I'll be darned if it didn't just happen again. Could barely hear S5100ANWW at my QTH in noisy Seoul, on my Icom 7300. Tweaked the daylights out of the radio, too... Twin PBT, bandwidth filter, unlocked the AGC... couldn't copy him. Switched over to the FT-891, and was just able to pick him out. Switched back and forth. Same thing. Probably related to front end and how the two radios handle noise, but loving this inexpensive little FT-891. My receive experiences are flying in the face of what all of the stats and hype say about the 7300 -- I realize that.
HI Jason! Nice to see U here!!! what in the world are U doing in VA?? Thought U were still in San Diego!
That's the kind of stellar product support we have come to expect from ham vendors. Thanks for trying, though.
Hello, Leaving aside the opinions on the FT-891, which does seem a good compromise and good value, there seems to be a lot of confusion here between TX phase noise and TX harmonic spur performance. I think Bob Allison's review comments are being taken out of context. Allison stated that the rig has low harmonics and spurs, and that this is neighbor friendly. This is very true for frequencies a good distance away from the TX one (i.e. harmonics) and also for sharp spurs at close-in frequencies. However, it would be a mistake to assume that this sentence applies as well to the close-in noise provided by the poor TX phase noise problem. It does not. (Bob's choice of words here are probably not the best.) TX phase noise is not "good neighbor" but in a different way, as it addresses a broadband effective raising of the noise floor for others nearby when you are transmitting in a crowded band. It is impossible to fix without ripping the oscillator out and putting in a new one (as oscillator noise is the most likely source). BTW, the phase noise is exactly the same effect as frequency modulating the oscillator with noise. Of course, these effects will not be apparent to you the user, because it is only happening when you are transmitting. Its effects are equivalent to a dirtier oscillator for every close-by RX. Finally, let's put some numbers on it. The 1988 two part QST article referred to earlier in the thread is an excellent one and well worth your read. In particular, Table 1 shows you that at an EIRP of 50 dBm (100 W), a maximum tolerable phase noise level at 20 meters band that will not cause a noticeable raise in RF interference for a receiver located 1 mile away is about -140 dBc/Hz given typical HF band noise. I agree with this value having done measurements and calculations independent of the article. The FT-891 review quotes -116 dBc/Hz as the measured phase noise at 10 kHz offset. -116 + 140 = 24 dB or a 4 S-unit increase. Therefore, if you are transmitting and your spectral neighbor is 10 kHz away and within 1 mile of you, he/she will see a 4 S-unit increase in noise every time you key up. I would factor this into your decision. Perhaps you care, and perhaps you don't. However, in an urban setting or a crowded contest time on a particular band, I would think it would not be great to the band neighbors. FYI, I do not own a FT-891. But if these calculations are wrong, then Nyquist-Johnson noise formulas do not work, the Friis transmission formula is broken, and Maxwell's laws break as well. I'll vote with them.
My issue that I have tried to make from the beginning, but might not be doing a good enough job, is that IF this radio IS in fact as noisy in transmitting that it appears to be, then we - as hams - should be concerned. Receiver performance that you are discussing, and how it compares to your 7300 is something we hams spend a lot of time debating and measuring. The Sherwood "list" is often quoted regarding receiver performance between radios, which is "better". However, a radio's receiver performance only affects you as the user. If you have a stellar receiver, or crappy one, is something that affects YOU. Transmitter performance, however, affects others. Because of this, I am dismayed that Yaesu has shipped a new radio with transmit phase noise that the ARRL described as the "highest they have seen" in the lab. That's the only point I am making - the price looks good, form factor, etc. I would have expected that radios TX performance should be improving, not sliding backwards. An analogy might be new car emissions - we expect (due to regulations) that newer cars pollute less than older cars. And that is what this amounts to - RF pollution. I think it's something folks should be aware of, and make a conscious decision about. That is all.
This is very well put, and I applaud KV6O for bringing up the subject. It's also important to realize that the pollution is a relative thing and decreases rapidly the farther apart you space the TX and RX by the square of distance - there's that Friis formula again. So in my calculation, if the RX and TX separation increases to 20 miles instead of 1 mile, this would not be discernible above the noise floor from the universe and also the atmosphere. It also depends on the direction the energy enters into the RX antenna and other things. But to say that TX phase noise specs are "signal purist snob" measurements is disingenuous and ad hominem, and contributes nothing to the evaluation of merits and disadvantages. Unfortunately the commercial YaeIcoWood manufacturers still have a ways to go in ensuring that all (not just some) TX have good phase noise for good RF neighborly behavior.
I see a lot about TX noise....at fd17 we had my station (891) in a tent with our 20/80m station not 3 feet away. He noted almost zero noise gain when I TXed. He did notice some but the level was so low he didnt know until I asked is it coming in. I ran everything from cw to digi, we were both very impressed with the rig. A year or 2 back we had another digi op and everytime he would call cq he would wipe out all 5 other stations.....this year we had zero of that. Read what you want think what you may but the use of the rig and the paper stats don't match very well. I am still blown away by the front end on this rig, for what it is and what you pay the only thing I hate is yeasu tech support thats a joke. 73 David
I think you're missing an important point. You say that at FD 2017 you had an FT-891 in the tent with the 20/80 station. Fine - but what band was the '891 on? The TX noise being discussed is for rigs on the same band. If you were on 40.....
