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Gotta roof? Use it! If you own your dwelling unit
(or have way cool landspeople as i do (props
to Tom & Barbara!)), you have no excuse! There's probably an existing TV
antenna cold chillin'; up there doing
nothing.
My Aim is True
Step one: turn it so it faces the Cyclotron (round building) and/or
the Lawrence Hall of Science in the Berkeley
Hills. The KALX tower is not painted and has no lights (the lighted tower
with dishes on the top is other UC stuff, and the
other lighted tower southbound is KPFA).
Step two: tighten it in its new position, find/fix/replace the
lead-in wire, and hightail it to yer receiver/tuner. You may be amaaaazed what even a rusty rooftop TV antenna can
do.
Speaking of aiming, remember: FM is great, but it's weird.
Sometimes you'll get better sound
pointed not quite at yer target, occasionally even 60-70° off. Since
you're already a nonconformist, don't
be shy about tilting the antenna front up or down (zenith adjust), or even
adjusting azimuthally, if this helps.
If possible, run a veryveryveryvery long headphone cable up to the
rooftop antenna, and listen whilst you twist, or see
about installing a rotator (bringing the receiver to
the roof negates the lead-in wiring, and may
produce deceptive results. Wireless headphones will add their own reception
problems to the mix, confounding
everything).
If you're presently using a rooftop configuration you inherited
from someone else, you're
disappointed with its performance, and you haven't personally inspected
roofland nor participated beyond sticking the
wire into the tuner, beware the following: FM traps, corrosion, broken
connections, aimed incorrectly, wrong cable. Despite
previous comments, clean, intact rooftop antennas
outperform rusty/corroded/broken ones. Though
you could get busy w/the steel wool, it's probably best to start with a new unit, complete
with state-o'-art oxidation reduction protection. Similarly, unless the
cabling is high-grade coaxial, start afresh. You may also need transformers to match 75 ohm coaxial
cable to a (typically) 300 ohm antenna, and possibly the receiver (consult
yer owner's manual or local audio guru if in
doubt). Aim per the preceding paragraph, and watch out for those pesky FM
traps! See, some wacky humans actually
want to watch television, and sometimes a powerful FM
radio broadcast station will interfere, and
ruin their pickypix. Those clever TV antenna guys'll install a filter (FM
Trap) at the antenna, in the
antenna (especially Winegards), or at the TV set. Some impedance matching
transformers include an FM Trap (they usually
will proudly declare such is the case on their housing). Since the trap's
job description is to dump as much 88-108
MHz as possible, needless to say you won't get optimum FM reception with
one of these in the line. Make it go
away.
If there isn't anything usable up there, or if you want the
absolute best sound you can possibly get, buy a
brand-new FM-only rooftop antenna, and new "lead-in"
wire. Although nearly
anything on the roof will beat anything in the house, get the biggest,
longest "deep fringe" antenna you can
afford, even if you live in Berkeley. Over the last 25 years, the best
brands have been Channel Master and Winegard. Here i
must reiterate my utter amazement at how little respect FM radio garners, and how difficult it has become to find what no FM
radio home should be without: a top-notch rooftop antenna with rotator. In
the process of obtaining current prices in June
1995 for a setup identical to what i've been using since 1986, i find
prices half again more than '86, and the
rotator company of choice out of business. Folks, do what you want, but if
enough of you don't start taking this
seriously, you won't have the choice of having near-CD quality
"underground" radio for oh, say another
decade, 'til digital radio drops, KALX goes digital, and you drop a few
Benjies on your newflimsyfangled offshore
digital receiver with the incomprehensible owner's manual, destined to
break within two years.... Your author has no
stake in any manufacturer nor retailer of antenna-related paraphenalia, and
i've got mine, so
doowhatchalike, but be forewarned: this may be your last chance for clear
sound on the music you like for quite some time.
Don't accept crap--insist on known quality.
I bought a top-of-the line Channel Master model 4408 in 1986 for
under $60. In the mid-90s
it's become the 3025, with a suggested list of (all prices US)$90.09,
though Pacific Valley in Dublin, CA @ (510) 829-
5960 (voice) has 'em for $80.12. It's big, sorta phallic & ugly, but i get
KALX with
no noise all the time in my rented
natural habitat here in Albany, and get
Napa, Cupertino and beyond quite listenably.
Any antenna of this type is highly directional (to block out other
unwanted stations on the same frequency, and
multipath "bounce" signals of the station you want), and requires a
rotation mechanism (unless you
never listen to anything besides KALX!).
If you're really a fabrication wizard, perhaps you'll make your own
rotation scheme. Most of us will
buy an electric antenna rotator. Simple concept: motor on pole turns
antenna, box in house controls motor. Not so simple to
do well--many cheap rotators stop dead in their tracks in just a few years.
And what happens when the wind changes
direction?
Look for motors housed in metal, preferably bare galvanized
aluminum. The Lance LC100A (formerly Alliance)
continues to serve well, despite many gnarly storms ($56 in 1986).
Unfortunately, you can't buy one new today, as the
company bit it around the turn of the decade. You could try the Channel
Master 9510 at $62.50 (Pacific Valley), though i
suspect it won't last long. If time is more valuable to you than penny
squeezing, head to your local ham shack (Ham Radio Outlet, The Big Oaktown, CA (510)
534-5757 and U.S. nationwide),
explain what you are doing, and walk out with one of their light-duty
models (what is extra-heavy-duty in the TV antenna
world becomes light-duty in the ham radio world), such as the Hy-Gain AR-40
@ $199.95, or the Yaesu G-500 @ $299.95.
Disclaimer: the author has never seen nor used
these or similar models. They are probably overkill, but in the mid-90s it
looks like you get overkill or
crap.
Since the typical KALX listener is good with
her/his hands, and doesn't enjoy
spending this kind of money (except, perhaps, at Amoeba or Mod Lang...),
Sonic suggests revisiting the homebrew approach,
or (better) scouring garage sales, Salvation Army, Goodwill, Urban Ore, etc. for used
antenna rotators. Buy early and buy
often.
Keep in mind that the rotator system consists of the motor box up
on the roof, special cable (usually 4 wires), and
a control box in the house. While the cable can be almost anything 18ga. or
bigger with the correct number of conductors and
hookup, the box must match the motor, unless you're a real hotshot (in
which case you wouldn't be reading
this). So get the motor and box together, or pay no more than $1, and keep
looking for the missing piece(s). Electronics studs
may be successful making their own control box (go all the way: link it to
your digital tuner presets to automatically rotate to
the current station, after a time delay {the motors aren't rated for
continuous duty}).

A top-notch antenna needs top-notch cabling. Don't even think about
using anything unshielded (e.g.
"twinlead"). I chose what the cable installers use(d): Belden 9114 Duobond
II CATV Coax (just ask for Belden
9114). This is a premium low-loss 75 ohm coaxial shielded cable specially
designed to carry TV/FM signals without mucking
them up, and you can actually still buy it these days ($99/1000' @ Pacific
Valley, and it's still state of the art. The
smallest box is probably 500', so you may need to go in with a friend, or
find a philanthropic CATV installer).
Many antennas (such as the 4408/3025) are 300
ohm, so you'll need a matching
transformer
(sometimes called a "balun"), to convert the 300 ohm antenna signal to a 75
ohm signal that the cable knows
how to carry. If your tuner/receiver has 75 ohm connections, connect the
coax cable directly there, otherwise you'll
need a second matching transformer for the receiver end. Some folks claim
RMS brand matching transformers lose less
signal--i don't know--they work for me.
You will also need assorted poles, mounting brackets, nuts, bolts,
and other goodies specific to your installation,
especially if there's no old TV antenna to evict. To figure out your
particular hardware requirements, consult a do-it-
yourownbadself book, or find sympathetic (and hopefully cheap) expertise
(my rate is $1 a minute). Antennae, rotators, and
relevant hardware are still barely available at well-stocked TV shops and
electronics stores. You will probably not be able to
get everything under one roof unless you opt for inferior brands/models.
Phone around, and beware of saleslime pushing the
brand they happen to sell....
When time matters more than money...
If you're really well-to-do or don't enjoy hanging out on the roof,
pay through the nose for someone
to do all this for you--it's worth it if you love radio. By the by, if
you're one of those aforementioned wacky
vidkid humans, all the above will getcha great off-air video too, if you
substitute a mondo-big VHF/UHF/FM antenna (i use a
Channel Master Quantum 1160A, and get Monterey & Sacramento on T.V.--with
snow), and throw in a signal splitter (NO
FM TRAPS!!-watch out!-many splitters have them).
If you twitched at every price listing above, and/or spend more on
each album purchase than the current value of
any component in your music system, stay put--there's hope...*if* you are
good with your hands and other tools, and
have lots more spare time than money. 30+ years of experience and 4 years
of U.C. Electrical Engineering have led me to the
following conjecturative conclusion: when it comes to making antennas, no
one really knows what they're doing. Sure,
there's a lot they do know, but it seems
to be more experimentation
and art than science. Whether or not the preceding statement has any
validity, this one does: no one
knows for sure what kind of antenna apparatus will work best/o.k./at all in
your domicile. No one. The world's top
experts would have a darn tootin'; good idea, but unless they've been to
your house, they can't be certain
(and if they've been to your house, why are you reading
this?). Any world's top
experts who happen across this article are implored to contact the author
at their earliest convenience...share your wisdom
with the world--we want to learn more!
Just about every VHF receiving antenna i've ever seen is based on
the dipole.
The standard 'T' antenna is a pure folded dipole,
optimized for the center of the FM band. To make
yer own folded dipole, get some '300 ohm twinlead' antenna wire
and follow fig. 1, or just go buy one for a
couple of bucks (if you don't already have one). Fancier antennas
(higher signal sucking and more directional) add
smaller elements in front (called directors) and/or bigger
elements in back (reflectors).
Certified technoweenies may wish to stroll around the Index of
/pub/dx/text/antennas/, consult the A.R.R.L. Antenna
Handbook, any of a number of communications textbooks, and/or back issues
of electronics magazines (i.e. Oct.
'75 Popular Electronics, p. 58-60)--normal people needn't bother.
Go ahead--what are you waiting for? Grab some wire (electrical,
coat hanger,...) and/or chunks of metal
(factory antennas are made of aluminum [or alloy] tubing with
weather-resistant coatings), string 'em together and see
what you get! Rig up yer own rotation arrangement (or buy one) and hoist it aloft! Nothing is too
outrageous if it's not a safety hazard and it works. And no one says it
has to be on the
roof....
Some Utah school of higher learning (whos contact information
i have diligently cast away to the bit
recycling netherworld) offers a course El En 554 -- ANTENNAS AND
WAVEGUIDES, which uses the following texts:
- Stutzman, Antenna Theory and Design, John Wiley, 1981.
- Lee, Principles of Antenna Theory, John Wiley, 1984.
- Balanis, Antenna Theory: Analysis and Design, Harper and Row, 1982.
- Johnson and Jasik, Antenna Engineering Handbook, McGraw-Hill, 1984.
- Jordan and Balmain, Electromagnetic Waves and Radiating Systems,
Prentice Hall, 1968.
- Gandhi, Microwave Engineering and Applications, Pergamon Press, 1981.
Obviously, yours truly has neither benefitted from reading any of them, nor
taking El En 554, but there's still hope for
you. return
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