I am considering asking Father Christmas to see if he could procure an FT891 for Christmas. This would be a replacement for a well traveled, yet reliable FT857. My main reason for considering this change is the stated FT891 close in dynamic range of 92dB at 2kHz spacing. ( I cannot find the spec for the FT857 but expect it will be in the 60-70dB range). My hope is that using the FT891, it will be easier to separate callsigns when trying to capture stations out of a SOTA pilup.

The downside is the absence of VHF/UHF, but that is not a showstopper for me. However I see that the RX current is advertised as a staggering 2Amp. If accurate, that is a high receiver power draining my battery! Also my FT857 is happy to deliver 50 Watts of CW down to 10.5Volts without duress, can the FT891 match this?

Any experience would be valuable.

David G0EVV

Try this link David


73 Allan

Set up my 891 for digital modes the other day on a shack power supply and noticed at a tx power of 30w on usb it pulls about 8 amps of current, similar to the 857 i had. The 891 is a better cw rig than the 857 and better rx all round compared to the 857 i had. I don’t use these radios for SOTA they are too heavy to cart up a hill as is the battery to run them but I have done several VKFF park activation’s with mine. Great radio for that job, I noticed there are a lot of menu functions required to get it to work on digital modes though even using the scu 17 Yaesu’s dedicated interface. But with perseverance and lots of head scratching you can gain full CAT control of it for digital modes. My reason for not using these radios any more on SOTA is perceived gain of 30w over 10w or even 5w can hardly be noticed compared to all the extra weight of radio plus battery to run it in my back pack.
Ian vk5cz …

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That right Ian

5w to 20 watts is 6db or 1 S unit and the same if we use a 20w radio and 80w

If weight is important then yeah leave that heavy beast at home but if SSB is your choice then the extra boost is handy and worth the extra weight in my mind

According to the video, 1 amp on rx.

Hi David,

A choice would be a lightweight 5W transceiver (FT818 or SRD) with low power consumption in receive mode combined with a cheap (far east) 35 W amplifier.
Of course you would have two pieces of equipment to put in the bag instead of one.
For SOTA I try to keep weight as low as possible.


“My hope is that using the FT891, it will be easier to separate callsigns when trying to capture stations out of a SOTA pileup”

Hi David,

if you are struggling a bit with CW pileups a far more cost effective solution might be to download Morse Runner and Pileup Runner. Both these progs allow you to set the number of stations calling you and even introduce qrm and qrn. A bit of daily practice for a few weeks and you’ll be working down the pileups without spending lots of cash on a new rig. The difference in dynamic range between one rig and another is not going to help on a typical SOTA pileup , well not that you would notice.




It is funny how that idea that one S point equals 6dB has persisted. I don’t know of any modern transceiver where that is true. The performance of the S meter is measured in the big Radcom reviews, and this is what they give for a random selection of recent transceivers:

FTDX101D 2.5 - 3.0 dB
IC9700 - 2.5 dB
TS890S - 3.5 dB
IC7610 - 3.0 dB
IC7300 - 3.0 dB

and germane to the discussion, FT891 - 3.0 dB.

This means that in practice with modern transceivers, 5 to 20 watts would show as 2 S points increase rather than one.

Going back to the video, I was disappointed that it only showed the current consumption for it with the audio blasting full out on the speaker, I think most of us would use headphones on a summit both out of consideration and to combat wind noise, and I would expect current consumption to be significantly lower, as it is with the FT857D. The FT891 looks a good rig, if and when my FT857D expires I would favour the FT891 despite the lack of VHF.

KX2 and a PA would be my choice if this was ever going portable. Not necessaryily an Elecraft PA though.

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I agree with Dec EI6FR, in terms of pileup mush better dynamic range wont help you. Its a result of almost all callers being bang on frequency (their radios all have a TCXO and a CW tuning display), very effective AGC’s that give you constant audio level S1 to S9+60 and probably unknown funnies in the DSP.

Morse Runner sessions + try turning the AGC off. On CW I always run my KX2 with AGC off, with the audio limiter on to protect my ears.

73 Gavin


I feel that my reference library of ARRL Handbooks need to be tossed

If the shift is to 3db then 2 S units it is

I will break out my generator to confirm S9 = 50uv

Now I know why my 7610 is always 5x9 plus 40 and my Drake C line is so stingy


I did a bit of quick Googling on this. As recently as 1981 the IARU in Region 1 made a technical recommendation that S9 = 50 microvolts, amounting to S points being equivalent to 6 dB, this following the informal practice of major American manufacturers. However the majority of modern transceivers are not made in Region 1 or the USA and it appears that the “big three” have settled on S points being in steps of ~3 dB. This, as you say, explains the difference between your 7610 and your Drake C line!

Hi All,
Thanks for the comments. Thus-far there seems to be little experience of using the FT891 in the field.
Yes the last few seconds of audio on the video suggests that when the audio amp is only supplying headphones or ear buds, the quiescent current will be <1 Amp. That is good, I can cope with that.
Regarding the ability to operate down to 10.8 Volts on the supply rail, that seems to be unproven, but I know a ham locally with an FT891 so a real test is possible.

Regarding the close in dynamic range, once upon a time I had a TS520. That has a measured Dynamic Range of 52dB. It had the worst RX I have ever owned. By comparison, at home I use a TenTec Orion II. This rig has a measured close in Dynamic range of 95dB. In comparison tests on busy frequencies it is chalk and cheese with the FT857.

I agree that the root cause of the difficulty is separating Sota stations in a pileup is unique to the way we advise our QRG. The callers tend to be nearly coherent and no matter what the dynamic range will we split them up. Roy G4SSH with a lot more experience of CW operating always called me a few 100Hz off frequence, sneeky but effective. That said I would like to try an FT891 in field conditions to see how it performs. The other alternative, as discussed, is the KX3, or similar, with a measured dynamic range of 107dB, I believe this has the best RX measurements for any portable rig.

I take on board the need for self training for picking out calls, that is a good line to go down. Remembering the frequent chaser calls is also very helpful when filling in the gaps. SP9A** , **0B and ***LEY being examples.

PS, I am a Yorkshire man by birth so I have a built in adversity to spending money, particularly my money!
Thanks for the information most appreciated. Watch this space.


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Made some quick measurements with my KX2:

The S9 reading corresponds to 50 uV (or - 73 dBm) input signal with the preamp on.
On the 80 m band between S8 and S5 the were 3 dB steps, otherwise 6 dB.
On the 40 m and 20 m Band I measured 6 dB per S-unit from S9+6 db down to S 5.

73, Peter

A particularly stupid characteristic that people from Yorkshire are proud of.

You worked all your life and now you are retired, so spend the money on something you want and enjoy it whilst you can. The alternative is to die richer and end up a rich man in the graveyard. Then your family will spend what was your money and laugh about how you could have enjoyed it but didn’t because you were a Yorkshireman. As they merrily open another bottle… :wink:


What a depressing view of family life! Equally he could die happy that he has passed wealth on to his descendants, if the government leaves any, that is! Now my view is buy it because its second hand value will be fairly high so you could enjoy it and then sell it and get the next enticement!

I don’t think dynamic range has much to do with separating signals that are close together. If the signal you want to hear is weaker than the interfering signal, any receiver will simply replicate that situation in your ears. The only way to separate them is by frequency. AGC will make the stronger signal sound stronger, and the weak one will be dimly in the background. I don’t see that as anything to do with dynamic range.
Plenty of dx was worked in contests using a ts520. Separation by frequency and concentration, and a lot of practice are the key factors in hearing weak signals IMHO.


I use the 891 for nearly all my chasing. It’s installed in my vehicle and does fine despite the fact that it’s common for temperatures inside to exceed 100F in Arizona. I have not measured current draw on rx but it definitely drains the 12Ah battery that I use every couple of days, so I assume it’s fairly high.
I especially like the easily adjustable bandwidth, which I normally set at 200-300 Hz which increases the SNR of cw signals nicely. I replaced the 857 with it and I think it’s much better for my purposes. It was also fairly well priced compared to other small HF rigs.
I have not tried to haul it up a hill but I think it could be a nice rig for activating as long as you don’t mind the weight including an adequate battery.

73 de Keith, KR7RK

Morning David

The FT-857 has the option of installing a narrow Xtal filter (500 Hz bandwidth or less) for CW. Does yours have one? Necessary in my opinion for activating SOTA. The extra power over the basic 5-10 watts raises the size of the pile up, especially on the 40m band. If the filter is not fitted you would get at least as much benefit from installing one than changing the radio for the newer architectured FT-891.

The FT-891 relies solely on DSP for narrowing the bandwidth to a similar level or better than the Xtal filter does. There is no provision for installing an Xtal fillter in the FT-891.

I believe the variable DSP is very effective on the FT-891 at narrowing the bandwidth for CW and the March 2017 review in Radcom by Peter Hart G3SJX reflected this.

73 Phil G4OBK

It is worth pointing out that the FT857D also has a DSP peaking filter for CW, with selectable bandwidths of 60 Hz, 120 Hz and 240 Hz. I’m not a CW operator but I have tried it out and it seems very effective, certainly better than the 500 Hz filter on my TS520S. From what I have heard, where the FT891 improves on the FT857 is in its rejection of adjacent channel interference problems.