wire counterpoise and over a vehicle body when not mounted centrally. Tilting in those cases does, in theory, have an impact on the groundwave RF.
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