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Mark V Field Off Frequency

Problem: I purchased a new Yaesu FT-1000MP Mark-V Field from Ham Radio Outlet in Atlanta on March 13, 2004. Within a week of putting the rig on the air, I began to wonder why it seemed that everywhere I went, everyone was off frequency! Soon I went to several WWV frequencies and did the “LSB and USB” thing, and found that the radio is right on at lower frequencies, such as the AM BC band and 160 meters, but begins showing a frequency error as you move higher in frequency, topping out at around 60 Hz off-frequency on 10 meters!

I did some in-house testing last night. A local ham friend of mine got on 10 meters with me; specifically, 28.400 MHz. I spent a good amount of time tuning him in, and the final result was, when he was on 28.400.00 (with his TS-850S), I tuned him in between 28.400.05 and 28.400.06. We then went to 3.820 MHz where his frequency display and mine were almost exactly the same. This confirmed observations I have made on various nets and other supposedly “set-frequency” conditions where I have found the rig to be pretty much on frequency on 80 meters, but 30 Hz high on 20 and 17 meters, where I do most of my operating.

But knowing his radio is not a known reference, I then put the 1000MP in CW mode and carefully zero-beated WWV at all frequencies, using headphones and the 1000MP’s SPOT function to get an exact zero-beat. Here’s what my rig’s display showed when zero-beated at each WWV frequency:

WWV 2.5 MHz: 2.500.00
WWV 5 MHz: 5.000.01
WWV 10 MHz: 10.000.02
WWV 15 MHz: 15.000.03
WWV 20 MHz: 20.000.04

I then reversed the CW sideband and left SPOT on so I could hear a 700 Hz tone on WWV. Leaving things set up in this fashion, I then used the rig’s keypad to enter each WWV frequency exactly, i.e. 2.500.00, 5.000.00, and so on. The tone I heard upon arrival at each WWV frequency was noticeably different on each frequency; i.e. 15 MHz had a noticeably higher tone (730 Hz) than 5 MHz (710 Hz); the difference was more pronounced between 20 MHz (740 Hz) and 2.5 MHz (700 Hz). This confirmed that the departure from being on-frequency varies between bands, getting worse as the frequency moves upward.

To summarize, the rig’s display is accurate at very low frequencies – i.e. 160 meters – and as you tune higher in frequency, the rig (or display) gets farther and farther off. By the time I’m on 10 meters the display shows a 60 Hz difference from the actual frequency. (The lack of a precise reference frequency like WWV kept me from doing a zero-beat test above 20 MHz, but I think you can see the trend in the measurements I listed above.)

I have e-mailed Yaesu about this and my warranty card, which was “returned to sender” as undeliverable. I have not received a response yet from Yaesu. (I went ahead and registered the radio on Yaesu’s web site.) I am hoping this is something that can be corrected without sending my 3-week-old rig cross-country, but the fact that the frequency error varies as you move up in frequency makes me believe this is not something that can be corrected by adjusting one pot or menu item – i.e. if I “zero” the display on 10 meters, for example, then the display could be 60 Hz low on 160 meters. This also confirms the absence of RIT (which I confirmed was off) or any other variable that would introduce an error of equal value across the entire frequency range – not an error that varies as you move up in frequency as is the case here.

By the way, I started this test by performing a “hard reset” of the radio, and then performed the WWV measurements twice – once about 15 minutes after turning the rig on, and again after having left the rig on for 6 hours. The measurements were the same both times.

I don’t tend to look for problems – I noticed this after hours of routine operating and wondering why EVERYONE seemed to be off frequency – even ECARS and the Maritime Mobile Service Net. After two decades owning “middle-of-the-road” radios, I bought this “top-of-the-line” one as a gift to myself for 25 years in the hobby. And I think an $1800 radio’s frequency should not be wandering around as you change bands – after all, my former radio, a TS-570D at half the price of this one, did not.

Has anyone else experienced this? If so, what’s the fix? I hate to think of how much it will cost to insure and ship this 33-pound, 3-week old beast from Virginia to California, not to mention how long I’ll be without a radio as a result. I’ll send an update when I find out what’s wrong.73,Meade K4CMD

Solution: I shared my information with HRO via e-mail yesterday, and within hours received this response from them; which they had received from a Yaesu technician:

"My input is, the reference oscillator is slightly off frequency, but a tiny tweak of its trimmer capacitor, performed while watching it at 20 MHz, should bring the hole unit back spot-on. You can see that the frequency variance is completely a multiplier function, so just get the radio warmed up and tweak the trimmer and it will be
fine. It's a little odd. . .we specify stability but not accuracy in our specs! I agree that it seems unfortunate to consider sending the unit across the country for something this minor, especially considering the risk that a bounce could throw it off again. Anyway, that's all it is. Sorry he has the problem, but it is easy to correct in a few moments after the rig is warmed up."

I e-mailed the Yaesu guy directly and said thank you, and within five minutes he e-mailed me back:

"Well, we're sorry it got a little off frequency, but perhaps the trimmer capacitor had a nice stretch after the long journey from Japan, and when the stretch was over it ended up not quite where it started. We hope and trust you'll enjoy this ferocious radio. . .a lot!"

In the meantime I found, via VA3CR's exhaustive FT-1000MP website, a very detailed page on locating the reference oscillator and making the required adjustment:

Download K0TO Information to assist with this

Went home last night, instructions and schematics in hand, and removed the top and bottom covers of my Field. I located the REF board, a small board about 2x3 inches in size, on the right-hand side of the radio just behind the front panel. Unlike the photo of the board on an FT-1000MP that was in the link above, Yaesu has changed the board and upgraded it with SMCs. In fact, when you pull the cover off, all you see on an otherwise barren REF board is a three-pin connector. You have to remove the board from the radio (four screws) to get at the components, which are mounted inward in a little group on the board on the chassis side. To my dismay I found that there's not a separate reference crystal and a handy separate pot like on the 1000MP's board, but instead a tiny (1/2x1/2) oscillator chip with the tiniest screw I've ever seen embedded in a wee little hole in the top of the chip. Alas, my smallest jeweler's screwdriver DID fit, but barely. Using WWV as a reference per Yaesu's instructions, I turned that screw carefully until I achieved zero-beat on 20 MHz, and then compared my results on 2.5, 5, 10, and 15. I took some time to do some careful tweaking, and my patience proved successful! The rig is spot-on everywhere I checked, even after another five hours of letting it stay on.

Let me say, however, that I don't know how mere shipment could've resulted in this maladjustment. The screw was quite secure, and I had to turn it much, much more than a “tiny tweak” – more like 1/4 turn -- to get the rig back on frequency again. New Field owners, I’d suggest comparing the tone you hear when you tune to WWV and switch between LSB and USB. If the tone is different on each sideband, your rig is off frequency and you should perform this little task. The only really hard part about it is manipulating the radio with the covers off and finding a screwdriver small enough to fit the oscillator. Happy again, Meade K4CMD

 

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