| Author |
Message |
    
Kmt36264
New member
Username: Kmt36264
Post Number: 2
Registered: 1-2006
| | Posted on Tuesday, February 14, 2006 - 5:09 pm: | 
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I know there has been a lot of discussion about the shortened 1/4 wave coil antennas like the 10K vs. the trusty old 102" ss. I understand from all the old post that the efficiency of any loaded antenna has to be less that a 1/4.
My question is in regard to take-off angles and gain at the horizon. Is there any difference?
What does basic antenna theory tell us?
I have the ARRL antenna book but haven't had a chance to read the whole thing yet. Is it feasable to build a 5/8 wave loaded vertical for mobile use (Big coil type) that is less than 9 feet? Has Kale or anyone else experimented with this?
I seem to make more DX contacts with the Predator than with the 102" ss. Locally, I can't tell much difference, maybe only marginally better with the 10K. Just curious.
Thanks! |
Marconi
Advanced Member
Username: Marconi
Post Number: 592
Registered: 11-2001
| | Posted on Tuesday, February 14, 2006 - 7:25 pm: |
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Kmt36264, there is probably more difference caused by the ground you are sitting on at any one place or point in time with a mobile than there is between these two antennas if they are installed correctly.
Even if the TOA is different how do you measure that and its effect plus I think they are both 1/4 antennas anyway and should show about the same TOA. I thought that had more to do with height and length of radiator to some degree. |
Tech833
Moderator
Username: Tech833
Post Number: 1216
Registered: 8-2002
| | Posted on Wednesday, February 15, 2006 - 1:05 am: |
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Do a web search for the Kinstar antenna for AM BCB use. You will see that a top loaded antenna will perform with 98% the efficiency of a full length 1/4 wave on the AM broadcast band.
A base loaded antenna will have a very high takeoff angle and much less efficiency.
However, for HF bands (like CB), the effect is minimal over an imperfect ground plane (like a car). |
Kmt36264
New member
Username: Kmt36264
Post Number: 4
Registered: 1-2006
| | Posted on Wednesday, February 15, 2006 - 2:19 am: |
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So is a Cowtown 10k with a 27" shaft a base loaded or center loaded type? And what are the properties of the center loaded antenna?
How about a longer shaft, a much longer coil and a short stinger for tuning....a top loaded 5/8 wave???
I'll be back after I read about the Kinstar. Thanks |
Alsworld
Advanced Member
Username: Alsworld
Post Number: 989
Registered: 1-2002
| | Posted on Wednesday, February 15, 2006 - 10:21 pm: |
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A base loaded antenna would be like your Wilsons, K40's, etc.
I've always heard that a top loaded antenna would be best (out of shortened 1/4 wave antennas), but hard to be solid if mobile with the weight at the top. Maybe Tech833 and Marconi can chime in, but hence why few if any are seen in a mobile environment.
I would consider the 10K to be a center loaded coil. Correct Tech 833?
Alsworld |
Wolverine
Advanced Member
Username: Wolverine
Post Number: 602
Registered: 2-2003
| | Posted on Thursday, February 16, 2006 - 3:53 am: |
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The best top loaded antennas that are 5/8's, are the skipshooter 5' and 7', everhardt tiger (Sott-5) antenna, and finally, the Wilson silverloads 5' and 6' antennas. I rate Firesticks dead last, because they're hard to get a good swr.
Wolverine. |
Hatchet
Intermediate Member
Username: Hatchet
Post Number: 102
Registered: 7-2004
| | Posted on Thursday, February 16, 2006 - 9:03 pm: |
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I dont believe the 10K is "loaded". I think its just a shortened 1/4 wave. Kale did make a loaded version though |
Hotwire
Advanced Member
Username: Hotwire
Post Number: 947
Registered: 1-2005
| | Posted on Sunday, February 19, 2006 - 12:53 pm: |
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I use the 6 foot silverload mobile. VERY top heavy and had to use a beehive mount on the trunk. This antenna performs better than any other I tried except the 102 which is ridiculous looking on top my car. Afraid I was gonna hurt someone with all the side to side sway. |
Georgeodjungle
Junior Member
Username: Georgeodjungle
Post Number: 36
Registered: 1-2006
| | Posted on Monday, February 20, 2006 - 12:43 am: |
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102 are beautiful.
other antennas are 2nd best.
so a 98% antenna is 2% less of the whip.
closer to 95% but any way...
we sqeeze these things for every lil bit we can get out of them.
for the serious only.
all the moble antenna shotouts we have done,
the whip won every time.
some do come close.
try it out for your self.
kind of funny when a $16 antenna out talks a more spendy one.
and thats funny "gonna hurt someone"
& i love that doinwinggg sound when it hits stuff.
& that bumper car sound when it drags on low over hangs. |
