I modeled your antenna using EZNEC both with one and two 33-foot radials.
Your SWR plots follow the results of my model embarrassing well. Addition
of the second radial brings the AZ plot pretty much to a circle. With the
single radial, the pattern is maximized along the radial.
Dave - WØLEV
On Wed, Jul 17, 2024 at 2:46 PM Barry K3EUI via groups.io <k3euibarry=
gmail.com@groups.io> wrote:

*
*

*My goal: build a simple _inexpensive_ vertical for LOW-angle take-off
for the 30m thru 10m bands*

*(I already have a 40m NVIS low horizontal wire for NBEMS nets)
*

*
*

*I began with a 30 yr old Cushcraft A10 (halfwave on 10m band only) all
aluminum vertical and took out the 10m parallel matching circuit LC
*

*and replaced it with a Palomar Engineering 9:1 UNUN (the bullet model).*

*I had no idea what kind of impedance this 18 ft vertical would show on
30m thru 10m.*

*But it was on hand after 30 yr as a single band 10m antenna, had no
expensive traps for each band (like the 5BTV Hustler), and not all that
imposing to folks in my apartment complex.*

*It kind of looks like a tall fishing pole.*

*I may put a bird house or bird feeder near the top to disguise it a bit.
*

*It is mounted on a 4 ft mast to get it off the ground a few feet.*

*
*

**

*
*

*Once it showed low SWR on these bands, I assumed that was a "good start".*

*And yes, I measured the SWR with the Nano VNA and SAVER software, from
the shack (at the end of 50 ft RG213 and a choke).
*

*I can certainly now tune this up on 30m thru 10m with a SWR of about
2:1 in the shack.*

*Shack tuner cleans up the rest to a 1:1 match for the rig to see.*

*Running about 25 watts at the moment, and tried FT8 (heard no PSK31,
MFSK, olivia or THOR on 17m)
*

*Whether it works (or not) is not a certainty shown by the low SWR test,
so we will see who actually hears me using PSK reporter.*

*
*

*I just added a second 30 ft radial on the ground (good advice) and this
is the new Nano VNA plots for SWR and RETURN LOSS.*

*Of course there are likely losses in the 9:1 UNUN and 50 ft coax since
the RETURN LOSS minimum is about 7 dB and maximum about 17 dB where
SWR is lowest.
*

*Yes, I am plotting RETURN LOSS as a negative value to have the same
shape as the SWR graph.
*

*
*

*de k3eui Barry*

*near Phila PA USA*



*Here are the stations who hear me (10 AM July 17) on 17m band (18.1
MHz) with FT8 *

*I am from the Phila PA USA region.*

*Not bad for a 30 yr old 10m vertical repurposed for six bands at just
the cost of one 9:1 UNUN*

*Maybe I could have wound my own 9:1 and saved some $*

*
*

Yes, I did also look at EL plot. With one radial, the RF is maximized
along the single radial and about 40 to 45 degrees above horizontal. With
the second radial, the AZ plot is almost circular and the launch angle is
between 30 and 35 degrees.
Dave - WØLEV
On Wed, Jul 17, 2024 at 6:37 PM Dave (NK7Z) via groups.io <dave=
nk7z.net@groups.io> wrote:

Dave (W0LEV),

Did you by chance plot launch angle? If so, was there a difference in
the model?

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 7/17/24 09:34, W0LEV wrote:

I modeled your antenna using EZNEC both with one and two 33-foot radials.
Your SWR plots follow the results of my model embarrassing well.

Addition

of the second radial brings the AZ plot pretty much to a circle. With

the

single radial, the pattern is maximized along the radial.

Dave - WØLEV

On Wed, Jul 17, 2024 at 2:46 PM Barry K3EUI via groups.io <k3euibarry=
gmail.com@groups.io> wrote:

*
*

*My goal: build a simple _inexpensive_ vertical for LOW-angle take-off
for the 30m thru 10m bands*

*(I already have a 40m NVIS low horizontal wire for NBEMS nets)
*

*
*

*I began with a 30 yr old Cushcraft A10 (halfwave on 10m band only) all
aluminum vertical and took out the 10m parallel matching circuit LC
*

*and replaced it with a Palomar Engineering 9:1 UNUN (the bullet

model).*

*I had no idea what kind of impedance this 18 ft vertical would show on
30m thru 10m.*

*But it was on hand after 30 yr as a single band 10m antenna, had no
expensive traps for each band (like the 5BTV Hustler), and not all that
imposing to folks in my apartment complex.*

*It kind of looks like a tall fishing pole.*

*I may put a bird house or bird feeder near the top to disguise it a

bit.

*

*It is mounted on a 4 ft mast to get it off the ground a few feet.*

*
*

**

*
*

*Once it showed low SWR on these bands, I assumed that was a "good

start".*

*And yes, I measured the SWR with the Nano VNA and SAVER software, from
the shack (at the end of 50 ft RG213 and a choke).
*

*I can certainly now tune this up on 30m thru 10m with a SWR of about
2:1 in the shack.*

*Shack tuner cleans up the rest to a 1:1 match for the rig to see.*

*Running about 25 watts at the moment, and tried FT8 (heard no PSK31,
MFSK, olivia or THOR on 17m)
*

*Whether it works (or not) is not a certainty shown by the low SWR test,
so we will see who actually hears me using PSK reporter.*

*
*

*I just added a second 30 ft radial on the ground (good advice) and this
is the new Nano VNA plots for SWR and RETURN LOSS.*

*Of course there are likely losses in the 9:1 UNUN and 50 ft coax since
the RETURN LOSS minimum is about 7 dB and maximum about 17 dB where
SWR is lowest.
*

*Yes, I am plotting RETURN LOSS as a negative value to have the same
shape as the SWR graph.
*

*
*

*de k3eui Barry*

*near Phila PA USA*



*Here are the stations who hear me (10 AM July 17) on 17m band (18.1
MHz) with FT8 *

*I am from the Phila PA USA region.*

*Not bad for a 30 yr old 10m vertical repurposed for six bands at just
the cost of one 9:1 UNUN*

*Maybe I could have wound my own 9:1 and saved some $*

*
*