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Author Topic: Will an attic antenna work?  (Read 1166 times)

K7JQ

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Re: Will an attic antenna work?
« Reply #15 on: May 01, 2020, 07:07:35 AM »

But there is RFI to your condo and others to consider, and you won't find that out until it's up and working. How much power you run will have a lot to do with that. That's on the transmit side.

73 and stay safe,  Bob K7JQ

Also when I first took my (unknown to me) next wife into my radio shack to show off my apartment, she said what is with all these radios and the wire on the ceiling, are you with the FBI or CIA or are you just weird?

Most eHamers know the answer to that question.... So yeah, if all you can do is a attic antenna go for it, just be aware of those Damn CBers.   ;) :) :) :)

Stan K9IUQ

Stan,

I'd go for "JUST WEIRD" ;D ;D. Like most of us hams ;).

When I was a 13+ year old kid in the late 50's and 60's living in my parent's row house in Philadelphia with a multi-band vertical (and later a tower-mounted TA-33) on the roof, TVI was the thing. But besides that, I was blamed for all sorts of happenings in the neighborhood. I was the weird ham radio kid down the block that caused their washer to overflow, toilet to stuff, water heater to leak, hair dryer to short out, car not starting, etc ::). Even when those things happened when I was in school, and not on the air! Those were the days.

But yes, if no other alternative, put a dipole in the attic and see what happens. Not expensive or labor intensive, and you might be surprised with the results. Any antenna is better than no antenna at all.

73 and be safe,
Bob K7JQ
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KL7CW

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Re: Will an attic antenna work?
« Reply #16 on: May 01, 2020, 10:09:14 AM »

Believe me K7JQ's story is not much of an exaggeration, we all have some good stories from the 1950's and 1960's with 21 MHz TV IF strips, channel 2 TVI from 6 meters, etc.  Back in the 1960's my wife and I rented an apartment in the Los Angeles area.  Between our apartment and another apartment there was a "no man's land" between the buildings which was fenced off and just covered with weeds. I put up a stealth antenna with very fine wire.  It worked (somewhat) , so after a few months I continued to expand my antenna farm. Early one morning we heard loud cussing from right outside our window.  I ran outside and the apartment manager was cussing (real nasty language) since he got all tangled up in the hair thin wire and was desperately trying to see where the wire originated.  I joined in with the language and said I would help him do something nasty to whoever put up the wires.  I sent him in all the wrong directions while I jerked out the wires from my window.  We moved away from "civilization" to Alaska a year later and bought a few acres of land. No TVI or antenna restrictions, but this far north, propagation "sucks".  However skiing, playing in the snow, etc. is much better than in LA.               Rick  KL7CW             
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G8FXC

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Re: Will an attic antenna work?
« Reply #17 on: May 04, 2020, 01:41:44 PM »

I've used attic antennae most of my life and they certainly work to some extent provided the roof over them is not metallic. They are never going to compete with a good dipole in free space or a beam, but I have worked VK from UK - admittedly around the sunspot maximum - on SSB with just 100W. As others have said, your biggest problem is likely to be RFI - both to your receiver from all the electronic devices in the house and to those other devices from your transmitter. Pay attention to good earths, good screening and try to get the antenna as close to resonant on the frequencies of interest. Also buy a large bag of ferrites and put them on every cable in sight!
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W8LV

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Re: Will an attic antenna work?
« Reply #18 on: May 04, 2020, 09:43:34 PM »

Insulation Foil is not a problem at HF, as previously stated here, and this was also mentioned in an episode of Ham Nation. The best antenna? Seems to me that the BEST antenna is/are the one(s) that you can put up... ;-)
Attic antenna has its advantages in that you are out of the weather, and out of the eyes of the HOA Jackboots. No climbing a tower. Cheap. REALLY CHEAP. So why not give it a go and see how it works? Either way: You learn and have fun for the price of a hank of wire, eh? Let us know how it works out!  73 DE W8LV BILL
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KD2HU

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Re: Will an attic antenna work?
« Reply #19 on: May 05, 2020, 07:57:01 AM »

Yes, a wire in the attic is cheap. (So am I.) Problem is: I don't have a rig. I'm trying to figure if I should drop a grand or more on a station while living in a condo. Maybe I should have said, "Will it work well enough to be worth the price?"
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K7JQ

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Re: Will an attic antenna work?
« Reply #20 on: May 05, 2020, 08:53:15 AM »

Yes, a wire in the attic is cheap. (So am I.) Problem is: I don't have a rig. I'm trying to figure if I should drop a grand or more on a station while living in a condo. Maybe I should have said, "Will it work well enough to be worth the price?"

The only way to find out is to give it a try. A home made dipole for the attic plus a little coax shouldn't cost more than $20-$30, if that much. Maybe you can borrow someone's HF radio to check it out. If not, an Icom 7300 is $900 new, shipped, after a rebate. Or buy one used for $750-$800. If the dipole operating doesn't work out, you can always get most, or all, of your money back by selling the 7300. I've seen some in the classifieds listed at $850. Why someone would pay that rather than a new one for $50 more is beyond me. They seem to retain their value, though. Good luck.

73, Bob K7JQ
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KD2HU

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Re: Will an attic antenna work?
« Reply #21 on: May 05, 2020, 09:37:35 AM »

Thanks for your input Bob and Bill. I'm getting very close to pulling the trigger on a rig. And if I cause enough TVI that the villagers come by with torches and pitchforks, I'll just crank the RF output down some and pretend I had planned to run QRP right from the start.
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K7JQ

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Re: Will an attic antenna work?
« Reply #22 on: May 05, 2020, 09:48:43 AM »

Thanks for your input Bob and Bill. I'm getting very close to pulling the trigger on a rig. And if I cause enough TVI that the villagers come by with torches and pitchforks, I'll just crank the RF output down some and pretend I had planned to run QRP right from the start.

With digital TV, cable, satellite, and streaming, TVI probably won't be much problem. It'll usually be with audio systems, advanced electronic appliances, computers, and other cheap devices not RFI shielded that others in the condo own.
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WB4BIN

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Re: Will an attic antenna work?
« Reply #23 on: May 05, 2020, 10:46:58 AM »

And if I cause enough TVI that the villagers come by with torches and pitchforks, I'll just crank the RF output down some and pretend I had planned to run QRP right from the start.

My attic antennas cause a couple of problems, when I run 100 watts.  I kept setting off one of the carbon monoxide detectors, so I moved it about 10 feet to another location, and that solved the problem.  And I still open my garage door whenever I operate CW on 20m.  I solved that by unplugging the garage door opener whenever I fire up the rig.   At QRP levels, all I do is turn on the light on the garage door opener. 

I've also heard of guys having trouble setting off smoke detectors, though I have not experienced that. 

Ultimately, I think you will just have to try it and see what happens.  Hopefully it will work well for you, and not end up being an expensive experiment.

Good luck.

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AC4RD

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Re: Will an attic antenna work?
« Reply #24 on: May 05, 2020, 11:08:42 AM »

Yes, a wire in the attic is cheap. (So am I.) Problem is: I don't have a rig. I'm trying to figure if I should drop a grand or more on a station while living in a condo. Maybe I should have said, "Will it work well enough to be worth the price?"

You MIGHT want to try buying (or borrowing) an older used rig, first, just to see.  As others said, when the bands are good you'll have plenty of action from an attic antenna--ten and twelve meters can be great for that when they're open.  PSK and CW are both great even at 5 watts and under, when the bands are even half-decent.

One thought:  I recently had trouble with a new outside antenna getting into the speaker wiring of a neighbor's sound system.  A low-pass filter (a Bencher I've had for 20 years) in line with my antenna cured that immediately, and was easier than convincing the neighbor to let me put chokes on his wiring.  :-)  (Yes, technically it IS the neighbor's problem to fix, but I always tell my neighbors to contact me right away if they have problems--it's only happened a few times, it's been easy enough to cure, and I stay on friendly terms with my neighbors, which is good.)

Good luck and 73!    --ken ac4rd
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KD2HU

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Re: Will an attic antenna work?
« Reply #25 on: May 08, 2020, 03:35:08 PM »

Thanks to all who helped me with this! I ordered my IC-7300 today and I'll be playing ham radio pretty soon now. After reading K7JQ's post about the used market for IC-7300s I took a look. There were a bunch of them, but all were marked sold. So if it comes to that, I can get a lot of my money back. Or I can operate portable in parks and seashore and have a good time, too. It should get here early next week, and I'll post again when I get it up and running. Again, thanks everyone for your input. 73
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K0UA

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Re: Will an attic antenna work?
« Reply #26 on: May 09, 2020, 06:34:12 AM »

Thanks to all who helped me with this! I ordered my IC-7300 today and I'll be playing ham radio pretty soon now. After reading K7JQ's post about the used market for IC-7300s I took a look. There were a bunch of them, but all were marked sold. So if it comes to that, I can get a lot of my money back. Or I can operate portable in parks and seashore and have a good time, too. It should get here early next week, and I'll post again when I get it up and running. Again, thanks everyone for your input. 73

You will enjoy the heck out of your 7300.  Let us know if you need any assistance.
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73  James K0UA

RADIOHAM

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Re: Will an attic antenna work?
« Reply #27 on: July 20, 2020, 02:06:43 AM »

A Magnetic Loop Antenna will likely work, yes, better than the usual non-magnetic wire antennas. the magnetic component of the radiation is attenuated less from the usualy material a house is build of, wich is why a magnetic loop works better from within a house.

your other question, when you can hear AM & FM Broadcast radio, that doesnt mean you will be likewise heard with an attic antenna, keep in mind those broadcast transmitters on AM often use like 200+KW & big antennas for tansmission, compared to that the effective radiation power from the attic by a radiamateur will be small, accordingly the signal from the attic so much weaker than the broadcast signals. it depends aswell how big the antenna in the attic is and how much transmission power is used.

you can build a Magnetic Loop Antenna from copper pipe & coaxial cable, i have a video here about how to build one for the 40m band.
https://www.youtube.com/watch?v=Cv_RnLpZ9gw

use those snap on ferrites on the coaxial cable directly on the transceiver, with the radiation in the building there can then be alot of inteference, the ferrites filter a great part of the interference away, use at least 10 snapp on ferrites on the coaxial cable, one or two alone wont do much. the ferrites will i think be more important on the newer transceivers like that ic-7300 that are like little computers, their parts will be more sensitive towards RFi.
the ic-7300 is praised by alot of people but it needs an extra preselector to filter away the QRM from the sides, there are videos on youtube where a ham demonstrates that effect. then alot of people have problems with the audio when they use a different mic on the 7300. of course its the buyers choice but thats what i found out and then didnt buy the 7300.

a magnetic loop is very directional, you can try to hang it horizontally or vertically to find out what works best. if you build a magnetic loop, i'd like to hear how you build it and how well it works.

73
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KE0VT

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Re: Will an attic antenna work?
« Reply #28 on: August 23, 2020, 12:30:46 PM »

Gentlemen/Ladies

I have been reading with interest this topic. I moved into an HOA restricted community thinking I would not be back on ham radio. Well, that was a poor assumption. My HOA restriction besides being outside with no antenna, it prohibits any "transmitting" antenna. I have lived here almost 7 years and lo and behold my wife suggested I get back on ham radio. In April I began putting together a totally new station. By July I was almost set-up and
by August operating. My early thoughts were what to do about an antenna. At my previous residence I had a 50' tower, 3 element tri-bander and 3 elements on six meters.

I have a broadband butterfly terminated dipole, 110' in the attic. It is 1.3:1 or better on 10-160 meters and 2.6:1 on 6 meters and that is not a problem with my new Kenwood TS590GS and its' internal tuner. I also have an Edison Fong 2m/70cm dipole. Finding antennas for individual bands
came easily with Isotron antennas manufactured here in Colorado. I have 6, 10, 15 and 20 meter isotrons also in the attic.There is a single feedline to the 10, 15, 20 meter antennas, a dedicate feedline to the 6 meter (I am thinking of adding a 17meter to it).

The Isotron antennas work well and I have worked from Alaska to New Hampshire.  The dipole needs to be raised, I have about 6-8 feet more height
available and will do this as the weather cools in about 60 days. I have heard Portugal, Brazil, Chile, Argentina and worked both Canada and Mexico
with the Isotrons.

I have made contacts on 6, 40 and 80 meters along with 20meters on the dipole. I have only heard one qso on 160 but they couldn't hear me. I have
no linear even though the Isotrons will handle 500W inside, 300 on CW or 1000 outside and 500 CW.

KD2HU, for $70 you can have a 20 meter isotron. It is 21 1/2 inches by 5 inches wide. I have all 4 of mine on a 10 foot mast raised to the roof top.
However, you must not have aluminum roofing for the isotrons as they are not effective with that. Three antennas on a single feedline with the jumpers which come without charge if you buy 3 antennas. The 4 antennas weigh less than 4 pounds.

Isotrons are very touchy to get to resonance. They are broadbanded. By using a good antenna tuner you can get very close to 1:1 and you will need to adjust once in the attic. In the attic changes the swr so it will have to be retuned. In my case it was the 20 meter that was most difficult. The
6, 10 and 15 are around 1.3:1 and the 20m is 1.8:1. Isotrons are omni directional.

The balun for the dipole is hard to find but Palomar Engineers has the 16:1 and a 1000K ohms resistor. ARRL handbook states that a 1KW signal will
require a 750 ohm resistor for a terminated dipole resistor. There is a good video for the BBTD antenna. See it by typing in Broadband Terminated
Dipole. The demonstrated dipole there is 132' long. The balun and resistor he uses is no longer available as the company manufacturing them closed 3 or 4 years ago.
 
I just run 100W max as I am barefoot and the dipole resistor handles the power easily.

Yes, they aren't beams but they do work so here is an answer to antennas for HOA restrictions. I believe that as conditions improve in cycle 25 they
will be more than adequate and may even get you some decent DX. One recent qso revealed that with a 20 meter dipole and good conditions the gentleman worked Russia from the mid-west with a 100W transceiver. I think he had it mounted outside though but not real high.

The entire set-up antenna wise, not counting coax, was around $550 including ferrites for all 6 antennas. Of that the balun and resistor were about
$160.

Well, it was long. I hope you enjoyed my efforts. I have a new call that I will get on eham later today. It is KE0VT. I look forward to comments and
working you all sometime.

73
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N9LCD

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Re: Will an attic antenna work?
« Reply #29 on: August 24, 2020, 12:29:30 PM »

Yes, but...

IMO "Attic Antennas" are seasonal.

Our QTH is a 60's vintage with real, massive timber.  Our crawl in attic has about 15 inches of pink fiberglass above the ceiling.

Access to the attic is by an uninsulated plywood hatch in the pantry's ceiling.  A couple of weeks ago, it was sunny and HOT, mid 90's outside!

Under the uninsulated access hatch it was 88 degrees, 13 degrees above the temperature in th rest of the house.

If the attic was anything like our garage, the temperature up there could easily have been WELL OVER 105, 10 to 12 degrees hotter than outside.

Conversely, I suspect that the temperature in the attic may be below 40 degrees.

Before going with an attic antenna:

Make sure there's enough height to work in a comfortable position.

Make sure there's no exposed insulation in the attic or you'll need respiratory protection.  Fiberglass can be as bad as asbestos!

Consider the ambient attic temperature.  Summer heat will limit the time you can work up there.  Winter cold may make it difficult to solder!

73 & good luck!
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