View Full Version : Comet RS-730 for Little Tarheel II antenna??
KD5ZPN
10-06-2011, 02:00 PM
Just wondering if anyone has had any luck with mounting these two together or if this would be a good idea. I ahve a new vehicle and I will not drill holes in it to mount my antennas, so I was curious if anyone has had any luck paring these two together or am I barking up the wrong tree. Thanks.
73's
Jeff
Curious? Why do you think there would be a problem? Interaction? I'm at a loss, so help me out.
KD5ZPN
10-07-2011, 11:35 AM
Not so much a problem with antenna working, but wondering if it had been done before....I know the best way to mount an HF antenna is was it grounded extremely well. I have already started bonding everything on the vehicle as per your website, and I was looking for another type of mount but I am getting a lot of "FLack" from the better half about having something coming out from underneath the vehicle....so I have to look at other options...I even had the steel to make a mount like the one you see attached but that got shot down as soon as she saw the pictures...so back to square one...just looking for some other ideas.
M0GVZ
10-07-2011, 12:56 PM
It'll work but you will likely have all kinds of common mode issues and when you're running on 40m and 80m you stand a real risk of bending the body panel as well as rusting around the bolts where they cut into the paint. On a triple magmount I couldn't run more than 50W into mine on 80m without it resetting the radio due to common mode issues and I suspect a lip mount will be equally as bad. After my experience I have absolutely no reservations about drilling a hole and when I come to sell the car, I'll fill the hole with a mobile phone antenna.
One thing I will say about that antenna though is to bin the stock whip, which will mean sacrificing 6m band, and change it for a 6ft one. It'll make the world of difference.
I'm a bit stronger about these sort of things. Like, who paid (pays) for the vehicle? My wife objected to having a 2 meter transceiver installed in her Civic, mainly because she isn't licensed. When I reminded her who bought the car for her, the argument stopped right there!
This is a bit off subject, but as I said I'm somewhat of a mobile fanatic. Antennas mounted on vehicles really don't need to be grounded in the normal sense. They obviously need a return for the RF, and that is usually accomplished by the mount itself. For example, and NMO mount assures a good connection for the coax shield directly under the antenna. The vehicle in this case, acts as the ground plane, all verticals need.
When it comes to HF antennas, few folks will mount the antenna in a similar fashion. Instead, the use just about every means they can come up with so they don't have to drill holes. This includes installations like the one on the photo above. And then.....
They run all manner of ground straps because they've been told that a the antenna needs to be well grounded. That is not the case. What the antenna needs is a ground plane! When mounted as above, a large portion of the return current is forced to return through the lossy surface under the vehicle, instead of through the vehicle's superstructure. A ground strap will not negate this premise, unless of course they're long enough to be a radial; an obvious faux pas!
KD5ZPN
10-07-2011, 02:03 PM
Well, I am not to worried about 6 meter, more in it for the real HF like 15, 17, 20 and 40 m. I am wanting to stay away from mag mounts as well.
Alan, I totally agree, but unfortunatly She does help make the car payments so I dont mave much choice but to compromise with her on how it gets installed. as I only have an FT-90 in here car....Since it was MICRO sized and not very noticable. But for my Suburban I am getting my choice of radio and antennas but she doesnt want it to look ridiculous when installed.
What other way would you suggest Alan for installing on a Suburban, Like I said I want to avoid drilling holes if at all possible but I want the best performance i can get with a mobile set up. I have started grounding the hood and doors and liftgate, along with the exhaust to make sure I eliminate as much RF noise as possible.
I have looked at all the possible mounts on the website along with the mounts on the Tarheel and Scorpion website, all with the same idea....how to make it the best possible and keep it neat. Thanks for all your help as I am just now really starting to get into this and working very hard to get my general, thanks to the practice test on QRZ.com
Vans, SUVs, station wagons (remember them?), all present mounting issues with respect to HF antennas. A lot of folks resort to mounting said antennas on the luggage rack, which is far from ideal in every respect, especially if you garage your vehicle. That is the main reason I never owned one. If I did, however, I'd mount the antenna on the right front where the coil wouldn't be near the body. I wouldn't use low mounting either.
Since you have a spousal issue, you might have to resort in a less than ideal scenario, like a trailer hitch mount. That way, when she's using the SUV, the antenna can be removed. A hood seam mount works on some vehicles, as long as the antenna isn't too heavy (hamstick). The only antenna I would never resort to is a short, stubby one.
KK4HP
11-25-2011, 02:35 AM
I realize this thread is a month old but I have the RS-730 mount which I use for my 2M/440 antenna and I have the Diamond D400 mount that I have for temporary use on the Little Tarheel II. In my opinion, the D400 is the minimum mount that I would use for the Tarheel. I have it on the vertical edge of the half door on an extended cab Ford F-150. The D400 has the added advantage of a tab that protrudes opposite of the lip mount which will give it additional support providing that there is a surface under it. The side edge of the hood or trunk lid would be best to eliminate the flexing issue. Make sure you carry the hex wrenches with you as the fasteners need to be checked, especially the first week, daily, because the rubber will compress, the screws will bite deeper into the paint, etc.
M0GVZ
11-25-2011, 09:07 PM
Magmounts will give poor performance and you'd need to have a triple magmount with the LT. They'll scratch the paint. You can use the lip mount but you have to cut through the paint to get a good contact and it'll most likely bend the panel its clamped to.
Both of the above do just as much damage as you'll perceive drilling a hole in the roof will do. However you'd need to repaint the roof if you use a magmount or replace the panel if you use a lip mount but with a hole, you just shove a mobile phone antenna in it when you sell the car.