This has previously been circulated on packet and in a modified form on Hap Holly's R.A.I.N. (Radio Amateur Information Network). Enjoy!--WA5OES
Welcome to the first edition of Condo Communications, 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.
The objective of this newletter is to encourage us to investigate means of employing all of the modes available to us for as many different purposes as possible. For examples, how can we use:
ATV SSB/CW FM Spread Spectrum Digital modes on HF thru microwave for Traffic handling Emergency communications Ragchewing DXing Technical exchange with QRO QRP on Batteries Portable generators AC Mains and Attic Invisible Portable/Temporary antennas while causing as little RFI as possible?
This part of Condo Communications will be devoted to station descriptions that you submit. I'll get the ball rolling with a description of my QTH.
I live in a wooden, 2-story townhouse topped with a modest attic. The usable space in the attic is about 25 x 25 feet and is floored with plywood. On top of the roof is a small wooden "cubicle" about 2.5 feet tall by 4 feet by 2 feet in which the air conditioner is housed.
The hf rig consists of a (somewhat modified) Ramsey kit 20-meter transmitter (at about 1/2 watt output), its companion 20-meter DC receiver, an MFJ tuner, a home-brewed artificial ground, and two antennas: a 1/2 wave 20-meter loop around the bedroom ceiling and an Isotron 20-meter "bird cage" poked away in the aforementioned air conditioner cubicle on the roof. An ancient GPR-90 receiver comes in handy for picking up WEFAX satellite photos relayed by Point Reyes and for just checking out the DC receiver under marginal conditions. Occasionally, I drag out the old re-conditioned DX-20, but 30 watts out is too easy (and too much TVI!).
The VHF rig is mostly used for packet: an Alinco DJ-F1 HT, an old XT clone, a home-built Bell 202 modem used with Poor Man's Packet, and a J-pole suspended from the rafters in the attic.
And what have I been able to do with such modest equipment? Quite a lot!
Operate from a townhouse, half a watt, with indoor antennas? Impossible, you say. Nay, sir. A gas! I've made plenty of QSOs throughout the country, coast to coast, and well into Canada and Mexico with this little arrangement. Every contact is DX as far as I'm concerned. Anyhow, the tx and rx, along with a rolled up dipole, a battery, and a few other odds and ends pack up neatly into two bicycle bags for the summertime bike ride to the local reservoir.
And QRP really cuts down on the RFI. I wouldn't mind running the DX-20 a bit more, but even with low-pass filters it wipes out channel 2 and does a bit of damage to channel 6 to TVs in my building and the one next door. I wonder if a good electrical ground would help? That's quite a ways off in this unit, and hooking up to the bathroom copper pipe made no difference.
With VHF packet I can connect to several nearby gateways for HF fun, local and occasionally DX, and have even hooked up with the Fuji satellite courtesy of N0NBH's pacsat gate. I even contacted MIR once on a very early morning pass, with just 5 watts to the J-pole. And I can pass and deliver NTS traffic via packet.
The HT, of course, can be chunked into the car for ARES work or for working with the other local weather spotters in the spring. Now, let's hear about your setups. How did you get around antenna restrictions? RFI? What do you use your rigs for?
Submit any technical notes or tips that might be relevant for condo communications. Examples are antenna construction for tight spaces, RFI problems (and solutions, if you have them), experiments with different modes that failed (or worked), and so on. What about some less common uses for your gear? Have you experimented with scanning schematics into GIF, TIF, or some other graphic format and pushing them around the local VHF/UHF packet LANS? How about swapping program code/data? Do you think you could become a packet gateway even though you operate from a broom closet in a garden- level apartment downtown? How about receiving GOES weather satellite images through a layer of wet shingles? How would you operate satellite from a QTH like yours? And how big did the coils get in that super-short dipole you've been experimenting with in the attic? Can you really convert the metal flue in that useless decorative fireplace into a 40-meter vertical?
Nothing particularly complex can go here as we aren't going to get away with trying to circulate via HF links any digitized graphic images or R95-converted binary code. But, if you can draw a simple schematic with keyboard characters, like -/\/\- or -||-, then try it and send it in. Of course, you can always leave an address so readers can submit SASE's for schematic photocopies, block diagrams, photographs, detailed descriptions, software code, etc.
Bibliography time. Here are a few articles that might prove interesting reading for condo communicators. I found these in magazines around the shack and will pass on more when possible. Send me bibliographic citations from articles you've read or have found in database searches. If you've read them, pass along comments or critiques as well.
Arland, Rich K7YHA
QRP
Worldradio
Sept. 1992
p. 56. Rich has an article for people who have limited space, work low
power, AND want to work the satellites. Receive on 10 meters, transmit
on either 15 or 2 meters. Mode A and K charts included.
Balsamello, Joseph W9KJS
Indoor 10-160M Pole-Lamp Antenna
Worldradio
May 1992
p. 68. A pole lamp with one tapped 90-turn, 2.5" diameter, 9"long air
core coil (#16 wire) and another identical coil (untapped) was tuned
(with a tuner) for operations on all bands. Operated from a 5th floor
steel-reinforced condo with good results on all bands. Read this one.
Frazier, Dean NH6XK
Baby Loopy: A Half-Wave, Inductively-Loaded Loop.
73 Amateur Radio Today
Oct. 1992
p. 34. A loop antenna, made to fit small spaces with inductive coils.
Provides 3-6 db gain in direction of feed point.
Galgan, Ig WA2VIA
A Clothesline Dipole
QST
Sept. 1991
p. 32. Clip your dipole to one of those reel-in clotheslines and you're
in business.
Krieger, Pete WA8KZH
Basic Steps Toward Eliminating Telephone RFI
QST
May 1991
p. 22. If you run more than a few watts with an indoor antenna, chances
are good you're going to get into the telephones. This short article
discusses troubleshooting, grounding, and filters.
Lau, Zack KH6CP/1
Build a Portable Groundplane Antenna
QST
July 1991
p. 33. A PL-259 plug and some #12 wire results in a quickie 2-meter FLAT
groundplane that you can hang in the window on one of those suction cup
hooks.
Sloman, Jeffrey N1EWO
The AEA IsoLoop (TM) 10-30: A Big Antenna in a Small Package
73 Amateur Radio Today
Oct 1992
p. 16. Thorough review of the IsoLoop antenna.
Thompson, Nigel KG7SG
A Plumber's Delight Dipole for 2 Meters
QST
Aug 1992
p. 43. A vertical dipole for 2 meters. Could be mounted in a tight
attic space or strapped to a chimney. VHF antennas like this are a
natural for "covert" operations.
Well, let me know if you've found this newsletter interesting. Send me stuff!
It'll go into the next issue which will be released whenever there's enough
stuff to go into it. There just has to be a lot of hams out there who, like
myself, have failed to achieve the American Dream of a large yard for Rover and
the tower, with understanding neighbors who don't mind when you key the kilowatt
amp, imploding their TV sets and warming their bath water a couple of degrees.
Inspirational note: There's jillions of Japanese hams living like sardines
packed in a tin. And we hear them. How do they do it?
73 de Art
WA5OES