Welcome to the fourth exciting, thrill-packed issue of Condo Communicator, a newsletter devoted to those amateurs who, for various reasons, must configure their stations to operate from restrictive areas such as condos, apartments, townhouses, neighborhoods with outdoor antenna restrictions, ships/boats, mobile homes, or wherever they fry their burgers and call QTH.
Hoo, boy, that's a lot of stuff. No wonder this is getting too big to distribute on packet!
Although contributors are the stars of this newsletter, I thought it was about time I put in my two cents worth regarding some RFI experiments I've been tinkering with. Here's one of them.
I ran a simple test this weekend. I dug the old DX-20 out of the closet. Placing it on top of the television, I fed its 30 watts into a dummy load. No matter which band I tuned up on, interference was extremely difficult to detect. However, I did see some loss of color in the picture when the rig was tuned up on 10 meters. From this I concluded that the rig itself was RF tight.
When I hooked up a long, shielded cable between the transmitter and the key, there was a bit more TVI. However, as soon as I carried the transmitter back into the bedroom and connected it to the tuner (which is connected to an artificial ground), tuned up on 20 meters and fed RF to the 20-meter wire loop in the attic, the television set practically exploded on channel 2. There was considerable interference on the other channels as well.
A low-pass filter between the DX-20 and the tuner had no effect. I even replaced the coax between the DX-20 and the low-pass filter with coax that had ferrite beads on it, to no avail. I don't think this is fundamental overload, as the interference doesn't show up on all tv channels with equal ferocity. What do you think is the explanation?
Would you believe you can work the satellites on as little as a quarter watt? Well, you can, though not directly. One way to do it is on packet, using pacsat gateways.
There are a couple of kinds of pacsat gateways that I know of: a live gateway and a bulletin-board gateway.
The live gateway consists of a complete ground satellite system, with OSCAR type antennas for uplinking on 2 meters and downlinking on 70 cm and about 170 watts or more of effective radiated power. Coupled to the radio is a multiport terminal node controller, capable of connections to regular 1200-baud packet signals on 2-meters as well as to the satellite. The fun starts when the station operator has the satellite in view and has connected to it.
After the operator has connected, then packet operators connected to that node can also connect to the satellite. A local ground station operator here, Paul, N0NBH, runs a Net/Rom setup. All I have to do is read his bulletin board from time to time to find out when the next few passes will occur of a satellite (in our case, usually the Fuji satellite, FO-20). Then, I connect to Paul's node and wait. If Paul is at the controls and hooks up to the satellite, I just connect to the satellite port and read the bulletins stored on it. I download messages for later reading. Offline, I type up replies then, at the next pass, connect to Paul's station and upload them. All this with an HT, a homemade modem, and Poor Man's Packet software. Sometimes I even have to connect to another mode first just to reach Paul's node! But the point is, the messages get passed, and I don't have to trot an antenna array out onto the sidewalk to do it (although I am looking into that).
The bulletin-board gateway looks similar to the one I just described except it is all automatic. You connect to the ground station to see what files have already been downloaded to the ground station or to see a menu of what is still available on the satellite. If you need a file from the satellite, you submit a message to the BBS at the ground station. On the next satellite pass, the file you want is downloaded from the satellite for you to pick up later. Uploading messages is just as easy. You post your message for satellite delivery and the station does it automatically. The software is in control, and the ground station operator need not be present to make everything run smoothly. The computer even tracks the satellite! The March issue of 73 magazine has a writeup on just such a station. Maybe someday we'll get one here.
Ask around on the local nets to see if anyone in your area has a pacsat gateway. It may be possible for you to reach into space from your condo using equipment you already have.
If you've listened to RAIN lately (the Radio Amateur Information Network), you've heard the story about the ham involved in a legal problem with his townhome association. The gist of this particular situation is that the ham, who rents the townhome, had been warned by another resident that he couldn't leave up his ground-mounted vertical antenna. However, the ham obtained verbal permission from a member of the association to keep the antenna as long as he painted it the same color as the exterior of the unit, which he did. Now, four years later, he is in trouble. Why? His landlord, years ago when he purchased the unit, signed an agreement which expressly forbade outside antennas of any sort. Verbal agreements notwithstanding, the townhome association is moving against the landlord (and the hapless renter, consequently). They are doing so at this late date probably because other hams wanted to install antennas, too. Listen to RAIN on your local net (or dial 708-299-INFO) for further developments.
The lesson for us is to carefully read any restrictive clauses in rental agreements or covenants (if we're buying) before signing anything. If we don't like what we see, then we should decide if we're willing to abide by those rules. And if the radio bug bites after you've settled in, then you might want to consider moving if you're not interested in covert ops.
But this topic brings up yet another:Why do we cave dwellers bother with amateur communications? It sure seems like a lot of trouble to go through. Instead of packet, for example, you could use the forwarding telephone bulletin board systems to pass messages and postings, just like on packet, and they're a lot faster, too. Internet, Computserve and Prodigy have more info flow than you could use in several lifetimes. Except for occasional use in emergencies when telephone and power lines are interrupted, why bother with packet?
The point I'm slowly approaching here is: why bother with amateur radio given the restrictive conditions in which we live?
As a friend of mine said when she sat in on a QSO: "Well, it's neat you can talk to a retired guy in Orlando, but you certainly didn't have much to say." Well, didn't I feel foolish, who had just gone down to Radio Schlock to buy a box with a microphone on it for the expressed purpose of talking to retired guys in Florida. I got a license for THIS? It's not like I'm some EE grad student who wanted to test out an idea for deep-space transponder buoys and needed a license to keep from getting arrested.
Or, I show up at work bragging about talking to a guy in France.
"So, what's his opinion on France's recent reversal of their
monetary policy?"
"Huh? I dunno."
"Well, did you ask him about the effect the EuroTunnel will
have on his business?"
"Er, no."
"Hmmm. Perhaps it wouldn't have mattered. What did he say he
does for a living?"
"I didn't ask."
"Does he have a family? Did you talk in French or English?
If English, where did he learn it? Does he talk other
languages? What does he like to do on vacations? What's a
typical day like for him? Criminy! What DID you talk
about?"
"Well...I was number 340 in the contest."
Back in the '20s and '30s, when people were experimenting with simple, one-tube transmitters, regenerative receivers and a long wire out the window, a contact with someone 500 miles away seemed truly magical. That impressed the neighbors. They didn't ask if you engaged in any deep philosophical conversation with the fellow in Florida. Just to reach Florida with a little pile of mostly homemade junk seemed a miracle. You MIGHT be able to call someone there with the telephone, but it would be pretty expensive and the connection not all that reliable. And the radio was sure faster than the mail. But now, where's the magic? You can call the guy in Florida on his car phone from your cordless phone as you relax in the swimming pool.
Maybe McLuhan was right: the medium IS the message. We build, or usually buy, a bunch of equipment so we can talk about the equipment (or watch it on fast- scan TV, or see pictures of it in fax, etc.) We cram our modest, yardless habitats full of electronic marvels with which to enrage the neighbors so we can discuss radios (maybe the weather) with retired guys in Florida. Cheesh.
I wish I could explain it. It makes as much sense as catching fish and throwing them back, or painting pictures that will never be sold, or writing stories that will never be published, or collecting stuff we don't need, or flying an airplane to no place in particular, or restoring old cars that are too valuable to drive around, or climbing mountains just to climb back down, or any of the other absurd things we do because we don't have to work 'til we drop like our ancestors did. We condo communicators try to get a 50-ohm match off of a chimney flue, or string 28 gauge wire to trees across the street, or load up rain gutters so we can ask retired guys in Orlando what kind of rig they're running or ask hams in France to repeat their exchange number.
So, given what we're up against, why do we bother? Maybe because we condo types enjoy the challenge of lashing some junk together with a makeshift antenna and doing what most hams think is impossible...communicating.
I saw the following Internet posting and reply, and thought it germane to our interests. Here 'tis:
In article <[email protected]> [email protected] (JEFF ZELL NK3O) writes: > > Hello > > I have been playing with a linear loaded 80 meter dipole because of >property size limits. I have been looking for articles about linear loading of >dipoles and even verticals with no sucess. Does anyone know where I could find >information about linear loaded antennas? One source has been Low Band DXing >however, it dosen't explain how you derive the spacing and fold back length. >Why is linear loading not a popular method of making antennas? From everything >I have read a linear loaded antenna, has less radiated power loss than an >inductively loaded or trapped antenna. Is it a problem of mechanics >(construction problems)?
If you are loading a quarter wave element try to do it on the end furthest from the feed point. In quarter wave elements the current is high at the feed point and most of the radiation occurs near the feed point. Just hang as much wire as you can horizontally and hang what ever you need to resonate the antenna down or tied off in some other direction. As a general rule high is better if you are horizontally polarized. If you go vertical the ARRL antenna book has a short 40 meter vertical that works well with a big capacitance hat.
I have had better luck with vertical antennas if I could not get my antenna very high. I currently use a piece of 1/2 inch pvc 8 feet long with a coil on each end and a long replacement rabbit ear element on each end that is perpendicular to the rest of the dipole. An alligator clip attaches the capacitance hats ( rabbit ears ) to the coil at each end of the pvc. I feed it in the middle and tune it with the coil taps and adjusting the length of the capacitance elements. It is rather tricky to tune but it can tuned to the point that swr is acceptable: 1.5 to 1 on the Icom 735 or 3 to 1 on the Heath 101. I usually run about 25 watts CW or 100 watts ssb.
The antenna leans in the corner of a first floor apartment made out of concrete blocks. It works ok for CW (no flames please) and so so for SSB. I have worked Italy, Mexico, Canada, New Zealand and Australia with it.
Fortunately I won't be using it much longer as the xyl has bought a house that will allow a better antenna.
Gordon Couger AB5DG Agriculture Engineering Oklahoma State University [email protected]
Now, on to the station descriptions! Speaking of antennas, covenants, and RFI, Derrick, KC4WEJ, of Raleigh, N.C., writes:
I live in a house on a "cheese-wedge" corner lot (yes, we
actually bought the place; we like the house, though).
Before closing, I checked into restrictive covenants, and was
told "we aren't aware of any."
Well, guess what? At closing, we learn "no antennas unless
approved by the Architectural Committee." Not COMPLETELY
restrictive, but some clandestine poking around leaves me
with the "snow-ball's chance" impression.
Commence covert operations! I strung up a 40M half-wave
dipole tied off one end of the house, back to a tree and over
to another. Completely invisible from the street. Have
worked several states, Canada and uth America. No tuner,
though (Kenwood 520S), so 40 is pretty much it (for
now).
Enter the RFI. At first, it appeared on our cable-fed TV in
the living room (but not in the bedroom), and in the
telephone. Added a "real" ground (10 ft. ground rod in
thanks-to-the-AC soggy soil), which helped the TV a little,
but the phone is still bad.
I then proceeded to rip all the TV/stereo/cable components
out and, adding them back in one at a time, attempted to
isolate the problem. It turns out the RFI was backflowing
into the TV through the connected stereo audio leads BECAUSE
of the stereo components' power cords being daisy-chained
into one another (to save plugs.) Plugged all power cords
into individual (grounded) plugs, added a RadShack filter to
the VCR cable input and even terminated all unused cable
jacks, and WHAMMO! No more RFI in the TV. Period.
The phone is still havoced when I operate. Save for checking
into filters at an upcoming hamfest, I'm clueless as to how
to even approach this problem. Any suggestions?
73 de KC4WEJ,
Derrick
Raleigh, N.C.
P.S. I don't know/haven't checked if I'm interfering with
anyone nearby. (I am somewhat estranged with my closest
neighbors due to an on-going battle with their back porch
light always being on.)
Steve, N2IC/0, of Boulder, CO, tells us that it's possible to run lots of power
from an apartment:
Even though I am far from being a "condo communicator" (2 big
towers, big beams, etc.) I enjoy reading your writeup.
Before the world worried about things like RF causing cancer,
I operated out of an apartment with a mostly invisible 120
foot end-fed wire and a KW. I had to be careful
to not let my lips touch my metal microphone, or I would get
one heck of an RF burn. I even fried my next door neighbor
on the metal "ringer level" control that old AT&T wall phones
used to have. It's pretty disappointing to see QST articles
saying things like "if you must use an indoor antenna, run
low power (i.e. 5 watts)". Talk about double-handicapping
yourself!
One idea I have seen applied is to use a mobile antenna
attached to your car. This assumes that you can park your
car near your home, and run coax out to your car. On the
high bands (20, 17, 15, 12, 10 meters), an 8 foot whip
outdoors will probably outperform anything you can do inside
your house. I recall reading about a homeowners association
suing for this being a covenants violation, but the ham won.
73,
Steve, N2IC/0
[email protected]
Have you seen the ad in QST for Jim Kearman's book "Low Profile Amateur Radio:
How to get on the air from almost anywhere"? Well, here's a station
description from KR1S himself:
I live on the second floor of a two-story building in a
complex, about 1/2 mile from ARRL HQ. For "serious" operating
I use an IC-751A. My 40-m QRP rig is homebrew. I have no
problems at the QRP power level, but I do get into trouble
sometimes when running 100 watts output. My antenna is a
full-wave 20-m loop (inside). I can open and close the loop
for different bands. I feed it with coax through a 1:1 balun
and a coil of coax, into a tuner. I have enough RF on the rig
that I can't key it with my computer, such as in contests.
The transceiver locks up in transmit mode. I have to turn it
off and on to get it to stop. I've never been able to solve
the problem.
In the past few months, operating in CW Sweepstakes, the
CQ World Wide and the 10-Meter Contest (CW only), I've worked
49 states (where is Utah when I need it?) and over 50
countries. I can work Europeans on 40, and out to the
Midwest on 80. I managed to work Clipperton on 17 meters.
RFI wise, wellll....I get into just about everything in the
place. My girlfriend gives up TV when I'm on the air. My
policy is to not tell anyone in the complex that I'm a ham. I
don't run 100 watts except in the odd contest, and if I
decide to chase DX, which isn't often. Mostly I just SWL
between contests. I wouldn't dare operate SSB, for fear of
someone figuring out what was clobbering the TV or phone!
I've tried RTTY and AMTOR, but I don't seem to have enough
soup for those modes. Besides, I just like CW better.
I like loop antennas. If you can keep them symmetrical, you
don't have to fuss with RF grounds. I built a clone of the
MFJ Artificial Ground box, but I haven't found it
particularly useful.
Good luck and 73,
Jim, KR1S
When I had mentioned to Jim that my artificial ground didn't do much to reduce
TVI, he replied:
It's supposed to move the voltage node away from the rig and
onto the counterpoise, so you don't get RF burns.
I noticed it affected the adjustment of my antenna tuner.
It became a real pain to tune up! That's why I like the
loop.
I knew that if I were just patient, someday, someone would tell me how they
loaded up a chimney flue. Mat, N2NJZ, of Boonton, NJ writes about the chimeny
flue antenna he uses in his condo:
The chimney flue is fed against ground using a wire going
from the tuner to where it [the flue] attaches to the
furnace. It is an aluminum flue pipe that goes 30 feet up
from the basement to the roof.
The station is located in the basement of the house, right
next to the cold water inlet ant the water meter. My ground
lines are about 3 feet long.
I have managed to work quite a bit of DX on this system, but
it is by no means an ideal system. Another point of
improvement is RFI susceptibility of the house - during the
summer I can turn on the air conditioner by keying up on 30
meters!
73 de Mat, N2NJZ
Perhaps you'll recall the station description of Howard Lester, KE7QJ, of
Tuscson, AZ. He installed an inverted vee on the flat roof of his townhouse.
Well, Howard adds:
Two months ago I worked a UA0, Kamchatka, with 15 watts CW on
17m. My report was 599. A few nights ago I worked Hawaii on
20m SSB with 10 watts. Remember, this is with a 30m dipole
fed with ladder line. It CAN be done!
But then:
*I* worked Tahiti just last night!! Amazing. 100 watts and a
dipole in a pileup on 20 meters and, after 20 minutes I got
through!!!
Tahiti is ONE place in the world I'd really care to visit.
Maybe Eddie (FO4OK) has a place for me to stay....
Hmmm. I wonder if you'd have to install your antenna on the roof, though?
John Shalamskas writes us from Hawaii.
Man, out here you practically need the Pope's intercession to
get an antenna OK'd. Lots of covenant restrictions. In my
case, my Mom happened to be the President of the Board of
Directors of our condo, so I got tacit approval to put some
low-visibility stuff on the roof. Works darn well, too, must
be the 110 foot height above street level :-).
I live in Honolulu, within 1 mile of thousands of
transmitters, from TV/FM/AM to Ham repeaters. I have become
adept at finding and using ferrite cores to squash the
interference they give me. Even managed to DF a power line
noise source (which is now fixed!) with a homebrew HF loop.
John promises details later on his DF'ing techniques. Don't forget to pass
along your call, John!
Adam Greenberg, N3NKI, of the University of Maryland, says don't forget the
dorm residents.
I don't know if you did include us, but you might want to
mention those of us working out of RESIDENCE HALLS. (I work
for the Department of Resident Life so I've been trained not
to say "dorms.")
I am running a Kenwood TR2200GX out of my room, with a max
power of 2 watts. I am using a 5/8 wavelength ground plane
vertical hanging upside-down from my ceiling (it's one of
those drop ceiling tile ceilings). I can reach
Virginia okay with the antenna up! My major problems are:
I'm on the first floor of my building, and there is a lot of
metal in my room (my radiator cover, the 3-foot by 6-foot
security grating on my window since I'm on the first floor,
and I have one of those 3-foot by 3-foot metal "Lite Beer"
signs in my room---College Kids!)
Only one entry this time:
Hamer, Harvard D. K9YHO
The "Apartment Dweller" dipole
Worldradio
March 1993
p. 69. An elaborate antenna that resembles a set of giant rabbit ears, but
which works on 80, 40, 20, and 10 meters. As Mr. Hamer says:
After moving into a second-story apartment, where no
outside antennas are allowed and where the attic is not
accessible, I spent a year thinking about ways to build an
efficient antenna for indoor use. The final result
provides surprisingly good performance while occupying
relatively little indoor space.
There are several photos in the article. You've got to see this thing. A
real condo dweller's antenna!
Okay folks, let's hear from you! Send your notes, ideas, station description, war stories, and so on to me at:
US Snail: Art Winterbauer
428 Francis Street
Longmont, CO 80501
WA5OES
Also, listen for snippets of this newsletter on Hap Holly's (KC9RP) Radio Amateur Information Network (RAIN), heard on various nets or by direct dialup (708-299-INFO, no charge except for long-distance costs). 73,72. Art.