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Apartment Hamming

Discussion in 'Becoming an Amateur Radio Operator/Upgrading Privi' started by NC4JB, Apr 21, 2010.

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  1. AB8RO

    AB8RO Ham Member QRZ Page

    Here are the rules of thumb for apartment antennas.

    1) Any antenna beats no antenna

    2) outside beats inside

    3) High beats low

    4) single band beats multiband

    I've had quite a bit of time to ponder what works indoors and, in my experience, if you can't get wire up outside then your best bet is a mag loop.

    I know that this might net me some flak, but, I'll say it anyway. Save your money and just study for the general. Take the tech/general at the same time. It's not that difficult and you will then have many choices to explore.

    A lot of hams in your situation just work portable. Go for a hike, set up an antenna, and make contacts. If you're interested in building, operating can be punctuated by periods of building.

    Edit: I see that you've already decided to take the general the same day. Good idea, you won't regret that decision.
     
  2. NC4JB

    NC4JB Ham Member QRZ Page

    Two questions:

    1. Is it possible to build loop antennas at less than a full wavelength (i.e. 1/4 wavelength for each side of a square loop antenna)? Doing the math, a loop antenna for 80 meters would need to be something like 75ft per side; not really practical inside the average apartment.

    2. Any antenna is better than none, but say I can only have one antenna, would it make sense to assume by designing it to work best on 40 or even 30 meters I could expect to get reasonable (though far from perfect) performance out of it on all the other HF bands?

    I can already see this thread getting moved to the antenna forums very soon... :p
     
  3. K0RGR

    K0RGR Premium Subscriber QRZ Page

    You need to look at the RF exposure charts a bit more.

    The only bands where you are likely to come close to the MPE are 10, 6, 2 and 220. If you run 50 watts or less on those bands, you aren't even required to do any MPE calculations. 50 watts on those bands is plenty most of the time.
    On the lower HF bands, if you are running 100 watts or less, you don't even need to make an evaluation. With 100 watts on 10 meters, you could be violating the guidelines with an indoor antenna that's close to people, either you, or the people in the apartments around you. But even then, your power is averaged over a period of time, and the duty cycle for SSB is quite low, so you would probably still be in compliance.

    There are ways to make full sized loops smaller. The Maltese or Pfeiffer Quad pulls the corners of the loop into the middle. http://pages.cthome.net/ampfeiffer/pfeiffer%20quad%20antenna%20system.pdf I did this with a 40 meter loop, reducing it in size by about 40%, with no apparent loss of performance.

    A full sized 40 meter loop will work on all it's harmonics - 40,20,15, and 10.
    If you cut it for around 5 Mhz. and feed it with open wire line to a manual tuner or place a tuner right at the feed point, it should cover 80 meters and all higher bands.

    Now, for apartment use, one of the hi-Q magnetic loops should work well, but they require retuning every time you change frequencies. MFJ markets two of them, and also sells a line of tuners designed to work with loops of your own construction. http://www.g4ilo.com/mfj-magnetic-loop.html
    Be aware that these small loops only work over a restricted set of bands. The two MFJ loops cover 40-15 or 30-10 meters. That would be a tough decision for me, particularly since they aren't cheap. I guess the consolation would be that it is easy to fit a full sized 10 meter antenna in an apartment.

    Before investing in any indoor antenna, string up some wire and see what you can actually hear with it. You may discover that your house is a great radio shield, and no antenna will have much chance.
     
  4. NC4JB

    NC4JB Ham Member QRZ Page

    Sat for and passed Tech (35/35) and General (33/35) today. VE told me to expect to see my call sign in the database sometime tomorrow. They practically begged me to sit for Extra but I haven't even taken a practice test for that yet, so I declined. Can't wait to see you all on the air! =)
     
  5. W2TXB

    W2TXB Ham Member QRZ Page

    Congrats on the new (imminent) General Class license! :D Taking the Extra just for the fun of it may have been interesting and educational, but right now your batting average is perfect. ;) Time for the Extra exam later on.

    I have a Super Antennas MP-1 here and have used it indoors with a Yaesu FT-817ND, and the results have not been too bad (much better outdoors), although I have not yet spent a lot of time with that setup. I will say that, while it is challenging, QRP is a lot of fun. Success depends largely upon patience and a decent antenna.

    A HT can work out well (as others have posted) if you are sufficiently near some repeaters, but that is an individual thing. If you know somebody who can loan you a HT for a short time, you would be able to see for yourself what can be done from your apartment.

    Keep us posted on how it works out for you.
     
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