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- Date: 25 Aug 90 02:54:33 GMT
- From: swrinde!mips!prls!philabs!briar!rfc@ucsd.edu (Robert Casey)
- Subject: FT470 extended VHF xmit mod file
- To: info-hams@ucsd.edu
-
- FT-470 mod extended VHF xmit....
-
- Here's the mod for the FT-470. (I have not performed it myself)
- 1. Remove Cover
- 2. Remove Lithium battery carefully
- 3. On left hand side locate some empty vertical pads, one above the other.
- It should be marked as R-69. There is also a chip resistor R-67 that
- is just below it to the left a bid.
- 4. Place a solder jumper across the two R-69 pads.
- 5. Reinstall the lithium battery.
- 6. Closeup the Radio.
- 7. Turn the radio of. While pressing down the up and down arrow keys,
- turn the radio back on.
-
- Note: This mod only opens up the VHF transmit frequency range
- beyond 140 to 150. The automatic repeater offset will
- be defeated so you will have to enter the +/- offset yourself.
-
- 73's Bernie NU1S @ K1UGM
-
- Note: I haven't tested this, proceed at your own risk. Don't
- transmit out of band, else you might get a fine or even do time.
- WA2ISE
-
- ------------------------------
-
- Date: 26 Aug 90 00:39:28 GMT
- From: mailrus!hellgate.utah.edu!uplherc!wicat!keithm@tut.cis.ohio-state.edu
- (Keith McQueen)
- Subject: FT-470 mods
- To: info-hams@ucsd.edu
-
- I have recevied enough enquiries about mods for the Yaesu FT-470
- hand held, that I have decided to post what I know.
-
-
- (This is a transcription of a letter that I received detailing
- the CPU programming jumpers that were found experimentally
- by Ed Boakes, WB3FLD. Keith, N7HMF)
-
- Dear Keith,
-
- A little while ago, I came across a Net News item from you about the
- Yeasu FT-470 handheld. You asked if anyone knew how to make it
- receive the public service band just above the UHF amateur band. Well,
- I've figured out how to do that. However, the bad news is that when
- you strap the unit for this mode, it only transmits from 430 to 440!
- Oh, well.
-
- I gave you a phone call a week or so ago, but it seemed that we kept
- missing each other. Anyway, here is what I've learned about the
- FT-470: I have located a total of eight straps, the four which you
- had written about, to the left of the lithium battery, and four others
- located under the flat white cable that interconnects the upper half
- with the lower half.
-
- YEASU FT-470 STRAPS
- R69 Vertical, at the 10 o'clock position by the lithium cell
- R68 Horizontal, to the lower left of R69
- R67 Horizontal, just below R68
- R66 Horizontal, just below R67
-
- R71 Vertical, the leftmost of three, to the left of the upper
- corner of the ribbon cable connector.
- R70 Vertical, the center of three of which R71 is the leftmost
- R72 Vertical, the rightmost of the three
- R74 Vertical, to the left of the ribbon cable connector, below
- the three. (Note that R74 is below an unpopulated capacitor
- that does not have a C number.
-
- There is no R73, or at least it is not on the circuit board and it is
- not in the schematic. And, yes, the order of those three is indeed
- R71, R70, R72, left-to-right.
-
- R70, R71, R72 select the mode for the UHF portion of the FT-470. The
- choices are:
-
-
- UHF CHOICES
- R71 R70 R72 Rx and TX Receive only
- 0 0 0 430 to 440 Mhz 430 to 500 Mhz
- 0 0 1 430 to 450 Mhz
- 0 1 0 430 to 440 Mhz
- 0 1 1 432 to 438 Mhz
- 1 0 0 430 to 440 Mhz
- 1 0 1 220 to 225 Mhz
- 1 1 0 430 to 440 Mhz
- 1 1 1 210 to 235 Mhz
- R66, R67, R68 and R69 select the mode for the VHF portion of the FT-470.
- The choices are:
-
- VHF CHOICES
- R66 R67 R68 R69 Rx and Tx Receive only
- 0 0 0 0 144 to 146 Mhz 130 to 180 Mhz
- 0 0 0 1 144 to 146 Mhz
- 0 0 1 0 1260 to 1300 Mhz
- 0 0 1 1 1240 to 1300 Mhz
- 0 1 0 0 140 to 150 Mhz 130 to 180 Mhz
- 0 1 0 1 140 to 174 Mhz
- 0 1 1 0 303 to 343 Mhz
- 0 1 1 1 8AL to 242 Mhz
- 1 0 0 0 144 to 148 Mhz
- 1 0 0 1 144 to 146 Mhz
- 1 0 1 0 1240 to 1300 Mhz
- 1 0 1 1 404 to 444 Mhz
- 1 1 0 0 140 to 160 Mhz
- 1 1 0 1 1260 to 1300 Mhz
- 1 1 1 0 101 to 141 Mhz
- 1 1 1 1 1R3 to 158L Mhz
- (Note: the receive only ranges are enabled by powering up the
- unit with the up and down arrow buttons depressed...kjm)
-
- When there is more than one combination which has the same frequency
- range, the difference is the default step size and/or the default
- repeater offset. Of course, choices that do not match the VCO and
- filters do not actually transmit or receive on those frequencies.
- A particularly strange example is that the VHF side of the set can
- be set to tune from 404 to 444 Mhz, but again, it won't actually lock.
- Even in the 101-141 mode, the VHF VCO will not lock - this must be for
- use with some other sort of VCO (It looks like this would cover the
- aeronautical band rather nicely.) There are two really wierd VHF
- settings, those for 8AL-242 and 1R3-158L. These must be for use
- with some other LCD controller - it displays truly unusual and
- non sequential thins when stepped through the "bands".
-
- R74 seems to have something to do with something like selecting
- the IF frequency, or something else like that that. When set, it
- really screws up the VHF reception.
-
- My technique for determining these straps is to remove the straps
- that come in the unit, solder wires to each pad, run the wires out
- of the unit to a bank of DIP switches, screw the unit back together,
- and then go through all of the DIP switch combinations. I usually
- use a stereo microscope and 30 guage wire for this. Since I didn't
- try powering the unit on with every combination of keys held down
- for each DIP switch combination, there may still be other secrets
- possible.
-
- Since I was looking for something like receive and transmit from
- zero to infinity, and I didn't find it, I kept looking until I got
- bored and wanted to button the thing up and start using it. I
- determined, from studying the schematic, that there should be a
- hiddem strapping diode from CPU pin 2 to CPU pin 22. I installed
- one, but nothing changed. In fact, changing it and powering the
- unit up did not cause a reset. Therefore, I concluded that this
- really wasn't a mystery strap, afterall. However, there could be
- others. I'm trying to get a data sheet for the CPU, from Hitachi,
- to see if any of the grounded pins are actually I/O pins -- they
- might be good candidates, particularly if their traces are routed
- in such a way as to be easily accessible for cutting.
-
- I've learned that one of the ways to get some of the other, new
- Yeasu handhelds to go out-of-band, involves dumping data out of
- the clone port, editing the data, and then dumping it back in.
- I called Yeasu and asked if the FT-470 could be cloned. They
- said no, so I ignored them. I haven't figured out how to get
- it to dump data, but I believe it will accept data. The clone
- mode is entered by powering up the unit with the F key held
- down. (It's also a neat way to see all of the indicators on
- the LCD!) The data must be presented in the ring ("right
- channel") of a stereo 2.5 millimeter plug which is placed
- into the mic jack. This is cryptically marked on the schematic,
- anyway. However, I have no idea what the format for the data
- should be. If you come across this, I'd love to know. This
- may be the trap door to getting the rig to receive and transmit
- in more interesting places.
-
- Have fun with you FT-470!
-
- Yours Truly,
- Ed Boakes
-
- CAll: WB3FLD
- email: att!hocpa!ewb
- work: (201) 834-1121
- Fax: (201) 834-1371
- home: (201) 957-0391
-
-
-
- Several interesting things that I have learned since I received this
- letter... According to the guys at Yaesu, the engineers in Japan
- appearantly wrote the full UHF rx/tx out of the ROM on purpose.
-
- The unit does a very good job as a cross-band repeater.
-
- To enable this, turn off the radio, hold the RPT key and turn on the
- radio. Now, anything heard on EITHER band will be re-transmitted on the
- other band. There are, however, a few problems.
-
- First, there is no real internal path for the audio to get from the receiver
- to the transmitter, so you either have to modify the radio, to provide a
- path, or do what I did which is build a short loop back cable connecting the
- tip of the earphone jack to the tip of the microphone jack like this:
-
- <=====----/\/\/\/\/\/\/=====---->
- 100K
-
- This is the way I did it, others I have talked to have used either just a
- resistor like me or a small capacitor, or a combination. On my radio, this
- value of resistor gave me a good range of tranmitted audio levels by
- adjusting the volume control.
-
-
- The other small problem is that the radio automatically selects low power on
- transmit in this mode. This is probably because of the lack of a real
- duplexer.
-
- After looking through the service manual, it became appearant that the small
- mystery hole on the side of the radio with the rubber plug was originally
- intended for an external power jack. I have not yet asked Yaesu if they will
- sell the jack for that spot. I also have no idea why they omitted it.
-
- All in all, I still love my FT-470. Its a great little radio.
-
-
- --
- Keith McQueen, Wicat Systems Inc. , (801)224-6400 | My opinions are |
- N7HMF @ NV7V.UT.USA.NA (84058), 147.34+, 449.675- | all mine... |
- UPLHERC!WICAT!KEITHM | ...so there! |
-
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-
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