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Subject: Yaesu Mods
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Subject: Yaesu Mods
The uP's in the FT-23R and the FT-211R/H can be set for several
frequency and memory mode combinations. These modes are contorlled
by the jumpers (solder pads) marked 7,8 and 9 on the processor
board of either radio. Here's a list of what can be done:
JUMPER CONFIG DISPLAY MODE
7 8 9 NUMBER
open open in 1 140 to 164 MHz, amateur mode
open in in 2 140 to 160 MHZ, amateur mode
in open in 3 144 to 148 MHz, amateur mode
in in in 4 144 to 146 MHz, amateur mode
open open open 5 220 to 550 MHz, commercial mode
open in open 6 440 to 450 MHz, amateur mode
in open in 7 50 to 300 MHz, commercial mode
in in open 8 430 to 440 MHz, amateur mode
Both of my radios (USA) were shipped from the factory in config #3.
They can be converted to config #1 without re-tuning just by changing
the jumpers. Tuning range can be further expanded by changing to
jumper config #7. The FT-211 has separate VCO's for transmit and receive
and will lock over about 38 MHz from approx. 130 to 180 MHz. The FT-23
has only one VCO and the overlapping lock range (Xmt & Rcv) is about
25 MHz from approx. 135 to 175 MHz. Don't forget, if you adjust the
VCO you must re-align every electronically tuned stage in the front
end of the radio. The transmitters can be tuned for somewhat higher
power output above 164 MHz but at a great power loss at 2m.
The commercial memory mode will cause these functional changes:
1.When in the MR mode, the channel number will be displayed instead
of frequency. You can toggle back to the original "amateur" mode
display by pressing F<up-arrow>. Pressing F<down arrow> takes you
back to commercial mode. However, when switching from D to MR, the
display will always revert to the commercial mode.
2.The function of the Dot<Pri> button will be exactly reversed. That
means now you can press just one button (Dot) to get into or out
of the Primary function. The Pri funtion (in memory mode) will
be indicated by a large "P" on the left side of the display.
3.The only indication of low power operation is in the memory mode.
A "C" will appear in the upper left corner of the display (where
the primary "P" used to be). The bargraph will always read 100%.
4.The band scan is now even more useless. The uP will painfully
count from 50 to 300 MHz.
I have been able to modify my FT-211RH to scan at about 10 chan/sec
by speeding up the uP clock. This also speeds up every other uP
function by x5, so you have to be fast on the "F" key. No squelch
sensitivity or synthesizer lock-up problems have been encountered
with this modification while scanning.
Basically, I replaced the 800 KHz ceramic resonater (pn CSB800K)
with a Radio Shack 3.58 MHz color burst crystal. The resonater is
located on a small (2.5 sq cm) sub-board that is stuck with double
sided tape to the radio's processer board. This sub-board is actually
an outboard clock for the uP. The schematic I got with the radio
showed the uP's internal osc. being used - so I don't know if my
version differs from newer radios. This mod works fine untill you
turn the radio off and then back on again. A startup glitch then wipes
out all of the memories. To delay the oscillator start up, I added a
220uF 10V electrolytic cap between the red wire on the sub-board
and ground. Positive goes to the red wire. A convenient ground is the
bare wire located diagonally across from the red wire (on the sub-bd).
So far I have been unsuccessful with this mod on the FT-23R H-T.
Since it uses the uP's on board osc, there seems to be no way to
delay it's startup. Every time you turn on the power the uP resets.
If anyone can solve this problem I would be very interested in
hearing from you!
These are not intended to be step by step instructions. Also, you
will want to have a service manual before you begin. If you're not
familiar around surface mount components you may want to "learn"
on something with cheaper consequences. Finally, don't adjust the
VCO's unless you are familiar with how a synthesized radio
works. Use your own judgement!
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