There is a nice article on a homemade bug-catcher in the Dec 1980 issue of QST. This can be down-loaded from the ARRL website if you are a member. This is authentic old time ham stuff. The author did not mention any kind of matching device in his article because the outputs (vacuum tubes) of 1980 vintage mobile radios had lot of built in tuning capability.
To use this with a modern (solid state) radio, you would need to add a matching device (shunt coil, un-un etc.) K0BG has these on his website.  

73 de Don N1QKH

Here are a few suggestions, based on my experience with the 1624.

1. Read the discussions of base-loaded versus center-
loaded antennas in the ARRL Antenna Book. This will get you off to a good start. I modified mine to be a center-loaded whip.

2. Do not be surprised if no one recommends this antenna. However, if you like to modify things, it might be ok. Note: A $600 screwdriver antenna will probably work better.

3. Any base-loaded whip antenna will tend to induction heat anything around it so, you need a big open area like a trunk lid or a car roof. You need a good ground-plane underneath it, too.

4. If you use a telescoping whip antenna, it will wear out from vibrating in the wind. Get a one piece whip the same length.

5. The MFJ catalog shows this with a mag-mount. This is not a good idea.

6. You need an antenna analyzer to set this up. You need to look at more than just VSWR. You need to think about resistive and reactive components at the same time and the VSWR display on your radio won't tell you "beans" about these.

7. Forty turns of #14AWG wire on a piece of 2” PVC pipe is about what you get in the 1624. Note: MFJ used a pre-made coil and simply slipped it over the PVC pipe. Also, they added and additional 3 turns at the bottom for a shunt coil. Note: SOME PVC PIPE HAS HIGH DIELECTRIC LOSS AND WILL NOT WORK.

8. MFJ made some tiny coil taps which clamp on with screws. However, they only furnished 3 of these with my antenna. You (and I) will want to use more and they will sell you these for $5ea, plus shipping.

9. If you buy or build one of these it will be a great learning experience. If you buy a $500-$600 screwdriver antenna from a catalog, you will still go through the learning process by the time you get it working, properly.

73 de Don N1QKH

In general, I agree with the 100 watt HF radio as a good place to start. In my own case, I went with an ICOM 706 which gave me HF plus 6 meters, plus 2 meters.
My original plan was to operate the 706 in the house and move it to the car, once I upgraded my license and once I got used to operating all of the many, many menus on the 706. I am still using my original 80 meter dipole, fed with ladder line, via the balun in my manual antenna tuner.

Now, I have a 746Pro in the house and the 706 has been moved to the car so, my plan worked OK.

Having said all that, here are a few things that I could have done better.

I should have signed up with ARRL and had QST coming in every month before I took the test and got my license.
Even if you totally disagree with ARRL and its policies, you must admit that, they give out tons of usefull information to get new guys get started.

Secondly, the 706 and its newer clone the IC-7000 work best when connected the car-type (small) antennas and may work less well connected to a tri-band beam in an urban area with a lot of strong signals, overloading the front end. (So, my success was partly due to being lucky as opposed to being smart.)

Finally, I am in total agreement with the recomendations to check out amateur-radio-field-day and find a local radio club. There is nothing like getting some input from a person who has "been there and done it". It is also, a great opportunity to twiddle the knobs on various radios and see which ones you like best. Also, don't get too excited over any particular brand. ICOM, Kenwood, Yaesu, Alinco, Ten Tec and others have all made very nice radios at one time or another. It will be up to you to see which one you like best.

73 Don N1QKH

Having a 2:1 SWR means that 11% of your transmitted RF is being reflected back into your finals. Many people consider this to be the upper limit of what is ok without abusing your transmitter. If your SWR is higher, you run the risk of blowing up your radio.

This has less to do with making contacts than, it has to do with damaging your equipment. If the manuafacturer recommends a lower SWR (1.5:1) then, go with that. It is always best to measure SWR at low power to make sure your antenna and feedline are OK before using a higher power. So, you would do this at about 10 watts (for a 100 watt radio) to be on the safe side.

73 de Don N1QKH

Conversation is where you find it. Some of my most memorable QSOs took place during poor band conditions and using a lousy antenna. The trick is to tune around until you find where different groups of people hang out on the bands. The "top" of 75 meters is a very different place than the bottom of 75 meters. The time of day counts for a lot too. Try calling CQ in the early morning when, gray-line propogation is working, and see what you get.

73 de Don N1QKH

In my local area (Vermont), we have 3-4 2meter repeaters that are active from 6:00AM to 9:00PM, most days. Sometimes I used to go on business trips to southern NY. This is a busy area for repeaters on all bands. In between, I would hit a few totally dead spots with no action at all. In these spots the best thing is have, at least, a general class license so, you can get on 20meters where, something is nearly allways happening. Do not let all this talk of low solar activity discourage you. It is possible to work DX on a day with zero sunspots (even with a QRP rig). If you plan to start your ham career with a 2 meter rig, that is fine. However, you need to think about getting onto HF which offers a more varied experience than VHF repeaters.

73 de Don N1QKH

I have talked to a few (mostly Germans) truckers who are pulling semi-trailer rigs where the trailer has a white fiberglass top. They run 1/4 wave length of wire (17 meters) right down the center of the fiberglass roof and use the aluminum trailer body for a ground plane. The antenna wire is held in place with duct tape. A short piece of coax is used to connect to the radio and antenna-tuner/coupler in the cab.

I would think this depends on dielectric loss in the fiberglass not being too bad (truck fiberglass contains some chromium for inproved stenghth) but, these guys seem to have good signals.

All of the guys, I've talked to, were on 17 meters but, this should work on 10, 20 meters too. The main thing is that these antennas are a full 1/4 wavelength and they have a full sized ground plain beneath them. I wonder if anyone has done a computer simulation of this setup.

73 Don N1QKH

I bought a 746Pro in 2001 and used it with a G5RV. The 746Pro has given good service and I would buy another if I had it to do over again.

Later on, I took the coax out of the G5RV (at 65 feet elevation) and fed it with ladder line via a 4:1 balun, using the internal tuner in the 746Pro. This worked on (all bands) 75m and above. This simple upgrade made the G5RV work a lot better on 17m and on 75m. When doing this upgrade, you need to take care not to let the ladder line be a 1/4 wave length at some frequency you want to use (adding a bit of ladder line or taking some away will fix the problem if one particular frequency is hard to tune. Many hams, I have talked to, have started out with the G5RV and then gone to the 75M dipole, fed with ladder line. This setup is easier for the internal tuner in the 746Pro to drive.

Either way, this will get you on the air and you will have no problem working all over the US and overseas, even with the not-so-good sunspot conditions we have, right now.

73 de Don N1QKH

Not a good idea. Ham gear is too delicate for the kind of abuse that industrial sputtering equipment takes on a continous basis. Sputtering supplies are typically expected to start at full power with NO LOAD. Then, the glow discharge strikes and the supply will see a load that depends on the pressure and process chemistry. This could be 50 ohms or 2Kohms. Then, we have the occasional arc to ground. Yuk!
Henry Radio used to make 13.56mhz amps for sputtering. It might be instructive to compare one of these with a Henry Radio Ham Linear amplifier. They are a lot different once you get inside.

73 Don N1QKH

Hi,

What year is your Prius? I need to surf around the Internet and gain a better understanding of how this works. I would like to understand if the added caps will introduce some new (and expensive) problem. Also, I need to get some idea of what the current through the caps would be. We don't want any caps to get hot and burn up out on the highway in the middle of February.

73 Don N1QKH

I am not sure that, I understand how a Toyota Prius works. This would be a very good time to have a schematic and see how the motor drive is referenced to vehicle chassis ground. Adding caps to DC lines is one thing; adding caps to lines with a chopped square wave is more complex. I don't think the Prius has a simple DC motor because I don't recall seeing anything that looked like a commutator in the Toyota marketing literature. Is this impression correct?

73 de N1QKH

To address your original question: using a large capacitor (usually electrolytic which is good a low frequecies and poor at high frequencies) in parallel with a small capacitor (usually ceramic, silver mica or monlithic which are good at high frequencies but become physically too large when large values of capacitance are needed)is and old and successful strategy. It is the most ecconomical approach. However, the inductance of the capacitor leads becomes an issue when, you are dealing with fast-ristime transients (switching spikes). You can try the 2KV ceramic disk caps but, it may not produce as much attenuation as you need. This would be a cheap way to test the idea. The coaxial-caps, mentioned in my other two posts, are better in this kind of situation.

73 N1QKH

Take a look at this website. I have no financial interest in these guys. Your mileage may very.
http://www.surplussales.com/Feedthrus/FTflangeMt.html

Note: If you go with military surplus parts, stick with capacitors made in the last 20 years and test them BEFORE installation. Old paper insulated caps from WWII are not a good choice.

73 N1QKH

There are capacitors made for bypassing DC lines as they pass through a chassis or bulkhead. These have leads at both ends (connected to each other, internally; the case of the capactor is the other connection. Many times the case is threaded and has nut and star washer to contact the chassis. Military surplus vendors would be a good place to look for these.

73 Don
N1QKH

I would go with the 17 and 20m hamsticks. The price is right and they easy to tune up. They are not all that efficient but, you can move up to something more elaborate if you "get into it", later on. The 40m hamstick will be more trouble to get working. An antenna analyzer would be a help in trying out different locations. You can be sure that a bad location for a hamstick will be a worse location for a screwdriver or bugcatcher because of the higher Q.

I don't get a warm fuzzy feeling about the copper braid  and alligator clip for a ground. Copper strap is better as long as it does not have to flex (wider is better). Clean bright metal connections with penetrox compound and bolts/screws are the way to go. If the alligator clip lets go in the middle of a QSO, your finals are toast.

73

Don N1QKH