Dangit, ExPo, you've convinced me! Getting my HAM license back...

[Martinjmpr]

Gotta thank you ExPo guys, if it wasn't for you my wallet would be clogged full of money and it would probably give me back problems. :sombrero::sombrero::sombrero:

Okay, seriously, after reading through the HAM vs GMRS thread I started I've come around to the fact that if I want decent comms, I need to get my HAM license back (for those that didn't read the thread, I used to be a Tech+ which is what they called a Tech who also had some HF privileges including voice privileges on 10m. My call sign was KB0LOG.)

I assume there are lots of places in the Denver area where I can get hooked up with a VEC (do they still call them that?) to take the test, and I know there is a Ham Radio Outlet store where I can probably get study materials (although I can probably get them on the internet for free, right?)

So I'm exploring the possibilities and I've decided a few things: First off, I want a mobile unit, not an HT (I had a couple of HTs in the past and wasn't impressed by their lack of range.) Looks like there are a lot of them available in the $300 - $400 range.

That brings the first question: How are you guys mounting your mobiles? I have a single DIN slot available below my radio (since I no longer have the factory double DIN deck), is that a decent location? I'm mainly concerned about heat dissipation since that part of the dash is not ventilated. Have folks with similar vehicles (3rd gen 4runner or 1st gen Taco) had any problems with such mounts? And if not in the DIN slot, then where else?

Also: Single or dual-band? From folks with experience, are you finding more repeaters or better comms with 70cm vs. 2m? I know 2m is pretty much the "standard" but in shopping I see that the 2m-only rigs can be found for ~$200 while dual-banders start around $300 or a touch more.

For those who have both, is the additional capability of the 70cm band worth the extra cost? For those that went single-band, do you now wish you'd gone dual-band?

It would be a bonus if the unit was removable or "hide-able" and for that reason I'm thinking something like the Yaesu FT7900-R that allows for a "remote mounting." What other "detachable face" 2m or 2m/70cm rigs are out there?

And then there's the big question: Antenna. My dilemma is that I park my 4runner in the garage, and there is probably no more than 6 - 8" of clearance above the roof (and that's without a lift, which I probably won't get, but is always a possibility.)

I understand that for the best ground plane a center-roof mount is best but I absolutely will NOT have an antenna that has to be mounted and dismounted every day. I'll accept a lower degree of performance in exchange for something I can leave on the truck. How are the hood lip mounts for performance? I also have a tube bumper and would be willing to do a bumper mount if that would be easier. What kind of 2m or dual-band antennas are folks using that are garage-compatible?

Thanks in advance. :ylsmoke::ylsmoke::ylsmoke:

 

[cnynrat]

Glad we could be of assistance ... :sombrero:

I assume you know that there are practice tests available free of charge on www.qrz.com. I also found the ARRL study book to be useful. Kind of depends on your learning style.

Mounting radios in modern vehicles with fully populated center stacks can be difficult. I think there is a thread around here about aesthetically pleasing radio installations.

I have a Kenwood TM-V71A that came with a nice mount that I stuck to the top of my dash. I'll try to take some pics and post them. You can easily remove the head from the mount, disconnect it with a single RJ-11 style jack, and hide it if you want. I usually just leave it there. The mount was definitely a factor in my choice of radio. Not the only factor, but certainly something I considered.

As far as single or dual band, I have not found any use for 70cm, but others may have. One thing to note, if you want dual recieve, you are likley to end up with dual band. I thought dual recieve would be useful, but frankly don't use it very often. I thought I might want to do things like monitor a repeater while communicating with my group on simplex. Just doesn't happen that often, at least for me anyway.

I have a Comet SBB-1 antenna mounted on a lip mount on my rear door. It's a 1/4 wave antenna - about 16" long, and is flexible, kind of like a rubber duckie antenna. I bought it to use in heavy trees where my 1/2 wave antenna was getting punished. The SBB-1 ends up staying on my FJC most of the time around town. It has reasonable performance, but I can certainly tell the difference when I put the 1/2 wave on. I put the 1/2 wave on the rig when I'm out in the desert and there aren't too many trees around.

 

[1911]

Ham radios generate a lot more heat than a stereo or cb because of their power, so mounting them in a DIN slot (especially next to another piece of equipment) is usually not a good idea. Most have heat sinks or fans, but they do need at least some access to air to shed heat.

I have my mobile 2M and dual-band radios mounted overhead, on the roof or the roll cage of both of my 4WD trucks, but not everyone likes that location.

As far as dual-band goes, it depends on where you live (and travel) and what you want to do. 70CM is fairly useless to me because there are not many active repeaters out where I live. It does do better than 2M however at getting out of canyons, if there is someone else to talk to. I have one dual-band mobile radio and two single-band 2M mobile radios. I use the dual-band radio so I can have APRS running all the time on side and still have the other side for voice, so I'm just using it as two 2M radios in the same case/installation.

A hood-lip mounted antenna will usually have enough ground plane to run whatever antenna you want. A 5/8-wave will give you good performance if the SWR will tune-up there. Tube bumpers are hit and miss for ground plane, it depends on the size and shape of them in my experience. If a 5/8-wave antenna won't tune-up on the bumper, then a 1/2-wave almost certainly will, with a small loss in performance.

 

[Martinjmpr]

How well do the half-wave antennas work on dual band, though? I see another member here has duplexed his antennas so he can run two of them. I assume that since 2m is the "primary" band and 70cm is the "secondary", the antenna would be tuned primarily for 2m? So how well does it work at sending a 70cm signal? Would half-wave be better than 5/8 or would quarter wave be even better still at 70cm, though not quite as good with 2m?

 

[hochung]

Martin, I think some of your questions might be answered as you study for your tech exam. Focus on the exam.

 

[Martinjmpr]

Well, the good news is I just took one of the sample tests at QRZ.com and failed. But I failed with 69.6% and that is without studying and with all my radio knowledge about 18 years out of date (1993.)

Of course, at least 4 of my "correct" answers were WAGs...

So I guess I need to hit the books.

 

[rocknrun]

Either Diamond or Comet (can't remember which) makes a motorized mount for a luggage rack. Hit a switch and the mount swivels the antenna down for low clearance. Of course the first time you pull into the garage and forget to lower the antenna.....

Welcome back to amateur radio!

 

[xtatik]

Ham radios generate a lot more heat than a stereo or cb because of their power, so mounting them in a DIN slot (especially next to another piece of equipment) is usually not a good idea. Most have heat sinks or fans, but they do need at least some access to air to shed heat.

I agree with this completely. When considering electrical components, heat is the enemy.
Also, get the dualband. Most of the larger linked repeater systems are on 70cm.

Oh, and BTW Martin, good move!

 

[xtatik]

Martin, I think some of your questions might be answered as you study for your tech exam. Focus on the exam.

Funny thing..how this happens. You can certainly tell the difference twixt the "memorizers" and the "studiers"(.......are those real wurdz?).

Martin, if you passed the the Tech+ in the past, you're gonna' find the newer Tech test to be much easier. Of course, as we get older our brains go to diahrrea:drool: But, you'll pass it easily.

 

[1911]

How well do the half-wave antennas work on dual band, though? I see another member here has duplexed his antennas so he can run two of them. I assume that since 2m is the "primary" band and 70cm is the "secondary", the antenna would be tuned primarily for 2m? So how well does it work at sending a 70cm signal? Would half-wave be better than 5/8 or would quarter wave be even better still at 70cm, though not quite as good with 2m?

Any multi-band antenna is going to be a compromise in any event. Ideally you would want a full-wavelength-long whip for each and every frequency, but since that is rarely practical, we either settle for some fraction of a wavelength that is a resonant multiple, or make up the difference in length with a coil, or both.

Since 70CM is roughly 1/3 the wavelength of 2M, you could have a 49" antenna that would be 5/8-wave for 2M and about 15/8-wave on 70CM. Or, you could have a much shorter antenna that would be close to both 1/4-wave on 2M (19.7") and 1/2-wave on 70CM (14"). In fact, both of these antenna exist in the market, and other combinations are possible too.

In very broad terms, the relative merits of various 2M resonant multiples in a mobile antenna are thus:

5/8-wave will usually give the best gain, but it requires a good ground plane to tune up.

1/2-wave is the most forgiving of (lack of) ground plane, but has less gain than 5/8-wave.

1/4-wave is the shortest and is the best for low-clearance situations, but has no gain and requires a good ground plane.

 

[matt s]

I like dual band myself. the 70cm with extended rx range picks up police and fire as well as FRS. Also many of our forest service, search and rescue, etc all work close to the 70cm in my area. Many of the main repeaters locally function on both 2m and 70cm. This allows you to work either side. With all our mountains I often getter better rx/tx off the 70cm and talk to people on the same repeater who are connecting via the 2m side. The other nice thing about this is that with my radio I don't have dual rx on the same band, I can get the same results by tuning in one repeater in 2m and another in 70cm. Since both repeaters are cross band, I catch all the traffic on both bands.

For the little extra $$ I think it's worth it.

Good luck with the test!

 

[FurthurOnTheFly]

I've got a Yaesu 8800 in my 98 4Runner. With the detachable faceplate I was able to mount the radio under my drivers seat and mount the faceplate anywhere...this is what I chose:

I ran an external speaker up the back of the drivers seat and its tucked in between the top of the seat and the headrest.

This is my current antenna mount:

Comet is making a spring loaded antenna now for brush and trees that I'd like to switch to.

 

[Michael]

A good compromise in a mobile dual band (2m/70cm) antenna is something like the Comet SBB-5 which has pretty good reviews. The SBB-5 and other antennas can be folded over when you need to get into the garage or a parking structure. There are some other Comet "bush rugged" antennas on the linked page with springs at the base for use on the trail. The fold-over feature is also nice because if you forget to stand it up, it will still transmit and won't hurt your radio's output amplifiers. If you were to remove the antenna to get in the garage and forget to put it back on, you may damage your radio if you tried to transmit. Don't laugh, many people have learned this lesson the hard way -- I always disconnect my mic when I take down my antenna Another good trick to know: if your antenna has an open coil (pig tail) in the middle, put some shrink tubing over it to prevent it from getting caught in overhanging branches.

EDIT: I forgot to mention another good trick: Sometimes on the trail you're more interested in the survivability of your antenna than getting 20+ mile ranges. When I'm in situations where there is a lot of overhanging antenna-killers, I just switch antennas. I carry a cheap (under $20) wire whip (e.g., a Larsen whip from HRO) that you can practically bend over flat without damage. The wire whip is only tunable to one band (you actually cut the antenna to the fractional wavelength for mid-band) but it will let you stay in touch with your buddies on the trail without risking your expensive/high performance/Gucci antenna . If you haven't studied for your technician test yet D), the wire whips come with a chart to give you the length to cut for a particular frequency.