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Reviews Categories | Antennas: HF: Vertical, Wire, Loop | Comet CHA250B Help


Reviews Summary for Comet CHA250B
Comet CHA250B Reviews: 117 Average rating: 3.7/5 MSRP: $469.00
Description: The Comet CHA250B broadband vertical antenna will amazingly cover 75/80 meters through 6 meters with no gaps! Transmit range is 3.5-57 MHz and receive range is 2-90 MHz. SWR <1.5:1. This 23.5 foot vertical requires no radials and weighs only 7.1 lbs. The antenna consists of five sections of aluminum tubing that slide into each other. The bottom section has the matching network built-in. Only two simple measurements are required during the easy assembly. It can handle 250 watts SSB and 125 watts FM. SO-239 input. Mounts on a 1 to 2 inch mast (not supplied). Rated for 67 MPH wind survival.

Product is in production.
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K6BRN Rating: 4/5 Dec 1, 2015 09:36 Send this review to a friend
Good small footprint or diversity antenna  Time owned: 3 to 6 months
I purchased one a few months ago and experimented with it at several different heights, from 5 ft above ground, attached to a steel tube driven 5 feet into the ground, then raised to 10 and then 20 feet and finally in a different arrangement up 35 feet and RF isolated from ground using a non-conductive mounting point and a Palomar Engineers 5-bead choke on LMR400 coax, right at the feed point.

The antenna was unhappy until the last arrangement (up 35 feet, isolated from RF ground) where is works very well as a diversity antenna when played against my A3S. In stand-alone use on 80, 40 and 6 meters it works reasonably well all by itself, though with the typical higher noise level of a vertical and relatively low transmit efficiency on 80. As a bonus, it tunes up on 160 meters as well, as some have reported, but I'd never run full power (100W SSB) on that band - matching network on the antenna is not built for it. I'm very happy with it, and after seeing how easy it is to put up, how well it works with local 10M and 6M repeaters, and that it works decently on 80M, a friend of mine will be purchasing one for himself.

Comet makes no grand claims about the CHA250B, calling it a compromise antenna suitable for tight spaces or portable operation and covering 6M to 80M with good SWR on amateur bands. They also recommend putting it up AT LEAST 35 feet in the instructions, and some versions of the instructions recommend adding a coax choke (unun). I've found this advice to be right on. BTW - the antenna goes together in minutes, is very light and relatively easy to install. Lower tubing is double wall for strength, in places, while the topmost tubes are fairly thin and easy to bend - but I've had no problems with this mechanical arrangement so far.

Note that the CHA250B is NOT a resonant antenna. It is effectively a vertical "random wire" length antenna with a fairly complex (internally) matching network at the base. Changing antenna length by a foot or two has minimal impact on SWR (I tried this). As such, on bands where it is electrically short (particularly 80M and 40M), the radiation resistance is low and the matching base absorbs a large percentage of transmitted power, which is why it is limited to just over 100 watts PEP input. But ask any QRP'er - even 20W out ERP is more than enough to work the world on 80 and 40M. This is NOT a competition grade antenna - it is compact and easy to put up, and gets you on the bands very quickly.

Trying to turn this antenna into a ground mounted (ground plane) with buried radials seems pretty silly. Ground mirror effects will make it electrically much longer, but will also interfere with the purpose-built matching network's effectiveness, raising SWR significantly, as I discovered. But up 35 feet, with a feed-line choke attached, it sings pretty well.
 
WA6BFG Rating: 4/5 Oct 26, 2015 13:18 Send this review to a friend
Wow much better than I thought  Time owned: 6 to 12 months
Wow much better than I thought. I've had numerous vertical Antennas in different locations in my 43 years in ham radio. Have had very good luck with verticals some better than others most the other verticals I used where following R6000,R7000 to name a few and they worked quite well. I have moved into a location six months ago that provides a little limited space so I thought I might try one of these 250B. I worked the contest last weekend just to give this guy a work out. Although I didn't open any bands I did manage to work quite a bit of DX with the 100 Watts. I'll give you a little rundown worked Bonaire , Asiatic Russian, Australia, Hawaii, Alaska, State of Maine sundry other US stations. The primary bands that we worked 10 and 15 and just a couple on 20. I could hear quite a few Europeans but I couldn't get through the pileups from the East Coast. About as far south as I could get was Mexico I heard some South American stations but no joy. I've got everything installed on aircraft aluminum tubing in the backyard at 12 feet I'm feeding it with Low loss coaxial cable 75 foot run from the ham shack to CHA-250B
 
N7DKL Rating: 5/5 Oct 24, 2015 21:27 Send this review to a friend
Much better than expected  Time owned: 3 to 6 months
I have very small lot that is almost all cement, so radials are not really an option. I thought I would give this antenna a try and really didn't expect much but WOW, I have been very surprised! I have it mounted about 20 feet in the air on an expandable flagpole (thank you Harbor Freight) and the only "radials" are the three guy wires from the base. I run a Kenwood TS-2000 at 100 watts and use a MFJ-929 tuner. I get less than 1.3:1 SWR all the way from 1.8-30 Mhz. I have made contacts all over the USA including Alaska, Hawaii and PR, as well as Canada, Australia, Finland, Cuba, Croatia, Japan, Cyprus, Estonia, Aland Islands, Russia, Columbia and the South Cook Islands. Not too bad for an aluminum stick.
 
AD4C2006 Rating: 1/5 Oct 22, 2015 08:57 Send this review to a friend
Not a good antenna   Time owned: 0 to 3 months
I always has been very curious about this "misterious" vertical that has a very low SWR from 3.5 to 55 Mhz and certainly its amazing how well matched is in all HF and VHF bands, the highest reading I have is on 3.8 Mhz which is just 1.7 but in the rest of all bands including 6M is less than 1.5 been only 1.1 in several bands.
But low SWR don't mean efficiency, I can put a dummy load in a pole capable of handling 250W and radio/amp will be happy but nobody will hear me far away and that is what this antenna is, I will call it an efficient dummy load.
I have it installed over a 20 feet galvanized pole without any radials and the bazooka dipole is also at same altitud but horizontally mounted.
The radiated energy compared with any other antenna is much less, I have compared it with my bazooka for 40M that is flat in that band but could be tuned in any other bands over 7Mhz and the difference is day to night.
When I get a solid S9 with the bazooka dipole, the received report from this vertical will be S4 to S5, an average of 50% less power radiated so be prepared to lose that amount of power if you are going to spend big bucks on this low efficiency vertical.
The antenna is quite and I guess is precisely because of lack of gain but is not the choice for a home restrictions place like I am living at.
Chances are that eventually I will put it down and replace it for any other more efficient multiband antenna but at least I fixed my curiosity. Nobody will tell me how good or bad this antenna is because I have tested it by my own.
 
N5UXT Rating: 0/5 Oct 5, 2015 12:44 Send this review to a friend
Design Flaw  Time owned: more than 12 months
This antenna work fairly good until about 4 years. The SWR went up on all frequencies. After talking to NCG the cost for a new Transformer is around 189.00 plus shipping. I only paid a little under 300.00 for the antenna back then.

After doing some research, I found there is a design Flaw in the seal for the 12:1 transformer. Water gets into the coil and causes the SWR to go up.

For a good Web site about this, feel free to look at http://www.vk5zd.com/CHA250/CHA250.aspx .

I would recommend the copy version of this antenna From Jetstream which is a lot cheaper $289.00 and according to NCG, it is just a copy.

Overall, I would not recommend this antenna all. It will end up going bad.

 
KC3AAF Rating: 5/5 Jul 10, 2015 12:41 Send this review to a friend
Works well for multiband vertical  Time owned: 3 to 6 months
I am in an antenna-restricted area and did some comparisons with other vertical antennas before choosing this antenna. A bit of advice I took from Elmers is always use low loss coaxial cable, so I used LMR-400 and have good results using this antenna. SWR is lelss than 1.5 across all bands. RX is a little better than TX, more so on 10m. I feel location of any antenna system greatly affects RX/TX. My location is elevated, and using a maximum of 100 watts has provided QSO's in WA, OR, WY, AZ, NM, SD, TX, MO, MN, KS, and most every state east of the Mississippi river on 40m SSB and 80m SSB. With 20 watts on 10m, 15m, and 20m I have also done PSK31 to South America, Spain, Italy, and England, besides around the USA. Overall, I am very pleased with The Comet CHA250B.
 
T88SS Rating: 1/5 Jun 28, 2015 23:50 Send this review to a friend
Poor  Time owned: 0 to 3 months
Later on, I will provide the pros and cons of my new Comet CHA-250B vertical antenna. Ive only had my antenna up a little over a month so my review is based on the amount of time it has been up in the air. As many of you are aware of, HF band conditions have been at their worse so I am taking that into consideration and just basing my comments on the stations that I have worked.

I was so excited when my antenna first arrived here in Palau. I was also surprised that it could be shipped via USPS without any special shipping and handling.

As so many other reviews have stated, this antenna is very easy to install and put up. And only requires two(2) measurements. One of the other strong points and one of the main reasons that I ordered this antenna, was how small and lightweight. Only 8 lb.

I guess the biggest problem if I really must pick one, is just how poorly this antenna receives. I work a lot of JAs from Palau and 99% of the time, my transmit signal is always stronger (much higher) than what I receive. Most of the time, my receive signal is 3 to 5 S-units lower. This varies from band to band, but not much improvement no matter what band I try.

Some good news and I will report back later once this matter is taken care of. I purchased my antenna from HRO in the states and they are aware of the problems that I am having. This is still in the works and I may write more about this later on.

I guess one bad thing to report is that I was told by HRO, to install some ground radials. What? Their ad states that ground radials are not needed. That was a big disappointment. Im living in an apartment surrounded by a concrete paved parking lot no matter where I look. And the other disappointment (which I did not see stated anywhere) is that Comet recommends mounting this vertical 35 feet up in the air. My apartment building is only 30 feet high. No way can I do this.

Even though this write-up does not reflect favorably on my new Comet antenna, I am not a quitter and I am still working to improve its performance. If I am successful, I will write a new review saying what improvements were done to make this happen.

Pros:

1. Very easy to install
2. Extremely lightweight for a vertical 23 feet long.
3. Well built strong polished aluminum and uses stainless steel hardware
4. Seems to transmit okay on most bands whenever band conditions are up

Cons:

1. Reception is very poor
2. Advertisement does state that ground radials are necessary
3. Advertisement does not state recommended operating height is 35 feet
4. Also states that being guyed is not necessary (guy wire ring is included)

Summary: How can such a beautifully, well-made antenna, not perform well? My guess is, they (the designers) tried to cover way too many bands and just failed to obtain optimum performance as advertised. Maybe they should consider making a high band and a low band HF antenna and see if that will work.

If everything else fails, meaning things that I try and whatever HRO recommends that I try, I will shop around and look for a replacement vertical. I just do not have the room for wire antennas. Cheers T88SS


 
KD9DLR Rating: 4/5 Jun 15, 2015 10:46 Send this review to a friend
Exactly as advertised  Time owned: 0 to 3 months
Purchased this antenna as I am space limited - no room for a wire, and definitely can't install ground radials. This was shipped fast (from HamRadioOutlet), assembled in under 20 minutes. SWR 1.5 or lower across the band, climbing rapidly as you neared the 160 band. I only had it up a few minutes on a tripod mount about 8 ft off the ground, but was able to test the radio and find some CW and data traffic. I hope to have it mounted on a mast by next weekend, but I would recommend it.
 
KD2BQM Rating: 5/5 Oct 9, 2014 05:42 Send this review to a friend
I LOVE IT!!!  Time owned: 0 to 3 months
I live in a typical Brooklyn working class neighborhood. As such, my house sits on a huge 20' x 100' lot..... and you all know what they say about a "tree growing in Brooklyn". So.... Not much chance of running a wire that would require any length. Looked around and finally bought the Comet CHA250B, mounted it up on my roof with the recommended 100' of low loss cable, (I've got to say that NCG offered great customer service in answering any questions I had), and BAM! I'm on 80 meters being told I'm blasting them with only 100 watts of power... A crystal clear 5 x 9 !! I then Played around on some other bands and got similar results! All of this without the need for radials or having to pound an 8' grounding rod into the ground with the heel of my boot :-). Yeah... I know that a Yagi will do even better, but from where I am in Brooklyn... and the limited space I have to work with... I LOVE MY COMET!!!
 
KC9JZF Rating: 4/5 Sep 8, 2014 14:49 Send this review to a friend
Great Service!  Time owned: 0 to 3 months
My first attempt at installing this antenna resulted in my helper (neighbor) dropping the 20 feet of mast and the antenna into some bushes, bending 3 of the tubes. I called Mick at NCG and he got my replacements out the same day! They even arrived before they were scheduled!

The second attempt went much better. I have the base at only 24 feet and I am working DX like crazy on several bands. This antenna is very broadband and I can even use 160 meters with my built in tuner. I am replacing a Gap Titan and I am very pleased.
 
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