Horsepoop!  Those who decry computer rig control with the 751A need to go and do something else.  The control is limited to frequency changes and memory assignments--but with the addition of an interface such as the RigBlaster or TigerTronics, does every digital dance you want to do.  There are knobs on the radio--twist them.  Change frequencies with the computer and log what you are working...

I run my 751A with Ham Radio Deluxe and DM780.  You can catch me every so often on 14.230 SSTV, running PSK on all bands, RTTY here and there, and toying with a couple odd modes.  

I have made multiple orders through UR--and have learned a few things.  Orders made on the website can take several days to a week to be packed up and sent.  An order placed on the telephone is usually packed the same day or next morning and is out and on the way.  Their site is very easy to navigate--and has much better descriptions, photos, and "related items" function than either HRO, AES, or R&L (all of whom I order through also).  But I can often get everything I seek at one time through UR.  The lesson is clear.  Make a list of PN# on the website, and call your order in...

Actually, a long hair black cat works much better than the testicles--lower SWR and higher gain.  One also has an audio test indicator of effective radiated power.

An interesting discussion emerged in a recent article.  An enterprising ham was using the Bluetooth feature of a cell/PDA device to achieve interconnection between the device and the rig.  The purpose was to achieve rig control through PDA software.  It was observed that such interconnection (especially if it included audio) might constitute a violation of Part 97, through the use of a Part 15 device as a retransmission node.

CFR 47 never anticipated the development of quite a few of the technologies we have at our disposal today--including Bluetooth and 802.11 WiFi connections to eliminate conventional CAT cables between computer systems.  Both systems of interconnection between computer and rig provide localized communication--it may be as simple as a wireless Bluetooth headset for audio in/out, or as complex as laptop control of a rig through a home wireless network!

Part of our goals are to expand the technologies of the ARS--and many options are emerging which mix Part 15 & 97 devices together.  Newer base and mobile rigs are beginning to incorporate this technology as well.  Are we violating some provision of the law, or operating within its scope with these capabilities?

73 DE N4PRT

Ditto, bad idea.  If you want to talk to your wife without benefit of licenses or basic protocols, get a CB.  That said, it's time for the trolls to roll out and beat the dead licensing horse...

Although no one really wants to deal with this fact, it is long since past time to retire Windows 98 as an operating system.  Microsoft extended support ended in July of 2006.  This means that there are no more patches, security updates, drivers, or fixes.  Self-help information was set to be deleted July 2007, so if it has not already this information could disappear anytime.

Unfortunately, for many users this means upgrading their computers as well.  Often this is a good deal more than just adding additional memory and a larger hard disk--it means a new computer.  

Good practice and electrical code suggest that you create a solid station ground.  As another poster noted, vertical ground lines can act as counterpoises--you may avoid problems with this by installing ferrite snap-on suppressors along the run.  Several ground rods are recommended, especially if you are intending on using any sort of lightening protection system.

Also very important: don't forget to tie your household ground to your station ground.  These have a difference in potential that can cause issues.  The only exception to this rule is when you are using an isolation transformer to provide your power and the station ground is the power ground.  

As was pointed out, water lines have become a very unpredictable way to ground.  Even when you are sure that the buried supply line is metal, the attachment point needs to be reasonably close to where it enters the ground--not further up the line.  Doing otherwise can cause deterioration of your interior distribution lines (presuming that they are copper or galvanized) and rapid consumption of the anode rod that is in your hot water heater.

Running without a good ground system is very much like driving around without wearing a seat belt.  You may never need it, but when you do...

There is a new web resource online for amateur discussions.  HamTechTalk just launched this week.  It is a full-featured site with news, propagation reports, articles (as they are added), comments, a full forum (quite feature rich), personal profile pages, a classified system, and soon a products review section.  The URL is:

http://www.hamtechtalk.com

I have been working on this for a couple months now, to give an alternative to the often contentious discussions that happen in several sites forums.  Check it out and see what you think.  Features will be added regularly.

73 de Patrick, N4PRT

Well, someone may want to build the feed into their personal webpage.  Or combine multiple feeds into a reader on the web browser.  

DXWatch.com is experimenting with one that works well in the browser, but does not integrate into any CMS/RSS modules.  

The answer here is simple.  They are contesters.  What you cannot see in the photo is that they have their shoes off and a keyboard on the floor--busily typing with their toes.  This way, they can work all modes for bonus points...

73 de Patrick, N4PRT

The webmasters do not choose to reply to paying subscribers who write them making note of this behavior either.  I do notice that they are quick to remove a CB linear that was posted in the classified list though.

All a matter of priorities...

73 de Patrick, N4PRT

Pete, the non-polarized electrolytic does not have a positive or negative reference lead, and behaves the same irrespective of the direction it is installed in the circuit.  Tantalum is the best bet for audio, however a common NPO crossover electrolytic will accomplish the same thing.  If a High-Z to Lo-Z matching transformer is used, any audio circuit designed for input and output will become isolated between the output and input stages.    The exception to this case is as I have noted, in professional audio equipment that utilizes the IEC 61938 standard of 48 Volt or 12 Volt phantom powering to microphone circuits.  48V @ 10maMAX is the most common.

A lot of consumer gear with built in or attachment mics use a 3-5V powered source that is a kind of phantom power.  Coupling in these cases requires the use of a blocking capacitor.  The thing to remember when applying a blocking capacitor versus a matching transformer is that a transformer passes the full range that the coupled equipment is capable of.  A blocking capacitor depending upon its value will serve as a filter that cuts off low and high values, passing only a certain range.  It is for this reason that they are used in speaker circuits to effect crossover to midrange and tweeter elements.  The .1mfd is a good value as it will effectively pass the bulk of the voice audio spectrum.

As Pete has noted, the design of balance and attenuation circuits can be simple or complex, depending upon the end result that is desired.  One solution that has not been mentioned here is one that will take care of all the issues that Northcountry is wanting to achieve--the addition of an inexpensive mixer panel as an interface.

This device will allow matching of Hi/Lo inputs and outputs, properly padded input and output level controls, and the ability to monitor visually what these levels are.  Rat Shack sells some inexpensive ones, as well as great deals on Flea Bay.  There is an extensive DSP & eSSB community operating in the bands that can provide a lot of information about audio handling, and equipment that lends itself to ham audio usage.  Do a google for eSSB and see what you turn up

73 de Patrick, N4PRT

10K ohms is considered a "High Z" or high impedence input/output.  500-600 is considered "Low Z" or low impedence.  These are pretty standard match values.  You may wish to look at an audio impedence matching transformer to properly balance your high to low impedence connection.  These are available at most Radio Shack's and similar audio suppliers to match microphones and line inputs to mixers and preamps.  It is even possible to rob such a transformer from an old computer modem.

I am not understanding if you are taking the audio signal off the headphone jack how that impedence could be 10K.  Modern audio output circuits are generally designed to operate from 4-16 ohms, with 8 ohms as the nominal value.  Perhaps your output value is coming from a connection on the back of your radio that says "record"?

The suggestion of a 10K pot will also reduce the larger output mV to the smaller desirable value.  Two varieties of potentiometer exist.  The first is called an "audio taper".  This means that the resistance of the potentiometer is not linear--there is more cumulative resistance at the low end, trailing off to an even distribution through the second half of the rotation.  This is commonly used in audio volume controls to prevent quick overloading of the speaker circuit and to bring volume up more gradually.

The second type is termed a "linear taper".  This means that the resistance of the pot is evenly distributed across the entire range of the device.  In your case, this type would be more appropriate and allow you to smoothly and evenly vary the input.

I misunderstood your earlier post, thinking that you were referring to the mic input of your transmitter.  Although this is not something of consideration for your case, many electret mic circuits use a "phantom" voltage--a small value such as the 8 VDC used in Icom rigs--to power the element.  When coupling with such a circuit it is necessary to isolate the voltage via a .1mfd non-polarized electrolytic cap.  Otherwise, you may let some of the smoke out of your gear!!!

73 de Patrick, N4PRT

Northcountry, tapping into the headphone jack will not give you "line output."  Usually headphone audio output is taken off just before the final audio amplifier, or is an attenuated version of what is being fed to the speaker--depending upon design.  It is still influenced by the preamp stage and a variable output (usually the volume) and tone circuitry control.

Line output is generally taken off just prior to the audio preamplifier circuit, and is not influenced by either the volume or tone controls.  Its relatively low voltage level makes it appropriate for feeding a variety of other outboard equalizer, compression, recording, or amplification devices.

Look over your schematic and manual.  Many radios offer an accessory plug of some sort that will allow you to tap in to both the line output and the mic circuit prior to further amplification.  These connections can range from phono pin, to multi-pin modulars, to DIN configurations.  Sometimes it is necessary to tap into the circuit itself.  If you do something like that, it is advisable to look at the need for some sort of impedence matching transformer or coupling capacitor (usually a small non-polarized electorlytic tantalum)to prevent possible circuit damage.

73 de Patrick, N4PRT

The last antenna I used when encountering problems with some of these small ATU's(MFJ-941 and a clone under the B&W label) was a 102' G5RV with 31' of 400 ohm ladderline coupled to 65' of RG-213 via a 5" diameter PVC air core 1:1 choke balun (windings are 21' of RG-8X).  The troublesome mode was RTTY, as I stated earlier.

As has been mentioned, the tuners will "tune" in several different control configurations.  What has been said gives me the suspicion that some of the poor copy reports I have gotten locally are due to little power actually making it to the antenna (but good SWR).  It looks like it might be good practice to place a wattmeter on the output side of the ATU and note the difference between transmitter output, and actual input to the feed line...

73 de Patrick, N4PRT