Easy HT Improvements

By N6JSX

We all know OEM (original equipment manufacture) HT rubber-ducky antennas are a dismalcompromise, at best, facetiously called "helical-dummy-loads." There are a few ways to improveyour HT'ing distance and experience. First and foremost consider buying an after-marketantenna, like the Diamond SRH77CA-SMA or RC77CA-BNC, or make a more economical full wave BNC Brass Whip and add a Tail. I found my 2m Brass Whip to work well on 70cm too.

Second, is to improve the antenna's counterpoise; an HT body is a very poor counterpoise! Aproduct I saw decades ago, called the `Tiger-Tail', seemed to have been the answer to thisproblem but it was just too easy for HAMs to reproduce, killing its sales. The Tail is a wave +5%counterpoise wire hung from the HT antenna connector creating a mock wave dipole. The trick inmaking an affective Tail is to insure a good tight fit to the HT connector. I duplicated the Tail byusing ring terminals but a problem with ring terminals are those darn BNC posts. I over camethis by filing a small notch inside the ring to fit over one post, twist it around the BNC barrel andslip it over the other post.

But with the advent of HT's going to a SMA connector the BNC post issue disappears makingthis Tail a much simpler and far easier to attach.

The Tiger-Tail is a wave + 5% length of wire hung from the HT connector.Thomas & Betts ring-crimp-terminals:

SMA = 1/4" eye for 14-16AWG wire (blue) T&B #14RB-14X

BNC = 3/8" eye for 10-12 AWG wire (yellow) T&B #10RC-38X

Black 14-16AWG stranded wire is soldered to the ring. (I do not crimp my tails but solder the tailwire to the ring terminal.) See Table "A" for wire lengths per band.

The hardest part of using this Tail is getting the wire to hang straight.

Easy wave BNC Brass Whip

Here is an easy `how-to' make a wave BNC whip antennathat I created in the 80's.

Parts needed:

BNC RG-58 type coax crimp connector, 3 piece.Brass welding/brazing rod 3/32" diameter.Heat shrink tube 3/32", 1/8", & 3/16" ~1.5" long each.

Method of build:

1. Cut the brass rod to table "A" plus 1 inch.

2. On one end grind/file off enough brass to securely fit thattip into the center pin of the BNC.

3. Solder the pin to this brass rod shaped end.

4. Slide 1.5" of 3/32" heat shrink over the brass rod and justcovering the top edge of the attached center pin andshrink.

5. Slide 1" of 1/8" heat shrink over the 3/32" shrunk tubingjust down to the brass rod and shrink into place. This willact as an insulting spacer to the BNC barrel.

6. Slide all into the BNC barrel - insure the BNC pinprotrudes well into the connector then slide 1.5" of 3/16"heat shrink tube over both the BNC barrel and rod, thenshrink tight. This piece of heat shrink holds the whole BNCantenna together.

7. Measure Table "A" dimension and cut to length or tune forbest VSWR.

8. Round off the top end of the brass rod.

Table "A"

146 MHz 19.3"222 MHz 12.7"445 MHz 6.35"902 MHz 3.1"1250 MHz 2.25"



NOTE: insure the BNC center pin & rod do NOT make anyphysical contact with the BNC outer housing.

Making this rod whip antenna with a "SMA" connector wasfound to be very difficult and then I was leery of its durability!

Some of the HT's sold today have different type male/female SMA connectors all SMA-to-BNC adapters pictured were bought from eBay. HT's are most difficult to quantifiably measureantenna performance from - you will just have to do it the old fashion way of over the airreports flipping between using a ducky vs. Whip+Tail under the same conditions, to judge.

Here are a few of my HT's with my Whip & Tail:

If you want to use your HT mobile seek or make an over-the-edge Stainless-Steal windowbracket (I designed & sold this in the `80's under Kuby-KommunicationsTM but an AES copierand then MFJ coping killed my sales too). It was simple but affective!

Never use coax length >5' RG-174 (1/8"dia) -1.65db/10' ; I only use RG-8x (1.4"dia) -0.4db/10'.

Writer BIO: Dale Kubichek, BS/MS-EET, GROL/RADAR, N6JSX - Amateur Extra; licensed in 1972.

PDF of this article, and many more, can be found in the `Files' folder "N6JSX Stuff" on my Groups:

http://groups.yahoo.com/group/HAM-SATs

http://groups.yahoo.com/group/RDF-USA