Concrete Barrel Tile Roof Conductivity

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N4IFE

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I live in a community with HOA antenna restrictions. My home is concrete block with a concrete barrel tile roof. As a result, the interior of my home is essentially an inefficient but nevertheless effective Faraday cage. Compounding the problem is a high level of electronic noise inside my home created from electronic light dimmers, electronically controlled appliances, multiple computers, etc. With respect to a reasonable HF receive only antenna, I need something external to the interior of my home and essentially invisible as even a small loop would cause some neighbors and the HOA to go thermo-nuclear.

I considered two solutions; using the rain gutters or running a long wire along the peak of the roof. The metal rain gutters, although long enough, are grounded, albeit poorly, and it is not at all obvious where the ground point(s) are. Therefore the rain gutters are not viable.

Are concrete tiles sufficiently conductive to seriously degrade the HF receive performance of an approximately 60 foot long wire literally attached to and resting on the concrete peak? I would be very interested in hearing from anyone else that might have tried this approach to see if it even approaches a worthwhile effort.

At least two homes in my 850 home community have flag poles in their front yards (they do not appear to be stealth antennas). For multiple reasons, including cost, appearance, and the obvious attention it will bring, make me want to want to avoid that solution.

I use a dual band UHF/VHF vertical in the attic for both transmitting and receiving but its performance is barely full quieting even with nearby repeaters but is sufficient to be usable. Although I would like to transmit on HF, right now my primary goal is to have a reasonable HF antenna for receive only but it must be 100% invisible.
 

RFI-EMI-GUY

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I think you will be happier with some stealthy wire antennas. Especially given the noise floor in modern homes, wired with Romex in Florida. Concrete has water embedded in it so the RF penetration will be compromised. Good to keep noise bottled up from your outdoor wire antenna, bad for indoor antennas. Be sure to install proper grounding and bonding of your antenna.
 

prcguy

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Cast concrete tiles with no metal lath inside are insulators when dry. Sopping wet they would be an RF lossy material and might reflect slightly at some frequencies. If you were to coat them with Thompson's Water Seal or similar then they would not soak up and retain water like a sponge and should remain to an insulator.

There are some very short active VLF through HF receiving antennas that could easily hide on a roof or sit inside an ABS roof vent pipe. Or there are some with about a 3ft thin whip and that could be painted a similar color to the roof so it blends in.
 

K6GBW

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Is there a backyard? Maybe an expandable fiberglass pole with a wire to create a vertical that can be quickly put up and taken down?
 

prcguy

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How bout you run some high power HF with an indoor antenna and wipe out all the neighbors TVs and stereos without telling anyone what you are doing. Then strike up a conversation with the neighbors about the interference you are also getting and tell them you have an antenna thing you can put up to help track down the source of the interference. Then put a scanner antenna on the roof.
 

RFI-EMI-GUY

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The solution is right here. You all can thank me later:

 

merlin

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The solution is right here. You all can thank me later:


Well, I lived in Miami beach (SoBe) back '93ish and never saw that. the peninsula is an incorporated city.
A number of hams and SWLers did live there, but the city frowned on 'antenna farms' they call unsightly.
Mobile antennas strapped to chimney's or vent pipes were about invisible. Longwire sort strung around eves you never see unless pointed out.
A few attic antennas in the lot. Satellite antennas had to be mounted such they couldn't be seen by passing by.
inoperable cars seen from the street got towed plus a fine. ( tow companies ran scams approved by the city).
 

merlin

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Concrete/cinderblock really has little/no effect, especially below UHF. Internal conduits or ROMAX will put a Monkeywrench in things.
Foil backed insulation in attics is the hardest to get around but makes a great ground plane getting above it.
Dealing with noise: one way is buy about 50(qty) .01 Uf/5 or 10 KV ceramic disc capacitors. Every socket gets one from neutral to the hot.
Corded PSUs you may need clamp on type ferrite blocks as close to the PSU you can get in reason.
My solution to longwire for HF down to VLF is a hidden dipole loop around the eave of the roof.
From the feed, run a wire each way completely around the building. Staple to rafters or insulated clamps that hold rain gutters etc.
Where the 2 wires meet at the same length, install a 1000 ohm resistor across the wires, the wattage the same as the expected transmit power.
The design here is a terminated loop. at the feed point, use a 19:1 balun and you can use like RG-8 coax. (I used 600 ohm twin leadin to a tuner.)
The performance I got from this antenna was the second best next to a folded tripole 120 foot long up 50 feet.
( If I can unearth a diagram for this, I will post it later.)
Rain gutters are poor if incorporated into antennas, they wont bother the loop I described.
Cheers
 

RFI-EMI-GUY

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Well, I lived in Miami beach (SoBe) back '93ish and never saw that. the peninsula is an incorporated city.
A number of hams and SWLers did live there, but the city frowned on 'antenna farms' they call unsightly.
Mobile antennas strapped to chimney's or vent pipes were about invisible. Longwire sort strung around eves you never see unless pointed out.
A few attic antennas in the lot. Satellite antennas had to be mounted such they couldn't be seen by passing by.
inoperable cars seen from the street got towed plus a fine. ( tow companies ran scams approved by the city).
I spent enough of my life there to make a couple visits to Beach Towing to retrieve my car. (Hint: the ample parking behind Pinks is not parking) I did see a part of the eruv along the palm trees separating the walkway and the beach off of Collins Ave. It was not that obvious, and of course I thought it was an antenna until it was explained to me.
 

merlin

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OK, here is the idea behind the loop I described, called butterfly by the originator.
I got this idea from a fellow ham. At his house, I never knew about this until he pointed it out to me.
They do have a bit of gain from the balun to the terminator.
As I mentioned, this performs nearly as good as a T3FD I once had up. Only antenna that beats that is a multi wave Rhombic.
73s
 

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merlin

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I spent enough of my life there to make a couple visits to Beach Towing to retrieve my car. (Hint: the ample parking behind Pinks is not parking) I did see a part of the eruv along the palm trees separating the walkway and the beach off of Collins Ave. It was not that obvious, and of course I thought it was an antenna until it was explained to me.
Well, you are in good company with the tow issue. Perhaps I just never noticed the strings. I was busy back and fourth on those 2 wheel scooters from the park at the jetty (south point?) to McDonalds on Washington.
 

RFI-EMI-GUY

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OK, here is the idea behind the loop I described, called butterfly by the originator.
I got this idea from a fellow ham. At his house, I never knew about this until he pointed it out to me.
They do have a bit of gain from the balun to the terminator.
As I mentioned, this performs nearly as good as a T3FD I once had up. Only antenna that beats that is a multi wave Rhombic.
73s
I like those. Pick a wire color to match the roof or soffit and if anyone asks, just say "what wire"? I don't see any wire...
 
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