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Be careful not to use metallic paint so you don't accidentally shield the entire antenna. :)

Look for this article for a better explanation. The Twelfth-Wave Matching Transformer by Darrel Emerson. The full article appeared in QST, Vol 81, No.6, June 1997, pp.43-44, published by the ARRL.

You would run 50 ohm cable to a 1/12 wave piece of 75 ohm cable followed by a 1/12 wave piece of 50, and then connect to the 75 ohm transmission line. On the other end, you would use a 1/12 50 ohm followed by 1/12 75 ohm and then back to your 50 ohm transmission line. Here's something I have...

Very limited quantity of Larcan 6-transistor 1.5kW amplifier modules. (upper picture) No mods needed for use at 222MHz. Gain about 16dB, 40 watts drive needed for full power. DC input power connector and schematic diagrams included. I've shipped several in a manner as shown below with...

You should remove the battery negative terminal any time you're messing around with the vehicle electrical system. If it is still connected while you're taking off the positive lead the wrench could make a very good jumper to the chassis if your hand slips. Removing the negative lead is much...

For most practical purposes the loss of a good quality connector or an elbow is negligible. The only reliable way to determine the loss through your particular connector is to use proper test equipment and measure it. If you want to put a few connectors in a box and ship to NovaScotia I'll...

Get a 7809 or similar voltage regulator to power the wattmeter. Batteries are needed for portable meters. No one would buy one if it came with a long AC cord!

Expedited parcel to USA should be within 5 business days. I've sent several packages lately. Some take a few extra days. The post office supplied a receipt with a tracking number. Use that number at Canada Post - Mailing, Shipping, Marketing, Shopping, Sharing or www.usps.com and find out...

No I don't agree. There isn't much effort or expense required to do it properly the first time. If he's going to invest funds into equipment, he should have the resources and knowledge to do it right. Do some study, learn how to do things, and then proceed. Following half assed advice from...

Your best lightning insurance is to have no antenna or radio gear. Tear down the house, dig a hole, and live underground. Read the documents referred to in the other message thread. Properly bond your antenna and AC grounds together and there is very little reason for concern. The...

No one seems to bring up the issue of bonding between ground systems. A typical radio station has at least two ground systems, one at the antenna and other other at the AC entrance. These must be properly bonded to shunt ground current between them instead of through equipment. In my...

And watch the power meter spin...

Nice tube. I have a new in box Eimac 3CX15000A7 in the garage. Should find it a home.

When I calculate power supply load, I assume the amplifier is 50% efficient. This is a reasonable starting point for most, although class A can be as low as 10%. For 500 watts output, you will need 1000 watts input. At 12VDC that would be 1000/12 = 83 amps. A deep cycle battery with a...

Almost anyone I've seen using open wire feeder has used an antenna tuner. However with proper techniques I'm sure you could connect it to a coaxial cable via a proper balun and have an acceptable swr. You can purchase plastic coated 450 ohm ladder line from many radio supply stores. I've...

For an overhead run, openwire or ladderline has the lowest loss and highest power handling capacity.

I still think it would be worthwhile to look into building your own. What transformation ratio is needed? 4:1 would be quite easy once you have the right cable.

All the high band 1kW amplifiers were built for 174-230MHz, so I'm assuming the driver was the same. Wide band with no tuning involved. Swap the modules between transmitters regardless of channel. The driver does not use the VSWR / bias board that is present on back of the 1kW modules...

I had a look at the rear panel DC connector. Two pins are soldered together with a copper strap between them. Remove the copper strap. The large stud is the PA connector. The small pin powers the bias board. Switch the 50VDC on the bias pin and problem solved. No mods to the PA and easy to...

The problem I have with lifting the bias line during receive is that the module would need to be modified and it wouldn't slide in and out of the drawer properly. Also modifying the module will mean it can not be swapped to use the drawer with different band amplifiers. I'd like to build...