Comet CHA-250HD

[tweiss3]

I've been reading a ton about vertical HF antenna options, and I know this particular antenna (and the original CHA250B) have a mixed bag of opinions/reviews. I believe that @prcguy (paraphrasing) called it a great dummy load for the end of one's coax. I did however find some comments intriguing, including the modeling. The most interesting comment related to a line in the old instructions for the "B" version:


Specifically the 35' mounting height. (This line is absent from current literature). While most indicate its related to takeoff angle (like all HF antennas, including EFHW), there was one that caught my eye. This gentleman thought there was more to that height than just the radiation pattern. It was thought that a 35' mast or tower would be quite the antenna counterpoise (without requiring radials) and very likely would boost the effectiveness of the antenna significantly. From what I understand of antenna theory, that actually makes sense.

My question is, those that have used this antenna (either the HD or B versions), how did you mount it? Was it near the 35', and was a mast pole used? Was it just clamped to a porch rail?

I have the complete understanding that it's neither the ideal antenna nor the most effective. In my scenario, I am looking for a backup vertical to connect to my spare FT-450D that is sitting on the shelf, since I recently had an issue that my EFHW for 10-80 fell and I was scrambling to get it up again. I'm trying to avoid radials and keep my cost down. I would only be able to mount it on a 20' mast, but I would guess that even that would improve performance over no mast/counterpoise.

 

[W2PAK]

I had an 250HD and changed it out for a 6BTV in 4 months due to poor performance and the fact that it only handles 250 W or so. I urge you to reconsider. 73's Paul

 

[prcguy]

I've used a number of verticals and for an elevated mast mount antenna without needing any major ground radials the Cushcraft R7 series worked well. I would think the newer R8 or R9 would perform similar and the R9 has 80m, although its probably very narrow band there. I would take any of those over a CH-250B even if it were free.

 

[vagrant]

I owned a Jetstream JTV680, a copycat of the CHA-250B. I purchased it right after licensing when I had no clue, as it advertised so many bands and low SWR. Magic beans you say...sure I'll take some. Here's my money.

Anyways, I tried it at different elevations from 16’ to 32’ on a mast. It was a extremely poor performer. I would have kept it as a RX only antenna, but it failed there as well. Still, I was able to make contacts with it, but I soon put up a 40-6M OCF and the difference was significant. 12 years later and I still use the OCF. I also compared it with an IMAX2000 on 10M with local operators who were also vertical and the difference was noticeable there as well on TX an RX. I sold that magic beans vertical antenna at a ham swap less than a year after purchase.

Set your expectations for regret. Also, when you think there is something wrong with your radio, it is not your radio.

 

[tweiss3]

The R8 & R9 seems like a promising option. Any opinion on guying? Instructions say guy kit is available (optional), but list it as an 80 MPH rating. Reviews mention its top heavy. The location that this needs to go guying is not probable.

 

[Golay]

It's interesting when I see the 250 critiqued. Although I've never run one, we have about a half dozen in our club that have. Every one of them likes it. One has it mounted to his deck and has WAS. Others have them at various heights and work the world.

One caveat of the original 250D antenna, and a couple of the guys have experienced this, the aluminum at the top of the antenna can't take a lot of wind without folding. One of them still works around the world with the top third of the antenna at a 45 degree angle.

If you look on DX Engineering's website, they show a
" ... improved Comet CHA-250HD features a new solid whip replacing the top aluminum section for greater flexibility and less strain on the lower sections in high winds ... ".

 

[prcguy]

It's interesting when I see the 250 critiqued. Although I've never run one, we have about a half dozen in our club that have. Every one of them likes it. One has it mounted to his deck and has WAS. Others have them at various heights and work the world.

One caveat of the original 250D antenna, and a couple of the guys have experienced this, the aluminum at the top of the antenna can't take a lot of wind without folding. One of them still works around the world with the top third of the antenna at a 45 degree angle.

If you look on DX Engineering's website, they show a
" ... improved Comet CHA-250HD features a new solid whip replacing the top aluminum section for greater flexibility and less strain on the lower sections in high winds ... ".

The improved version is stronger. And still a poor performer. Many people who have one only have that antenna for HF and nothing to compare with. Yes there are lots of users that make contacts across the globe and that's nice. I can do that loading up a metal trash can. It's when a CHA-250B owner finally compares their antenna to something else that is actually good (that probably costs less), then they understand what they've been missing.