Thinking of getting HAM radio for truck

Amen brother! Totally agree!

 

You would need to use something! If you understand HF antennas, (and I am sure you do), you know that at 75 Meters, your feedpoint impedance is going to be around 18 ohms. Generally, the natural impedance of an HF antenna increases with frequency. We are looking for an impedance of 50 ohms at the feedpoint. The antenna will still have to be tuned to frequency. Traditionally, hams have used various methods of "feedpoint matching" such lily pad caps, toroids, and coils wound in series/parallel to ground. I prefer the coils because, to me, they offer more flexibility and ability to really match the WHOLE system.
They are also very forgiving and will allow one to match a screwdriver antenna to ALL HF frequencies from 3-30 MHZ without multiple "taps". Once one finds a 50 ohm impedance at 3 to 7 MHZ, the screwdriver will almost always "follow" the frequency all the way up to 30 MHZ without changing a thing, and also give an SWR reading of 1.1 or 1.2 X 1 at ALL frequencies. One can use one of the little "impedance matcher" boxes (which uses caps or resistors), but my experience with them shows that one will be having to changing the settings as he goes up the band.

The coil setup with the screwdriver antennas gives hams the most wonderful world of frequency coverage anywhere, IMHO! Not only does it tune to ALL bands, it does so on the FLY, and allows one to adjust for changing conditions all to boot! I can go from amateur to FEMA to US military all on one antenna with just about the best signal one could hope for. With 100 watts (and I could go to "more" legally if I needed to), I can talk to the world with *almost* base station signals taking into account conditions, etc!


Recently someone in a parking lot got curious about my matching coil, grabbed it and gave it a twist! I can't understand why *some* people can't keep their paws off stuff! So I had to make me a new matching coil. I had some wire and a form to wind it on. So I wound me another matcher, BOLTED it to the mount, and it will be 3X as hard to break it this time, dadgummit!

BTW, for the 11 Meter guys wondering if some some sort of coil will "help" their signal, the answer is "No". It won't! At least, not usually. Most 11 Meter antennas don't really need feedpoint matching as the natural impedance is already close to 50 ohms. If, however, you've got an antenna that doesn't seem to want to tune @ 27 MHZ, get someone to check SWR AND impedance with an analyzer. You *may* be able to 'fix' your impedance problem with a matcher!

Hope this helps, folks.

 

I've got a Kenwood TM-V71A and usually have better luck finding talkers by scanning the 2M repeater frequencies. I'll set one side to scan 145.2 - 145.5 and the other 146.6 - 147.4. If someone breaks squelch, I reach up and stop the scan. If I feel like talking, I'll switch on tone squelch and turn the knob to find out what tone frequency they're using.

 

Since I fixed my feedpoint impedance coil, I've been having fun on 40 and 75 Meters. 12 Meters was open the other day and I made a contact into France. It was one of those contesters doing the "CQ, CQ................yer 5/9, blah, blah, QRZ" thing. I don't really enjoy contesting; I just wanted to see how my antenna was workin'.

 

I have that same radio. I haven't yet read into how to do what you have described.

 

It's been so long since I set it up, I can't remember. And of course I can't find the manual anywhere.

There's 10 VFO scan limit memories. Once you set up two sets for the 2M repeater ranges, you configure each VFO to use one. With that, I press and hold the VFO button to start the scan. Click the tuning knob to stop it. To enter the scan ranges (and a bunch of local repeaters and other settings) I cheated and bought the RT Systems programming kit at HRO. I don't recall how to select the search range memory on each VFO, but I believe I had to do that via the panel.

I actually had a chance to meet the RT folks the day I bought the radio and their programming kit. Happened to be an HRO open house event and they had a bunch of the factory reps in there.

 

I thought 12M was a no contest band???

 

Yes. NO 'official' contesting, but I don't think there's any prohibition on an individual calling CQ?????? That's what the French guy was doing. I just answered him to see how my antenna was working. Now if somebody is calling "CQ Contest", or there was some "officially sponsored" contest, THAT might cause trouble. My post might have been confusing because, I was speaking generally that I don't like the contesters anyway and don't normally respond to them. This guy was simply calling CQ and operating LIKE contesters. I just responded to him as a test. If I responded to his call, I don't think that's illegal because my intent might have been to engage him in QSO. I could be wrong.

 

Thanks for the clarification, I did read it as the french station was participating in a contest. I'm with you, can't stand contest weekends, which seems like every weekend ... lol. I wonder if there ITU has ever considered a no contest zone in the non WARC bands???? not that the contesters would honor them ...

 

While there is a "gentleman's agreement" among the organizations to not allow contesting on the WARC bands, there is no legal prohibition against contesting there.

Honestly, I think a "QSO Party" on 18m would be a blast.

Seriously, though, why do people STILL call them the WARC bands? We've had them for 35 years. Heck, WARC doesn't even exist anymore. (It's now WRC.)