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Author Topic: Comet CHA-250B - The Inside Story  (Read 5257 times)
WB2WIK
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Posts: 20540




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« Reply #15 on: February 23, 2009, 01:48:05 PM »

With a light bulb antenna, don't they make models for various power levels?

Can you pick up 3 dB going from a 75W bulb to a 150W bulb?

:-)

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W3LK
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Posts: 5644




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« Reply #16 on: February 23, 2009, 01:53:22 PM »

And if you use a horizontally-mounted PAR-38 reflector lamp, does this give you a directional signal with additional gain?

Logic says it will have a terrific Front to Side and Front to Back ratio! Smiley

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
N3OX
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Posts: 8852


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« Reply #17 on: February 25, 2009, 08:48:01 PM »

"Logic says it will have a terrific Front to Side and Front to Back ratio! Smiley "

Yeah... at 560 Terahertz ;-)
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
N4MAW
Member

Posts: 1




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« Reply #18 on: March 02, 2009, 03:11:17 PM »

I have had one of these antennas for just over two years now.  The antenna is mounted at about 33ft above ground level at eht apex of my house and has no counterpoise, no radials, and no tuner in line to the rigs (Yeasu FT897D and an UIcom IC-700.)  This antenna maintains excellent SWR (1.5 or less) on all bands 80 through 6 meters including MARS frequencies.  This is an excellent antenna for space limited installations.  I have confirmed QSOs with Ducie Is, Madeira Is., Spain, France, Dominican Rep., and more with this antenna.  I highly recommend this antenna.  If this antenna dissipates most of the RF energy as heat, as some here seem to say it does, then I would hate to think of the contacts I could make at the bottom of the solar cycle if it actually worked as advertised!  From my experience ove the past two years, this antenna does in fact work as advertised.

73,
Michael Wright, N4MAW, AAR4GJ
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KG4RUL
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Posts: 2676


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« Reply #19 on: March 30, 2009, 05:32:27 PM »

Got to use a CHA-250-B that was bought for use at our county EOC.  A total PITA to assemble compared to the Diamond BB-7V.  I replaced my 23' Force 12 Flagpole Antenna with the CHA-250-B.  Stations that I could previously work with difficulty were totally unreadable.

So, I ended up buying the Diamond antenna.  A really slick piece of engineering but, a real DOG for performance.  Again reolacing the flagpole with the BB-7V produced results similar to the Comet.

I ended up putting the flagpole back in place but, with one notable difference.  I removed the 'matching network' from the BB-7V and fastened it to the top of the flagpole using the existing clamps.  The wire that went from the radiating element to the 'matching network' was attached to the top of the flagpole.

Viola!  A 43' vertical that works great!  A few more radials are in the works but, I am satisfied.

So, bottom line, if the ONLY antenna I could get away with is one of these, that is the ONLY reason I would buy one.

Definitely a 2 of 5 for either.

p.s. all testing was done using an MFJ remote antenna tuner.
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G7TOK
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Posts: 16




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« Reply #20 on: September 10, 2009, 06:02:49 AM »

Well, I've worked the world on a 6m loop of wire in my loft tuned by an SG-231 coupler.
VK's, VU's JA's, you name it.
That must mean it's a good antenna !
Can I sell it for $440 now ? (not including the SGC)
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2E0SFX
Member

Posts: 5




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« Reply #21 on: February 08, 2010, 07:13:12 AM »

Hi where is your loft on top of the post office tower,
seriously though very interested in your setup.
Thanks
Damian
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