Dual band ham antenna recommendations

[tacoclifford]

That must be one rigid antenna. I have run both the Browning BR-180-b dual band antenna and the Larsen NMO150-b 2m antenna on both the roof and the front fender with no issues and they get smacked against trees daily. If there was a large branch right at roof level I may have an issue but smaller branches haven't been a problem.
I also run a Browning BR-140 CB antenna on the fender, a Tram 1181 on the roof for GMRS, and a 102" whip. Since the Tram is the smallest it is quite a bit more rigid than the others, I left it on the roof going into a parking garage and it scrapped the concrete support beams but other than losing some paint it was fine. All the other antennas are very flexible stainless whips and if you are mounting it on the front fender it will have no problem bending over much lower than the roof line. If you have a branch that is low enough to break the antenna at the base while mounted on the fender I would be worried about breaking the windshield.
One thing I didn't like about the Browning dual band was the enclosed coil in the middle of the antenna that caused it to whip around a little more due to the weight. The Larsen 2/70 has an open coil though that could get caught on branches so pick your poison I guess.
Since 2m is my primary I went with 2m antennas without coils but carry a Browning dual band antenna just in case I need 70cm.

The antenna is fairly stiff. Even at 70 and 80mph on the highway it stands straight up with a slight bend. I only chose it because of where the coil was and the height. The coil is slightly above the roof line. I figured I’d want that as high as I can get it with our mounting it to my roof. It’s currently mounted at the base of the windshield on a tacoma. Between the windshield and the back of the hood.

I’ll have to give those a look though .

 

[axlesandantennas]

You trim the antenna base to account for the length of the spring to bring the SWRs back into specs. I’m running two 108” SS whips trimmed for 10m and CB on 8” springs. my 2m antenna is a modified Lil-Will magnet mount with a 4” spring. The Lil-Will has been in my roof for 8 years and I haven’t knocked it off yet. I hear it rolling around from time to time, but never has it come off.

Yes, but like I said, it does effect your swr out of the box when you add X amount of length to it IF the spring is part of the radiating element.

 

[M Rose]

Yes, but like I said, it does effect your swr out of the box when you add X amount of length to it IF the spring is part of the radiating element.

Yes... but all antennas are supposed to be “Tuned” out of the box... some are within reason while others not so much... also talking 2m and 70 cm whips, most have a lot of fudge room so going with a 4” spring isn’t going to make the SWR above 2:1 and most modern day transceivers can accept a 3:1 SWR before the radio shuts down or damage is done to the finals.

 

[axlesandantennas]

Yes... but all antennas are supposed to be “Tuned” out of the box... some are within reason while others not so much... also talking 2m and 70 cm whips, most have a lot of fudge room so going with a 4” spring isn’t going to make the SWR above 2:1 and most modern day transceivers can accept a 3:1 SWR before the radio shuts down or damage is done to the finals.

Perhaps on an ideal location. However, everyone's placement may be different. Too close to a vertical metal support, you may need to re-tune. I can't mount an antenna directly on my roof because I have a plastic jeep top so I mount on my roof rack and have to retune. My CB antenna on my front bumper may be good at 1.5 on ch 19, but probably higher at the edges since a physically short antenna loses bandwidth. And mount behind the spare tire? No way.

I would not run a 4 inch spring on a dual band vhf/uhf antenna without first checking SWR. A 1/4 wave 2 meter antenna is about 19 inches, so 4 inches is about 20% more length and you are almost doubling the 70 cm band with those extra 4 inches.

 

[M Rose]

Perhaps on an ideal location. However, everyone's placement may be different. Too close to a vertical metal support, you may need to re-tune. I can't mount an antenna directly on my roof because I have a plastic jeep top so I mount on my roof rack and have to retune. My CB antenna on my front bumper may be good at 1.5 on ch 19, but probably higher at the edges since a physically short antenna loses bandwidth. And mount behind the spare tire? No way.

I would not run a 4 inch spring on a dual band vhf/uhf antenna without first checking SWR. A 1/4 wave 2 meter antenna is about 19 inches, so 4 inches is about 20% more length and you are almost doubling the 70 cm band with those extra 4 inches.

Correct you are doubling the 70cm and effectively easing the dB gain as well... I didn’t say not to check SWRs i was saying even an antenna out of the box needs to be checked and possibly tuned for peak performance.
For your keep top, you could run a 5/8 wave antenna since it doesn’t require a ground plane, or run a grounding strap from the connector to the roll bar, or use tin foil to make a ground plane.... lots of options... personally on my Bronco (still has the fiberglass top) I run three bonding straps from my roof rack mounts to my forward cab, and then run a single strap to each of my NMO mounts. (I run 2 VHF/UHF radios and a single HF, so three NMO mounts and 3 antennas).

 

[Jay McClellan]

I use a Comet SBB-1 that's only 16 inches long and super flexible, and it has taken many hits from branches without any damage. It's totally adequate for short-to-medium-range communication, and I carry a longer dual-band that I can swap in when I need more range but then I need to be much more careful not to hit anything with it. The SBB-1's gain on 2M / 70cm is 1.5 / 2.15 dBi compared to 3.0 / 5.5 dBi for a typical 40-inch dual-band so you only lose about 1.5 / 3.3 dB. That means the longer antenna should reach about 1.2 or 1.46 times further, which is usually not very significant.

 

[DRAX]

I use a Comet SBB-1 that's only 16 inches long and super flexible, and it has taken many hits from branches without any damage. It's totally adequate for short-to-medium-range communication, and I carry a longer dual-band that I can swap in when I need more range but then I need to be much more careful not to hit anything with it. The SBB-1's gain on 2M / 70cm is 1.5 / 2.15 dBi compared to 3.0 / 5.5 dBi for a typical 40-inch dual-band so you only lose about 1.5 / 3.3 dB. That means the longer antenna should reach about 1.2 or 1.46 times further, which is usually not very significant.


View attachment 200871

Don't forget that more gain means a flatter radiation pattern which is not good in hilly terrain, so sometimes it's good to have a couple of antenna options or one good general-purpose antenna.

 

[Jay McClellan]

Don't forget that more gain means a flatter radiation pattern which is not good in hilly terrain, so sometimes it's good to have a couple of antenna options or one good general-purpose antenna.

View attachment 200891

Good point. In typical overland conditions there may not be much observable difference between the flexible stubby and a longer antenna. I can say from my own personal experience that the flexible stubby works much better than a longer antenna that has just been bent sideways by a tree!

 

[El-Dracho]

Don't forget that more gain means a flatter radiation pattern which is not good in hilly terrain, so sometimes it's good to have a couple of antenna options or one good general-purpose antenna.

View attachment 200891

This is a very good information. Because an essential point, especially in amateur radio, is the vertical radiation angle of the antenna. A flat radiation angle against the horizon, as for example a vertical antenna has, is advantageous here. The flatter the antenna radiates vertically, the more transmission power is redistributed from the vertical to the horizontal direction. This redistribution ensures that not so much transmitting power disappears vertically upwards towards space, but is directed towards other transmitting/receiving stations on earth, e.g. fellow rigs. Vertical antennas can be optimized down to very small radiation angles (we see this especially in the VHF and UHF range).

However, a small angle of radiation can have disadvantages for overlanding radio use. We are often on the road in hilly terrain, and with a flat beam angle, the reachability of nearby receivers, such as vehicles located in a valley, suffers. The sketches you have shown make this really clear! Thank you for sharing here! It's really great how much knowledge is shared here! Great!

Well, the choice of antenna is a compromise between performance, application, clearance height of the rig (or off-road capabilities) and installation situation.

 

[OTH Overland]

I also use the Browning BR-180-b dual band antenna, have it mounted on a Comet CP-5NMO hood lip mount. Both have held up very well, and as a pair have a really good SWR match. We were up on a NW overgrown trail last weekend and it was getting beat constantly, hitting the window at times with no noticeable damage. On the way back, we just loosened the thumb screw and folded the antenna back about 45 degrees, reduced almost all the bending. Have half a dozen of these on my rigs for ham and scanners, all have been great. Only issue is making sure the set screws in the loading coil are tight from the factory so you don't lose a section of whip. used to buy Larsen's, but they seem to have changed their materials and the whips were snapping off at the base.

 

[WTSMatt]

I am new to getting interested in mobile HAM, don't have radio yet and only on the preface of the study guide but trying to figure this stuff out. In regards to antennas mounting location I was wondering if I were to mount it at base of rack on bed rail basically between vertical rack support and C-pillar so that it would be protected somewhat by cab but could still get a bit of length? Or does all that aluminum (truck body and rack) mess with signals. Again, super noob on this topic so I apologize if covered elsewhere.

 

[Prerunner1982]

@WTSMatt that would not be a recommended mounting location as both the C-pillar and the rack support will bounce signals around and would likely interfere with the antennas tuning causing a high SWR.
I would suggest on the roof or on the rack if at all possible, even if you have to use a shorter antenna. With VHF/UHF comms antenna height is important for greater range.
The front fender would be the next best option.