On 13 May 2007 16:55:44 -0700, dykesc wrote:

Richard, I tired measurements again with my twin lead directly
terminated to the 259b. I got better, more consistent results after
taking great care to insure the analyzer and line were well isolated
from ground, other conductors, and myself.

Hi Dykes,

It should be comforting that observing standard precautions produces
repeatable results.

I then took the same
measurements with the 4:1 balun between the twin lead and the
analyzer. Unfortunately the results create new concerns. For example
at 7.185 Mhz with the balun in the circuit (tuner in bypass mode) I
got 19 -j48. Again at 7.185 Mhz with the balun out (twin lead directly
terminated to 259b) I got 159 -j443. Doesn't look like 4:1 to me.
Similar spreads in the 80m and 20m bands.

This sounds like you've inserted the entire tuner to obtain the 4:1
BalUn (once you threw the right switches).

If, as you say, education is a principle goal, then build a proper 4:1
current BalUn. It is actually quite simple and requires only two
transmission lines and a several dozen beads. Basically it is two 1:1
current BalUns fed in parallel and loaded in series.

You will be simultaneously checking your system, and testing the
authenticity of the MFJ claim:
The MFJ manual for the 993b tuner says the balun is a 4:1 "current"
balun. Haven't looked inside to confirm this.

You have the means to test the assertion, use your 259 to measure the
isolation of the BalUn. This was the subject of a recent thread.

Thanks. I'll search for the thread. Sounds like fun.

If after a fruitless search (it's easy enough to get slogged down in
the snow drift of useless posts here) you don't find it, ask for help
here. Mentioning you tried the archives will save others from whining
about how much effort they went to answer a stupid question. (I won't
whine, and I never call any question stupid - although I frequently
dope slap some of the denser questioners.)

Fixation on BalUns has clouded a simpler solution: wind a choke in
the line and dump the ferrites of suspect quality.

Would you please elaborate on this? Wind a choke where? In the twin
lead?

Sure, twist it candy cane (or barber shop pole) style and wind it
around a liter bottle with at least its width as separation between
windings.

In the short transmitter to tuner coax line?

Actually for severely unbalanced dipoles (and yours qualifies for
Queen of the May), you may need a choke at the feed point to the
antenna, and then again a quarter wave away from there.

Thought I read somewhere that only coax can be used for simple 8 to 10
turn chokes. Balanced lines (i believe because of mutual conductor
inductances) can't be coiled as chokes.

Even if I'm wrong, it is both cheap and instructive. So few here
actually step up to the bench that I don't take their flabby word that
I'm wrong. You may be the first with authentic achievement to break a
record! You've already lapped the field of these arm-chair analysts.

Many antennas work just fine until the operator discovers a new tool
that proves it doesn't (in spite of a wall full of QSL cards).

Partly the reason I'm trying to learn all I can about the
configuration I've currently got. That and I like the technology
aspects of the hobby as much or more than I do operating.

Where this hobby whose technological demand largely consists of
pushing a credit card across a sales counter, antennas still have the
capacity to stretch the imagination.

Thanks for helping out a Stuggling Crippled Newbie Street Urchin.

Wait until you face the sewer rats of Rio.

OK I'll bite. Who are the Rio rats?

This is an allusion to an SK who compared those who couldn't exercise
their minds as being fodder for the orphans of Rio, who had more will
to succeed than they did. He characterized them as sewer rats gnawing
on our lazy carcasses.

Thanks for your help. Any thoughts on those measurement results
earlier in the post will sure be appreciated.

They will reveal more in comparison to those measurements that follow.

73's
Richard Clark, KB7QHC