[Mobile-Portable] New car and considering new antenna setup!

[Zyg Skrobanski]

>I don't know why you would think that a thin top loaded antenna would 
>work better in a mobile environment, and in fact, the thin design to 
>allow top loading if that's what the Comet's do, leads to less 
>efficiency than centerloading.

The Comet CA-HV, is the antenna that I use, and relative to its length its
coil is at the top (i.e it is top loaded) with a stinger attached that is
only several inches in length, depending on the band in use.  The small
stinger is thin, but the rest of the antenna is thicker than the flexible
whip that is attached to a typical screw driver antenna.

The thickness of the antenna affects its bandwidth, and not its radiating
efficiency.  The coils of the Comet are thin, and consequently are rated
for 100 watts or so - it's not a high power antenna.

Not only do I think that the Comet CA-HV works and works spectacularly
well, but I know that it works.  I have worked over 140 countries mobile
since installing the antenna on my car three years ago.  However, that is
not the ultimate test.  I have worked a number of DX-peditions whilst
mobile, all on SSB using the CA-HV.  You can see this for yourself by going
to the online logs and verifying that AF4MP/M has worked the following:

VP6BR Pitcairn Island on 17m
K5K Kingman Reef on 10m and 17m
D68C Comoros on 10m and 15m
TI9M Cocos Island on 10m
XR0X San Felix on 15m
VP6DI Ducie Island on 15m

Ducie Island was the ultimate of ultimate tests for a mobile contact!

>>>Further, there have been 
>>>numerous shootouts on 75 meters and 40 meters with the same output power 
>>>comparing antennas like the Screwdriver and the Comet, the Comets lose 
>>>every time.

The Comet CA-HV does not operate on 75 meters, so I guess it would lose out
on that one.;)
 
>> I haven't seen any reports of such shoot outs.  Though I suspect that an
>> honest comparison would show that the low cost Comet and Diamond antennas
>> to be a lot better than many would have otherwise thought!  

>You haven't been on this list long enough, they've been posted several 
>times.  You might also want to look at the September 1995 issue of 
>WorldRadio for one sample.  You can also search google's back list for 
>internet postings.  In fact, on this list, the results have been done 
>several different times.

How do you know how long I have been lurking and reading posts on this
list?  I don't have a copy of the WorldRadio for Sept 95, but the Comet
CA-HV was not available in 1995.  There is, however, a review in QST a year
later in September 1996.  I haven't seen any "shoot outs" incorporating the
CA-HV on the internet, or on this board.

>When I add in the 
>fragility and the like, it's an even worse choice.  

What fragility?  My antenna has been on the car for three years and has
survived unscathed a number of low garage hits etc.

>Quite frankly, for 
>about $170, one can buy a working W6AAQ screwdriver, and one can build 
>one for even less, using plans that are readily available. 

The Comet antenna is available for less, and as I have shown does work.
Incidently, there is now an upgraded version of this antenna available, it
is the CA-UHV.
--
Zyg AF4MP
Roswell GA USA