Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Telescoping HT antennas  (Read 2663 times)
KT0DD
Member

Posts: 277




Ignore
« on: March 18, 2013, 05:16:04 AM »

I see several telescoping antennas for HT's advertized by MFJ and the China offshore companies. Some extend to @ 16" and others extend to @ 42".

Do these antennas really help? I always thought a homemade counterpoise "tiger tail" radial element would be more help.

Thanks for any replies.

73. Todd - KT0DD
Logged
AD4U
Member

Posts: 2150




Ignore
« Reply #1 on: March 18, 2013, 05:27:54 AM »

When compared to a typical rubber duck antenna they definitely "help" often by a large margin.  To make them work even better add a "tiger tail".

Dick  AD4U
Logged
K7RNO
Member

Posts: 279




Ignore
« Reply #2 on: March 18, 2013, 10:50:34 AM »

An example:

Fully extended, my Smiley 270A is a 1/4 wave on 2m. I can reach a repeater 34 miles away from inside my home in the valley.
With the top two elements down, it is a 5/8 on 70cm.
Fully retracted, it is a 1/4 wave on 70cm (and shorter than the rubber duck that came with my FT-60). In this position, I can also hear several 2m repeaters around my valley, so I am always connected and simply pull out the antenna when I want to transmit.

FTR, I did NOT find any improvement from installing a centerpoise.

If you can find value in this, then you have one answer to your question.
Logged

73,
aRNO
NAQCC #6870, SKCC #11131
AD6KA
Member

Posts: 2232




Ignore
« Reply #3 on: March 18, 2013, 11:46:46 AM »

I would weigh any advantage you get on these
long telescoping HT antennas against the fact that
over time they WILL put a lot of strain on the
antenna connector, possibly breaking that connection
inside the radio.

Some of these antennas are 3+ feet long, and
they act like a lever if you bump them into anything
or anyone, putting a lot of force on that BNC or SMA connection.

I might carry one in my backpack to use in an emergency
while hiking, but I wouldn't leave it on the radio as my
"every day" antenna.
YMMV.
GL ES 73, Ken  AD6KA
Logged
K7RNO
Member

Posts: 279




Ignore
« Reply #4 on: March 18, 2013, 07:25:03 PM »

I would weigh any advantage you get on these
long telescoping HT antennas against the fact that
over time they WILL put a lot of strain on the
antenna connector, possibly breaking that connection
inside the radio.

Some of these antennas are 3+ feet long, and
they act like a lever if you bump them into anything
or anyone, putting a lot of force on that BNC or SMA connection.

I might carry one in my backpack to use in an emergency
while hiking, but I wouldn't leave it on the radio as my
"every day" antenna.
YMMV.
GL ES 73, Ken  AD6KA

What if it had a spring at the base? Like the Smiley?
Logged

73,
aRNO
NAQCC #6870, SKCC #11131
KB4QAA
Member

Posts: 2245




Ignore
« Reply #5 on: March 18, 2013, 09:40:43 PM »

I have had an AEA Hotrod telescoping antenna for years.  When I'm out and about on foot in fringe areas I take the rubber duck, the Hotrod, and a 19" counterpoise.  The whip and the counterpoise help tremendously.

I don't leave the whip extended except for immediate transmissions, because the lever arm is so great.  The counterpoise can stay on all the time.

Yes, I can end up juggling antennas, but it works, and has worked for almost 25 years without damaging a radio.
Logged
AC4RD
Member

Posts: 1236




Ignore
« Reply #6 on: March 19, 2013, 09:01:48 AM »

I would weigh any advantage you get on these
long telescoping HT antennas against the fact that
over time they WILL put a lot of strain on the
antenna connector, possibly breaking that connection

Ken is right about that, but it's also very true that these antennas are significantly better than the average 'rubber duck."   Years ago, when I routinely carried a 2m HT while walking the dog, I often used a 19" whip antenna made from a piece of flexible piano wire soldered to the center connector of a BNC plug.  This worked very well, it was breakproof, and didn't damage the HT a bit.   One caution: fold the piano wire over at the top of the element and then glue something like a button or a ping-pong ball to the end.  As the mother told Ralphie about the BB gun, "You could put somebody'e EYE out with that thing!"  Wink
Logged
AD6KA
Member

Posts: 2232




Ignore
« Reply #7 on: March 19, 2013, 11:42:42 AM »

I guess the consensus is "Yes they work but take care".  Grin
Like the man said, best to telescope it out only when
you need to.

Almost any after market antenna will work better
than the factory duck (except maybe those "stubby" things!).
I have a Comet 19" flexible whip on my VX-150 and it works
much better than the antenna it came with. It's a great HT
for hiking. I've dropped it several times, no problems.

The FT-60 uses an SMA antenna connector, if I am
not mistaken, so you will need the SMA->BNC adaptor.
(HRO gets $8.99 for those, and the Icom version is $18.95!)
I have not seen a telescoping HT whip in SMA, but I
could be wrong.

For hiking emergencies, I have been thinking of making
a "roll up" J-Pole out of Ladder Line fed with maybe 12-15'
of RG-58 or RG-174. Toss it up in a tree if I am in a place
where I can't get out well. (Though %95 of my hiking is
in the hills above L.A., where I can hit many repeaters
AND have cell phone service. But every other year my family
goes to Yosemite, where there is a repeater above the Valley).

Has anybody tried the "roll up" J-Pole? Or wouldn't it work all that
much better than a long whip? I am more of an HF guy!
73, ken  AD6KA
Logged
KT0DD
Member

Posts: 277




Ignore
« Reply #8 on: March 20, 2013, 05:08:33 AM »

Thanks to everyone for the info. I'm putting together a SAR kit for camping and emergency operations. I will need to be able to get out in rugged terrain here in the western colorado rocky mountains. I have radios with SMA female connections, so I will call Smiley and see if they will custom build one as they advertize. Otherwise I'll have to send to China.

Thanks again.

73.  Todd - KT0DD
Logged
WB6BYU
Member

Posts: 12985




Ignore
« Reply #9 on: March 20, 2013, 09:55:15 AM »

I've carried HT's, ham and commercial, in the mountains for work and play.
My choice of antenna depends on the application.

When I worked in Alaska our radios had telescoping whip antennas.  The
radio worked well enough on receive with the antenna down (telescoped
inside the case, where it was protected.)  I tried carrying it with the
antenna up and lasted about 2 days before I broke it - after that I had
to use an 18" clip lead until I could get back to the radio shop for a
replacement.  The radio tech used a rubber duck when he worked on the
repeater sites, but everyone else used telescoping antennas because
they gave better coverage in poor terrain.

The same applies to any full quarter-wave whip antenna.  I like to carry
a spare telescoping whip for backup, but usually leave a rubber duck on
my ham HT for local work, or a flexible quarter wave whip for more
difficult paths.  (I have one with a flexible wire inside a length of plastic
tubing that works quite well.)

Adding a quarter wave radial makes a big difference:  I've measured up
to 9dB for virtually any antenna up to 1/4 wave in length, though other
measurement attempts give different results.  It's a good idea for any
rubber duck or quarter wave whip if you are using a small HT.  (Older,
larger HTs may provide an adequate ground plane.)

The larger whips work best with radios having a BNC connector.  You
need to spread the force out over a wider area if you have an SMA. 
Even at that, I wouldn't use it for a long period of time in a high-
vibration environment.  (I used a rubber duck on my bicycle for a
while, and even the short 6" antenna wobbling back and forth was
enough to wear down the center pin of the BNC connector.)
Adding a ground radial to a half-wave whip is not likely to make
much improvement.

The longer half wave whips such as the AEA Hot Rod can give a
significant improvement in signal strength, though I wouldn't
carry one on the radio when I don't need it.  They should be
about 36" - 38" long.  The longer 5/8 wave whips are NOT a good
idea on an HT:  not only are they longer than necessary, but the
angle of radiation (due to the phase of the current on the radio
chassis, and ground radial if you use one) is unsuitable.

So the telescoping whips are a good choice when you are standing
around, but not when you are in motion.  My solution to that was
to mount a half wave whip (from a mag-mount CB antenna) on a piece
of PVC pipe that fit into the top of my pack frame.  That was quite
rugged, put the antenna up high in the air, and took the stress off
of the antenna connector while hiking.  It was tunable for both ham
and SAR work, and gave 2 or 3 times the range of other members of
the team.  The only problem was that the tall whip knocked the
dew off overhanging branches and I got rather wet in the mornings
when hiking through understory.

I've used several roll-up J-poles over the years:  I have at least two
on hand in my emergency kits.  I'd recommend using 300 ohm twinlead
with RG-174 or other small coax to save space and weight, and the
radiator portion can be cut down to a single conductor as well.
The larger windowed twinlead and RG-58 are a better choice of
size and weight aren't constraints, or a simple wire ground plane.
That allows you to get the antenna up higher in a tree, and height
makes the most difference in signal strength.

Height is still a good idea even if you don't have an external antenna:
at one location in Alaska I was behind a ridge from the local repeater, but
by climbing 30' up in a spruce tree I could contact the dispatcher directly
(70 miles away) and this became a daily routine to call for the helicopter
at the end of each day.  I also taught the SAR team how to walk up the
side of a canyon somewhat to get more height when their radios didn't
work from the bottom.  (One freezing night we walked up to a hilltop
to call in our report, and in the process found the footprints of the
missing person that everybody else had lost.)
Logged
K7RNO
Member

Posts: 279




Ignore
« Reply #10 on: March 20, 2013, 01:17:07 PM »

Good information in this thread.

I wanted to point to one telescopic HT antenna that is available for SMA: Diamond's SRH789. I posted a review here in the review section. As you can read there, I returned it and am now a happy owner of a Smiley 270A.

For a solid SMA-BNC adapter, I found the Diamond BNCJ-SMAP a perfect design. It has a solid base with a rather wide OD, and if it doesn't make direct contact with your HT's body, you can sandwich an o-ring and create a strong base that way, protecting your delicate SMA stub from breaking off.

A general question from this newbie: when the term "whip" is used, shouldn't that refer to a flexible antenna, and not to a stiff telescopic one? I am confused.

Logged

73,
aRNO
NAQCC #6870, SKCC #11131
WB6BYU
Member

Posts: 12985




Ignore
« Reply #11 on: March 20, 2013, 02:49:15 PM »

Quote from: KG7BJM

A general question from this newbie: when the term "whip" is used, shouldn't that refer to a flexible antenna, and not to a stiff telescopic one? I am confused.



Generally refers to a vertical radiator, especially one that acts as a solid
piece.  For example, a helical-wound mobile antenna may be called a whip.
In other usages it may refer to just the top portion of a mobile antenna above
the loading coil, especially if the lower section is much stiffer.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!