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Reviews For: Yaesu MTU - Mu tuning units

Category: Filters, RF: bandpass, duplexer, lowpass, highpass, RFI/EMI

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Review Summary For : Yaesu MTU - Mu tuning units
Reviews: 15MSRP: $400.00
Description:
The Ultimate Low-Band DXer RF Preselection Filter: YAESU’s Exclusive µ-Tuning!
On the lower Amateur bands, the signal voltages impinging on a receiver can create noise and Intermodulation effects that can cover up weak signals you’re trying to pull through. So YAESU’s engineers developed the µ (Mu) Tuning system for the FTDX9000, and it’s now available as an option for the FT-2000. Three modules are available (MTU-160, MTU-80/40, MTU-30/20), and these modules may be connected externally with no internal modification required! When µ-Tuning is engaged, the standard VRF (Variable RF Preselector) system is bypassed, but the fixed Bandpass Filters are still in the received signal path. The µ-Tuning filters utilize a stack of large 1.1” (28 mm) Ni-Zn Ferrite cores, driven through a silver-plated coil assembly by a precision stepper motor. The resulting high Q (typically over 300) provides a very steep resonance peak near your operating frequency. The peak may be adjusted away from your frequency, for even greater protection from a specific station, and a graphical depiction of the µ-Tune filter alignment appears on the front panel of the transceiver.
Product is in production
More Info: http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=102&encProdID=66EA91711DFB68C03DED4AD35153E12C&DivisionID=65&isArchived=0
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
25154.3
K6BRN Rating: 2023-01-24
Well-made RF Front (Front) -End Preselector Time Owned: more than 12 months.
The Yaesu MTU-160, -80/40 and -30/20 were designed as the ultimate in (internal) RF front-end protection for Yaesu’s top of the line, no expense spared FTDX-9000 tranceiver. Yaesu later developed somewhat funky external packaging (looks like a high-end techno-Deco stereo component fron the ‘90s) for these units, to allow them to be used (externally) with other transceivers, including the present day FTDX-5000, -3000 and -1200.

In previous reviews, the MTU units have variously been called a charade (fake gear that does nothing but looks like it does to ignorant users) or a wonder tool for improving reception (presumably by the ignorant users). I purchased all three to use and test, both with lab equipment and connected to a well-used FTDX-3000. And have formed some (free) opinions.

Note that my 5-star rating does NOT mean you should buy them. They solve a very specific problem, and if you do not have that problem, you don’t need them and will probably disappointed with their lack of usefulness.

IN SUMMARY:

1. The Yaesu MTU-160, -80/40 and -30/20 are very solid, well made passive/tuned RF pre-selector units, and were initially quite expensive – now much cheaper on the used market, particularly since few stations need them and so many operators have no idea how too use them. 2. They really work, and work well, to solve a specific problem – out of band interference, 3. Yaesu instructions and marketing can be misleading to operators who do not pay attention to details and do not understand the context Yaesu marketing and instructions are written from. 4. Because of their unusual design, they can be placed between a receive antenna and ANY brand of receiver (do NOT TX through them) when used as a fixed, very narrow band-pass filter. Some have reported very good results when paired with the Icom IC-7300. Tuning, if desired, must still be done using the Yaesu control protocol.

MY THOUGHTS ON COMMON MTU QUESTIONS:

Should you buy these units? Are they worth whatever you pay for them (used or not)?

YES – but only if you regularly suffer from strong but out of band interference, either industrial (like a nearby AM BCB station) or under Field-Day like conditions. Because the MTU filters are too broad to mitigate in-band interference well, though they are MUCH narrower that most RX band-pass filters. Because they are tunable, it is possible to attenuate nearby in-band interfering signals to a degree, but they are not really suitable or designed to do that. The 1st IF (sometimes called “roofing”) and (typically) 2nd IF filters (either digital and continuously variable or fixed/switched/crystal) in your receiver have MUCH better selectivity with the 2nd IF filters specifically having the job of suppressing interference very close in.

Why don’t the MTUs help with nearby interference? Yaesu says they are “Ultra-Sharp”. Are they lying?

Yaesu markets the MTU filters as providing “…ultra sharp RF selectivity for the front end of the transceiver”, and that is EXACTLY what they do, and they do it WELL, with a typical 6db bandwidth of 40-60 KHz (with a typical, measured insertion loss of about 6db, not much) compared to perhaps 1-6 MHz for a typical band-pass filter. In context, the MTUs are “Razor Sharp” compared to the band-pass filters. Remember too that Yaesu said “RF selectivity”, not “IF selectivity” or “channel selectivity”, and they said “…for the FRONT END of the tranceiver”, i.e. before ANY active electronics. If you’ve really read and understood this, you’ll immediately realize this is NOT the filter to use to tune out Ralph, next door, running 1.5 KW, just 2 KHz away. But if Ralph is one band down or up, this will do the job just fine, defending your receiver’s front end from overload with minimal signal of interest attenuation (a pure attenuator cannot do this) and in combination with your IF fiilters for final channel selectivity. That’s what its for. When examining the Yaesu MTU filter shape graph, LOOK AT THE FREQUENCY SCALE CLOSELY.

If the MTU preselector is so wide, why is it tunable rather than fixed?

Because the MTU filters, on all but the very narrow 30M band, have enough additional roll-off at band edges (typically 6 db) beyond their insertion loss to be perceptible within the ham band in use. This can be tuned out. If the filter was fixed, the operator would have to live with about twice as much loss at band edges. CW operators, in particular, would not be happy.

Do the MTU preselectors improve signal to noise ratio (SNR)?

Yes, they do. Because much less additive noise and interference is actually making it past them into the active electronics of the receiver. In essence, the receiver noise bandwidth is severely reduced, which reduces noise power into the receiver dramatically, while the signal of interest is reduced in amplitude by just the insertion loss (about 6 db). Note that the NOISE FIGURE of the front end, which is a completely different metric, gets slightly worse, because the signal of interest IS attenuated by insertion loss. To bring it up to its former level would require amplification, which introduces more noise, and this slightly degrades noise figure, which is already quite good in modern receivers. Regardless, in most cases where we have a usable but noise/interference swamped signal, improving the SNR is what “pulls it out of the mud”, with receiver noise figure being a distant second order effect.

So… if MTU insertion loss is only about 6 db, WHY does my S-meter reading drop by 2-3 S-units or more (you’d think this would be about 12-18 db)?

Yaesu S-meter calibration is generally 3 dB per S-unit and does NOT follow the loose “6-dB per S-Unit” meter standard often quoted on-line, so this reflects 6-9 dB of insertion loss in the center of the filter pass-band for the MTUs.

Note that significant out of band noise and interference power can be eliminated by the MTU pre-selectors, depending on band conditions, allowing RF gain to be increased for the key signal(s) of interest within the adjustable MTU pass-band. But even if gain is not increased when using the MTUs, a less noisy signal with a lower S-meter reading and less applied gain can still be much more legible. Skilled operators from days gone by who were used to manual RF gain control knew this very well and used reduced gain as a form of noise reduction.

Why do the MTUs perform better in the lower frequency bands like 160M, 80M and 40M?

160M, 80M and 40M typically have much more background noise and interference than the higher bands, pumping more unwanted power into the receiver front and and (at best) causing desense due to too high an ALC level (to turn down RF front-end amplifier gain) … and … MTU bandwidth is much narrower on the lower bands, making them more effective in limiting noise and interference. The MTU preselectors relatively narrow bandwidth, compared to the receiver’s band-pass filters, lets less noise through, preventing receiver de-sense and preserving dynamic range for the bandwidth of interest. 160M in particular is very noisey - AM BCB interference is just below and lots of man-made and natural noise above that.

Do the MTUs improve receiver dynamic range?

Yes and no. They do not change the dynamic range capability of your receiver at all. But they do limit out of band noise and interference from consuming the dynamic range you do have. In a modern receiver with very good ALC action and wide dynamic range to begin with, expect a modest but real improvement. In receivers with broad front ends, limited dynamic range and limited analog/RF gain/ALC action, the improvement will be more dramatic. Perhaps for this reason, MTU benefits appear to have been more pronounced on earlier Yaesu Tranceivers.

MTU UNIT MEASUREMENTS:

Now, here are a few actual measurements of MTU performance, done with a spectrum analyzer/tracking generator to evaluate -6db bandwidth, insertion loss, in-band roll-off and ultimate band-to band rejection. Both signal source and load impedance were 50 ohms and coax jumper loss and tilt (which was pretty small anyway) was calibrated out before testing. Note that the MTUs have RCA jack RF inputs and outputs.

MTU-160 - Insertion loss at 1.9 MHz: 6.3 db, -6db bandwidth: 45 KHz, Additional attenuation at band edges when centered in mid-band: >17 db, AM BCB attenuation: >28 db, 80M band attenuation : >34 db.

MTU-80/40 on 80M- Insertion loss at 3.75 MHz: 6.2 db, -6db bandwidth: 110 KHz, Additional attenuation at band edges when centered in mid-band: >17 db, 160M band attenuation : >42 db, 60M band attenuation: >29 db.

MTU-80/40 on 40M- Insertion loss at 7.15 MHz: 5 db, -6db bandwidth: 254 KHz, Additional attenuation at band edges when centered in mid-band: >7 db, 60M band attenuation : >30 db, 30M band attenuation: >27 db.

MTU-30/20 on 30M- Insertion loss at 10.125 MHz: 6.1 db, -6db bandwidth: 233 KHz, Additional attenuation at band edges when centered in mid-band: >0.5 db, 40M band attenuation : >36 db, 20M band attenuation: >31 db

MTU-30/20 on 20M- Insertion loss at 14.16 MHz: 6.1 db (not possible to set MTU exactly on band center), -6db bandwidth: 359 KHz, Additional attenuation at band edges when centered in mid-band: >5.1 db, 30M band attenuation : >35 db, 17M band attenuation: >28 db.

As with any amateur review, this is my experience and opinions only, and as I’m not blessed with the divine characteristic of perfection, errors may exist in this write-up. Tests were casually done, out of curiosity, and made available to the community as they might be useful to those considering Yaesu MTU purchase (there is a lot of confusion regarding them). This is not an exacting evaluation, nor does it pretend to be.

Best Regards,

Brian – K6BRN
KB6HRT Rating: 2022-12-03
Work's for me! Time Owned: more than 12 months.
Have had a FTdx9000MP from before C19 and it was the 2nd Ftdx 9000 I have owned, GREAT radio for sure, my FTdx9kmp went down about a month ago so its going back to Yaesu next week for repairs, so I have used the Mu tuning units for improving signal to noise ratio on weak signals, that works for me big time, am and older HAM with poor hearing, this help me stay in the game,
Using The FTdx5000 a very good radio in its own right
added a 40/80 Mu tuning last weekend, and the FUN in HAM radio is back, the MU 80/40 unit has made the difference in Q5 copy for me for sure, makes the Ftdx 5000 sound much like the FTdx9000MP but with out the extra 200 watts........73s.......kb6hrt
KE7TRP Rating: 2021-03-16
Shocked at lack of knowledge for reviewers Time Owned: more than 12 months.
These are preselectors. I am shocked at the outright lack of knowledge by some of you reviewing these. These are high Q preselectors. These will not help you on frequency signals or even near by signals, These are made to block out out of band signals for that band. Or possible very strong stations with in the band not not close by. This is NOT A ROOFING FILTER OR SSB FILTER. It will not help in any way if a station is 2 or 3 KC away. Example is broad cast interference from a near by AM radio station. Other examples are DXedpition or contest station with multiple stations on different bands all in the same shack. Why any of you would think this would help you within that band is really a sign of how little most ham radio operators know! That being said, IF you are having interference from a BC station OR another HAM station these will knock that out instantly.
https://youtu.be/F-inSzBKzH8
K1GUY Rating: 2016-03-09
Makes the Yaesu FTDX3000 OUTSTANDING Time Owned: more than 12 months.
lots of controversy around this preselector. it does take time to learn how to use this and 'tune' it. much like the VRF in the old MK5 and in present day Yaesu 5000. Makes filtering on the Yaesu 3000 FAR more effective, and reduces phase noise on a crowded band. it becomes a different radio. i have the 80/40 unit. so i can only speak to that unit. i hear they on not as effective on 30/20. Collins had a great idea when they started the preselector thing. its a keeper. and yes, there is insertion loss which you can make up for by using your pre amp.
K9TWO Rating: 2014-06-17
Great Time Owned: more than 12 months.
Having worked in the two way radio service industry since 1975, I can appreciate the value of a hi- Q preselector and understand their usefulness and how to use them. They reduce broadband noise and give your rig a very high q front end. I use mine with my FTDX-3000 and can hear stations on 40 meters my Icom 7600 cannot hear. I won't go into how to use them since you can do the research on that. Art Collins knew the value of a preselector. Unfortunately, most hams do not understand what they are and how and when they should be used.

73. K9TWO Since 1959
AA6VB Rating: 2013-12-17
OK on signals outside the 25 khz bandwidth Time Owned: more than 12 months.
I have the 160 and 80/40 meter units. The filters are quite wide, about 25 KHZ in fact. The reason many people feel they help is because the filters have so much attenuation (insertion loss) that they fool people into thinking the signal to noise ratio has improved, when the filters really cut down the signal and the noise equally on signals within the 25 KHZ bandwidth. The lower volume creates the illusion the signal to noise ratio has improved.

It is another story if you are bothered by signals outside that 25 KHZ bandwidth in which case the filters can provide some benefit.

These can help, under the right circumstances. Frankly, I don't think they are worth owning and they have never done anything for me since I am not bothered by out of band noise.
N4GG Rating: 2013-12-17
Design issues, disappointing Time Owned: more than 12 months.
First off, the review that gave a 0/5 should be ignored. The call-sign used has no hits on QRZ - this person is never on the air. Or, the call-sign used was someone else's.
Meanwhile, this unit has a design flaw Yaesu won't acknowledge. I have the B unit - it covers 80 and 40. On 80 it works as advertised and it steps along following the radio. The steps are nicely calibrated, the center of the MTU passband is always centered on where the radio is tuned - just like it should be. On 40, its a different story. The MTU tracks, but is always about 5 clicks to the right (up the band), from where it should be. The filter passband is not centered on the receiver passband. You can manually adjust the MTU to center it up, but moving just a few KHz makes the MTU track up the band with you, and it goes to the spot that was pre-loaded and is wrong again. There is no way to calibrate this error out. If you are tuning up the band for DX or in a contest this will add a big operating burden. You will constantly be readjusting the MTU frequency manually. Yaesu says: "Its always centered, that's how its design." Sorry Yaesu, its not always centered and I have the lab data to prove it. Yaesu also acknowledges that they get lots of calls about this - that's not surprising, and that the 160M MTU does it as well. This could be fixed in firmware I believe, if or when Yaesu admits the design has a flaw.

As a filter, its a mixed bag. The filter is about 12 KHz wide, which is quite good. The insertion loss is -10 dB, that's A LOT. On 80 and 40 it probably means moving from IPO1 to preamp 1 on the FTdx5000. The loss is unacceptable for receiving on a K9AY w/o a preamp. Its probably marginal for receiving on a Beverage w/o a preamp. Meanwhile, you probably don't need an MTU on a K9AY, signals are too low to block the receiver. Its a different story on a Beverage where signal levels can be large. Utility is rig dependent. On the 950 and 2000 radios, which have mediocre blocking dynamic range compared to today's best radios, these MTUs will offer an improvement in digging things out of the noise. The FTdx5000 sits on top of Rob Sherwood's chart - it has better blocking dynamic range that anything else on the market (including the K3), except for the KX3, which is a 10W toy radio with other poor specs. The radio is so good its nearly impossible to drive the front end into blocking and the MTUs are no help if blocking has not started. They might come in handy at Field Day or other multi-transmitter sites where front end overload can be an issue.
If you have an FTdx5000, I would skip these. For a 2000 or 950 they will help, particularly if you RX on the TX antennas.

The price? Well, they are expensive to make. Value for the money seems fair. Utility for the money is highly questionable.
K4TB Rating: 2012-08-12
Nice Tools Time Owned: more than 12 months.
I have the 80/40 and 30/20 meter units and have used them with an FT-950 and now my Ftdx5000. They really add an extra layer of QRN protection against both continuous man-made noise and impluse noise like lightning. The improvement in S/N is substantial in those cases. They can also be used to attenuated close-in signal interference but sometimes it takes playing with their tuning and compensating by switching out attentuation or switching in a preamp to get the most out of them. I know they improve parameters like IMD, etc. but no one has published such data to my knowledge. Sort of a throw-back technology to the early days of radio. Guess you don't find them in most radios today because they would greatly increase the size of the radio.
DJ0RD Rating: 2012-08-11
FTdx-5000MP Turbochargers Time Owned: 3 to 6 months.
I have the 80-40 an 30-20 µ tune units installed on my FTdx-5000MP. They make a fantastic receiver even better. Just to prove it, watch the band noise when tuning them. I live in a high RF noise pollution Condo environment and these units pull signals out into the clear, when I can barely hear them without the µ tune. The guy who gave them the bad rating either had other expectations, or didn't know how to use them. Maybe they weren't properly connected? Vy 73 de DJ0RD/WU5T
N0AZZ Rating: 2011-01-12
With Practice these are Excellent Time Owned: more than 12 months.
These worked ok (20-30, 40-80) with both of my FT-2000's but really came into it's own when I hooked them up to my FTDX-5000MP which was very good to begin with. All in all a worthwhile purchase that have given my 4 trouble free years of service. It does take time to get used to using them properly but it's worth it.