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