- Today, we're taking a look at the
Shark distributing's HF stick antennas.
Should this be your next mobile or portable antenna?
We'll find out on the next episode of Ham Radio Q&A.
(upbeat rock music)
Hi I'm Michael, KB9VBR, your host for Ham Radio Q&A.
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Well today, we're gonna take a look
at the Shark Distributing's HF stick antennas.
Now, if you follow the Parks on the Air activities,
you'll find that the Shark sticks are a popular choice
with activators for their performance and convenience.
So, we're gonna take a look at these antennas,
so you can decide, for yourself,
if you wanna add one to your antenna arsenal.
In full disclosure,
I purchased a set of Shark sticks with my own funds,
and the content of this review
has not been influenced by the manufacturer at all.
Well, according to the manufacturers,
the Shark antennas represent an economical solution
to mobile HF operations.
Each antenna is made in American,
and it covers a single HF Band,
with the power rating of 250 watts, peak envelope power.
Each antenna features a 44 inch
black fiberglass section, with an integral coil,
and an adjustable four foot stainless steel whip.
The base of the antenna has a 3/8 by 24 threaded connection,
and the antennas don't include a mount,
so you're gonna either a magnet base of some type,
or a 3/8 by 24 threaded type of antenna mount.
This review is on the Shark full size whip antennas.
Shark distributing also has a mini whip version
that I didn't test.
I think the only appreciable difference between the two,
is that the mini whips have a shorter whip section,
makes it a little bit easier to use mobile
than a full size version, which has that 48 inch whip.
If you're gonna go mobile, or size is an issue,
then the mini whip version may be a good choice.
But I'm reviewing the full size version of the antennas.
Shark also used to sell a five pack
of their most popular sized whips,
but the packaging appears
to have been recently discontinued.
But you can still buy these whips individually.
Like I mentioned,
the bottom half of the antenna is a hollow fiberglass rod.
Wire is wound around the rod,
and then it's covered with shrink wrap tubing.
The amount of the wire wound around the rod
really depends on the band the antenna is operating in.
In effect, the fiberglass section
becomes a loading coil for the antenna.
If you take a look at the lower bands,
like the 45 or 75 meter models,
you'll find that a section of tightly wound wire,
the 75 meter antenna, is almost entirely wound with wire.
At the higher bands, say the 10 meter model,
the coil is virtually absent.
So the advantage of this is that the
tightly wound sections creates an inductance that
electrically shortens the antenna,
making it more manageable for mobile use.
But, the downside is, is that it also
increases the Q of the antenna,
so your bandwidth gets progressively narrower
as you drop in frequency.
So much so, that you need actually two antennas
to cover the entire 75 and 80 meter bands.
One for the lower half, for the 80 meter band,
and another one for the upper portion or the 75 meter band.
We'll talk more about bandwidth in a bit.
The top half of the antenna is a stainless steel whip
with a ferrule that holds that whip in place
with two sets of Allen screws.
The weird thing is,
is that the Allen screws are two different sizes.
The antenna does come with a pair of Allen wrenches,
but I recommend that you invest
in a inexpensive set of Allen wrenches,
as the individual ones always tend to get lost and whatnot.
So to tune the antenna,
you're gonna need to adjust the whip length.
Shark provides a little chart
that gives you a starting point
for each of the different bands for whip lengths,
but your actual length of this whip is gonna differ
depending on what center frequency you choose
to tune the antenna at, and how the antenna is mounted.
So, I think that the chart may be
for the mid-points of the bands,
'cause when I was tuning these antennas,
I found that mine were a little bit shorter
than what was recommended,
but I was picking frequencies
that were in the upper portions of each of the bands.
The easiest way to tune these antennas,
is with an antenna analyzer,
but you can also do it with the SW meter
in your transceiver,
by turning your power down to its lowest setting,
taking a reading, using a constant carrier mode,
like AM or CW,
and then performing an adjustment to the antenna.
Repeat this process until you're satisfied.
Well the good news is,
is that the tuning process seldom needs to be repeated,
unless you're drastically changing how your operation,
or how the antenna is being mounted.
Since we're talking about tuning,
I need to mention a problem I'm having
with the 40 meter stick.
On the other antennas in the set,
I have no problem getting the SWR down to 1.3 to 1 or less,
with the exception of the 40 meter HF stick antenna.
For that one, the best I could actually get it down to,
is about 1.9 to 1.
Now I've done a little bit of research,
and talking with others about this issue,
and it appears that the 40 meter stick
can be quite sensitive to the capacitive coupling
that occurs between the magnet mount base and your vehicle.
Some people report that using a larger magnet base,
like one of those tri magnet bases,
seems to solve the problem,
'cause it gives you more capacitive coupling,
while others say it doesn't.
Other people recommend that adding a counterpoise
to the magnet base also seems to work.
It appears that 40 meters is quite sensitive
when it comes to capacitive coupling,
and it wants to be,
there's also big bit of variability in deployment
and other external issues
that really affect how this antenna is tuning.
So it can be difficult to say
if a particular solution will work for you or not.
But on that issue, I recently talked to Dave KZ9V,
who has had a lot more experience with the Shark sticks,
and also has really spent a lot more time
working out that SWR issue with the 40 meter stick.
And here's a portion of our telephone conversation
that you might find interesting.
(phone ringing)
- [Dave] Hello.
- [Michael] Hey Dave, it's Michael Martins calling.
- [Dave] Wow, the world-famous Michael Martins? (laughs)
- [Michael] Well, I don't know if I'm world-famous,
I guess I might have a certain level of notoriety.
- [Dave] (laughing) Yeah. (Michael chuckles)
Hey, the Shark stick.
- [Michael] Yeah, let's talk about that a little bit.
- [Dave] I bought a mount to screw
onto the back of the tail, not on the tailgate,
but on the bed of my pickup truck,
and I didn't really wanna drill any holes in it.
But it's a 10-year-old truck,
and I figured this won't hurt anything,
so I put it on the back of the bed,
back by the passenger side taillight.
But it screwed hard to the metal of the truck,
so it eliminates anything to do with magnets,
and three magnets, or one magnet, or five inch magnet,
there's no magnet at all with this thing.
I put the 40 meter stick on it,
and it made no difference.
- [Michael] Okay.
- [Dave] So the VSWR with a mag mount on the rough,
is exactly the same as if it's
metallically bonded to the truck.
So, the mystery still remains on that 40 meter stick,
and the magical solution, which,
I've tried it several times now,
and I just can't get it to fail,
is that stupid ferrite clamp,
20 feet 3 inches from the base of that magnet.
- [Michael] Mm-hmm. - [Dave] It's bizarre.
- [Michael] Yeah.
- [Dave] But you look at the VSWR sweep on the analyser,
and it's textbook, I mean it's just beautiful.
And I don't know.
- [Michael] And, evidently,
that must be just, 40 meters,
just must be a problem with that style of antennas.
Because if you read online,
everybody's got the same gripe when it comes to 40 meters.
Some people, they don't have issue with it,
and others it's just hunky dory.
And some people say the tri magnet works,
and some people say clamping it works,
and I don't know. (Dave and Michael chuckle)
All right, well, I gotta go.
- [Dave] All right. Good deal, have fun.
- [Michael] Oh yeah, you too. - [Dave] Stay in touch.
- [Michael] Take care. - [Dave] All right. Buh-bye.
- [Michael] Bye.
So, in replicating Dave's experiment,
I placed the 40 meter antenna on the roof of my car,
added 25 feet of RG-8X coax to the existing 16 feet
included with the mag mount base.
And then I then ran the coax perpendicular to the car.
The SWR dropped down from 1.9 to 1 to 1.5 to 1,
but the center frequency also moved
from 7200 kilohertz, up to 7350.
I then extended the whip as far as it would go,
and got the resonant frequency
back down in range to 7204 kilohertz.
Putting a ferrite at about the 20 foot mark
on my entire run of coax, helped a lot,
and I ended up with a final SWR
of 1.2 to 1 at 7204 kilohertz.
In this configuration,
the coax is acting like a counterpoise,
so there is a bit of variability in the SWR,
depending on how the coax is laid out.
And if you use the ferrite as a choke
to control the length of the counterpoise itself.
Finally, let's talk a bit about bandwidth,
as this can be an issue on the lower bands.
When we describe bandwidth,
we talk about 2 to 1 bandwidth,
or the amount of frequency spread
when the SWR is 2 to 1 on either end of the sweep.
So, the great news is that the 10 meter antenna
covers the entire 10 meter band,
so you can tune it for 28.5 megahertz,
and the 2 to 1 bandwidth covers everything
with a bandwidth of over 2.6 megahertz.
For the other bands, it starts to get a little bit narrower.
The 15 meter antenna has about 1.4 megahertz of bandwidth,
and the 20 meter antenna
has about 500 kilohertz of bandwidth.
Both of which capably cover those respective bands.
As we move to the 40 meter band,
you can see on the chart my SWR issue.
Initially, the antenna was showing an SWR of 1.9 to 1,
with 60 kilohertz of bandwidth.
If we can get the SWR down lower,
the bandwidth will increase.
So in my lengthening of the coax,
I found that I was able to increase the bandwidth
to about 170 kilohertz with an SWR of 1.2 to 1
at the center frequency.
This makes the antenna usable on the top half of the band,
but not really in the CW or digital portions,
as I had to use the entire whip length
in order to get there.
Dropping down to 75 meters, the bandwidth gets paper thin.
Literally 60 kilohertz,
with a center resonant frequency of about 1.2 to 1.
75 and 80 meters is a really big band,
and you can see how that can be an issue
with antennas like this.
In order to test their operations,
I took the antennas out on two
Parks on the Air activations this past winter.
The first, was in early January,
was at Rib Mountain State Park in Wausau.
I used both the 40 and the 20 meter sticks.
SWR on the 40 meter stick averaged about 1.6, 1.7 to 1,
but the noise floor of that location
prevented me from (radio static)
really working any contacts on that band.
Moving to 20 meters though,
the tuning was much better,
and I picked up about 35 contacts in 40 minutes time.
I did try the 75 meter antenna on the mountain.
Dave KZ9V lives about 90 miles away from me,
and while he could hear me
just above the noise floor on 75 meters,
I could not hear him.
But a vertical antenna isn't the best choice
for short distance contacts on 75 meters like that.
So a couple weeks later,
I used both the 40 and the 20 meter sticks again,
for the Winter Field Day,
when I was activated High Cliff State Park
near Appleton, Wisconsin.
It was a busy weekend on the bands,
and I had no problem gettin' through many of the pileups
on both 40 and 20 meters with the Shark sticks.
On the air reports were quite good.
I received excellent signal reports using the antennas.
Now I put links to both of these videos
in the video description below
if you wanna see and hear more
of the actual operation of the antennas.
Otherwise, I'm pretty satisfied with how
the Shark sticks handled on both of those bands.
So what do I think about the Shark sticks HF whip antennas?
Well, first off, they're well constructed,
and they seem to be quite durable.
They are quite convenient, once they're tuned.
Band changes are easy as swapping out the antennas.
And finally, they're inexpensive.
At under $25 an antenna,
they may be one of the best values
for an HF antenna that you can find.
And now for the bad.
Mostly, the downsides have to do with their bandwidth
and tuning on the lower bands.
The bandwidth at 80 meters is paper thin,
so you're gonna need two antennas
to really cover that band,
one for 80 and then one for 75 meters.
And also, the 40 meter band antenna
is problematic to tune.
Its capacitive coupling is iffy,
so you have to deal with workarounds
to get a good tune on that band.
And finally, their convenience is also a bit of a hindrance.
You need separate antennas for each band.
So while it is easy to change bands by changing antennas,
you also have to take the effort to change antennas.
But all in all,
I think that the Shark HF sticks are a good deal,
and I've enjoyed using them as part of my
wintertime Parks on the Air activations.
I'll most likely continue to use them
as a vertical antenna option for future activations.
I like that they are a good choice for HF mobile,
especially if you work HF on one band only,
or have the ability to stop the vehicle and change bands.
I also recommend that if you plan on buying
more than one of the Shark sticks,
to purchase a set of these couplers,
as they make changing the antennas fast and easy.
And that's it.
I'd like to thank Dave White KZ9V
for helping me with this video.
Consulting with him several times was crucial
in working out the issues with the 40 meter antenna.
And for my Patreons over on Patreon, as a bonus,
I'll upload the entire telephone conversation
Dave and I had about the issues with the 40 meter antenna,
and also the SWR plots of each of the antennas.
You can check that out on patreon.com/kb9vbrantennas.
Well do you have questions or comments
about the Shark HF stick antennas?
Well please leave 'em in the comments below.
I'll filter through them,
and follow up on them, and who knows?
Maybe your question will end up in our next,
Your Questions Answered livestream.
But for more articles and information,
be sure to check out my blog at www.jpole-antenna.com
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Well that's it for this time,
I'm Michael, KB9VBR, have a great day and 73.
(upbeat rock music)