HFp Antenna User’s Guide
HFp
HFpHFp
HFp
The Ventenna Co. LLC
User’s Guide
7 MHz – 30 MHz Amateur Radio Antenna
Citrus Heights, CA, 95611
Vertical
Vertical
VerticalVertical
P.O. Box 2998,
www.ventenna.com
entenna
HFp Antenna User’s Guide
Table of Contents
The HFp Antenna ------------------------------------------------------------------- 3
HFp Vertical Parts List ------------------------------------------------------------- 4
Assembling the antenna for use --------------------------------------------------- 5
HFp Vertical Configuration ------------------------------------------------------- 7
HFp Configuration tables ---------------------------------------------------------- 8
Fine Tuning -------------------------------------------------------------------------- 9
HFp Antenna Notes ----------------------------------------------------------------- 10
Antennas --------------------------------------------------------------------- 10
Set Up Hints ---------------------------------------------------------------- 10
Frequency Adjustments --------------------------------------------------- 10
Radials and SWR ---------------------------------------------------------- 11
Guy Lines ------------------------------------------------------------------- 11
Inter-Element Connectors ------------------------------------------------ 11
The HFP antenna,
assembled in its 40
Meter configuration,
with included guy
lines attached. It’s
about 11 feet tall –
you can just see the
top whip against the
tree background. If
the guy lines were
black, it would almost
completely disappear!
Page 2
HFp Antenna User’s Guide
The HFp Antenna
The HFp design provides a highly efficient vertically polarized antenna design in an extremely
portable package — the entire kit weighs just over 2 pounds (1 kg). The antenna is highly
configurable, and covers all the Amateur bands from 7 MHz to 30 MHz (as well as most
frequencies in between). An optional coil is available for 80 Meters, which also provides
operation of 75 and 60 Meters. Typical setup time is about 5 minutes.
In this User’s Guide, you will find two tables showing optimum configurations for each Ham
band. One table is for use with the HFp on the ground, and one is for the HFp elevated off the
ground. The elevated configuration is when the antenna is on a balcony, or mounted with the
optional Pole Mount Kit. There is also a laminated card in the antenna bag, with the same
configuration tables on it. The card makes it easy to take the setup information with you on your
portable operation trips.
The antenna is configured for different bands by the selection and orientation of the seven
elements that are included in the kit. Four of the elements are marked with a single stripe and
contain no loading coil. One element is marked with two stripes and contains a small inductive
load. One element is marked with three stripes and contains a larger inductive load. And one
element is half the length of the others, and has no stripe.
In addition to using combinations of elements, the orientation of the loaded elements (the two
and three stripe elements) either UP or DOWN determines the operating frequency. In the
configuration tables later in the User’s Guide as well as on the laminated configuration card, you
will see elements marked, for example,“2-stripe up”. If you assemble these elements in the
wrong orientation, the antenna will not tune to the desired frequency. The one-stripe and
zero-stripe elements have no orientation, and may be assembled into the antenna either “up” or
“down”.
We have run extensive tests on the antenna, and our research verifies the “physics” of antennas:
vertical antennas require radials to perform at their peak efficiency. Further, tuned radials
optimize that efficiency.
The HFp is designed to operate optimally with three tuned radial wires. This is true for ground
mounted operation as well as elevated operation. The antenna will certainly radiate with one or
two radials, but unless you are hanging from a cliff, you’ll make a lot more contacts by taking
the two or three minutes to set up all three. The radial wires are coiled on plastic spools, and are
marked in several places along their length. In use, the ring terminal is attached to the antenna
base, and the wire is un-spooled to the correct mark for the band in use, as indicated in the
Configuration Chart. This length is the correct “tuned length” for the radial wire, not the
quarter-wave length, and will be different for ground-mount or elevated mount locations.
Guy lines are included with the HFp for use when it is windy, or when the antenna will be left up
for some time. It is recommended that the guys always be used for the 40 meter configuration.
The guy lines have lug rings which are placed between two of the upright elements (typically
between the fourth and fifth elements from the bottom). The lines are then run out to their full
length and secured with the aluminum stakes provided, or tied to a handy rock. Some small flag
material attached to the guys will help prevent people from walking into them. If the guys are
run in the same direction as the radial wires, they will help protect the radials from being tripped
upon, as well.
Page 3
HFp Antenna User’s Guide
HFp Vertical Parts List
Before assembling your antenna, verify that you have all the parts in the list below:
Item Description Quantity
Zero-stripe element 1
One-stripe element 4
Two-stripe element 1
Three-stripe element 1
Collapsible Whip 1
Inter-Element Connector 8
Base Insulator 1
Ground Lug Assembly 1
Base Plate 2
Base Feet 4
Coaxial Pigtail 1
Radial Wire Spool 3
Guy Spool 1
Radial/Guy Stake 6
Laminated Setup Card 1
Guy Line Sliders 3
HFp Wrench 1
Page 4
HFp Antenna User’s Guide
Assembling the Antenna for Use
1) Assemble the base by first screwing the four feet
into the ends of the aluminum base pieces. After the
HFp is set up, you can adjust these feet to make it
vertical.
2) Insert the base insulator bolt with its split lock
washer through the holes in both pieces of aluminum
and install the Base Insulator on the bolt. Tighten
the insulator, while holding the two base plates to
form them into an “X”, as shown.
3) Screw the Ground Lug Bolt without the split lock
washer into the threaded hole just offset from the
center hole in one of the base pieces. Install the bolt
from the bottom (the same side the black feet are
on). Use the Wrench to tighten the bolt in the hole
(gently - not TOO tight!).
4) Install the Wrench on the top of the plate, place
the split lock washer on top of the wrench, and screw
the nut on top of the washer. Use an IEC to align the
Wrench to the IEC removal hole.
5) Place the center conductor lug of the coaxial
pigtail over the top hole of the Base Insulator and use
an Inter-Element Connector (IEC) to hold the lug in
place.
6) Place the shield lug over the ground stud on the
aluminum base plate, and screw the wing nut on top
of it - not tight - you will need to take it off in a
minute. Then place the base on the ground or another
flat surface.
7) Place the lug from each of the three radial wires
over the ground lug and secure them tightly with the
wing nut. Arrange the Radial Wires in an equallyspaced triangular pattern from the base.
Page 5
8) Next, use the Configuration Tables or
the Laminated Card to determine which
radiator elements you need for the
frequency band on which you wish to
operate, and their assembly sequence.
9) Install the elements in the correct
sequence, set the Top Whip to the
correct number of sections, and adjust
the Radial Wires to the correct mark
(see "Final Assembly Details", below).
Adjust the base feet so that the antenna
is standing vertical. Install the guy lines
and secure their ends. You may use one
of the Ground Stakes to hold the base
assembly down, if you like.
HFp Antenna User’s Guide
HFp Configuration
On the next page are the Configuration Tables for the HFp. There are two tables – one for
Ground Mount and one for Elevated Mount installations. Be sure to use the correct table for
your setup.
Note that the length specifications for the extendable whip are in “Sections”. The whip fully
collapsed is one “section” long. The whip fully extended is six “sections” long.
The different configurations each calls out a specific setting for the whip, although it is important
to remember that these lengths were determined with the HFp set up in an open area, away from
any nearby objects. The antenna may be affected by nearby objects in any particular setup
location, and the specified lengths may need to be changed. Thus the lengths in the
Configuration Tables may be deemed “starting points” for resonating the HFp at your frequency.
In some situations, where there are nearby objects affecting the antenna’s resonant frequency
(typically lowering it), shortening the whip all the way may still not bring the SWR to its lowest
level. If this is the case, simply change the top 1-stripe element to the zero-stripe, and move the
whip to the top of the (now shorter) HFp. Then, once again, fine-tune the whip for the best
SWR.
Be sure to notice the orientation of the stripes on the two-stripe and three-stripe elements.
They are always specified as “stripes – up” or “stripes – down”. Remember that the one-stripe
and zero-stripe elements may be assembled either “up” or “down”.
In each table, “Element 1” is the bottom element – the one screwed onto the base insulator.
With time, the element ends may become dirty, or develop corrosion. One of the “Scotchguard”
abrasive sponges works very well at cleaning the element ends to assure good electrical contact.
The threaded inter-element connectors may also occasionally require cleaning , as well. An old
toothbrush works well to clean the IEC threads.
Page 6
Table 1: Configuration for GROUND Mount
HFp Antenna User’s Guide
Band
40m cw
40m ssb
30m 1-stripe
20m 1-stripe
17m 1-stripe 1-stripe 1-stripe
15m 1-stripe 1-stripe
12m 1-stripe 1-stripe 1-stripe
10m 1-stripe 1-stripe 1-stripe None None None 1st mark
Element 1 Element 2 Element 3 Element 4 Element 5 Element 6 Radial
Length
3-stripe
up
3-stripe
up
2-stripe
up
2-stripe
up
3-stripe
down
2-stripe
down
1-stripe 1-stripe 1-stripe 1-stripe Full
1-stripe 1-stripe 1-stripe 1-stripe Full
1-stripe 1-stripe None None 8th mark
1-stripe 1-stripe None None 7th mark
2-stripe
down
2-stripe
down
None None None 3rd mark
2-stripe
up
None None 5th mark
None None 2nd mark
Table 2: Configuration for ELEVATED Mount
Whip
Length
4 ½
Sections
2
Sections
2 ½
Sections
5
Sections
4 ¼
Sections
2 ¼
Sections
1 ¾
Sections
Up all
the way
Band
40m cw
40m ssb
30m 1-stripe
20m 1-stripe
17m 1-stripe 1-stripe 1-stripe
15m 1-stripe 1-stripe
12m 1-stripe 1-stripe 1-stripe
10m 1-stripe 1-stripe 1-stripe None None None 1st mark
Element 1 Element 2 Element 3 Element 4 Element 5 Element 6 Radial
Length
3-stripe
up
3-stripe
up
2-stripe
up
2-stripe
up
3-stripe
down
2-stripe
down
1-stripe 1-stripe 1-stripe 1-stripe Full
1-stripe 1-stripe 1-stripe 1-stripe Full
1-stripe 1-stripe None None 8th mark
1-stripe 1-stripe None None 6th mark
2-stripe
down
2-stripe
down
None None None 3rd mark
2-stripe
up
None None 4th mark
None None 2nd mark
Whip
Length
6
Sections
3
Sections
1
Section
4 ½
Sections
4 ¼
Sections
2 ¼
Sections
1
Section
5 ¾
Sections
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HFp Antenna User’s Guide
Final Assembly Details
Using the correct Configuration Table, extend the whip to the length for the band.
(Remember – fully collapsed is one “section”.) Screw the whip into the top
element.
Tightly screw the bottom element for the band you want onto the base insulator IEC (finger tight,
not wrench tight). Be sure that the stripes are oriented “up” or “down” as required. Using the
threaded inter-element connectors, assemble the remaining elements – all finger-tight.
Unwind the radial wires to the proper mark and stake the spools down with the provided stakes
(or use rocks to weigh them down). You should try to evenly space the radial wires — place
them approximately a 120 degree angles from each other.
If it is windy, you may wish to use the guy wires to secure the antenna. To do so, place the lugs
between two of the elements and stake the other ends. (We recommend you always do this for
40m and longer configurations, or if you are going to leave the HFp up for a while… the wind
can come up quickly.)
Your antenna is now ready for use. Connect your coaxial feed line to the pigtail. We have found
that the SWR is lowest if you run your feed line parallel and close to one of the radials (lay it
directly on top of the radial).
Fine Tuning
Using a radio to set up the antenna, the procedure is as follows:
1. Set up the HFp according to the chart for the band of interest.
2. Set the radio to AM mode, and for SWR indication. If the radio has adjustable power,
use a low power setting.
3. Transmit a very short carrier at the low end of the band. Note the SWR reading.
4. Transmit a very short carrier in the middle of the band. Note the SWR reading.
5. Transmit a very short carrier at the top end of the band. Note the SWR reading.
Ideally, the SWR should be lowest at the middle of the band, and higher toward the top and the
bottom of the band. If the SWR is not acceptable in the band, then do the next steps.
6. If the SWR is lower at the bottom of the band, and increases through the band, then the
antenna is resonant at too low a frequency. Shorten the antenna whip one section, and do
steps c) through e) again.
7. If the SWR is lower at the top of the band, and increases through the band, then the
antenna is resonant at too high a frequency. Lengthen the antenna whip one section, and
do steps c) through e) again.
If changing the whip length does not get the SWR to an acceptable level at your operating
frequency, then the antenna will need to be re-configured. Use the techniques in Frequency
Adjustments to change the antenna configuration to raise or lower the antenna’s frequency.
After each change, do steps 3) through 5) again. When you get close, use the whip adjustment to
refine the SWR to the best reading.
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HFp Antenna User’s Guide
HFp Antenna Notes
The following hints and kinks can ease your setup, as well as provide you with ideas for
experimentation. While we have defined configurations for the ham bands, you can arrange the
elements into other configurations to cover the same, or other bands. In fact, the HFp can be
configured to ANY frequency between 3.5 and 35 MHz (when used with the 80M coil). We
encourage you to experiment. If you find interesting configurations, please email us and tell us
about your experiments at HFp@ventenna.com. There is also a User’s Group on Yahoo.com
where HFp users exchange interesting ideas.
Antennas
Any antenna truly worth the name will exhibit as large a “capture area” as possible. That is, it
will present the largest possible amount of resonant structure to capture (or radiate) signals. The
larger the “capture area” the better the antenna works. The HFp configurations shown in the
configuration charts were designed to have large capture areas, but it is possible to achieve a
resonant antenna in a smaller assemblage of the elements, if having a smaller physical structure
is desired. Experimenting with the mix of elements may result in different combinations of
elements for any particular frequency. Just remember that the shorter antenna won’t reach out as
far as the longer one.
Set-Up Hints
One of the AEA or MFJ portable SWR Analyzers will make setting up (or experimenting with)
the HFp antenna very easy, especially if the antenna is being used in an enclosed space, or a
location where there are large objects nearby, which may make the configuration different from
the chart.
Frequency Adjustments
Note - If you need to adjust the resonant frequency of the HFp because nearby objects are
affecting it, most likely the resonant frequency will have to be raised.
1. Lowering the resonant frequency – Moving an inductive load position lower in the
antenna will lower the frequency. This can be accomplished by turning over one of the
loaded elements (putting the stripes “down”), or moving it down in the assembly of
elements. Adding a zero- or a 1-stripe element (making the antenna longer) will also
lower the resonant frequency. Extending the whip will lower the resonant frequency.
2. Raising the resonant frequency – Moving an inductive load position higher in the
antenna will raise the frequency. This can be accomplished by turning over one of the
loaded elements (putting the stripes “up”), or moving it up in the assembly of elements.
Removing a 1-stripe element, or replacing a 1-stripe element with the zero-stripe (making
the antenna shorter) will also raise the resonant frequency. Shortening the whip will raise
the resonant frequency.
Page 9
HFp Antenna User’s Guide
Radials and SWR
Although we have determined that the HFp will operate properly with the three radials provided,
adding radials may help lower the SWR in some situations, particularly in elevated mount
installations or over difficult ground. It is easy to add extra wire to the radial system to see what
effect more radials might have.
You can also affect the performance of your antenna by lengthening or shortening the tuned
radials. Change all the radials the same amount, a little at a time, and follow the “Fine Tuning”
procedure to check SWR.
The HFp configuration charts define the tuned length radials for each Ham band. These tuned
lengths are an important concept in the proper operation of a ground-mounted vertical antenna.
A write-up available on the Ventenna web site explains the effect of different radial lengths, and
especially the problems which can be generated by radials that are too long.
Guy Lines
On the lower frequency bands you usually need to take off the top assembly of elements in order
to get to the whip to adjust it for the lowest SWR at your favorite frequency. Depending on
their attachment point, the guy lines and attachment lugs can be a problem when you try to
unscrew the elements above the guy attachment point.
But, if the guy line lugs are installed underneath the inter-element connector at the top of the
fourth long element, and that inter-element connector is tightened a bit more than normal, then
the top portion of the assembled antenna can be easily removed without the guy lugs loosening
up and interfering. This makes whip adjustments on the longer setups much less of a hassle.
A set of three Guy Line Sliders is included in the kit to allow for easy tensioning of the guy lines.
Inter-Element Connectors
The Inter-Element Connectors (IECs) are solid brass for best corrosion-free connections between
element sections. But, after some use, they may collect some dirt. One of the “Scotchguard”
abrasive sponges works well at cleaning the IECs and the element ends.
An IEC may sometimes be hard to remove from the end of an element, if it has been tightened
too hard. A special HFp Wrench is included in the kit to help with these stubborn IECs. The
HFp Wrench is usually attached to one of the base plates for easy use. Just put the stud of the
IEC into the hole in the base plate, align the nut with the wrench slot, and turn the element to
loosen the IEC. The wrench may also be used in the hand. if necessary. And, as mentioned
before, an old toothbrush works well to clean the IEC threads.
Page 10
HFp Antenna User’s Guide
The Ventenna Co. LLC
P.O. Box 2998
Citrus Heights, CA 95611
www.ventenna.com
1-888-624-7069
entenna
©2002, The Ventenna Co. LLC
Last Update : July, 2007
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