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File Notifications
#file-notice
Group Notification
Rex K0KP <rex@...> updated folder //Alignment Procedures The following items have been updated in the Files area of the [email protected] group. By: Rex K0KP <rex@...> |
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Disclaimer!
Your results may vary, hi.
Let me know if this found it’s way to you. Big problem with these is they go microphonic because of the VFO. I took a few of these apart in the beginning and kept finding bit of plastic rolling round in the VFO. Well apparently they had a micro phonic problem and just glued a piece of plastic in place. Worked for the first 50 years? I think that is covered in Elcon manual about reversing the VFO. If you are going to bring one of these back there are some things you really need to do. Mirophonic, if your not familiar with the term is an old one goes back to hi-fi gear. Means when you tap it you get a boing, sorta echo? Anyway if you take the cover off the VFO and tap on it it will probably make some interesting noises on receive. Then look for the piece of plastic that has probably fallen down into the cheese grader and hope someone didn’t use a pair of pliers to turn the VFO. At any rate dig it out and bridge all the components in the VFO. I use copper braid on the big gaps. One problem solved. Get rid of the divider on the back of the pre-mix board. That was a bandaid they tried and it causes the radio to not track between tx/rx minutely. Just enough that it appears the other person is of freq. just a bit. Hence, “crab walking”. Very important to clean everything before starting. I really do wash them with soap and water as I did Collins and even TV’s back in the day. Water doesn’t hurt electronics components. Electricity hurts electronic components, if they are wet. This time of year not much sun so set in front of wood burner for a couple of days. I normally hose out all wafer switches an front panel switches at this time with fu-fu juice. I try to do it while still wet to displace the water. Fu-fu juice. Back in the day they called it tuner wash. But since TV’s don’t have tuners anymore it called contact cleaner. THEY ARE NOT ALL THE SAME! Use non silicon fortified cleaner! It only collects dust. De-oxit is aggressive but works. Hope this helps and found it to where it is supposed to go? Back to work here. Cheers Dave |
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301 stuff
开云体育
Mod-VFO Drehrichtung_en.pdf
Mod-VFO Drehrichtung_en.pdf
FT-301 9 mhz misc. allingment.rtf
FT-301 9 mhz misc. allingment.rtf
Selectable filter mod 7-20.rtf
Selectable filter mod 7-20.rtf
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Re: FT-301D: Transmit audio quality
开云体育I built a manual years ago. Organized with a tab for each board with mods and allignment procedures. Unfortunately it is mostly hand written. I did send some doc’s to g4fph can you ask him to forward what I sent? I’m ok on radios but never learned computers. And I need an E mail address. Can I assume that you are at [email protected]? It’s not like I’m looking for a project but do enjoy sharing 301 stuff. I sent also a step procedure for restoring one to Mark. I will see if I can find that Email as it is not easy for me to get this stuff right on the computer. And you have a good ser.# number there!Dave
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VFO and 9meg IF
I can send pics of VFO strapping if needed. Appears not to be in VFO manual from Elcon.
FT-301 9 mhz misc. allingment.rtf
FT-301 9 mhz misc. allingment.rtf
Mod-VFO Drehrichtung_en.pdf
Mod-VFO Drehrichtung_en.pdf
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Re: FT-301D: Transmit audio quality
gm Dave, it seems you have quite an experience with the FT-301! Can you upload your 9MHz IF Alignment hints to this group? There might be several owners who are interested in a correct alignment (e.g. with an audio generator). I too am among these, as? I got a FT-301D #7M.... on a Ham fest and now want to bring back on air. 73 Gerhard DF1DA www.QRZ.com/db/df1da? |
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Re: FT-301 - miniVNA as External VFO
开云体育Elcon sells a VFO stabilizer for the 301 VFO. I have bought many of them. They work great. Easy to install.Dave
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FT-301 - miniVNA as External VFO
For many years' now, I've had one of the early 'miniVNA' units from Mini Radio Solutions sat on the shelf. It doesn't get much use these days, as it's functionality is bettered in most respects by a nanoVNA from China that I also have.
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The oscillator in the miniVNA is a DDS-type, using the 14-bit, AD9951 IC by Analog Devices. Output from the 'DUT' (Device Under Test) BNC is a high-quality sinusoidal wave at exactly the right level to apply to the FT-301 external VFO input:-)
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I hacked together a quick programme for the PC (using the ancient BBC Basic for Windows language) to allow entry of data for band, stepping of the (RF) frequency and trimming of the DDS reference number. The programme does the necessary maths and formatting and sends the required data (simple ASCII text strings) to the miniVNA to get it to output frequencies in the 5 - 5.5 MHz range.
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While the stability of the internal VFO of the FT-301D I have on the bench is excellent, now I have a 'digital' alternative. Ironically, the reference crystal for the DDS in the miniVNA seems to drift a little until it's been powered up for an hour, or so. In fairness, this drift is not an issue when using it for what it was intended for.
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It would be a straightforward job to drive the miniVNA from an suitably programmed Arduino, with some buttons, display and shaft encoder and dispense with the PC altogether. One day, I just might...!
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Regards,
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Mark, G4FPH.
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Re: FT-301D: Transmit audio quality
Just to round out this thread.
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Given a good crystal filter on the NB Unit, there would seem to be no real need to modify the transceiver to bypass this when RF PROC = OFF.
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By chance, I came across a recent video on YT from Stefan, DL7MAJ. He had a Yaesu FT-101ZD on the bench, on which the processor did not appear to be working. In his video, he showed the relevant part of the circuit of the '101ZD. It looked quite similar to that of the '301D, except that it had a bypass path around the second crystal filter for when the processor was off.
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For anyone interested, the '101ZD circuitry is:
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The circuitry needed to implement such a facility of the '301D would be very similar - something like this:
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I may try this on the board with the faulty filter, as it would make the board partially usable in the transmit path. Out of curiosity, I may first try bypassing the filter entirely. I doubt this would give spectrally satisfactory results with the processor on, due to the distortions that the RF clipping process introduces. The original G3LLL RF Clipper that was used with early FT-101, the FT-101E/F and the FT-101Z all had crystal filters to 'clean-up'.
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Regards,
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Mark, G4FPH.
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Re: FT-301D: Transmit audio quality
Dave,
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Thanks! The serial number for the one I have on the bench is in the 7G 110xxx range. I believe that decodes to May of 1977.
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This morning, I installed the NB Unit from one of my other '301. Wow - what a difference! The transmit audio now fits with my definition of 'nice':-) The bandwidth of the transmitted signal has broadened nicely and properly fills out the 2.4 kHz nominal at RF. The response looks balanced across the passband - way better when compared with the peaky / restricted response when using the other board. The audio sounds better with the RF Processor switched in too - very similar response, just 'louder' on my check receiver.
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I suggest you just include your alignment info. in an post in reply to this one - either as text, or copy and paste it in, or attach it as a file (paper clip icon in the toolbar above the box where you compose your message, if you compose your messages while on the website. If you just send e-mails, then send it to those addresses you have already replied to.
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Weather is getting warmer here over the next dew days, which is nice for walking, but more wind and rain too, which is less good. Enjoy your pint - cheers!
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Regards,
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Mark, G4FPH.
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Re: FT-301D: Transmit audio quality
开云体育Are you Mark?The way I have this stored I have to have an E mail address to send it. Can also send a pic of a finished one. These sold for just under 1,000 US back in the day. More than a 101 EE!! But they were lemons so few got used. I’ve bought over 20 of them and it is rare to see the escutcheon worn like on a KWM-2. But they are very fixable!! Time for my walk here. The little woman comes out and the bird, dog and the misses and I go for a mile hike in the woods. They say that’s what old people got to do to stay old? Then it’s time for a pint. 73 Cheers Dave
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Re: FT-301D: Transmit audio quality
开云体育Look at the back of the front cover. Bottom of the page. Will say; This manual is……………………Lot No. 015015 is the newest manual I ever found and it isn’t right. You’ve nailed it. You would think you could set the SSB rock to what’s on the can or 1.2. —1.5 either side of the IF but not this one. These are really nice radios once you over come the bugs. They never finished de-bugging because the WARC bands were released and they changed to the 107M. A yellow radio? Really? Do you know how to read the set. #? Anything before a 77C would be problematic. From there into the AD they didn’t change much of significance. Pardon my computer ignorance. I’m old and not bad on radios but computers……….. Where do I send the info to? Dave
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Re: FT-301D: Transmit audio quality
开云体育Oh. And PS. I modified a few of the IF boards per Roland. He’s a smart guy, has a doctorate in electronics! Way smarter than me but the IF mod didn’t work right. Had a side effect so I put all of them back to stock. I think he’s close with his theory that there is an impedance issue with the filter board
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Re: FT-301D: Transmit audio quality
开云体育The filter on the NB board is only on the hi power models. Forget the computer stuff. You need a tone generator and a signal generator. I use a IFR 1200S and a Motorola two tone generator to adjust the SSB osc's. That is an EXCELANT mic!! Very valuable today. I used to sell them in my store for about sixty bucks. I have a few. With a stock mic I get people asking what mic I’m running? I run 301’s on all bands using transverters and Swiss displays and VFO stabilizers. Whens the last time you worked AM on 220 mhzs? Hi hiDo you want a copy of the 9mhz alignment? There never was a service manual and the latest owners manual was obsolete when it was printed and can’t be trusted. The key is to listen to the receive signal on USB and LSB. They won’t be the same. That’s the problem. Your on it but it takes a bit of doing to tune it up right. Dave
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Re: FT-301D: Transmit audio quality
开云体育The 301 had a couple of bugs out of the gate. One is the “crab walk” problem on the pre-mix board and the other major one is the one your working on. I wrote an a alignment procedure for the one your on. Seems like an impedance mis match going onto the filter board. As you indicated ?the carrier point that is how I resolved that. Built many of them and they all sound great with good audio reports. To long to go into but can forward alignment instructions if you wish. No need to change anything just realign. I have many parts and spare radios. I thought they would be worth something someday but was wrong. Today, if it doesn’t have a computer connection, what good is it. The Elcon library is a good place to look also.Dave
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Re: FT-301D: Transmit audio quality
Dave,
Thanks for the mails.
Yes, please send a copy of your alignment procedure. You clearly have a lot of experience with these old things.
Agreed, no service manual, as such (not like for the FT-221R and FT-101E). I was following the alignment in the back of the regular / user manual.
I've tried setting the carrier oscillator frequencies to their book values. The LSB one nets just fine, but the USB one doesn't quite get there - it's about 100 Hz shy. I'll look at that in due course. I also tried varying the LSB one to give optimum audio, but made no real improvement - still sounded cruddy to my ears.
Interesting that the extra filter was only on the qro version (which all mine are). I've sketched out a simple mod. that would bypass this filter when processor = off, if needed.
Regards,
Mark.
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Mark Hill - G4FPH
Sent from a mobile device
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On 19 Feb 2025, at 18:47, n0eds@... wrote: The filter on the NB board is only on the hi power models. Forget the computer stuff. You need a tone generator and a signal generator. I use a IFR 1200S and a Motorola two tone generator to adjust the SSB osc's. That is an EXCELANT mic!! Very valuable today. I used to sell them in my store for about sixty bucks. I have a few. With a stock mic I get people asking what mic I’m running? I run 301’s on all bands using transverters and Swiss displays and VFO stabilizers. Whens the last time you worked AM on 220 mhzs? Hi hi |
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Re: FT-301D: Transmit audio quality
Digging into this a little more today.
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Using my SDR transceiver as a narrow-band, RF spectrum analyser, I checked the DSB TX IF signal going into the Filter Unit. Audio fidelity from the mic. I selected as best match to the '301 (an old Astatic MOD. 575-M6) was very good, with modulation sidebands extending to at least 4 kHz either side of the (suppressed) carrier, and with some signs of roll-off from around 3.3 kHz. So, I think the issue is likely to be the response of the second crystal filter on the NB (/ RF Processor) Unit.
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Even with the processor turned off, the (now SSB) TX IF signal still passes through this second filter, which seems like an odd decision by the Yaesu design engineer(s). I see references in the service manual that the filter is optional, but I think it is present in all three of the transceivers (one -301 and two -301D) that I own. It's not listed as an option in the English brochure that I have a PDF of.
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Later this week, I will pull a complete NB Unit from another '301 and try it instead of the one I have been using. Depending on results, I may even try removing the filter on the NB Unit to see what difference it makes. I assume it is present principally to clean up artifacts arising from the RF clipping process, so it would be nice to retain it for that. Perhaps a modification is possible...?
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I note that 'ELcon' () published a modification for the Filter Unit that better terminates the filters in order to improve the response on USB. My testing has all been on LSB so far.
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Regards,
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Mark, G4FPH.
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FT-301D: Transmit audio quality
Hi to all in the group!
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I'm close to the end of repairing an FT-301D transceiver and trying to get the transmitted audio quality sounding anything like 'nice'. It's proving surprisingly challenging.
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Looking at the transmitted RF spectrum, one issue would seem to be that the SSB filter response is very narrow - more like 2.0 kHz rather than the supposed 2.4 kHz. I've tried moving the carrier point around and different microphones, all with no real improvement. This morning, I grabbed a Filter Unit from my spare radio and tried that. No real improvement:-(
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I imagine it's possible that the crystals in both SSB filters I have tried have aged the same way and their responses have degraded. If that is the case, then I'm stuck with the problem. I do have a minVNA and could remove the filter to test it, but it would be nice not to have to. The receive audio response with either filter sounds generally OK.
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I'm wondering whether aged coupling capacitors in the mic. amp. could also be a factor. I've not looked into that as yet.
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Any experience out there of this issue?
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Regards,
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Mark, G4FPH.
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Gerhard Wagner DF1DA
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