Topband: 160m Four Square Array; FT-1000D Keyclick mod

[K1ZM@aol.com]

Hi Gang

Here's a suggestion on the  FT1000D APF mod.

Take the BOARD out - buy the three surface mount resistors that must be 
installed (in place of what's there) and if you are not comfortable doing 
micro soldering - have it done by a professional.

Here locally, I have HAM CENTRAL and there is a fellow there named Eric who 
had an optical loup and a really professional soldering station.

5 minutes with Eric and I had the three SMT resistors installed.

Putting the board back into the Ft1000D is not all that hard - all the jumper 
harnesses are pretty simple to re-connect as well as putting the screws back 
to hold the board in the radio.

Rick is right - the improvement is WELL worth the effort.

If the APF in your D sounds muffled - has a broad peak (or no PEAK) - you 
NEED this mod.

If CW signal levels actually DROP when you engage your APF - or if the peak 
seems to muffle the signals into oblivion, then you NEED this mod.

With the correct values in place, there is a DISTINCT, SHARP CW peak around 
9-10PM on the face of a clock  - with the APF control engaged - and weak CW 
signals on Topband literally LEAP out of the radio.

Since I posted this mod some years ago, I have learned that Yaesu has at 
LEAST 5 combinations of resistors on that board - depending upon which 
version/release of the radio it happens to be.

The very best set of ones were in there during the late 1991-early 1992 
production era.  Since then, they have been experimenting with all kinds of 
values.

But, if you install the ones recommended in the mod, you will find your radio 
restored to about what was there in the 1991/1992 period.

I personally cannot stand the APF in a D that is set up without the proper 
values.

Finally, the history of why this all happened is almost comical. The truth of 
the matter is that some early FT1000D customers complained that the original 
values caused the CW sigs to RING in a D with the APF on and PEAKED properly. 
 (So Yaesu started experimenting with different value SMT resistors in order 
to lower the effective "Q" of the audio peaking filter).

The complaint about ringing is somewhat true if you listen on SPEAKER at HIGH 
volume levels.  But personally, I have never found this to be a valid 
complaint.    If  you listen with phones on and at comfortable audio levels, 
this MOD really does the trick on weak sigs that we often find on Topband.

Some years ago, KA1PE (now K1GUN) used to say that on VK9XY long path at his 
sunset, the signals would come up from 449 to about 569 with the APF engaged. 
 I know this to be true from personal use at my station - so if you are game, 
this is a MOD well worth making if your APF doesn't do much when you turn it 
on on your FT1000D.

Good luck and hope this us useful to someone out there.

73 JEFF

K1ZM/VY2ZM


K1ZM@aol.com