IPX 6 Heavy Duty, based on the Smiley SAR Antenna: 'The antenna preferred by AMGA and ACMG examiners'
IPX6 line shown with both SMA-M and SMA-F base types. Antennas are color coded to denote frequency range. Base has reflective tape for finding antenna in pack at night. Green line indicates where to cut for swapping counterpoise adapter onto antenna.
Are you hard on your rubber duck? Recently, the US Forest Service pulled all their HT antennas from the fire line at the end of the season and had them tested. They were new at the start of the season, but at the end of the season, 60% of them failed testing, and had to be replaced.
Personally, between my day job and my recreation, I damage about 3 ducks a season. Not being as pedantic as my 'mentors', the damage is caused from either being in a hurry, or not paying attention while carrying my radio on my duty belt, or stuffing the radio into my pack or saddlebag with the antenna still attached. I may be lucky because the incomparable folks at Smiley keep me well provided for, but we decided we really needed antennas are reinforced (like Smiley does for the US Marines) for use in extreme conditions such as those encountered by AT Skiers and First Responders, but who may still need to use a Rat Tail in the backcountry. The IPX6 is our own aftermarket, value-added, solution to this problem. As such, it is overbuilt and over priced for recreational or HAM use. This design addresses the problem encountered by many of our specialist users who damage their antennas by bending them to the point where they are kinked.
So introducing the IPX6. This antenna has become the Gold Standard for a majority of commercial cat and heli ski operators, guides, and SAR teams. The IPX6 design requires a modification for the use of the Rat Tail and changing the base out, because it is sealed at the base with a shroud for maximum resistance to dirt. (The modification involves circumsizing the antenna with an exacto knife where the green ring is). It is water resistant to beyond an IPX6 rating, and is meant to resist getting bent and kinked. It is our standard 5/8 wave SAR center tuned antenna, reinforced with overlapping single wall polyolefin tubes. This series uses adhesive lined double wall tubes. With a dull surface, it has a rubbery tactile feel. It is designed to allow for some flex without cracking and continues to flex in the cold. If you want to have a heavy duty antenna, but use the Rat Tail or swap out base connectors, then you must circumsize the base about 1" up from the bottom to allow the base connector to be unscrewed and the counterpoise wire to be screwed on.
The tubing we use on these antennas affects the velocity factor (the velocity factor of a coax cable is the speed an electromagnetic wave travels along a coax cable relative to the speed in a vacuum. In these antennas, it is affected by the dielectric that is used within the coax cable and the tubing, and this has the effect of slowing the signal down.) Normally, if resonant lengths of RF coax cable are to be used, then it is necessary to know the velocity factor of the coax cable. It is often possible to determine this to a sufficient degree of accuracy from a knowledge of the dielectric material. And although we know that the velocity factor of our tubing is about .695, we have instead tested the antennas for optimum tune by measuring Standing Wave ratios and forward and reflected power, and then tuning the antennas to length accordingly. This substantially mitigates the effects the velocity factor presents to this antenna design. Tuning based on SWR and power ratios has also resulted in the IPX6 antennas being slightly shorter in length than the stock Smiley 5/8 wave ducks at the same center tuned point.
At the thickest part (where the stem flares over the coil) the IPX6 is 5.1mm and weighs 44g (for the 145-155 model), the standard S&R is 3.3mm and weighs 34g.
I recently got a comment that these antennas seem pretty pricey. I had not really given it much thought up to that point, and then realized, that compared to your average asian made antenna, at perhaps 4x the cost, they are indeed pricey in comparison. On top of that, each one of these can only cover 10MHz of bandspread, so you need three of them to cover the complete spread of commercial VHF frequencies. But in fact there is very little comparison, these antennas are worlds apart from even the highly touted antennas such as the Diamond. First of all, in spite of what they claim, there is no rubber duck made that can actually cover a range of 136-174 MHz without creating standing waves that not only make it hard to reach your target, can damage your radio over time.* So here is some trivia regarding the providence of these antennas that may shed some light on why they cost what they do:
- The stock antennas are made in the USA by Smiley.
- Smiley then shared with us the technology they use to produce a value-added antenna series for the US Navy Seals.*
- We tweaked the design so we could color code and print the frequency range of each antenna under the dual wall tubing.
- We had to find a source for the dual wall tubing that could supply all the colors, plus the transparent, and buy it in rolls from Asia.
- We hand tune each antenna to the specific frequency, and then have to apply the tubing sections and labels: three separate stages in all.
- The dust skirt on the bottom (for SMA-M bases) then has to be trimmed by hand.
- The total labour time is about 15 minutes per antenna.
- That equates to us making less than $45.00 per hour for the time we spend making these antennas.
- Last time you had a mechanic work on your car, or a plumber fix your pipes, what did they charge per hour?
* There is no performance increase between the stock Smiley and the IPX6. The latter are more rugged, the color coding and labelling make selection easier, and the addition of a reflector band at the base makes them easier to find at night, especially if the radio is lost on the ground. If you are a recreational user that does not place rugged demands on your gear, then the IPX6 might be more antenna than you need and the stock Smiley will work fine for you.
* Q: Why do you say that it is not possible to make a broadband antenna that covers 144-174?
A: Rubber ducks are 'resonant antennas'. Making an antenna resonant is one way of tuning out the reactive components (inductance or capacitance) and is why loading coils are used in short whips for example, which are electrically very short and so have a significant capacitive reactance component. The problem with resonant antennas is that as they use the antenna's self inductance and capacitance for resonance - this is true at only one frequency - and unless it is a very lossy antenna, will rapidly leave resonance when tuning high or low. In many cases, the application of broadbanding techniques is more about adding loss in the antenna to reduce Q which in turn flattens the tuned circuit skirts, hardly an efficient system.
Antennas can be special ordered with your own color codes, requires an additional $10.00 setup fee per order.
Good morning John
I received my new antenna on Monday the 6th. It's been working great so far, I figured you might want to see glamour shot. So attached you should find a picture of the antenna on my HT1250. Thank you for another amazing product
Thank You, Andrew Wrublesky