[CQ] city antennas

[AF6MQ]

if your roof is fairly flat and accessable to all of it,
and if you could cover it with a "blanket" of wires,
or chicken wire, or lots of ground radial type idea,
then a mobile HF vertical like a screwdriver,
or a "hamstick", or a "buddypole", or any coil-loade vertical,
you should be able to do pretty good.

but,
#1, it will be all about the "carpet" of ground.
if you can do chickenwire, and electrically make it "one",
you will have a good signal.
lots of radials from the antenna base will work to,
the more the better.  vary lengths if you plan to work multi-bands.
make sure they can not go blowing away, and touch power lines.
SF marine layer (fog) is super corrosive, so plan for that too.

#2, any near obstructions like phone poles, buildings,
anything with metal especially, will block or skew your signal.
so if there is already drain pipes or chimneys, 
know that they will play with your field.
can use this to advantage for direction gain if planned.

#3, urban RFI sucks.  you may find some radials behaving
like a beverage pointing right at neighbor plasma tv etc.
nearby power lines, phone lines, all that, makes for
a terrible listening experience.  not to mention
the new digital ballast grow light horror...
you will likely have to "fiddle" a lot to get good RX.
short verticals are the worst for listening,
so a second "random long wire" for RX in the backyard might help.

usual disclaimer about grounding, lightning, ladder falls, etc.

73 de Always Finding 6 More Questions

--.



On Jul 27, 2013, at 10:53 , Drew Smith wrote:

> Hey Noisebridge,
> 
> I'm new to the city, having moved from my live-aboard cruising trimaran in Mexico to take a job at a startup and save some money - we're hoping to circumnavigate, but the whole 'working over the internet' thing sucks when the internet is a scarce commodity. So, two or three years here, then I'm out.
> 
> I brought the boat ham radio though, and a tuner and a power supply. I live in a three-story apartment building in the lower Haight, I'm on the ground floor but I have easy roof access and judging by the rest of the complex nobody complains about wires running up to the roof.
> 
> My *only* experience with ham radio antennas is tuning a backstay on a sailboat, and maybe a bit of handheld stuff. The roof is wide and flat, and there are wires strewn across it - I *might* be able to get away with a short mast, but honestly I have zero experience with this stuff, so please, with any tips, explain the technology to me like I'm five years old. :)
> 
> My question to you folks is simple… what is the best budget antenna rig to build in this situation, including feeding it from my tuner, out the window and up two stories to the roof?
> 
> (radio rig: Icom IC-7000, LDG AT-7000 tuner, Icom power supply)
> 
> Cheers,
> - Drew.
> 
> --
> Drew Smith (mux) <drew at riotnrrd.com>, VA7DSX / VE0TF
> Encrypted e-mail preferred, public key at http://riotnrrd.com/pubkey.gpg
> 
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