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Author Topic: RAIN GUTTER ANTENNA  (Read 3812 times)
N9LCD
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Posts: 157




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« on: December 14, 2012, 07:49:46 PM »

I've gutters on  about decided to use the rain gutters on our house for my first HF antenna.  Yeah, there are better antennas - whatever is your favorite and works for you.  BUT the gutters would save the cost of an antenna, supporting mast(s), guys, etc. and the joys (hi, hi) of installing an antenna.

Our house is approximately 25 feet wide by 45 feet long, with an east-west orientation.  My general plan is:  bond the gutters for electrical continuity at the southeast and northeast corners; electrically isolate the gutters facing west; electrically isolate the downspouts for safety reasons; and feed the gutters/antenna with a high voltage wire from a wide range tuner.

The gutters are approximately 12 to 15 feet above the ground.

I know I'll never get 6-band DXCC, WAS and WAZ, but, after 20 years on VHF and UHF, I want to get on HF and the "gutter antenna" meets the constraints I face.

QUESTIONS:

Does anybody have any experience using their rain gutters as a HF antenna?

Any guidance for the planning & implementation processes? 

What could I expect from a transmitting & receiving standpoint running 100 - 150 watts output?

What kind of a pattern could my "gutter antenna" have?

Thanks & 73!


N9LCD



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WN2C
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Posts: 428




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« Reply #1 on: December 14, 2012, 08:07:38 PM »

In the 'old days' they use to say load up the bed springs.  I've never heard of load up the rain gutters but I have heard of guys using the drip edge on the roof.  What "other constraints" do you have.  I take it they are either Wife or HOA constraints?

de wn2c  Rick
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WB6BYU
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Posts: 12985




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« Reply #2 on: December 14, 2012, 09:33:36 PM »

The pattern will depend where you connect the feed wire.  If you feed it at
one end then the pattern on 40m will be mostly omnidirectional, but with
strongest signals to the EAST/WEST.  On 20m the maximums will tend to
be NORTH/SOUTH.  On higher bands there will be multiple lobes and nulls
in the pattern.

80m is generally omnidirectional, reasonably good for local NVIS contacts.

A good set of ground radials will help a lot on 40m and 80m where the
feedpoint impedance will be low (6 to 20 ohms) due to the low height
above ground.

Feeding at an end is probably a better choice than at some point in the
middle of the antenna.
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N4NYY
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Posts: 4742




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« Reply #3 on: December 15, 2012, 04:35:10 AM »

Use something like an SG auto tuner and run some ground radials. That would make it ideal.
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W6GX
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Posts: 2298




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« Reply #4 on: December 15, 2012, 05:50:49 PM »

My first HF antenna was a rain gutter antenna.  You will make some contacts with it.  And it loads up nicely SWR-wise as most of the power is dissipated as heat in the coax.  Unless you have HOA restrictions you'd be better off with something else.  If you have an attic you could mount a dipole hidden in the attic.  You're welcomed to try the gutter but I guarantee you will not be satisfied with it in the long-term.  There are truly better alternatives.  GL.

73,
Jonathan W6GX
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WB6BYU
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« Reply #5 on: December 15, 2012, 06:40:22 PM »

Quote from: KF7BBJ
...And it loads up nicely SWR-wise as most of the power is dissipated as heat in the coax...


These two conditions go together only if you have excessive loss in your coax
to start with.

If you use a remote tuner at the antenna feedpoint, the coax losses will be low.
That might be an auto-tuner, or a manually-switched tuner, or even a tuner in
the shack if the feedline is very short.  In the case as originally described, where
the antenna is matched with a wide range tuner, the main source of loss will be
in the ground system unless there are enough radials to make a good ground.

The main performance limitation above 40m is due to the low antenna height.
Depending on the exact length (in wavelengths) on each band, in some cases
the vertical wire will be responsible for most of the useful radiation.
On 40m the antenna performance will depend on the ionospheric conditions
and where the band is open.  On 80m the antenna will work reasonably well
for local stations, but the ground losses will be important.

In any case, you need a good ground system to feed it against, and if the
tuner is close to the feedpoint the coax losses will probably be insignificant.
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N9LCD
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Posts: 157




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« Reply #6 on: December 15, 2012, 07:33:19 PM »

WN2C:

My constraints are:

COST: the antenna, required hardware, masts, guys, etc.  The gutters are paid for.

ELECTRICAL SAFETY: staying away from the power lines at the southwest corner of the house.  I don't want an antenna that parallels power lines into the house (line noise) or that power lines can fall on.

PERSONAL SAFETY:  working on the roof.  The XYL doesn't want me breaking something  if I fall off the roof.

THE QTH:  avoiding problems caused by drilling into the roof.

THE ATTIC:  really a crawl space -- height at highest point, about 4 FEET.  Fiberglass insulation between ceiling joists(?) may have aluminum foil backing.

RETIREMENT:  no antenna to take down and sell (or give away) if this venture doesn't pan out.

73

N9LCD

 
 
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WD8KNI
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Posts: 137




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« Reply #7 on: December 16, 2012, 01:22:05 AM »

Logged several hundred CW contacts loading rain gutter.  My suggestion is to dump the idea, why.. damp wood, rain, snow.. you and the gutter are screwed. its like mounting your antenna on a conductor..  After I figured out the problem, I glued an insulted wire in the brick grout line, that worked very well..  Fred
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W5WSS
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Posts: 1604




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« Reply #8 on: December 16, 2012, 03:36:26 AM »

Perhaps the best answer is it depends.

Some thoughts.

Feedpoint position is conducive to  pattern development, along with the physical orientation of the vertical drop vs the horizontal half.

In this case one may feed it at the junction where the two different halves travel away.

The antenna would be a somewhat off center fed L not knowing the two dimensions I am just hypothesising. A 2:1 ratio horizontal to vertical?

The gutter is as good a prospect as many indoor antennas. Except for the moisture and snow etc but indoor antennas suffer the rooftop being loaded with snow ice or wet with rain no getting around it.

A good wide range tuner may be needed to adjust for those additional problems.
And  in any application of multi band service anyway.

Indoor antennas are weather proof but affected by the the snow on the roof etc.

As a reference standard A mono band center fed L where the feedpoint is a 1/2 wave above ground and the bottom vertical end is 8ft above the surface would be a predictable point of reference. See W4rnl website for patterns modeled or model it yourself. Your antennas pattern will obviously be different by some unpredictable amount. That is not to say that the antenna will not offer a utility to you. because it can.

OTOH. End feeding and a remote tuner along with ground radials may be really fun where the antenna operates as a vertical with a L shape.

The pattern again may be compared to a standardised convention and yours could be close minus the house structure and mutual coupling to nearby conductors etc.

The point is depends is not soley pessimistic but rather hopeful.

Have fun A remote tuner at the feedpoint might give you more of what you like.
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M6GOM
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Posts: 864




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« Reply #9 on: December 16, 2012, 07:58:43 AM »

Use something like an SG auto tuner and run some ground radials. That would make it ideal.

I'm sure the SGC230 manual even shows using gutters as one of the options for stealth antennas.
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K5LXP
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Posts: 4439


WWW

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« Reply #10 on: December 16, 2012, 08:00:23 AM »

Indoor antennas are weather proof but affected by the the snow on the roof etc.

Snow is essentially transparent to RF until you reach frequencies in the GHz range.  It's mostly air with nonconductive ice crystals.


Mark K5LXP
Albuquerque, NM

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W5WSS
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Posts: 1604




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« Reply #11 on: December 16, 2012, 06:40:24 PM »

Ok Mark by the way I heard you on 15m during the summer at a mountain cottage in Tennessee.

The remote tuner or even a manual variable matching network can compensate for the loading effect that the material causes.

 otherwise a mechanical non variable matching network such as a tap and coil can not.

A  horizontal section gutter full of frozen Fresh water or snow attenuates radiation to some extent and I did not quantify it, I  think it worthy to note as a precaution. Alas It melts.

Powder type snow is not as dense as solid frozen water.

 When someone decides to use a rain gutter antenna compromises are expected and would not stop me in any case.

Probably affects the bottom cup shape which constitutes 50% of the horizontal conductor.

That's about all. 73

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K5KNE
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Posts: 65




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« Reply #12 on: December 16, 2012, 11:05:05 PM »

You can try it, but don't expect it to work like a dipole in the clear of close obstructions.  You know that the length for the frequency you are working will require you to have a gap in the gutter at the proper length.  If you have a composition roof there may also be a drip flashing that runs around the roof line.  It will be a problem for your gutter antenna if it does not have a gap at the same place the gutter does.

Consider how close the wiring in the house is to the gutter too - and it also may have a lot of noise on the wiring with will be picked up by the antenna.  Also consider that you may make interference on your TV or Stereo in the house by having the antenna so close.

Eventually you will come to the conclusion that the rain gutter is not a very good antenna and put up a conventional antenna like an inverted V or dipole using a tv mast or chimney for the support. I suggest that you find a way to start out with a reasonable antenna and improve it from there.  There is not much way you can improve on a gutter antenna.

Good Luck  Walter  K5KNE
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WN2C
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Posts: 428




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« Reply #13 on: December 17, 2012, 04:01:05 AM »

Gerald, after looking at yout QTH on QRZ, it looks like you have a small back yard.  How about a ground mounted vertical or a ground mounted screwdriver?
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W1JKA
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« Reply #14 on: December 17, 2012, 04:22:17 AM »

WN2C:
             Re: Reply #6
                         
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