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*? ?? RAIN? GUTTER? ANTENNA?? on upper HF bands*

*
*

*I've been experimenting with a variety of HF antennas here at my new QTH at Crosslands Retirement Community in Kennett Square, PA.
*

*I have some space limitations, but live on the first floor of a two-story apartment building.*

*Lots of RFI from everywhere inside the building? - S9 on 80m and 40m, less noise on 20 and 10m.
*

*
*

*I have a? 140 ft end-fed wire with a 49:1 UNUN which tunes up easily on 80/40/20m? and not so well on 17m/15m/10m.*

*This end-fed is horizontal, low to the ground (winds among trees) and is good for high-angle NVIS radiation on 80/40m.*

*I use it on the PA NBEMS net (3583 kHz) and on the Mid-Atlantic NBEMS net (7068 kHz)
*

*
*

*
*

*I'd like to get up something with a _low-angle_ signal for DX on? 20/17/10m bands. *

*But can I keep any HF antenna "hidden"?*

*
*

*What I am now trying is the aluminum _rain gutter_? for our building, vertical for about 20 ft, makes a right angle turn and runs horizontally for about 20 ft.*

*The coax attaches at the base of the gutter, near ground, to a 9:1 UNUN with a sheet metal screw into the gutter for a decent electrical connection.
*

*
*

*So overall, about 40 ft of thick (painted) aluminum gutter radiating element - in the shape of an inverted? L and? not resonant on any ham band.*

*Lowest SWR around? 16 MHz.? It looks like it might work out on the 30m band as well (10.1 MHz).
*

*I have a Palomar Engineering? (500W rating) 9:1? UNUN on? 50 ft RG8X? coax into the shack (closet).*

*I have one counterpoise wire about 20 ft long attached to the UNUN?? ground terminal.*

*Then a good manual tuner in the shack to an HF rig for very low SWR on any band.
*

*
*

*Here is what I see on my Nano VNA from 10 - 30 MHz: ? not bad SWR? (under 2.5:1) ? in the shack on 20/17/15/10 meters.*

*I'll give it a try over the next few weeks and see if the local noise is more/less on these bands, compared to my 140 ft end-fed.*

*
*

*I'm often running QRP on these bands, CW and digi modes only.
*

*
*

*de k3eui? barry*

With the maximum SWR ± 2.5 : 1, you must have a lot of loss in the system.
Likely due to that crazy 9:1 transformer. You have a NANOVNA, so measure
the through loss of that transformer.

I'd suggest just feeding your gutter directly without the transformer with
a counterpoise. Lay a wire on the soil surface of a good length as a
counterpoise instead of a ground rod. Then let a capable manual antenna
matching network correct the SWR to keep the transmitter "happy".
I was once in your situation having to use a downspout as an antenna in a
large apartment complex at the east side of Loveland, Colorado. Yes, the
RFI was something to behold!! We were on the third floor, the top-most
floor, and I ran coax out to the downspout with an ugly balun at the
feedpoint. I used the small patio railing (scraped the paint off one of
the mounting legs for contact) as a very small counterpoise. I had a
manual matching network inside to correct the SWR. It sort'a worked, but
the RFI was unbelievably horrendous!

One early morning I decided to try 75-meters. OK, I matched the end of the
feedline with the matching network at 10-watts. I slowly increased the
power to the system. When I reached 25-watts, the fire alarm for the
entire complex (about two city blocks) tripped. Needless to mention,
everyone hit the parking lot with no fire present. Be careful what you do
in any apartment complex. ????? Would I do it again?
Absolutely!!

Lunch and supper times were especially "interesting" at and around 2.45 GHz
on the spectrum analyzer. All the microwave ovens became active. Don't
think for a picosecond those ovens don't leak! With the broadband horn
antenna, I could pick out nearly every one, even from several blocks away.

Dave - W?LEV



On Tue, Mar 4, 2025 at 2:55?PM Barry K3EUI via groups.io <k3euibarry=
[email protected]> wrote:

* RAIN GUTTER ANTENNA on upper HF bands*

*
*

*I've been experimenting with a variety of HF antennas here at my new
QTH at Crosslands Retirement Community in Kennett Square, PA.
*

*I have some space limitations, but live on the first floor of a
two-story apartment building.*

*Lots of RFI from everywhere inside the building - S9 on 80m and 40m,
less noise on 20 and 10m.
*

*
*

*I have a 140 ft end-fed wire with a 49:1 UNUN which tunes up easily on
80/40/20m and not so well on 17m/15m/10m.*

*This end-fed is horizontal, low to the ground (winds among trees) and
is good for high-angle NVIS radiation on 80/40m.*

*I use it on the PA NBEMS net (3583 kHz) and on the Mid-Atlantic NBEMS
net (7068 kHz)
*

*
*

*
*

*I'd like to get up something with a _low-angle_ signal for DX on
20/17/10m bands. *

*But can I keep any HF antenna "hidden"?*

*
*

*What I am now trying is the aluminum _rain gutter_ for our building,
vertical for about 20 ft, makes a right angle turn and runs horizontally
for about 20 ft.*

*The coax attaches at the base of the gutter, near ground, to a 9:1 UNUN
with a sheet metal screw into the gutter for a decent electrical
connection.
*

*
*

*So overall, about 40 ft of thick (painted) aluminum gutter radiating
element - in the shape of an inverted L and not resonant on any ham
band.*

*Lowest SWR around 16 MHz. It looks like it might work out on the 30m
band as well (10.1 MHz).
*

*I have a Palomar Engineering (500W rating) 9:1 UNUN on 50 ft RG8X
coax into the shack (closet).*

*I have one counterpoise wire about 20 ft long attached to the UNUN
ground terminal.*

*Then a good manual tuner in the shack to an HF rig for very low SWR on
any band.
*

*
*

*Here is what I see on my Nano VNA from 10 - 30 MHz: not bad SWR
(under 2.5:1) in the shack on 20/17/15/10 meters.*

*I'll give it a try over the next few weeks and see if the local noise
is more/less on these bands, compared to my 140 ft end-fed.*

*
*

*I'm often running QRP on these bands, CW and digi modes only.
*

*
*

*de k3eui barry*

--

*Dave - W?LEV*


--
Dave - W?LEV

I also live in an apartment complex. One of my antennas is a rain gutter,
about 50 ft horizontal and it includes the downspouts. Inside my apartment
is a 10-meter-long counterpoise along the wall.

I feed it: radio --> an LC matching network --> a 1:1 balun. This gives
me a good match on 7.120 MHz. I only transmit about 5 watts.

I used the nanoVNA to find the L-C match. It told me a 2.2uH series
inductor, with a 142pF shunt, for my gutter antenna.

If i want to use the gutter on, for example, 20 meter WSPR, i use a 9:1
unun with no matching network. That worked really well also at 5W although
5W is overkill for WSPR.

I have better antennas than the gutter, like an attic brass slinky dipole,
and a rooftop dipole that is pretty much invisible, and a couple mag loops
inside the apartment (QRP < 20W), but i do like my gutter.

73 de WN1Z Orrin

On Tue, Mar 4, 2025 at 08:26 AM, W0LEV wrote:

you must have a lot of loss in the system.
Likely due to that crazy 9:1 transformer.

In this case, Dave, it's highly likely the gutter system will have much more loss than the transformer. A gutter can be a reasonable antenna if all of the joints have good RF connections-but that most often requires work.

Mine sucks

On Tue, Mar 4, 2025 at 9:24?PM Stan Dye via groups.io <standye=
[email protected]> wrote:

On Tue, Mar 4, 2025 at 08:26 AM, W0LEV wrote:

you must have a lot of loss in the system.
Likely due to that crazy 9:1 transformer.

In this case, Dave, it's highly likely the gutter system will have much
more loss than the transformer. A gutter can be a reasonable antenna if
all of the joints have good RF connections-but that most often requires
work.

In college, while living in the "half underground" lower level of a new brick 12-plex, I used the downspout(s) as a random vertical antenna. My counterpoise was the AC wiring in the building and an aluminum knitting needle pushed into the soil at the bottom of he spout. With my trusty HW-8 and Argonaut 509 (amd crappy MFJ manual tuner), this was a DX machine. I was too inexperienced to realize that it really shouldn't have worked...
Years later, in a new-ish townhouse, my downspout antenna was a total dummy load, no matter what. I replaced it with an attic-mounted 40-meter horizontal loop fed with a remote autocoupler (antenna about 26 feet AGL)...and THAT was an even better DX machine. My townhouse was at highest point in the county, and I could receive TV signals perfectly from 50-70 miles away with the TV Yagi laying on the asphalt driveway...

With spout antennas, each is unique.
And yes, ditch the UNUN, as you almost certainly don't need it.
Best of luck,
Kirk, NT0Z

My book, "Stealth Amateur Radio," is now available from www.stealthamateur.com and on the Amazon Kindle (soon)

Twice as good as bed spring antennas thrown on the roof.. EVEN better if your house is on wheels and you can turn it with a pickup truck..

Follow me for more REAL Ham Radio Solutions, Insight and Advice...

Larry W8LM
ARRL Life member- Licensed 59 years

Ha! Loved Dave's (W0LEV) fire alarm story! :)

I did the exact same thing a couple years ago in my 3rd floor apartment back in Texas. I was using my SlinkTenna dipole (Google it) and had a blast for the 4 years we were there. It was stretched out under the metal balcony roof (12 feet long) and I was able to keep my power to 30 watts and work 80 - 6 meters! BUT, 30 meters was out of bounds, and when I tried one day to crank up the power on my ICOM 7300 to 20 watts, it tripped the fire alarms for the entire building. Fire engines arrived and it took 30 minutes before all the commotion died down. Very embarrassing, and I never loaded up on 30 Meters again!!!

However, a compromised antenna that gets you onto ANY ham band is a good one, if that's all you've got. Don't let anyone tell you differently. So many of us hams have to deal with all types of restrictions, so my hats off to any ham that is creative and tries to use any type of antenna system to radiate RF and get on the bands--provided it's safe, doesn't pose a threat to others and doesn't irradiate you unnecessarily with RF.....

So, if a rain gutter antenna is all you have, then use it, pay careful attention to the limitations, keep the RF power low and enjoy it!

Stan - WB5UDI

Ok, stealty antennas. How about my cat-net-tenna?
Got a 6 meter wide balcony (spanned with a cat net) on the 6th floor of a
appartment building.
The surface of te facade is all metal. Using a 64:1 unun grounded to te
metal surface

Spending months, weaving patterns. (Zig-zag, coiling, from front to back,
al kind of hybrids). My Vna shows this:



(Back and forward)

Since i was aming 10, 20 and 40 mtr, not bad!

The only thing: the huge metal groundplane seems to act as a reflector
facing south.

PD2I, Imre




Op wo 5 mrt 2025 16:05 schreef Larry Macionski via groups.io <am_fm_radio=
[email protected]>:

You may want to also post this question on the ham-antennas forum.

DaveD
KC0WJN


On Wed, Mar 5, 2025 at 14:48 Imre Biacsics via groups.io <geld.probleempje=
[email protected]> wrote:

Ok, stealty antennas. How about my cat-net-tenna?
Got a 6 meter wide balcony (spanned with a cat net) on the 6th floor of a
appartment building.
The surface of te facade is all metal. Using a 64:1 unun grounded to te
metal surface

Spending months, weaving patterns. (Zig-zag, coiling, from front to back,
al kind of hybrids). My Vna shows this:



(Back and forward)

Since i was aming 10, 20 and 40 mtr, not bad!

The only thing: the huge metal groundplane seems to act as a reflector
facing south.

PD2I, Imre




Op wo 5 mrt 2025 16:05 schreef Larry Macionski via groups.io <am_fm_radio=
[email protected]>:

Twice as good as bed spring antennas thrown on the roof.. EVEN better if
your house is on wheels and you can turn it with a pickup truck..

Follow me for more REAL Ham Radio Solutions, Insight and Advice...

Larry W8LM
ARRL Life member- Licensed 59 years

At the advice of many, I simply removed the 9:1 UNUN (Palomar Engineering) and made a "direct" connection to the rain gutter via a sheet metal screw.
Then ran one radial along the ground (I will try more radials later).
Much to my surprise, it now loads better on the 10/15/20 meter bands.
I will try it on the air today (QRP power only) to avoid setting off any fire alarms here (TU for that advice).

I realise that the information from the Nano VNA in my shack has limited value - TU.
Coax is 50 ft RG8X (decent quality) and a couple of "isolators" (RF chokes) in the shack.

de k3eui barry Philly
March 06 2025

Just want to understand correctly why the fire alarms went off.
I'm thinking the fire alarms are on the 450MHz band somewhere. So are they set off due to some harmonic from the HF bands you all are trying, or is it just plain RFI from the non-resonant attempt for an antenna?
Thanks and 73.
Jim - N?TRP

Just simple overload of the sensors. They typically are tied together
throughout a single installation which may consist of a whole apartment
complex. If one is tripped, the whole complex is tripped.

For example, if you connect a fast diode to a couple of clip leads and
measure the developed (rectified) voltage while you're transmitting, it's
easily enough potential to "trip" about any modern semiconductor into
conduction. You'd be surprised how sensitive modern electronics are to
stray RF fields!! I used to do just this for Uncle. I can't confirm or
deny anything.......

Dave - W?LEV



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On Fri, Mar 7, 2025 at 4:24?PM Jim Blanchard via groups.io <proptop12=
[email protected]> wrote:

Just want to understand correctly why the fire alarms went off.
I'm thinking the fire alarms are on the 450MHz band somewhere. So are they
set off due to some harmonic from the HF bands you all are trying, or is it
just plain RFI from the non-resonant attempt for an antenna?
Thanks and 73.
Jim - N?TRP

--

*Dave - W?LEV*


--
Dave - W?LEV

"You'd be surprised how sensitive modern electronics are to
stray RF fields!!"

Not at all surprised. I recently had to remove the flatbed scanner from the desk where the computer it is connected to sits, which is near the 530. Every time I tripped the transmitter to load the thing or test something, the scanner would do a start-up cycle.

"I used to do just this for Uncle. I can't confirm or
deny anything......."

Yeah. Me too. Never happened.

I have fault tolerant outlets in kitchen and bathroom. Any time I key up on 70cm band within a few meters of those outlets, they trip! The 2M band doesn't do this...

Matthew KD6KVH