Continuing Education for HAM/CB

Ask an Elmer
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Continuing to build my shack, put up antennas, purchasing equipment.

I am looking for advice on what type of antennas to mount on my roof (chimney).

I would like to put up a couple of antennas at the same time that can help extend my ranges since I do live in somewhat of a valley so the higher the better.

I have HAM/GMRS/CB radios and can mount 2-3 antennas while I am up there. My question is what opinions everyone has on how to do this would make the most sense allowing to put up the least number of antennas but help with each type of radio I have. Can some antennas do double duty?

Lastly, if they are used individually, and they all work on different frequencies, does it matter how close they are to each other?

I currently have a single 2M/70CM antennas to go up (RW X30 Dual band), suggestions on what else to mount? Everyone has their favorites, I am sure.

Thanks for any advice :slight_smile:

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Should be a good Antenna to start with. If you use an LMR400 coax you will get the maximum to the antenna. Whatever the power of your radio it should about increase to about double. Also, get a lightning arrestor connected to a ground rod for safety and Tx improvement.

Do this for each antenna.

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Good advice, I just ordered the lightning arrestor and will order the cable soon. From what I have been reading and hearing it is good cable, just stiff and hard to work with.

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Depending on your operating style, you’re going to want to get some separation between those antennas so radios/antennas don’t interfere with each other. Is it necessary to have all mounted in one location? If you can get at least a wavelength of vertical separation between antennas or greater for horizontal separation, you’ll do best. Otherwise, if you transmit on the 440 band, you’ll probably come in on your GMRS radio and your CB radio might even interfere with your 2-meter communications, or perhaps 10 meters, for sure. You just never know given the environment. Separation helps.

As far as using antennas for double or triple duty, it may be possible, but SWR is going to be an issue. It would be highly recommended for you to purchase an SWR meter so you know whether your antennas are able to accommodate a broad band of frequencies, plus whether you’re getting a lot of power back down the cable to the radio, potentially damaging it because of high SWR.

I run a number of repeaters on VHF and UHF and have had difficulty using general coverage antennas on like bands, such as 440 and GMRS. An antenna that works well on GMRS might have crappy SWR on 440. I have found that antennas tuned for your frequency work best, but then again, it’s more mission critical with a repeater and the RF coming back down the pipe to the repeater.

There are some antennas designed to cover 440 and GMRS, but I haven’t tried them. Likewise, 2M, 440 and possibly GMRS. But you most likely will find dual-band 2M/440 antennas. I’d check the specs while shopping and then ask questions about the antennas in forums such as ours here.

At one time, I had Comet dual-band antennas on all my repeaters and remote bases at my site, but eventually went to the Ed Fong antenna for my GMRS repeater because I needed something highly tuned to the GMRS frequency that the dual-band amateur antennas were not offering me, and causing SWR readings too high. I still have trouble getting great SWR readings for the dual-band antennas on the 440 repeater, a commercial VHF repeater and a 2M/440 remote base, and probably will swap them all out with single band antennas at some point. I even went to half-inch heliax cable for the GMRS repeater, but still have some occasional issues with the 440 remote base getting into the 440 repeater. And with my TV antenna mounted about 10-feet away, the VHF repeater knocks out some OTA channels, as well as FM broadcast reception when it is transmitting.

The thing about antennas is there is a lot of experimentation. My guess at this point is that you can use a dual-band 2M/440 antenna for amateur, another antenna for GMRS to get past SWR issues and the need to swap out coax all the time, and if you shop around, you just might find an antenna that will give you coverage on both 10M and 11M so you can get by with just one for that. I would try and get vertical separation between the 2M/440 antenna and the GMRS antenna (at least a wavelength or greater – a minimum of 10 feet, perhaps 15 feet) and some horizontal separation for 10M/11M by perhaps mounting on the other side of the house. The cable length on HF isn’t as critical as it is on VHF/UHF. But don’t skimp either on the long coax run.

I hope this helps a little.

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Hi Chuck,
Thank you for the thorough detailed information. A friend here at the local HAM club was kind enough to drop off the ARRL antenna book yesterday. Quite a lot of reading :slight_smile:
I picked up what I needed to ground all of my equipment in my shack, my question is, even if it is a piece of mobile equipment, does it still require grounding?
I saw a picture yesterday of someone that had placed their GMRS antenna in their attic vs. outside. I can try experimenting with that process. I have plenty of room/headspace in my attic to put one in there. I just wonder how the shingles on my roof will effect their sending and receiving.
I just yesterday ordered an SWR meter, getting things together one piece at a time.
I understand that this can become quite the expensive hobby depending on just how into it you become and the amount of experimenting one is willing to do. I hope others are getting info from my list of questions, LOL.

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@KC3TDX If you have an antenna on the roof, it’s a good idea to ground it because of possible lightning strikes. Even nearby strikes can cause an issue. Back in my 11-meter days, I was operating on an old tube radio during a storm and as the lightning cracked real close, I felt the jolt in my hand on the old handheld mic. That was enough for me to always be careful of lightning. Luckily, even as a junior high kid back in those days, I still grounded the antenna.

It doesn’t matter whether you have a base or mobile or handheld radio for your home station. You still want to protect both your equipment and your home during a potential lightning strike. Give the lightning a direct path to ground, rather than to inside your home. I have seen enough people with fried rigs over the years. It’s the antenna you are grounding. Think of it as a giant spike in the air over your home. Antennas up high have a tendency to attract lightning. Think of old homes that used to have lightning rods all around their roof to protect the home because of their height. Same principle.

Depending how far you want to reach out on GMRS (simplex vs repeater, etc.) an attic-mounted antenna may prove sufficient. In my effort to separate antennas at my site, I have receive 2M antenna on a crossband base mounted in my garage attic with the 440 link transmitter antenna mounted outside, and it seems to work fine. The difficulties you may encounter with an attic antenna is 1) What is on your roof … shingles generally don’t cause an issue, but if you have a metal roof, then it may not work because that metal shields your antenna, and 2) What else do you have in the attic that could interfere with it – mainly metal. That’s lesser of an issue than a metal roof. If you can get the antenna at one end of the attic, as opposed to being in the middle of the attic, the signal may penetrate through your siding on that side better than the roof, too. Experiment, if you can!

Hope that helps. You’re on the way to a great station.

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Thank you Chuck for more great advice! I actually just purchased a UHF Lightning arrestor PL-259 for my antenna (any experience with those?).

As close as the local repeater is (2 miles or so), I could probably mount my GMRS antenna on one end of my attic and the 2m/70cm on the other end inside.

If I mount a GMRS antenna, it may make me want to put up a repeater as there are zero in my area. I have been learning about them, I can use two radios or buy a repeater premade.

Learning is what I do, the more the merrier, I want to eventually in time work up to where I can reach out to see if I can make contact with my son in Missouri, but that is some time away as I pick up equipment and learn the ropes.

I hear there is a good deal of negativity in the HAM hobby about GMRS but I am unsure why. It is the same, just different LOL.

I will get to work on my antennas and see what I can learn. Thank you again for the great advice and time responding to my inquiries.

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That’s a typical lightning arrester, so it should be sufficient. The trick is to divert the strike into the wire running down to your ground rod. Just be sure to get it far enough into the ground. Too often, it’s easy to give up when you start hitting rock and you only go about halfway in!

The trick with GMRS repeaters is you want to be able to offer coverage. Too many attic-mounted repeater antennas just don’t offer the range. You might be lucky if you get two miles range, and quite honestly, you can get that coverage with just a base radio on GMRS. I do operate a GMRS repeater and have the antenna outside as high as I can go (actually mounted higher than my 440 MHz ham repeater antenna) and it does quite well, giving me coverage of almost my entire rural county. Mounted in the attic, I was lucky I was getting out 1-2 miles, which did nobody any good. Keep in mind that if you don’t use a duplexer on your GMRS repeater that you need pretty good vertical separation between the two antennas so that the transmitter doesn’t get into your receiver and desense the mobile signals.

Have you checked MyGMRS.com and RepeaterBook.com for any repeaters in your area? Often times, they might be listed, but not active. Then you can find out who the owners are so you can request permission to use them (unlike open repeaters on the ham bands!).

No need to worry about negativity about GMRS in the ham sphere. It’s mainly by the uneducated. In some areas, many GMRS licensees are ham operators and vice versa. I know that in Minnesota, there are many new GMRS repeaters going on the air primarily by dual ham/GMRS ops. Many GMRS machines are run almost like ham repeaters, too. Then there are those GMRS ops who rebuff hams. It goes both ways. No worries!

Hope your station comes together well, @KC3TDX!

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