Thanks for the answers.  Lou at King Conversions had all the parts I needed for a reasonable price (compared to hunting all over) so I'm going to build it with 10M from the start.

I appreciate the feedback.

Bob

For those of you who own an amp with 10M coverage, do you ever use it?  I am debating whether or not it is worthwhile to add 10M to an SB-221.  My experience indicates that when 10M is open, it is usually possible to work anyone I can hear using 100W, but I'd like to hear some opinions.  I don't want to get into a QRO/QRP debate here - just to focus on how often those with amps actually turn the knob to the 10M position.

Thanks,
Bob

If you still want to do this, you could mount a female BNC connector in the plastic and use four 19 inch strips of copper adhesive tape on the underside to act as a simple ground plane.  Solder the copper strips and the coax shield to a washer before you adhere the ground plane to the plastic.  Connect a rubber duckie type antenna to the BNC, and you have a simple antenna.  It won't be very efficient, but it would be reasonably safe.

I suspect we'll need to know a bit more in order to provide feedback.  Are you running it on 120V or 240V?

IF (and only if) you're comfortable working with live circuits that can kill you, can you check the voltage on the primary of T2?  How about the voltage on T2's 8V secondary winding?

What is working?  

Please let me know if you need a copy of the service manual.

Bob

I've found a small vise and a magnifying lamp to be handy.  I gently clamp the mic plug in the vise with the solder end facing up and peer through the magnifier to solder the pins.  I tin the pins, strip about 3/16 of insulation from each wire, and then twist and tin each wire.  After that it's just a matter of holding each wire end parallel to the mic pin and touching both the wire and the pin at the same time with the tip of the iron.  I found a vise with a verical groove in each jaw that holds the connector so it doesn't twist.  

Once I've soldered all the wires, then I disassemble the whole thing, slip on the rest of the mic connector that I forgot the first time around, and do it all again...

I love my 6BTV, but it's very narrow on 80.  I set it for a net frequency and use a dipole for any other contacts on 80.  I wouldn't bother trying to make it resonant on 160.  You might get a match across a few KHz with a network at the bottom, but it would still be a poor radiator.

I agree.  Radials!  I added 60 and it works like a dream.  30-32 seems to be the sweet spot.

There is a list of good reasons to not do this.

The guy on the other end can't tell the difference.
You might become well known for your bad signal.
It can eventually kill your finals.
It can defeat SWR protection.
... and so on.

All of these are true, but for a lot of people, those suggestions have to compete with the satisfaction of seeing the watt meter neede rise.  

Here's an experiment.  Hook up both rigs side by side, make a contact, then switch the antenna.  Ask the person on the other end to tell you the difference in signal strength.  Or, make a contact with someone (a friendly net is nice) and gradually decrease your output power.  Ask the other stations where they start to notice a meaningful difference.  It's a fun exercise.  It convinced me to leave power adjustments alone.

73,
Bob

The serial port can be used to drive a transistor switch for keying, but it will probably not switch your transmitter by itself. If your TX only needs to switch 12 volts at a few milliamps to ground, you can try making a single transistor switch by conecting a NPN (2N3904/2N2222,NTE123, etc.) transistor as follows:

- 1K resistor from serial port pin to Base
- Emitter to ground (maybe through a current limiting resistor)
- Collector to TX line of radio

You may want to look at Meter software at http://tonnesoftware.com/meter.html

 

WX7G said, "The inner conductor from RG-58 can be used to 15 kV in continuous service."

Thanks for the tip!  That's a handy bit of info.

Bob - K0BT

Correction:  The 5KV stuff is PVC insulated.  That's what I used and it was an exact replacement. It runs about $11 for 50 feet.  If you just need a couple of feet, send me your address and I'll stick some in the mail.  I have an extra 48 feet of it ;-)

Look for test lead wire.  The silicone insulated wire is rated at 10KV and the PVC is rated 5KV.  I just picked up a 50' chunk of #18 from Allied Electronics to replace the HV wiring in an old National amp and it was an exact replacement.  Allied Electronics has it.  You can see it on line at:    http://www.alliedelec.com/Connectors-Wire-Cable/Wire-and-Cable/?N=4294965155+4294818103

I need to get a building permit to install my TX-472 on my property in AZ.  The last time I did this was in another state almost 20 years ago.  Local buddies tell me that I may need updated engineering drawings (mine are from 1989).  Has anyone done this recently and, if so, can you tell me how I would go about this?  Does anyone have a recent set of drawings, or do I have to get them from US Tower?  I have a call in to the building department, but I don't expect it to be returned anytime soon and I'd like to get my ducks in a row.

We used to modify the GE Custom MVP radios as mini repeaters by replacing the audio board with a  controller board and adding another antenna connector.  It was a simple mod, but I can't remember the name of the company that made the controllers.  The Custom MVP shares a lot of parts with the Master II series.  They are inexpensive on the used market and has enough internal isolation to work well as a repeater.  They're small, easy to work on, and have a clean internal layout.  I agree with Dick, AD4U, that the Master II also makes a solid repeater.

Check out http://www.newegg.com for a computer case designed for a home theater system or for an external enclosure.  They make great project cases.