After I received two complaints about key clicks during the Stew Perry Top Band Memorial Contest in December 2002 I took up cudgels in an effort to reduce the width of my CW transmissions on 160m. I viewed the W8JI website, archive info on topband@contesting.com and the information provided by International Radio with their key click modification kit for the FT1000MP.
I felt that an easy option would be to do the mod on the IF board suggested by International Radio. A capacitor and resistor are placed across a surface mount capacitor on the bottom of the IF board. It's a very cheap mod, but a risky business with my rather poor eyes. I did it and there was absolutely no improvement in clicks with that mod. If anything my signal was wider. There appeared to be extra key click sidebands created further out than previously. So I removed the RC network and put the rig back together. I delved into the W8JI Website and decided I would go for the full gallon. The mod is very well explained on Tom's site and there are some good close up photos. Total cost of the best available components was £3.28 UKP or $5.15 USD.
That was for three capacitors, two multiturn minature variable resistors and a four way
terminal board.and fitted inside my FT1000MP >>>>>>>>>>>>>>>>
I don't have the test equipment that Tom has, so I pressed
into service my standby Yaesu FT847 as a monitor receiver with a
2" screw in the antenna socket. To simulate true transmitting conditions I
ran 20 watts of FT1000MP clicky RF into my normal topband TX antenna.
The results on my monitor Rxer before and after the mod were STAGGERING.
I also tested the click bandwidth of the FT847 as a comparison. That rig
remains unmodified and is quite acceptable. Having completed this mod I can go back on
160m with confidence that my signal is clean. In my opinion it's much less risky to solder one wire
each on the RF and IF boards and then route to a small terminal board as
suggested by Tom, than to try and solder fixed components onto the boards
themselves.
My results below:
FT1000MP S/No. 9C390068 Monitor Rxer Yaesu FT847
S/No.8H090447
7th January 2003
1500z
TX Antenna: 3/8 inv
L
RX Antenna: 2" screw(RX in shack)
Power out:
20w
AGC on - Bandwidth normal 2.2 KHz
Pre Mod Key Click Tests - dots at 28 wpm:
Freq: 1816.8
KHz Clean
- no sigs audible on 2" screw
Freq: 1818.3
KHz Solid
clicks just starting to break up
Freq: 1825.1
KHz S1
All clicks
Freq: 1826.2
KHz S3
A little tone but mostly clicks
Freq: 1828.3 KHz S7 Centre TX Freq
Freq: 1828.8
KHz S3
A little tone but mostly clicks
Freq: 1829.5
KHz S1
All clicks
Freq: 1836.6
KHz Solid
clicks just starting to break up
Freq: 1837.1
KHz Clean
- no sigs audible on 2" screw antenna
Pre W8JI Mod: Click Bandwidth on shack monitor FT847 = 20.3 KHz
FT1000MP S/No. 9C390068 Monitor Rxer Yaesu FT847
S/No.8H090447
8th January 2003
2100z
Antenna: 3/8 inv
L Antenna:
2" screw (RX in shack)
Power out:
20w AGC
on - Bandwidth normal 2.2 KHz
Post Mod Key Click Tests - dots at 28 wpm:
Freq: 1824.5
KHz
Clean - no sigs audible on 2" screw
Freq: 1825.9
KHz S1
Tone no clicks
Freq: 1826.4
KHz S3
Tone no clicks
Freq: 1828.3 KHz S7 Centre TX Freq
Freq: 1828.7
KHz S3Tone no clicks
Freq: 1828.8
KHz S1
Tone no clicks
Freq: 1829.0
KHz Clean
- no sigs audible on 2"screw antenna
Post W8JI Mod: Click bandwidth on shack monitor FT847 = < 4.5 KHz
Extra Click Tests on monitor transceiver FT847: Yaesu FT847 S/No. 8H090447 Monitor Sub RX FT1000MP S/No.9C390068
7th January 2003 1600z
Antenna: 3/8 inv L Antenna: 2" screw
Power out: 20w AGC on - Bandwidth normal 2.4 KHz Key Click Tests dots at 28 wpm: Freq: 1823.6 First freq LF when clicks are gone
Freq: 1825.3 S1 A little tone mostly clicks
Freq: 1825.4 S3 Mostly tone
Freq: 1828.3 S7 Centre TX freq
Freq: 1829.4 S3 All clicks
Freq: 1829.7 S1 All Clicks
Freq: 1831.7 First freq HF when clicks are gone
Click Bandwidth of unmodified FT847 = 8.1 KHz
We got a result - pre mod the FT1000MP was twice as nasty for key clicks than the FT847. Post mod the FT1000MP is now twice as clean as the FT847. Many thanks to Tom W8JI for doing all the technical spadework, providing his website and helping me make this mod an undoubted success.
I hope manufacturers realise the importance of CW signal bandwidth. I had the same problem with a Yaesu FT107M in 1984, but couldn't improve it despite various mods so I ended up selling it on. So I have to say, it doesn't look like things will change in the short term.
73 and Good DX Phil Catterall G4OBKPage updated 6th April 2003