If you can remove another radial from the antenna, take that radial and the aluminum replacement rod you have to a local machine shop and ask them to add matching threads to the end of the replacement rod.  Should cost very little.  A box of donuts might even get 'er done.

73,

Terry, WØFM

An antenna "rating" usually suggests a publicized claim by the manufacturer.  In my experience, the claims are typically based on one of the following:

1.  Technical calculations.
2.  Field testing
3.  Technical Calculations AND Field Testing.
4.  SWAG  (Silly Wild-A**ed Guess)
5.  Flat out marketing lies.

It's up to us to determine which of the above the manufacturer used.  Generally, I would tend to believe something to the lower side of any power claims in literature and advertising because anything other than numbers 4 and 5 require some financial outlay by the manufacturer.

73,

Terry, WØFM

I have had mixed results with the "smoke and mirrors" of passive repeaters over 37 years in the business.  For the money invested in a passive repeater, it's certainly worth a try, but don't count on it. 

As Mike suggested, a decent BDA (B-Directional Amplifier) is the best fix.

Terry, WØFM

Chuck, Before you get too overwhwelmed in our OCD tendencies, just keep this in mind:  I STILL have to REMEMBER where I've filed the Excel spreadsheet!  I know it's here somewhere.   

73 Terry, WØFM

My old ARRL paper log books have spaces for START and END QSO times.  After abandoning the paper logging process years ago, I now always log only the Start time.  And that reflects the current UTC time and date, even if my QSO for that station lasts a week.   

Terry, WØFM

I tried to keep up with documentation for years using photos, drawings, etc.  Then I realized that everything changed so often that it was an impossible task using those approaches.  I now have a simple Excel spreadsheet.  I have sections labeled "Radios" with subsection for each individual model (until I trade it)    Another section for "Antennas" with an entry "row" for each antenna and corresponding columns for cable numbers attached near the connectors of each coax.  A subsection for meters and other accessories with an Alpha-Numeric reference (B3, C1)) to jumper cable numbers for cables/power cords connected to each one.  At my PowerPole distribution system, the power cords for the radios and accessories are numbered at both ends and match the corresponding equipment in the spreadsheet.

All of this is quickly and easily updated in the spreadsheet.  Cables can (almost instantly) be shown to now route elsewhere.  Radios can come and go.  As can antennas and accessories.

As a bonus, I now have justification for every new piece of gear I'd like to buy..."I will be sooooo easy to document this new SWR meter in my spreadsheet".

YMMV.  Good luck.

73 de Terry, WØFM

(Oh, and going forward, I will add a column for a hyperlink to a PDF copy of the manual for that device.  Click and read.

If it were me, I'd add a 1/4 wave piece of wire (cut for your 80M operating freq) to the ground terminal on your tuner.  Lay it along the floorboard in the room.  It doesn't have to be cut perfect, but should certainly help. 

You are working with half a non-resonant dipole and all kinds of wierd things will happen.  The counterpoise wire should help things.

73,

Terry, WØFM

Here's how I run cables under concrete sidewalks.  Take a length of stiff aluminum or copper tubing a bit longer than the width of the concrete. Put a wooden dowel down the center of the pipe.  Dig down around both edges of the concrete.  Pound the pipe with the dowel in it through the soil under the concrete.  (Helps if the soil is damp).  When one end pokes out of the ground on the other side of the concrete, pull the wooded dowel rod out.  Insert the radial wire into the pipe and push it through so you can grab the end when it's visible on the outer side of the concrete.  Feed the proper length through the pipe.  Then pull the pipe free.  Secure the radial wire to the sod with landscaping pins, etc.   Repeat the process as needed.

You might need to put more than one radial through each hole.  If the path under the concrete is not too far from the base of the antenna there should be no problem (better with insulated radials).  If the distance the radials share in the hole is too long, the lenth of your radials may need to be lengthened a bit, but that's nit-picking for me.  Remember, ground-mounted radials don't need to be cut to resonance.

This is a "home-brew" installation process that I made up as I went along and used twice.  There are many other ways to pull this off, so others may have alternative (and easier) methods.  Just tossing it out there for consideration. 

73,

Terry, WØFM

How far away from your rig is the antenna?

Terry, WØFM

Hmmm.  I may have read your post incorrectly.  Does the existing balun actually have an SO-239 connector on it?  Or does it have coax with a PL-259 on the end?  If the connector on the balun is an SO-239, then connect a short length of ladder line to a PL-259 connector and plug it into the balun.  The loose ends of the ladder line then connect to the tuner's output studs.

Terry, WØFM

The SGC couplers typically don' like coax on the output end.  Hence, the insulated studs.   I have always connected my wire antennas directly to the output's insulated stud.  Radial system to SGC ground lug.  You can put an SO-239 on the end of a short length of ladder line, then connect the PL-259 to the SO-239 and the ladder line legs to the studs on the coupler.

73,

Terry, WØFM

I've used a compact home brew VHF antenna tuner similar to this:

http://www.youtube.com/watch?v=z3joEsPLOpg

with a coaxial A-B switch on the VHF Marine antenna on my boat to use that antenna on 2 meters.  It's a "set-it-and-forget-it" arrangement and works quite well.  When the switch breaks the connection from the marine transceiver and makes the connection to the 2 meter ham rig, the tuner is permanently in line for the ham rig and is already tuned.

I don't know why a similar arrangement would not work with your VHF aircraft antenna.  Good luck.

73,

Terry, WØFM

OK, I figured it out.  I apparently hit the "Notify" button while in the "Board" mode and not the individual post mode.

Nice feature.  Fat fingers.

Terry, WØFM

Recently, I've been receiving email alerts from eHam to threads on the site that I don't recall ever asking to follow.  Has there been a change in how this works?  I notice that the emails refer to an eHam "board" I've been following, as opposed to a "thread" or posting.  Is "board" simply a broader range of "notification" that I accidently activated?

Just curious.

73,

Terry, WØFM

Other manufacturers would have a hard time making a mobile microphone that was as nicely matched to your radio than that made by your radio's maker.  And, if they could, they could not be very competitive on price.  So the mobile mic that comes with the radio is often (not always) pretty hard to beat.

Most of the major amateur equipment manufactures also offer a basic mobile microphone for their radio that doesn't feature the DTMF and other buttons.  If you want just the basics, check with your dealer.

73,

Terry, WØFM