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Re: rain gutter antenna

I also have one rain gutter antenna it's about 50 ft long and 8 ft above
ground level. For one 40-meter freq i use a 1:1 balun (indoor 10-meter-long
radial) plus a matching network i designed using the nanoVNA. Low power,
about 5W, talking on CW across town but haven't tried any distant contacts.

The same rain gutter and radial i've used on 20 meter WSPR using a 9:1
balun with no add'l matching network. I was heard worldwide on 20m WSPR,
when conditions were good, but that's not a 2-way contact.

Anyway i have better antennas than that, but it's fun to play with.
Apartment complex, so i have an attic dipole and an invisible wire dipole
on the roof (13 ft AGL) that i was allowed to have because the wires are
tucked under the shingles and are almost impossible to see.

Best 73 de WN1Z
Orrin


El vie, 25 abr 2025 a la(s) 9:00?a.m., W0LEV via groups.io (davearea51a=
[email protected]) escribió:

Out of a major forest fire, insurance put us up in a large apartment
complex for 2 years. I chose the 3d floor - the top - for RF reasons. Of
course, the apartment complex came with its manditory set of rules:
Absolutely no antennas of any kind. However, being on the 3d floor, we had
quite an assembly of rain gutters on the external surface of the building.
The light went on......

I used the small metal railing on the miniature patio as a counterpoise. I
snaked two wires through a drain hole at the bottom of the sliding door to
the miniature patio. One wire connected to the coax braid and the other
wire connected to the center conductor. The two wires were twisted to form
a "sort'a" transmission line. Of course, the briad wire connected to the
railing (after scraping a small amount of paint). The center conductor
wire connected to one of the downspouts (after scraping a bit of paint).
Once inside, I made an "ugly balun" by winding extra coax around a 3"
diameter cardboard tubing. I vaguely remember around 15 turns of coax on
the tube. From there, the coax was routed to the loft and fed an antenna
"tuner".

Well, it worked OK. But the RFI generated within the apartment complex was
so bad, I could detect it on a crystal set using the rain gutter antenna
directly connected to the crystal radio. Yes, I made a few contacts and
had excellent reports, but the RFI severely compromised reception.

Yes, rain gutters do work as makeshift - and "invisible" and unsuspecting -
antennas. However, one morning I got the bug to attempt 75-meters with the
antenna "tuner". That was a mistake. At the low power level of 20-watts,
I set off the fire alarm throughout the entire complex (about 2 city blocks
in area). Would I do it again? Absolutely!!!

Fortunately, we no longer reside there!!!

Dave - W?LEV

On Fri, Apr 25, 2025 at 3:33?PM Barry K3EUI via groups.io <k3euibarry=
[email protected]> wrote:

*
*

*How good can a RAIN GUTTER be on HF bands?*

*
*

*Since moving to a "retirement community" last year I have been
searching for a reasonably good HF antenna.*

*I have tried a few 10-20 ft verticals (not well hidden) and a 140 ft
long wire end-fed wire (which everyone can see).*

*
*

*So how about a commercial aluminum (painted) rain gutter.*

*I feed it with 50 ft RG8X into a Palomar Engineering 9:1 UNUN
with two counterpoises: 15 ft and 30 ft.*

*I have a wide-range tuner in the shack, so now SWR issues.
*

*Well, it is "hidden" and it does tune up on 160m, 40m, 30m, 17m, and
10 meters with SWR < 2.5:1*

*but that may mean it is just "lossy" (the UNUN).*

*
*

*I'll give it a try this weekend with Fldigi, running no more than 25
watts on CW, PSK, and Olivia/Thor modes.*

*I'm really curious about 160m at night - I have never operated on that
band.*

*Are there "watering holes" (freq) where different sound card modes hang
out?*

*Seems like everything is FT8 these days.
*

*10m should be easy, as it is both vertical and horizontal polarization.
*

*
*

*Here are Nano VNA SWR and RETURN LOSS graphs.*

*I plot RETURN LOSS as a negative number to have the same shape as the
SWR curve.
*

*I did one run from 1.8 to 8 MHz, and the other run from 8 to 30 MHz.
*

*I'm excited about this new antenna. No one can "see it".*

*But how well will it work?
*

*de k3eui barry*

--

*Dave - W?LEV*


--
Dave - W?LEV

Out of a major forest fire, insurance put us up in a large apartment
complex for 2 years. I chose the 3d floor - the top - for RF reasons. Of
course, the apartment complex came with its manditory set of rules:
Absolutely no antennas of any kind. However, being on the 3d floor, we had
quite an assembly of rain gutters on the external surface of the building.
The light went on......

I used the small metal railing on the miniature patio as a counterpoise. I
snaked two wires through a drain hole at the bottom of the sliding door to
the miniature patio. One wire connected to the coax braid and the other
wire connected to the center conductor. The two wires were twisted to form
a "sort'a" transmission line. Of course, the briad wire connected to the
railing (after scraping a small amount of paint). The center conductor
wire connected to one of the downspouts (after scraping a bit of paint).
Once inside, I made an "ugly balun" by winding extra coax around a 3"
diameter cardboard tubing. I vaguely remember around 15 turns of coax on
the tube. From there, the coax was routed to the loft and fed an antenna
"tuner".

Well, it worked OK. But the RFI generated within the apartment complex was
so bad, I could detect it on a crystal set using the rain gutter antenna
directly connected to the crystal radio. Yes, I made a few contacts and
had excellent reports, but the RFI severely compromised reception.

Yes, rain gutters do work as makeshift - and "invisible" and unsuspecting -
antennas. However, one morning I got the bug to attempt 75-meters with the
antenna "tuner". That was a mistake. At the low power level of 20-watts,
I set off the fire alarm throughout the entire complex (about 2 city blocks
in area). Would I do it again? Absolutely!!!

Fortunately, we no longer reside there!!!

Dave - W?LEV

On Fri, Apr 25, 2025 at 3:33?PM Barry K3EUI via groups.io <k3euibarry=
[email protected]> wrote:

*
*

*How good can a RAIN GUTTER be on HF bands?*

*
*

*Since moving to a "retirement community" last year I have been
searching for a reasonably good HF antenna.*

*I have tried a few 10-20 ft verticals (not well hidden) and a 140 ft
long wire end-fed wire (which everyone can see).*

*
*

*So how about a commercial aluminum (painted) rain gutter.*

*I feed it with 50 ft RG8X into a Palomar Engineering 9:1 UNUN
with two counterpoises: 15 ft and 30 ft.*

*I have a wide-range tuner in the shack, so now SWR issues.
*

*Well, it is "hidden" and it does tune up on 160m, 40m, 30m, 17m, and
10 meters with SWR < 2.5:1*

*but that may mean it is just "lossy" (the UNUN).*

*
*

*I'll give it a try this weekend with Fldigi, running no more than 25
watts on CW, PSK, and Olivia/Thor modes.*

*I'm really curious about 160m at night - I have never operated on that
band.*

*Are there "watering holes" (freq) where different sound card modes hang
out?*

*Seems like everything is FT8 these days.
*

*10m should be easy, as it is both vertical and horizontal polarization.
*

*
*

*Here are Nano VNA SWR and RETURN LOSS graphs.*

*I plot RETURN LOSS as a negative number to have the same shape as the
SWR curve.
*

*I did one run from 1.8 to 8 MHz, and the other run from 8 to 30 MHz.
*

*I'm excited about this new antenna. No one can "see it".*

*But how well will it work?
*

*de k3eui barry*

--

*Dave - W?LEV*


--
Dave - W?LEV

*
*

*How good can a RAIN GUTTER be on HF bands?*

*
*

*Since moving to a "retirement community" last year I have been searching for a reasonably good HF antenna.*

*I have tried a few 10-20 ft verticals (not well hidden) and a 140 ft long wire end-fed wire (which everyone can see).*

*
*

*So how about a commercial aluminum (painted) rain gutter.*

*I feed it with 50 ft RG8X?? into a? Palomar Engineering? 9:1? UNUN? with two counterpoises: 15 ft and 30 ft.*

*I have a wide-range tuner in the shack, so now SWR issues.
*

*Well, it is "hidden" and it does tune up? on 160m, 40m, 30m, 17m, and 10 meters with SWR? < 2.5:1*

*but that may mean it is just "lossy" (the UNUN).*

*
*

*I'll give it a try this weekend with Fldigi, running no more than 25 watts on CW, PSK, and Olivia/Thor modes.*

*I'm really curious about 160m at night - I have never operated on that band.*

*Are there "watering holes" (freq) where different sound card modes hang out?*

*Seems like everything is FT8 these days.
*

*10m should be easy, as it is both vertical and horizontal polarization.
*

*
*

*Here are ? Nano VNA??? SWR?? and ? RETURN LOSS graphs.*

*I plot RETURN LOSS as a negative number to have the same shape as the SWR curve.
*

*I did one run from 1.8 to 8 MHz, and the other run from? 8 to 30 MHz.
*

*I'm excited about this new antenna.? No one can "see it".*

*But how well will it work?
*

*de k3eui?? barry*

On Wed, Apr 23, 2025 at 06:31 PM, Clyde Spencer wrote:

This can be improved by adding a small Common Mode Choke at the VNA end to
help isolate the coax from the case of the device.

Clyde, in HTs used for their purpose, which is portable communications, the body of the HT, and even the body of the operator are all part of the antenna. If you mount a rubber duckie directly on a NanoVNA, possibly on a metal bracket, and hold it in your hand, you emulate this situation, and get values close to the real thing. But if you isolate the rubber duckie from the instrument by means of a common mode choke, you will create a very different situation, and totally mess up the measurement!

A rubber duckie at the end of a coax cable will behave totally different than when mounted on an HT.

Manfred

This can be improved by adding a small Common Mode Choke at the VNA end to
help isolate the coax from the case of the device. The frequency being
measured also has an impact.

*Clyde K. Spencer*



On Wed, Apr 23, 2025 at 1:28?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

Yes, I have noted that the SWR changes when holding the VNA vs. not
holding it, and touching the SMA connector vs. not touching it. The
readings generally are better when touching vs. not touching.

Ken, W4KRR


On 4/23/2025 12:20 PM, Manfred Mornhinweg via groups.io wrote:

I have a whole load of rubber duck antennas that I'm checking so see at
what range they should work best.

Ken,
the behavior of rubber duckies depends significantly on the radio they

are attached to. So, to get reasonably accurate results when measuring them
with the nanoVNA, I suggest that you build a metal bracket about the size
of a typical HT, covered with some insulation to mimmick the plastic body
of an HT, mount the nanoVNA in that bracket, its measuring port bonded to
the bracket, and then hold that contraption in your hand like you would
hold an HT, while making the measurements.

You could even use a plastic box the size of an HT, covered with

aluminium foil on the inside, properly bonded to the nanoVNA's port.

Of course you need to run the nanoVNA without an USB cable connected.

You will see that depending on how you grab that test contraption, the

measured values will shift somewhat. If you mount the antenna directly to
the nanoVNA, they will shift more, since the nanoVNA is a lot smaller than
an HT, at least the 2.8" screen version. I haven't compared the size of the
H4 version to that of an HT. It should be closer, but maybe not close
enough.

Perhaps someone else can comment on how accurate the measurements come

out when mounting a rubber duckie directly on an H4?

Manfred

Yes, I have noted that the SWR changes when holding the VNA vs. not holding it, and touching the SMA connector vs. not touching it. The readings generally are better when touching vs. not touching.

Ken, W4KRR

I have a whole load of rubber duck antennas that I'm checking so see at
what range they should work best.

Ken,
the behavior of rubber duckies depends significantly on the radio they are attached to. So, to get reasonably accurate results when measuring them with the nanoVNA, I suggest that you build a metal bracket about the size of a typical HT, covered with some insulation to mimmick the plastic body of an HT, mount the nanoVNA in that bracket, its measuring port bonded to the bracket, and then hold that contraption in your hand like you would hold an HT, while making the measurements.

You could even use a plastic box the size of an HT, covered with aluminium foil on the inside, properly bonded to the nanoVNA's port.

Of course you need to run the nanoVNA without an USB cable connected.

You will see that depending on how you grab that test contraption, the measured values will shift somewhat. If you mount the antenna directly to the nanoVNA, they will shift more, since the nanoVNA is a lot smaller than an HT, at least the 2.8" screen version. I haven't compared the size of the H4 version to that of an HT. It should be closer, but maybe not close enough.

Perhaps someone else can comment on how accurate the measurements come out when mounting a rubber duckie directly on an H4?

Manfred

make the swr trace active and then press on calib (without recalibrating) and then save to slot 0 (default slot on boot up) ... i do the same if i want other settings to be saved (be it avg setting or number of points or whatever)

dg9bfc sigi

Am 22.04.2025 um 11:36 schrieb Torbj?rn Toreson via groups.io:

QUOTE: Be sure to calibrate to the end of the coax at the antenna. Coax
will influence the measurements, especially if it is longer than a
wavelength. (unless is is electrically an odd multiple of a half wave.) You
will find your measurement make more sense at VHF/UHF frequencies with the
NanoVNA calibrated to the antenna end of the coax.

****

A bit of a correction is in order:

1) COAX WILL NOT INFLUENCE THE MEASUREMAENTS. But if there is a mismatch
at the antenna where the coax connects to the antenna, the COAX WILL ALTER
the IMPEDANCE. That alteration is what you will measure between the
antenna feedpoint and the shack end of the coax.

2) ANY WHOLE NUMBER MULTIPLE of an electrical 1/2-wavelength in the coax
will reflect the actual antenna feedpoint impedance with a bit loss
included. A 1/2-wavelength is also fully around, 360-degrees or
2π-radians, the Smith Chart.

3) Once you calibrate the feed coax at the end where it would connect to
the antenna feedpoint, you will measure the actual antenna feedpoint
impedance at the shack end of the coax regardless of coax length.

Dave - W?LEV

On Tue, Apr 22, 2025 at 10:25?PM Russ via groups.io <u.rusty=
[email protected]> wrote:

On Tue, Apr 22, 2025 at 08:10 AM, Kenneth Roberts wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of

144-174,

and then I change the range to, say, 144-148, do I need to re calibrate?

I always do, just to obtain as much accuracy as possible.

Also: Be sure to calibrate to the end of the coax at the antenna. Coax
will influence the measurements, especially if it is longer than a
wavelength. (unless is is electrically an odd multiple of a half wave.) You
will find your measurement make more sense at VHF/UHF frequencies with the
NanoVNA calibrated to the antenna end of the coax.

--

*Dave - W?LEV*


--
Dave - W?LEV

Thanks to all for the advice.

I have a whole load of rubber duck antennas that I'm checking so see at what range they should work best.? Some of them I don't even know what band they're supposed to be designed for.?? Good learning experience for using the Nano.

Ken, W4KRR

On Tue, Apr 22, 2025 at 09:22 AM, Jon wrote:

As the second range is well within the first range

With the second range within the first range, the nanovna does an excellent job of interpolating between the calibration points, and you will get good readings, especially for general tasks like return loss, SWR, attenuation, etc. But if you need the best precision in the results, do a calibration at the new range.

I myself wouldn't be sure of the results. I would re-calibrate it for
144-148 MHz. Then store in a different memory slot than the one I stored
144-174 MHz in. It only takes a few minutes to calibrate it.

Zack W9SZ

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Tue, Apr 22, 2025 at 11:22?AM Jon via groups.io <vu2jo0=
[email protected]> wrote:

As the second range is well within the first range, you may be able to get
away with it, though the ideal way is as Dave has mentioned.

73
Jon, VU2JO

On Tue, Apr 22, 2025 at 8:40?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

I would re-calibrate when I change to 144-148 MHz. That way I'd be sure.
I'd probably save that in a different memory slot than the 144-174 MHz.

Zack W9SZ

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Tue, Apr 22, 2025 at 10:35?AM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

Just received my H4. If I calibrate for a range of, say, 144-174 MHz, can
I change the range to 144-148 without recalibrating? I guess I'm asking
under what circumstances is recalibration necessary?

As the second range is well within the first range, you may be able to get
away with it, though the ideal way is as Dave has mentioned.

73
Jon, VU2JO

On Tue, Apr 22, 2025 at 8:40?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

You will only have valid measurements within the frequency range you calibrated. You can decrease the frequency range and the firmware will interpolate between the calibrated points but the accuracy will decrease.

Just received my H4. If I calibrate for a range of, say, 144-174 MHz, can I change the range to 144-148 without recalibrating? I guess I'm asking under what circumstances is recalibration necessary?

When changing sweep ranges, it's always a good idea to recal.

Dave - W?LEV

On Tue, Apr 22, 2025 at 3:10?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

--

*Dave - W?LEV*


--
Dave - W?LEV

I'm new to the NanoVNA H-4.? If I calibrate for SWR in the range of 144-174, and then I change the range to, say, 144-148, do I need to re calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I need to re calibrate?

By design, slot 0 is activated on power-up, not any other slot.

Yes, if you calibrate, then change trace and display options, then save calibration again, it save the currently active calibration and current display/trace setup, no matter which slot (or SD card file name) you save it to.

On Tue, Apr 22, 2025 at 06:05 AM, PE0CWK wrote:

Maybe the firmware version of my NanoVNA -H4 is important.

Yes I think the nanovna firmware version needs to be somewhat recent. This capability was added a year or so ago I think. You can also get the current firmware for the H4 from DiSlord's nanovna-d github page.