HF/VHF/UHF attic antenna options for 30'x25' attic?

Discussion in 'General Technical Questions and Answers' started by Pushraft, Oct 23, 2008.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    ::pssst: You don't get it. Puscraft has analysis paralysis. That's a disease, and I'm not kidding. It manifests itself in overanalyzing everything, and thus never really accomplishing anything. I'd just let it go.

    WB2WIK/6
     
  2. G0GQK

    G0GQK Ham Member QRZ Page

    You could try a couple of 50 ohm loops, for 15 metres, long side 16 ft 4 ins, short side 8 ft 1 in, 20 metres, long side 24 ft 5 ins, short side 12 ft 5 ins, as per W6SAI, the other bands put the loop through a tuner.

    Its OK suggesting dipoles but they have to be tuned and a loft space is not the place to mess about tuning dipoles, but if they are brought into resonance with a tuner this will ensure they work well.

    G0GQK
     
  3. G4ILO

    G4ILO Ham Member QRZ Page

    A loft space may not be the nicest environment but no-one ever died falling from their loft space doing antenna adjustments, like they do from towers.

    If you are going to use a tuner it doesn't really matter about adjusting it for perfect SWR, if it's 2:1 or better then the tuner will match it and RF won't notice the difference.

    If you prefer to use a single dipole on multiple bands then that's usually called a doublet. It doesn't matter much what length the elements are as long as they are both equal and not close to a half wavelength on any band. There will be a lot of feeder loss if you try to feed it with co-ax, so if you don't want to mess with open wire feeder and a balanced tuner, just install a remote powered auto ATU of the type made by SGC right at the feedpoint.

    MFJ magnetic loops work well in attics as well, but they won't outperform a dipole, even if the elements are bent into a Z shape, and they cost a lot more.
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    ::You guys are wasting your time.
     
  5. W0IS

    W0IS Ham Member QRZ Page

    I think WB2WIK has it pretty well summed up. You're spending too much time over-analyzing things.

    When I operate from a campground or a motel room, I take a look around, try to figure out the least worst antenna I can put up (without the benefit of an EE degree), and then take five minutes to put it up. Then, I hook up one of my five-watt radios (one of which has exactly four controls, including the on-off switch) and start making contacts. I don't think I've ever been stumped.

    So far, nobody has sent me any food stamps, but if you would like to make a small contribution, my address is available by typing "W0IS" into the little box above and clicking on the "callsign" button.

    If you want to get on the air, you'll do quite well with an attic antenna. The design that I mentioned will work well, and so will the ideas posted by other people. None of these antennas is expensive. You can get all of the needed parts at any hardware store. With a bit of creative thought, you can probably get all of the needed parts at a well-stocked supermarket.

    Most of us don't have giant beam antennas, and most of us don't have EE's.

    None of us can prove that our ideas will work. The only way to find out is to get a license, try one of them, and see what happens.
     
  6. Pushraft

    Pushraft Banned

    Unfortunate HF antenna sizes

    It is unfortunate that the HF antennas are so large. Imagine if UHF had similar DX properties as HF. If that was the case, why would anyone erect huge HF antennas?

    ¿3C￾P>This is one of the hurdles for getting my ticket. I like playing around with antennas but the smaller ones are SO much more manageable. If I got my license and then had to put up an attic HF antenna, in a way I would be going backwards because I am used to using gain UHF antennas. I suppose I would start out on 70cm.

    Another thing that I think deters people from the hobby is the depth of knowledge "required". If a newbie has very shallow knowledge, what would they talk about on the radio? An analogy is a stereo audio system. Many people use them but I suspect very few know how they work internally. People can enjoy their stereos without having to know about impedence, capacitance, phasing, cutting equal length wires... With amateur radio, it is much different.

    I am still trying to figure out what attracts a newbie to the hobby the most. I can see the excitement of making contacts hundreds of miles away that seems like it would be cool. What if the conditions are right one time and I make a contact 200 miles away but those favorable conditions either never return or take a long time to return? I will have made a "friend" but cant talk to him again.

    Also since conditions change rapidly sometimes, how would someone know if the antenna tweak they did improved their signal or if is was just improving conditions that did it? With direct wave I am using it is different. For example, if I talk 2 miles on CB with an omni antenna on a parked vehicle and then quickly erect a phased array and it sounds better in both directions, it seems safe to assume the array made the difference. This doesn't seem like it would be the case with DX. I've read that fading can be severe and since youc ant control the atmosphere, it seems like it would be somewhat frustrating since antenna tuning is only a small part of the results, the rest is somewhat of a "crapshoot".

    I am still having fun with FRS and I even have some old functioning 27 Mhz HTs and a mobile CB as well as my scanner which picks up lots of stuff.
     
  7. W0IS

    W0IS Ham Member QRZ Page

    If you are worried about this potential heartbreaking situation, then you should avoid talking to the guys 200 miles away. As I mentioned above, this particular distance will be within your skip zone for most of the bands that I would recommend starting with.

    If you stick with guys 500 miles away, then you'll be assured of being able to reliably contact them on a daily basis.

    If you are really concerned about sharing your friendship with guys 50-200 miles away, then you will need to put up a loop for 80 meters. Then, you'll also be able to talk to this (literal) circle of friends.
     
  8. Pushraft

    Pushraft Banned

    Sounds like a challenge. I think I will keep taking practice exams and when I am ready, get my general ticket and start simple like a monoband dipole and work my way up to more sophisticated antennas. I am getting much better and confident moving around in the attic so I suppose I would put up a HF antenna.

    Check my other thread for variable length dipole antenna.
     
  9. KA9VQF

    KA9VQF Ham Member QRZ Page

    For me the whole idea of getting a ticket was so I could talk to people all over the world not just the folks in my town, county or even the state.

    I’d already done that with my CB rig. I managed to talk to folks all over the 48 states into Canada even Mexico and Brazil with the legal AM/SSB CB setup I had.

    When I was living in the small northwestern Wisconsin town of Bruce I even made a contact with a fellow who lived in Sussex England once. He sent me a picture of him standing on his thatched roof bungalow pointing at his Star Duster antenna.

    CB contacts that far away were rare especially considering I was not using any extra power. Or even a beam antenna at that time.

    I really wasn’t looking to make lifelong friends with these people but if it worked out that way I was not opposed to it.

    A high school friend of mine moved to Australia shortly after we graduated in 1971. He got his amateur radio license there as soon as he could. Though we have tried to make contact a lot of times since then we still have not managed to accomplish that small thing.

    A lot of licensed hams have gotten licensed for similar reasons and some for other reasons. Any reason is a good one. Even if it is just as a personal status symbol to only you.

    There is little challenge in getting a license any more, the real challenge is working the world especally lately with no solar activity to speak of. Get the ticket now. get a rig and antenna going, and wait {like the rest of us} for the world to open up to you.
     
  10. Pushraft

    Pushraft Banned

    I settled for a 20m dipole going slightly diagonal across my attic. It is working fairly well on 20m however I am trying to reduce the noise. It also seems to work fairly well on 40m and I even heard a powerful amateur station on 80m 1000 miles away using my 20m attic dipole. I am thinking about using a temporary outdoor 80m antenna but I am trying to figure out a way to keep the wire untangled because I will need to roll it up neatly when I am done. Any suggestions?
     
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