Comet Antenna

[ScanWV]

Anyone have a Comet CSB-750A or CSB-770A? I am going to buy a Yaesu FT-7900R trying to find out if this is a good antenna. If anyone has pros and cons it would be helpful, thanks.

 

[wyomingmedic]

Let me see of I can impart some of my years of mobile radio ops

Most of these Comet mobile antennas are known in the ham circles as "pacific rim". They are not known for quality and generally have some significant structural and electrical problems. The antennas you are looking at are known fro breaking at the loading coils as well as getting water inside.

Also look at the mounting options. The antennas you are looking at are PL259 connection antennas. That connector WAS NOT DESIGNED to hold antennas. They are not physically strong and can leak very badly. MANY problems with those mounts.

The standard in mobile radio mounts in the NMO (stands for new motorola). They have been in existence for 40+years and are proven. They are waterproof, even if the antennas are removed.

Now, the Comet (and other pacific rim antennas) do come in NMO mounts, but they are slightly different. I suspect that this is a way to get around U.S. patent laws. They look the same and KINDA mate, but not properly. The thread pitch is different.

What I would recommend is the Larsen NMO2/70. Take a look at 90+% of antennas on fire trucks/LEO/ambulances and you will see a Larsen antenna. It is not coincidence. They really are the best made. Many stories of 30+ year old Larsens being on 10 vehicles. Not the case with Comet or other cheap (but still costly) antennas.

Just be sure you do not play the "gain game". Most antenna manufacturers inflate the gain figures of their antennas to make them look better. The reputable don't (Larsen, Maxrad, Antennex, Laird). So that is my recommendation.

WM

 

[mass-man]

I totallly second the Larsen recommendation. Have been using them for over 30 years, and no problem. Never had a Comet or Diamond mobile antenna, but can't see the PL259 mount being worth the time and money!!!!

 

[n5ims]

Just be sure you do not play the "gain game". Most antenna manufacturers inflate the gain figures of their antennas to make them look better. The reputable don't (Larsen, Maxrad, Antennex, Laird).

Agree 100%, "gain" is easy to overstate on comparison. Want an easy increase of 2+ dB, report your gain figure in dBi not dBd (Knowledge Base Article - Antenna Gain: dBi vs. dBd Decibel Detail - Support - Digi International). dBi is used for antenna theory while dBd should be used for actual antennas.

One good rule of thumb when looking at antennas is if a maker reports their gain in dBi, simply walk away. If they lie about (or more accurately misrepresent) this spec, what other spec are they less than 100% truthful about!

 

[Hooligan]

For what it's worth, my decades worth of mobile radio ops differs greatly than wyomingmedic's years of mobile radio ops, and I think he's using a lot of faulty 'logic' in his response. I have used the "Pacific Rim" antennas with SO-239/PL-259 connections as well as NMO connections, AND I also have direct experience with the Larsen NMO mount antenna he recommends.

I do not believe that "ham circles" generally share a negative experience with Comet/Diamond/Maldol antennas, let-alone those using SO239/PL259 mounting systems. Wyomingmedic seems to not know that even Larsen makes some mobile antennas with the So-239/PL-259 mounting system! I've been to plenty of amateur-radio related events & seen plenty of Comet/Diamond/Maldol antennas (using SO-239 mounts) on people's cars, just like I've seen plenty of Larsen types.

I have about 350,000 miles worth of driving using a variety of Comet/Diamond SO239 mount antennas on 3 different vehicles over the past two decades, including about 150,000 miles in SE Michigan (cold, frozen Winters, rainy Spring & Fall). The mounts had always been mag-mounts. With minimal preventative maintenance (removing the antenna & mag-mount twice a year to visually check & clean everything) none of the couple mag-mounts & 5 or 6 different antennas ever had any issues beyond ones caused by me (failing to fold-over the antenna when pulling into a parking structure). I have used one of the biggest Comet/Diamond mobile antennas -- the SG7900A, which at 57" long, they specifically advise should not be used with a magnet mount. I did use it with a mag-mount, and the antenna was physically strong-enough to hold-up at highway speeds, with the 239/259 mount unless I was doing 80MPH+ into heavy winds, ion which case the wind-load was too heavy for the mag-mount to take, and the antenna/mount would keel-over, slapping the roof of my car (but no real damage done to the antenna or mount).

The very first ham antenna I put on my car was back around 1988 & ironically, it was a Larsen NMO 2/70 & Larsen mag-mount. Within two years, the bottom loading-coil had cracked -- I assume due to moisture ingress & then freezing & expanding.

For my new vehicle, I decided to drill holes & go with permanent mounts. Due to depth clearances at the locations I chose, I had to go with NMO mounts. I bought an Maldol antenna (which I guess is one of these so-called "pacific Rim" antennas) with an NMO mount & while I didn't count threads, the NMO mount screwed-on just fine & the antenna worked very well. *I* suspect wyomingmedic's suspicions about the "Pacific Rim" NMO mount being different is an old wive's tale or just silliness being spread on the air by old geezer hams who don't like foreign-made antennas.


We agree that most US public safety vehicles do not use Comet/Diamond/Maldol antennas. But the reason for that is simply because those companies don't make or market many products to the non-amateur/public-safety market! As someone who has done some comms stuff for a variety of law enforcement agencies, I had to laugh at his notion that "most" public safety agencies use Larsen products because they are "the best." I've gained lots of undeserved admiration & respect (& some $$) with a few public safety agencies by simply replacing their lowest-bidder mobile antennas with a relatively inexpensive but rugged & higher-gain overt or covert antenna, but this is a separate argument, since his Larsen vs. Comet/Diamond public safety antenna fielding argument is TOTALLY INVALID.

I don't expect to be seeing a Comet or Diamond setup at the International Wireless Communications Expo this week in Las Vegas, whereas Larsen will be at Booth 4003...


Tim

Let me see of I can impart some of my years of mobile radio ops

Most of these Comet mobile antennas are known in the ham circles as "pacific rim". They are not known for quality and generally have some significant structural and electrical problems. The antennas you are looking at are known fro breaking at the loading coils as well as getting water inside.

Also look at the mounting options. The antennas you are looking at are PL259 connection antennas. That connector WAS NOT DESIGNED to hold antennas. They are not physically strong and can leak very badly. MANY problems with those mounts.

The standard in mobile radio mounts in the NMO (stands for new motorola). They have been in existence for 40+years and are proven. They are waterproof, even if the antennas are removed.

Now, the Comet (and other pacific rim antennas) do come in NMO mounts, but they are slightly different. I suspect that this is a way to get around U.S. patent laws. They look the same and KINDA mate, but not properly. The thread pitch is different.

What I would recommend is the Larsen NMO2/70. Take a look at 90+% of antennas on fire trucks/LEO/ambulances and you will see a Larsen antenna. It is not coincidence. They really are the best made. Many stories of 30+ year old Larsens being on 10 vehicles. Not the case with Comet or other cheap (but still costly) antennas.

Just be sure you do not play the "gain game". Most antenna manufacturers inflate the gain figures of their antennas to make them look better. The reputable don't (Larsen, Maxrad, Antennex, Laird). So that is my recommendation.

WM

 

[kb0nly]

I have been using a Comet SBB-7 dualband with my FT-7800 in both mobiles for years now, no problems with either. These are the PO/PL-259 type. I have a SBB-7 and a SBB-25 that are close to five years old now, no trouble at all with the antenna or mount.

I have had less trouble with PO mount antenna's than NMO mount. The problem with a lot of the ham band NMO antennas is the cheesy spring tab they use for the connection. If you go NMO make sure you get a good one with a spring loaded push pin in the center of the antenna for contact with the NMO, a lot more durable and don't suffer connection problems over time. I have replaced NMO antennas due to those problems with PO mount.

If you want a good dual band antenna from Comet check out the SBB-7, its one of the best they sell in my opinion, i have two of them and two other local hams bought them after seeing the difference compared to their antenna when i swapped mine onto their vehicle to give them a test drive.

 

[fineshot1]

I echo the comments above from kb0nly and Hooligan.

I have been using the comet line of antennas both SO-239 and N mounts
for many years - just as long as I have also been using some of the Larsen
antennas and most have held up pretty well except I had a couple of the
Larsen 220Mhz NMO mount base loaded coils get a water infiltration
problem so I stopped using them, so I have had zero problems with the
comet and diamond(NR-124) antennas. I also have a hustler SF-220
for many years which has held up very well also, this is what replaced
the Larsen NMO 220.

At work we have been installing a large number of Antenex and Maxrad
antennas and they have held up very well with a large fleet of vehicles.

 

[N6RDT]

I have used a maldol so239 antenna on a l bracket and had no problems. I prefer a permanent nmo mount on the roof and whenever possible, do it that way. I use larsen nmo antennas also.

 

[ScanWV]

thanks for the info everyone. Im not a fan of drilling into my car, and im trying to stay away from mag mounts. I'll do some more investigating and then make a decision.