Experiments

[N9TTX]

I would like to see how many different ideas people can come up with for ham radio experimentation on antennas, amps, tuners, rigs, and other misc. projects we all have laying around. If not to help out the fellow ham that may be looking for "just the thing I need," but also to help out the author of that project in the refinement or possible glitches that will be found.

Just to start out, I have on many occasions heard hams on the bands that are looking for various "stealth" antennas for their apt. complex or wherever. I happen to live in a trailer court where no new antennas (apparently for 2-way communication) can be erected as there are numerous satellite dishes and TV antennas going up here and there. Between myself and a few other hams, we have come up with a few ideas. One of which is the sneaky "ventenna." This 2 meter antenna works well but has limited gain, and is near invisible to put up as it looks like a vent stack for the house. This is the only antenna specifically marketed for the ham community in this post.

A second antenna is the common "flagpole" antenna. My particular version uses a standard 3/8-24 thread mobile whip mounted inside the top part of the PVC pole. The whole flagpole is about 20 feet tall, and the base of the mount for the antenna is at approximately 15 feet. I am a machinist, and came up with a piece of aluminum which I turned on a lathe at work which mounts the antenna to the inside of the pole somewhat like a mirror mount bracket does. It took a bit of deft work to connect the antenna/mount assembly inside the 1 1/2" ID pipe, but I found if one already has a tapped hole on the side of the mount, a quick measurement and a small hole drilled in the side of the pipe let the builder attach the assembly in one place in the pipe, and two or three more drill/taps around that perimiter securely mount it. I also made sure I ran a length of coax and a ground line (also attached before assembly) down the pipe so that they hung out the bottom. (hint: if you have nosy neighbors stuff the coax/ground into the end of the pipe so it is not visible, then while burying the end of the pipe in the ground pull the lines out.) It also is a good idea to run direct bury quality coax from the pole to the house. This antenna I have found loads well on 10 thru 40 meter. Performance and loading may be different depending on the choice of mobile whip.

The third antenna is a wire dipole cut for 20 meters, with a second radial cut for 6 meters off the feedpoint. I have a, I do believe, 4:1 balun at the feedpoint. This antenna has been strung up at the peak of my wooden barn-style shed (about 8 feet high), the dipole legs then run down at an angle until they are about 4 feet from the ground, they take a 90 degree bend (compass wise) and run parallel to the ground for about 6 feet or so. This effectively gives me an omnidirectional radiation pattern albeit with a very interesting take off angle. I have loaded this antenna up through 80 meters. 160 will work but the FT 101E spits at me more often than not when trying. Both the Flagpole and the dipole work well. I get great signal reports and I can hear very well.

The fourth antenna I have tried is a Radio Shack 190 mile TV/FM antenna. I have not had much chance to get reports back or figure out the pattern on it, but what I have gotten feedback about seems to be favorable. The description is as follows:

Do not connect the "X" links between the two sections of boom,
fold them back parallel to the elements they are riveted to.
Attach a "live driven" (50 ohm--hot lead tied to one side, braid to
the other side of the element pair) to the 2nd pair of VHF
elements on the "directive" (or boom half with all the extra UHF
elements) side of the antenna (coax1). A second "live driven"
coax may be attached to any of the "reflective" side pairs
(coax2). This configuaration has given the following bands:

coax 1: 2 meter communications with an SWR of 1.2-1.5 through
the entire band.
220 communication (haven't checked with a meter yet, but
the radio didn't complain.
going to meter out this weekend...but the 220 band
seems to follow 2m close for swr
440 communication with an swr of about 1.4
(1.2 G MAY work with more reconfigging. we did not try
this however)
This is all on the same coax line...so a duplexer/trplexer or
switchbox may be needed for multi.
I am only using it for 2 meter at this time.

Coax 2: 6 meter communication with a tuner (otherwise it loads
up flat about 47-49 Mhz)

It works on FM repeaters/simplex even though horizontally
polarized. Field tested with an MFJ analyzer, a 440 handheld and
on the air tested with a Yaesu FT-736R.

These Antennas effectively give me decent communication from 80 meters through 440, and one can only really "see" the modified TV antenna. Oh and there is a copper J-pole at the top for the masting for the TV.
I hope to see some more posts on some ideas on antennas, and on other items for the shack...even if the ideas are not finished. I can be reached at n9ttx@yahoo.com if anyone has any questions about these experiments. Happy Hamming. 73

Dave...N9TTX

[n8ary]

If they allow TV antennas, they really can't disallow amateur radio antennas within reason, can they?

My favorite is the mobile whip dipole. #You could put one in the flag pole as an HF vertical.

You could also make a j-pole out of a TV antenna tower or any vertical structure which is the right height.

I have also built one of those "buddipoles" and mounted it on a camera tripod for portable use. It's about like a pair of mobile whips in a dipole configuration.

[w6th]

I won't go into too much detail at this writing, but have been trying to evaluate the Slinky Helical antenna for all bands from 160 through 10 meters. At the present time I have been able to get 93.3 percent efficiency radiated power from 40 through 10 meters. #I believe there are now patents pending on the Slinky Antenna and have no intentions of selling such an antenna, but shows a lot of promise as to what a great antenna a toy will make. It may in time no longer be a toy, but be as popular as the G5RV antenna and the Center Fed Zepp, which most antennas are copied.

# # My design is not the type that you find on EBAY, but a much highly technically designed unit for rugged use and permanent for fixed or portable use. #This antenna will be for use in-doors or out-door use.

# # The antenna has done very well on 40 meters through the WARC bands and to 10 meters. Yesterday on 20 meters I made contact with JT1CO, 7 Jan 03 at 0238Z on the first call. This is not a new concept, but a fun project and for $9.00 gave me a lot of fun on the air and away from the computer.

# # # # # # # # # # #I am a non-dx'er but love dx.
# # # # # # # # # # # # # 73, #W6th

[WD8MGO]

Good Evening Dave,
# # Never say never in regard to getting on the air covertly. #I have my three aluminum window panes tied together and hooked up to an L-network antenna tuner.
For the counterpoise I use the MFJ counterpoise tuner.
This antenna setup feeds either my SG-2020 or the
Ten Tec Century-21(also my new used K-1 Elecraft). Have you tried SWLing outside the Ham bands?
I spend the majority of my listening time monitoring
shortwave broadcasters, Utility stations, Military as well as numerous VHF and UHF station. #I am lucky to have
WPAFB(Wright Patt Air Force Base) nearby. #
# #I have found listening to an open frequency on any wavelength interesting. #It is like looking and observing the forest instead of studying a specific tree. #Aids in increasing one's listening aptitude.
# # # # # # # # # # # # # #


# # # # # # # # # # # # Good Luck,
# # # # # # # # Fred Lehman WD8MGO

[we4vb]

Don't forget the rain gutter antenna. #Make sure the sections are physically connected together (soldered is best, but strapping with sheet metal has also worked) if it isn't a seamless gutter. #Load it up with a tuner and you are on the air!

WV8HAM - Rick

[NO7S]

I will echo the previous suggestion for the mobile whip dipole. I have one that I've been experimenting with and I will soon mount it permanently on the tower.
It is a pair of Hustler MO-3 mobile masts blended with something made by a back-packer antenna company (I forget the exact manufacturer) but the model is the MP-1 (it's designed as a mobile attachment) which comes in
2 pieces: a 2 ft. aluminum extention and a stainless steel stinger. All 3 pieces have with the standard 3/8"x24 threaded male. So you will have to visit a CB shop to pick up 4 of the double ended female 3/8x24 nuts. Each leg is 10' 6" long and it tunes 10 thru 20 meters quite well. (It loves 20 meters). My most memorable contact was with this antenna on 17 meters with an aeronaughtical mobile: a private Gulf-stream IV (over 40,000 ft.) which was near the same maidenhead as Ascension Is. (approx. 7 deg. S. and 18 deg. W.). The clincher for you is that I had it on an Ultimate Support Speaker stand (10 ft. max.) and on my deck about 2 feet of the ground. 12 ft. total!!! What if you were to "U" bracket some PVC to the side of your home and try to telescope it up when you are using it and lower it when you're not. The elements could just rest on the parallel surface lenghwise and no-one would see it in that position. Of course, you would be using the "armstrong" method for rotation, but you could feed it with 450 ladder line and have no loss since you will need to only rotate it 90 deg. at the most since it has no parasitics. It has great side rejection too.
Last of all, it is pretty study, but I did support it against gravity by guying it with 20 lb. monofiliment about 2 feet above the mount and tying it off with a loop and small zip ties at the farthest female nut on each element.
Hope you like this one. Good luck.

73-Bob

[W1LKE]

Speaking of the Rain Gutter antenna, one thing a friend of mine, (memory loss moment on the call), put up his
Christmas lights on his house using those little plastic clips, when he took down the lights, he put up a wire antenna. He decided teh clips were more visible than the wire, so he took everything down, painted the clips back and put it all back up. I don't know how well it works, but his XYL is not complaining.

Chris Wilkie
W1LKE
Jonesboro, Georgia, USA

[n5zvp]

I picked up some GPS modules at the local surplus electronics store here in DFW. Great for all sorts of ham projects depending on the features each; #APRS, DGPS and locking a frequency standard to the PPS signal. Various hams have come up with designs to do all these.

Also got a DDS/PLL module that will do 1Hz to 40MHZ with steps way less than 1Hz, (about 1/32 of a cycle, I think...). I'm either going to convert this into a the heart of #signal generator or a LO for an HF radio. A lot of research and planning is yet to be done for this project.

Not to mention all the antennas in the garage that need to be mounted and the feedlines that need to be run.

Chris
N5ZVP

[k5dvw]

To w6th> I'd like more information on how you achieved 93% efficiency on a slinky (which if I remember correctly are made of iron which is a horrible conductor and likely to have more real resistance than radiation resistance). How did you measure your efficiency?

I am quite interested in details about multiband HF helix antennas. After much experimenting and researching, I've found them to be inherently narrow banded and they, like any well designed monopole, require extensive RF grounding to work well.

So, I'm curious in how you are getting one to work so well.

Feel free to write me directly at my email if you'd like to share the details privately.

Thanks

Darrin
K5DVW

[AD5IX]

If you are allowed to put up a TV antenna then a good solution is readily available. Use a tall push-up pole for the TV antenna...one that requires guy wires. A bit of creative engineering will allow you to utilize the guy wires as di-poles for several different bands in an inverted V configuration. Your vertical (mobile) antenna in the flag pole could likely benefit from it's other half! Either a good ground system or a twin to use as a vertical di-pole. There are a lot of creative solutions out there but I think your TV antenna is the key. Not only can you use the guy wires as di-poles but you can load the pole as well using the TV antenna as a cap-hat!

[w6th]

Hello Darrin, I tried to send you email on this slinky, but your server has denied the mail. So here is what I have tried to send to you.

Hello Darrin,
# # I will be working on my computer today and putting in a new processor and more memory so when done will give a complete set of information as to my work on the helix (Slinky) antenna. #

I will mention that the dc resistance of the Slinky is 2 ohms and much less than the ground, earth resistance. The Q is very high and does limit the bandwidth, normal.
# I will put all information on QRZ for all to see, no hidden secrets.
# # # # # # # # # # # # # # # # # # # # # # # # #73, #Vito # W6th

[kb1dig]

My Wife Kim, and I have a Hampage.

Several different ideas are posted.

Kim is also a Ham and her Call is KB1GTR. #We have a lot of fun doing this Web project together.
It's mostly hi-tech low budget ideas. #Always good to save a few $$$. #Some VHF antenna experiments. #
Most of the parts for these antennas can be found at your local hardware store. #

(4) different 2-meter colinear designs.
(1) 2-meter Halo
(1) 6-meter Halo

Also:

Go-Kit page
Portable Station for Field Day Events or emergency use.

http://home.attbi.com/~buck0/hampage.htm

This has been our way to give back to the hobby. #We enjoy receiving e-mail with images of
design variations form others experimenting. #Little tweeks and mods. #Each antenna design has
a comments section and several of these images and refinements are posted.

Great topic, Dave.

-73 Steve KB1DIG

[K3CW]

Glad to hear your flagpole antenna is working well. #I suspect it might work even better if you just ran a conductor inside the length of the pole and fed it at the base against ground radials. #You could also leave the hamstick in place and run the wire to it to make a top loaded flagpole-length vertical. #

I mounted 30 feet of aluminum tubing on the roof deck and added a doorknob sphere at the top to make my "flagpole". #I feed it against the plumbing (there's a water faucet on the deck) and the internal tuner in my rig matches it just fine on 80 through 10 meters. #

No complaints from the neighbors. #In fact the lady next door had been telling me I "needed a flag for my house"! #Here's a few pictures:

[w6th]

Hello Darrin, K5DVW #The information you wanted.

1/4 wave resonant at # # # 14.158 Mhz
Helix wire pitch # # # # # 46.2mm
Length of wire on Helix # #14.3 Meters
Total inductance # # # # # 9.5 Microhenry's
Coil self capacitance # # #13.3 Picofarads
Rod capacitance to ground #0.1 Picofarads
Total effective capacitance 13.4 Picofarads
Radiation resistance # # # 11.8 Ohms, referenced to base
Wire HF loss resistance # #1.23 Ohms. # #.. # # #.. #..
Feed point input resistance 17.04 Ohms # .. # # #.. #..
Transmission bandwidth # # 286.8 Khz between 3db points
Power radiation efficiency 69.3 percent
Loss relative to ideal # # #1.6 db or.2 s points
Base matching capacitor # #313 Picofarads for 50 ohm match

Notice: This is for a Helix, using a Slinky toy as a vertical. (Height of 3 meters or 9.84 feet.) mounted at ground level and used with radials.

# # The Helix I used to contact CJ1CO was a 3/8 wave Helix Vertical ground mounted with 12
70 foot long radials and a 2'x 2' copper plate at the bottom of the base of the Helix
which was used to bolt the radials to. The height of the Helix was set for a radiation resistance of 150. Equal to 3/8 wavelength.
# # The matching of the 3/8 radiation resistance was a linear device, using open
wire line spaced at 6 inches and used as a 1/4 length matching section.

# # #There you have it Darrin and you should have no problem if you construct your
Slinky antenna according to Theory. Also for very little cost you can get much info
from ARRL QST magazine. # Good luck on your next project.
# #Oh, the 93 percent was on the 40 meter horizontal, using RG-8 Coax.

# # # # # # # # # # # # # # # # # # # # # W6th.

[n7nmd]

I have been working overseas, and wanted a decent HF antenna to listen to news, and catch the regional ham action. (No HF ticket yet for me here) Trick is I live in an apartment, and strange antennas are very much frowned upon, and wasn't worth getting kicked out over.

One thing that IS common is clothes hangers, the type where you put up your wet clothes to dry. THAT's when I got the idea...

I got the arrl antenna book, and made and tweaked a loop antenna for 14-28 Mhz. I brushed all the oxides off, and painted it white - the same colour as the complex. Where the paint chipped, I used white electrical tape. I used a white electrical box for the capacitive tuning assembly.

After testing, I mounted it to the balcony with hose clamps so that it can swivel in and out. In for testing and adjustment, out to hear W7 stations - and to dry my freshly washed dress shirts.

Response from the community has been minimal. I occasionally get a question about why I made my own clothes hanger instead of buying one. Little do they know...

The antenna preforms pretty much as prescribed in the book, except I get a lot more high-angle signals than I should, due to the nearby metals from the complex and balcony. Oh well. I estimate around 6dBi from the thing, and as noiseless and static free as one could ever hope from a loop antenna.

-Dan
9w2du / n7nmd
n7nmd@arrl.net

[KA8FFM]

Hello, lots of neat ideas on this topic. My contribution is for QRP users, as these antennas cannot take much power. I have an FT 817 that I love to take into the field. I use a salvaged telescoping antennas taken from old 11 meter walkie- talkies for ten meters. I very often find these handheld radios at hamfests and garage sales for next to nothing. Many of them are center loaded and work very well. I just solder a 12 ga. copper wire from the little screw hole used to attatch the whip to the walkie talkie to the center pin of a coax connector. A little piece of cpvc or pvc pipe slips over the whip and back of the connector for rigidity, heat shrink over the pvc to hold toghether, and it is ready. I use a 90 degree coax adapter to attatch to back port of the 817. Tuning is simple...set the rig to low power with onboard swr meter on and send cw carrier while sliding in first top section with plastic tweezers. Works great. Worked Europe several times on cw and fone from picnic table..No coutnerpoise required...Vince KA8FFM EN67qc

[wb4jhs]

http://www.qrz.com/iB_html/non-cgi/emoticons/wow.gif #I've hidden the Solarcon A-99 inside PVC to make the flag pole and now it is put along side the upper section of a 35 foot tall palm tree and painted to hide it in the natural color of the tree. #Ground the base and tuned with a MFJ-948 the A-99 will DX on 10-30 meters! #The tip of the A-99 sticks out on the top for the palm and looks like a palm-fron tip, hardly noticeable. #I'm curious to try the ridge vent although I bet I'll have trouble. #Anybody tried the ridge vents???
http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif #http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif #http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif #http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif #http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif

[N9TTX]

In addition to the original post, (as I thought it was getting a bit long winded to start with as I am wont to do..*LOL*), the Flagpole antenna had to be put up once with no fiddling with it after as the neighbors are a bit nosy to begin with. I used a five foot whip (to get the feedpoint as high as possible) and if any are interested it is actually a full wave 11-10 meter mobile whip called a skipshooter. I have used these mobile for years and they have gotten me as good or better signal reports than most other whips I have tried. I have used a ground wire to ground the antenna mount bracket to earth ground 15 feet below.

The trailer house is of metal siding construction with a tin roof (I plan on putting shingles up this summer). I originally tried an indoor dipole for 10 meter, but the siding/roof sheilded it too much though I did get out and make a few contacts on it...Also I found out by using it I shorted out the home stereo power amp which in turn cooked all four bass drivers for my speakers....oops. Like the saying goes: "do not try this at home"..*LOL* all in all it worked out okay but costly. $35 for the amp, $80 for 2 new 12" poly cones to replace the paper ones, and I still haven't replaced the bose 301 8" drivers yet. Anyhoo, the stereo does sound better now, but it was a bad time..*L* Soooo...that is why I use the outside (inside the shed) dipole. It is fed by a double sheild military grade 9913 size coax.

The TV antenna has not been modified so that the casual observer would notice. (one can see the coax is not fed to the standard posts and the X-rods can be seen to be disconnected) but that is only if one knows what to look for. Again, this is just to get me on the air until I can possibly persuade the park management to let me put up some VHF beams (no 6M as I KNOW that will definately get into the electronics around here). For contesting I drag my portable tower out and raise what antennas I need on it.

I am also trying to think up a way to make an antenna out of a clothesline rottissarie (sp?). It has a vertical pole which supports an "H-pattern" of tubing from which the clothsline should be run. It is just a matter of mounting it and somehow burying the feedline at the same time so no-one knows what I am doing..*L* (project for the spring I think).

I am planning on possibly stringing some wire antennas up as guy wires IF I get permission to do the small beams for VHF from management.

Another project is as follows as found on a modification site:

"Converting 11 Meter band to 12 Meters for the Yaesu FT 101 series ..

Although this procedure hardly qualifies as a "mod" (too easy), it is certainly useful for the FT 101 series
owner. Conversion to the 12 meter WARC band is as simple as replacing a crystal. The 11 meter xtal is
replaced with a 30.52 Mhz 3rd overtone xtal in a HC-25/U holder as specified in the FT 101 series
maintenance manual. No other modifications are necessary as the new band is close enough to the original
that the current components work. To replace the xtal, remove the oop cover and find the xtal board located at right front of the rig.
Xtals marked xxxx are standard while oooo are optional on some units. X5, for the 11m, band is an option
and may or may not be installed.

10B xxxx xxxx 80
10C xxxx xxxx 40
JJY/WWV (1) xxxx xxxx 20
160 oooo xxxx 15
xxxx oooo < X5 the "11 meter" socket
.... xxxx 10A

The xtal was ordered from Marden Electronics (800-222-6093) although it is probably available from the other companies which offer this type of item. I'll skip the business details here, but it is cheap. I found fat fingers, a hindrance when yanking the old and insterting the new so I used a hemostat (narrow nosed locking type device with "seconds" often found in hardware stores, etc.). After checking with a local ham who monitored my transmissions to make sure I was where I thought I was, I was in business with 12 meters for my FT 101B.

How'd it go ?? After warming up the rig, I spun the dial a bit on what has been a mostly dead band this
summer. The first station I heard was a little weak .. AA5QC .. no it's A35QC. I had no idea where that was,
but I gave him a call. It turned out to be JF1WQC vacationing in TONGA, my first African contact and a 59
report at that! So here's an easy way to add a WARC band and open new possibilities for DX adventure with your FT 101 series rig. Please let me know if you have any additional feedback or comments on what has to be one of the easiest "mods" ever."

I plan on doing this to my 101E and B...I tried the marden number but it did not work, but I did get ahold of Jan Crystals...and they can supply what I need.


Also if anyone has any ideas on how a switchbox might work for a 5th band on a Yaesu FT-736R let us know here. I would like to try and find a 6 meter module for the 736 and as I have 144 thru 1296 in it already, I am looking for a way to make an external box for the said 6 meter module with a switch to change from one of the internals to the external, but not sure if it will work. Any ideas??
If anyone wants diagrams (hand drawn of course..*L*) or measurements of these just send your request and street address to my email addy n9ttx@yahoo.com I will be happy to show via picture what I have done. Thanks again for the continuing input and ideas for all the projects.

Dave.....N9TTX

[KD5JZN]

Try antennas and more for a few ideas.They also sell tech notes for some of they're antennas. antennasandmore.com Hope it helps. 73's kd5jzn

[KD5JZN]

Ever try to load the metal flashing around the bottom of the roof? Try it,you might like it. kd5jzn

[we4vb]

More Slinky Antenna info...

A Slinky resonates as a quarter wave between 7 and 8 MHz when it is stretched to lengths between 5 and 15 feet.

To tune the Slinky within that range just extend the coil to approximate size, then expand or contract it to reach the desired resonance. At a length close to 7-1/2 feet a Slinky is quarter-wave resonant on 40 meters. So a 40 meter dipole made from a pair of Slinky coils will fit in any apartment, balcony, or hotel room.

Dipoles resonant at frequencies above the 7-8 MHz range may be created by removing turns to shorten the helices or by shorting out turns.

A twenty meter dipole can be made by cutting a Slinky coil in half or simply by feeding it with a delta match in the center.

For target frequencies below 40 meters, you just adds turns from another Slinky coil or clips wire pig tails on the ends.

By adding one more coil to each side and stretching the whole to about 30 feet in length, you can make an 80 meter dipole that will fit in most attics or motel hallways.

You can use monofilament fishing line fed through the coils to suspend and support each side.

WV8HAM - Rick

[N9TTX]

I keep forgetting. Here is a link to my next door (soon to be across the road) neighbor's site.

Darrell...KB9LVK.... http://highlander868.tripod.com/

[kf6nfw]

I have been experimenting with LASER. I have been building two complete rcvrs, and trxs. I plan on using them as a repeater on my property. Why? well I though why not! I plan on shooting the lasers back and forth about 1000ft.

[KE6QCV]

They (The home owner associations and trailer park owners) may try to regulate what you can put up on your roof, but they can’t touch your mobile rig. If you have an Icom 706 MK2G (or equivalent) you’re in luck, just buy enough separation cable to reach inside (park close to the house) and an external speaker and you have an instant base station. Also make sure to put a battery charger in your mobile and your set. You could put lots of antennas on your mobile and what can they say. Also the new log periodic from Cushcraft does look like a big TV antenna, it works on 6 meters, maybe it would tune up on lower bands???

Note: take the keys for the mobile (new base station) away from the wife and kids so you don’t have to buy too many extension cords and separation cables.

Cell site owners are starting to buy fiberglass antennas that look like trees, if a big enough need is out there, maybe one of the manufactures could start producing a line of HF / VHF / UHF antennas for Hams. Or if someone has some time on his or her hands, take a look at some of the plastic trees that have wire centers.

A good design could have an auto tuner (AH-4?) in the base, (looking like a redwood planter box) and a fir tree type look for lots of branches to do the loading for different bands. If the design gets too big you could attach it to a concrete pad to keep things from tipping over in the wind. Make sure it doesn’t block someone’s view, and they allow trees and plants. This is a good plan for homeowners with some owner association breathing down their neck.

“73’s”

Terry

[n8ary]

I wonder if Laser would make a good feedline substitute. It would be like an IR remote mount.

[KA7IEN]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kd5jzn @ Jan. 11 2003,13:22)</td></tr><tr><td id="QUOTE">Ever try to load the metal flashing around the bottom of the roof? Try it,you might like it. kd5jzn[/QUOTE]<span id='postcolor'>
Interesting idea. I've successfully loaded up a 1970 Cadillac and a 15' boat trailer on 20 meters. A good ground rod was required in both cases.

[K3CW]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (N9TTX @ Jan. 11 2003,13:00)</td></tr><tr><td id="QUOTE">I am also trying to think up a way to make an antenna out of a clothesline rottissarie (sp?). #[/QUOTE]<span id='postcolor'>
I think you could get one of those "clothesline rotisseries" to act like a short antenna with a big capacitive top hat. Just make sure the clothesline running around the perimeter is conductive and in good electrical contact with the horizontal members and make sure no one is hanging laundry when you're on the air!

In fact, the 13th edition of the ARRL Antenna book describes how to build a very short 40 meter vertical that looks exactly like one of those laundry-go-rounds. The top hat is 7 feet in diameter and a loading coil is placed just below it. The antenna is only 6 feet high.
p. 213

[n8zux]

http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif #For a few things I done like my sister yelled after playing around a Vaccum tube radio trying to find a antenna hookup only to find 170 volts off a 365 pf. capacitor and the antenna was a steel wire clothes line for the antenna in the back yard that was 1972 .

another fun site was Grand Rapids YMCA 9th floor running a moblie whip clamped to a steam operated radiator/ heater worked gr8 on 11m. great grounding structure I cannot remember the range few miles at least.

I set someone up on the sheet metal flooring which was approx 12 ft X 30 ft. area again using a mobil whip vswr was 1:2:1 .

if you planning on operating that idea for 10, 12 Meters make sure you have enough grounding 1/4 wave length in a square guessetimate of a #8 ft. to 10 ft. square sheet of metal or a large heating steam system of several rooms, and flors even better, I would sugguest about running 40 to 80 is who knows long as no one gets a RF poke # #http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

also have a drop celing system ? try soldering wires to each part of the frame. #better yet run a antenna above in a loop and tune it up , #running 144- 1200 Mhz. ?? #a little thinking of hiding antennas in planters, putting antennas on guard rails, might work, so long #as antenna, coax & rail match .

I like the one post of Cell sites using plastic trees, I just thought of something, why not buy a fake tree and install the antenna in the fake plant?? #of course Christmas trees that are 6 ft. have a metal core of 5ft. is a temporary deal, and use is short season, unfortunately unless of an example of a person who left their tree up until febuary http://www.qrz.com/iB_html/non-cgi/emoticons/confused.gif ( challenged here and few screws fell out ) #http://www.qrz.com/iB_html/non-cgi/emoticons/tounge.gif

also NOT A RADIO PERSON !!

I know that there is a real neat flag company in the West Michigan Area sells these teloscopic locking flag poles, approx 3 #" diameter, and somehow all peices need to be conductive weather a tilt over mast is best for this, then install jumpers and seal them I think that it would be a great antenna, bury the wire black, also check specs on outside jacket if it will resist soil acids, otherwise outdoor PVC Electric piping for it to run inside the coax, around GR area seems alot of these small 6 to 10 ft. metal windmills also are selling another source for an antenna , some sort of way to install it ??

I am pertty glad I own my own and in the rural farm TWP. and a full ant is up, have more to do XYL calling 73

http://www.qrz.com/iB_html/non-cgi/emoticons/wow.gif0--></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kc8pmm @ Jan. 12 2003,16http://www.qrz.com/iB_html/non-cgi/emoticons/wow.gif0)</td></tr><tr><td id="QUOTE">I wonder if Laser would make a good feedline substitute. #It would be like an IR remote mount.[/QUOTE]<span id='postcolor'>
If one is going to the trouble of modulating and demodulating an IR laser, why not use optical fiber? #Very low loss, you don't need visual line-of-sight and it's completely immune to RFI. #If you can use the plastic optical fiber, it is also cheaper than decent coax. #The down side is that it is not a "wireless" link, which might be why he's using the laser in the first place. #I wonder if he's modulating the laser with the baseband signal only, or if he's beaming the modulated carrier?

[kd3v]

Here's my latest apartment roof antenna. Photos were taken on the car but that was for testing and tuning only. It would work well as a fixed mobile installation but it is for the rooftop. I had been using 4 band version for the last year but wanted more choices of bands... so I added the spacer and used the second adapter to get three more bands.

Design criteria:
1. for apartment use, I have occasional roof access
2. portable and quick assembly/disassembly
3. as many bands as possible on one feedline
4. no tuner needed
5. 360 degree coverage, means a vertical antenna
6. use of "off the shelf" parts
7. cheap but good components
8. fun to build and use
9. low wind load and lightweight

This "7in1" is now a working 7 band HF & 6m antenna.
I chose 40, 20, 17, 15, 12, 10 & 6

I tried 75m instead of 6m but the bandwidth on 75 was a little too narrow compared to the utility on 6m. There are at least eight repeaters on 6 that I can hit from here in the LA basin.

I will add 75m after I get a tuner.... IF I get a tuner.

Currently I get 100Kc BW on 40 and full coverage of all SSB portions of the other bands.

The magmount is the Iron Horse triple-5" version and there are 2 Hustler VP-1 tri-band adapters which I doubled up to add stiffness (4 total). Th photo only shows one of the two being doubled.

I used a flattened "tower computer case" as the base for the magmount and that sits on a pair of 3'x10' sheets of chicken wire which seem to provide a nice groundplane.

Results? When used with only 4 bands... 40, 20, 17 and 10, I had contacts into V51 on 40m with 100watts (ask V51E) and easy long path contacts to India and South Africa on 20m (ask VU2ELJ and ZS6AN).

This multiband "Hamstick Array" was first used on my car (ONLY two whips in use while driving) with the above results! It worked so well I added another for my apartment roof. I followed the idea of "using the path of least resistance" in more ways than one on this project!

73
KDa3Ve

[KE4MCL]

antenna gestapo got you down???

i recently acquired a neat book called "aerials 2". its a paperback written by a few guys that had some fun loading up common items and making contacts on them. they loaded up things like shopping carts, baby high chairs (minus baby), metal garbage cans, etc. it was cool to read all their experiences. they actually made lots of contacts with their oddball antennas, antenna tuner and a 100 watts on hf.

having been one of those people that were raised on a "beam" mentallity, i found this book alot of fun. its like a new dimension to ham radio... lets see how many things we can radiate off of!

robert
ke4mcl