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Reviews For: Comet GP-9 dual band base antenna

Category: Antennas: VHF/UHF+ Omnidirectional: verticals, mobile, etc

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Review Summary For : Comet GP-9 dual band base antenna
Reviews: 50MSRP: 200 about
Description:
Ultra High Gain Dual Bander for 146 & 446Mhz
Product is in production
More Info: http://www.cometantenna.com/base.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00504.5
KB5UIA Rating: 2008-03-09
VERY HAPPY Time Owned: 0 to 3 months.
Very easy to assemble... only small bit of common sense needed. Very light (~5 lbs.), so easy to carry/install. My only negative issue is one of the three tapped holes for the radials was not threaded properly. Had to re-tap hole to get radial to seat all the way like it should.

SWR Performance:
( @ 50w, 20' RG-8 coax jumper, 3' RG-8 coax jumper, and 100' LMR-400 coax with perfectly soldered connections )

144.000 = 1.4
145.000 = 1.1
146.000 = 1.2
147.000 = 1.1
147.995 = 1.1

435.000 = 1.1
440.000 = 1.4
445.000 = 1.3
446.000 = 1.4
447.000 = 1.2
448.000 = 1.3
449.000 = 1.4
449.995 = 1.2

Current setup is only until I get my tower up. Current setup only has antenna up ~12' from ground (i.e. tip of antenna is ~28.5' high).

Range:

QTH = Huntsville, TX

Can bring up repeaters in Galveston & Tyler... both are over 100 miles away with 50w. Can hit Conroe repeaters (~30 miles away) with only 5w, all day long, any day, no matter rain or shine. Can have simplex ops to mobile with 5-9 report up to ~15 miles out... through mainly forest-type area (i.e. mobile has lots of tall pine trees all around it at all times). Have been labeled as "full quieting" from all our typical contacts (repeaters out 15 to 40 miles out).

W5SDC Rating: 2008-03-04
Seven years old and still going strong Time Owned: more than 12 months.
My GP9 has been in and on the air for 7 years and has held up well in the Texas sun and wind. SWR is almost flat at 5W on both bands and around 1.3 at 50W on both which isn't too bad.

If you handle a fiberglass antenna thats been out in the weather for awhile, don't make the mistake of not wearing gloves!
KB3MMX Rating: 2007-11-03
Kick Butt Vertical!! Time Owned: more than 12 months.
This thing works outstanding, as good or better than my 6270-13 Cushcraft beam ever did on VHF/UHF!! .....With less clutter on the tower that saves space for horizontal antennas to use on SSB!!!
This antennna is an exceptional performer for working those distant stations and repeaters!!
VA3JDL Rating: 2007-07-03
Great Repeater Antenna Time Owned: more than 12 months.
I set up the GP-9 as a repeater antenna for VE3JOP our VHF/UHF repeater system in Toronto.
The antenna has been up since early 2004. From day one performance has been great with flat SWR.
Performance on both bands is nothing less than excellent. Hears just as well as it gets out!
I would recommend the GP-9 over the standard repeater antennas on the market.


N8EKT Rating: 2007-05-16
NEEDS MODIFICATIONS Time Owned: 0 to 3 months.
I JUST PUT MY GP-9 UP YESTERDAY.
FIRST, THE INSTRUCTIONS WERE WRITTEN IN BROKEN ENGLISH AND IT WAS SO BAD THAT I HAD YO READ SEVERAL SENTENCES MULTIPLE TIMES TO UNDERSTAND WHAT THEY REALLY MEANT TO SAY!!
MY FIRST IMPRESSION WAS THAT IT WAS A LIGHT-DUTY ANTENNA COMPARED TO THE DIAMOND X-510 AND X-500. THE TINY SET SCREWS CAN EASILY GET LOST DURING ASSEMBLY,
THE BIGGEST DISSAPOINTMENT WAS THE ABS SECTION COUPLERS.
MO MATTER HOW TIGHT I MADE THEM, THE SECTIONS WOULD STILL SPIN OR PULL OUT!!!
THE SECTION FASTENERS ON THE DIAMONDS ARE FAR SUPERIOR.
THERE IS NO WAY I WOULD USE THE GP-9 ON A REPEATER OR WHERE I COULDN'T EASILY TAKE IT DOWN FOR REPAIRS.
I MAY TRY TO EITHER EPOXY OR SILICONE THE ABS COUPLERS SO THAT IT DOESN'T PULL APART AND START FILLING WITH WATER.
WT0P Rating: 2006-07-26
Quality Antenna Time Owned: 3 to 6 months.
This is an excellent performer, Great VSWR except right around 144.0 where it gets a little higher than my rig likes. It goes together beautifully and has already withstood some unusually powerful storms that ripped through our area recently. Not exactly cheap but I'm getting too old to get up on the roof so a solid reliable antenna matters to me. Its a winner!
KB3RMX Rating: 2005-10-02
NOT WHAT I EXPECTED Time Owned: more than 12 months.
I've had the gp-9 for a little mre than a year now, I'd thought I'd give it some time before I made a review on it. Needless to say this is about the best in its class, but I'm very dissappointed in its performance for an antenna that costs more than $200.

Pros:
Gets out very good
Very good ears
Very sturdy in bad weather
Easy to construct

Cons:
Very high swr's below 146 mhz
High swr's on 50 watts or more
Does not work well on 440
Need an antenna tuner for <146 mhz and high power and 440
Had to solder a cold joint above the inductor

I would have given this a better rating, but Comet 's ad is misleading on this antenna.

Am going to use a quad in place of this in the near future.
KG4TBQ Rating: 2005-04-30
Excellent antenna Time Owned: more than 12 months.
I am getting great coverage with it.I have it in a 40ft tree in the back yard using lmr 600 coax. Both bands the swr is 1.1. It works equally good on both bands. I spend most of the time on 2m.I live in central florida and work stations on all sides of the state and once in a while up into Ga. and Ala. with good conditions.That's using only 55 watts out of the radio.The antenna seems to me to be very sturdy because it went through all three hurricanes last year up in that tree and still is working great.
W8GTX Rating: 2005-02-13
Ok antenna Time Owned: more than 12 months.
Good gain on both bands. Big difference on 440 compared to my V2000 Diamond. Down side is the match, it's never been great on 440 and is a little tight on 2m.
K6RSG Rating: 2004-08-17
Phenomenal, Durable, Outstanding!! Time Owned: more than 12 months.
This antenna has far exceeded my expectations. For the past fourteen (14) years, it has performed flawlessly. Working so well, in fact, that for many years I used nothing more than an HT with it, and frequently requiring no more than Extra Low or Low power to reach nearly all the Los Angeles area repeaters. And, with the power of a mobile or fixed station it has been suprisingly easy to reach repeaters, fixed stations, and even mobiles well over 150 miles away.

Mounted to a short mast at about 18 inches above the apex of the roof it has survived the UV exposure, blazing summer temps, and gusty Santa Ana winds here in Woodland Hills, CA.

It was purchased for $150 on August 23, 1992 when it was designated Comet model: CA-2x4MAX.

The original specs are:
Freq/Gain: 146/8.5dB, 446/11.9dB
Impedance: 50 ohm
VSWR: Less than 1.5
Length: 5.4m (17.7 Feet)
Max Pwr: 200w
Weight: 2.6kg

I beleive it is essentially the same thing as today's model GP-9.

Just last Sunday, the antenna/coax system was checked (for the first time in 14 years!) with an MFJ-249 Antenna Analyzer and it was astounding how flat the SWR remains.

As stated in the oddly worded original product sheet: "CA-2x4MAX is wide band having low VSWR as shown above. Needs completely NO Frequency Adjustment. However, please pay extra attention on Water-Proof works at each joint parts, by adhesive glue, self-melting tape and/or vinyl tape."

This antenna has served me well and although sold as a dual bander, I've used it regularly on 220MHz as well.

This is one fantastic antenna, which I highly recommend!

'73

Rob
K6RSG