Lesson 4.2, Antenna Fundamentals

2 Responses to Lesson 4.2, Antenna Fundamentals

1. dave says:

   March 4, 2012 at 9:07 pm

   Hi Kevin. I’m delighted that my videos were helpful! That’s why they’re there! And congratulations on getting your Tech license. Hopefully your callsign will appear online soon and you can start operating. Let me see if I can address your questions:

   a) Yes, I agree, the best first radio is usually a handheld. I have more to say on that subject here. I have a number of posts on the subject of handhelds. Now, with regard to your vehicle, I think you’ll find that an amplifier would be about as expensive, if not more so, than simply buying a mobile rig that you dedicate to your car. Speaking of that, the key element of any mobile installation is the antenna. You’d be amazed at what happens if you connect your handheld to an antenna atop the car. I always suggest that new hams go for simpler equipment – all those bells and whistles just really aren’t necessary and end up complicating your experience. I have been a ham for 37 years, and my VHF/UHF base station consists of an ICOM IC-2100 and a Yaesu FT-7800, both very basic (and much less expensive!) radios. I’ll point out that as you get more experience you will accumulate radios, so don’t think that your first radio needs to be too fancy.

   b) The car antenna is critical to operating mobile. Ideally, it would be a quarter-wave vertical mounted right on the center of the roof. However, a wire sticking straight up certainly doesn’t blend well with design of a sports car! An alternative you can try is putting the antenna on the trunk lid, or perhaps between the trunk lid and the rear window. It’s a compromise, but better than any antenna inside the vehicle. As for polarization, all VHF FM is vertically polarized, so trying for horizontal simply complicates the situation. I always recommend a magnetically-mounted antenna because that way you don’t have to drill any holes. But, do remember to clean and wax under the antenna, otherwise dust and junk collect there which can mar the car’s finish.

   b1) If there’s one think hams like to play with, it’s antennas! The sky is the limit, literally. However, that said, I suggest an omni-directional antenna mounted mid-vehicle. Yes, the placement does affect the antenna pattern, sometimes dramatically. I recommend joining the American Radio Relay League. Their monthly magazine, QST, is always full of ideas, plus their website is replete with info, some of which is available only to members. The membership price may seem a bit steep for a college student, but I recommend it anyway. The League publishes several books on practical antenna systems. A large portion of the League’s membership are new Technician hams, so lots of the articles are written for people in just your situation.

   c) Working HF with an indoor antenna is a compromise, but yes, it can be done, and effectively so. I recommend a simple wire dipole on ten meters, which will be five meters, or about 16 feet, long. It can be tacked up on the wall or wherever is convenient. You’ll need an HF radio to do this. I’m of two minds on this subject. On the one hand I think that Techs should take advantage of their ten meter privileges, but on the other hand I normally do not recommend that a Technician purchase HF equipment until they actually have their upgrade CSCE in hand! HF rigs are in another price class by themselves, significantly more expensive than VHF. (It is entirely possible your college has a ham radio club which might have its own club station.)

   Thanks for replying via a comment—I see every one and try to reply. The fact that you have questions means that other people also have the same questions, so this gives me a chance to reply to everyone!

   73, and good luck!
   Dave, KEØOG
2. Kevin Moultrie says:

   March 4, 2012 at 9:40 am

   Dave thanks so much for such a good resource!
   Just a little background about me, I’m a college senior, and was reading a book on Monday (Feb 27) and decided to get my amateur radio license and GMRS license. I found that a test would be given in my area on Saturday (March 3) and decided to go for it. Five days of study later, and I’ve passed my Technician exam, thanks to your videos, and other online resources. At the test I also became a member of the Bridgerland Amateur Radio Club (the local club in my area.) Anyway, I’ve been researching radios and I have some questions. I don’t yet know anyone in my club, since my first meeting is Saturday (March 10) and as you can see from my timeline between deciding to get a license and actually getting one, I’m impatient. I was hoping you could answer a few noob questions I have. I’ve been researching them, but have not found satisfactory answers and I feel like they’re simple enough that they could be answered by one knowledgeable person. Don’t worry, once I get to my club meeting I’ll have someone else to annoy with my ignorant questions, so here goes.

   a) I’m thinking my first radio should be a multi-band handheld. My thought was to also purchase an amplifier for the handheld that I would keep in the car, that way I could transmit at higher than 5 watts with out buying a separate radio. Are there any inherent problems with this plan that would be obvious to you that aren’t occurring to me because of my lack experience?

   b) Car antenna. I drive a sort of a sports car and an external or magnetic antenna is unappealing to me, however, using a handheld or mobile fm radio without and antenna inside a vehicle would work very poorly. Is there any sort of internal car antenna available on the retail market, or could I make one for myself? Many cars have their fm radio antenna horizontally inside the windshield or rear window, is it possible to install an appropriately sized copper wire horizontally near the top of the windshield and or rear window? I know that if I did that the polarization would be horizontal, but that would still work for ssb transmissions right?
   1) Would installing an antenna in this way also it beam like? If so would it be possible to install antennas on each side of the car?

   c) I mentioned that I’m a college student, and I have to move around a bit (moving again this May) so setting up a base station is less than ideal, however I’m also interested in working on the 10 meter band, is it possible to do this in a temporary set up with out the ability to set up permanent outdoor antenna’s?

   Thanks for taking the time to read my questions, sorry for such a long comment, I would have sent this via email, but couldn’t find it on your blog.
   Regards
   Kevin

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