FT8 power level

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Just wondering what power levels everyone is using for FT8. I keep it low but I'm not sure how low it should be.

Also, I had to add a mapping for FT8 to DATA in TSQL to get it to upload to LOTW.
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Pat

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Posted 11 months ago

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Bob G W1GLV

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Pat, I use between 5 and 10 watts with any of my wsjt transmissions.
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Pat

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thanks Bob
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PA1EC

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25 watts max
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Paul Mandel

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2-3 watts
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YV5WZ

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25 watts for all wsjt-x
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KY6LA - Howard, Elmer

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60-100W depending on the signal of the receiving station

Found I needed close to 100W for reliable connection with weak stations below -17

Like JT65 I do not th9nk FT8 is a low power mode.

Did some tests on FT8 using pskreporter.info at different power levels to see how far I am heard. Not to my surprise I went much farther at high power than low power of say 25W.

Suggest you run similar tests
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Kevin - KS0CW

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Makes sense, it’s my understanding FT8 is a “weak signal” mode that some equate to being low power.

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KY6LA - Howard, Elmer

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I think this erroneous concept of using low power is a hold over from PSK31 days where the 3rd order IMD products swamp the signal and decrease decodes using power levels over 25W

JT65/9 are definitely NOT low power modes.. but as you said they are weak signal modes.. which many erroneously assume to be equivalent to using low power,

My experiments with FT8 also show that it is also NOT a low power mode

To test this out

Work a QSO at say 10W, then another at 25W and finally one at 100W

Then lookup your call on pskreporter.info and you can easily gauge how much further your signal goes when you increase your power.

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Bob G W1GLV

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Howard, I've made contacts in Australia using about 7 watts.
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KY6LA - Howard, Elmer

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Obviously the propagation gods were favoring you that time... But realistically when I see a FT8 contact with a -17dB or worse there is no way in heck he is going to decode me with only say 10 or 20W... you need to crank up the power yet still NOT overdrive the audio (so its clean) to work the weak ones...


Bob

I am an empirical rather than a theoretic person


Call CQ at different power output levels and look at your propagation on psekreporter.info   You may be pleasantly surprised at how much further you are heard when you crank up the power...

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Mark

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Howard,
I live in an area north of Phoenix where all the hams have got into these modes now. They run at least 100W. Guess what happens? The band gets swamped! 6M becomes unusable when openings happen. I disagree with your recommendation for 100W. It is definitely low power, if your are going to operate anywhere near other hams. Radios are not built for the wideband requirements of these modes and in turn be able to quickly tune an IF to reject the neighbors.
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Ria - N2RJ, Elmer

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I use legal limit on FT8 all the time. These modes were built for weak signal EME and meteor scatter, therefore high power is perfectly acceptable. That said, you use the minimum to carry out the desired communications. I start with 50 watts and increase up to 1.5kw if necessary. I have worked as far as Indonesia and Japan from my station on FT8. 
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Ned K1NJ

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   My first and only  -24 -24 contact was on 80m with a Ukrainian station.
I was running 250 watts.  Another kw or so would have been needed for
more than a simple exchange.

                      Ned K1NJ
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W5XZ - dan

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how do you get down to -24???  i rarely do better than -20 on 160m..
 with agc off, and wnb / nb sometimes, maybe...

73, w5xz
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KY6LA - Howard, Elmer

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1.84 RC3 will go down to -24
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W5XZ - dan

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howard, i've knocked aroung the wsjt-x site, but for the life of me i can't locate 1.84, rc3...any tips?

73 w5xz, dan
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KY6LA - Howard, Elmer

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This is the latest release as at 10.27.17.. which is later than RC3

https://physics.princeton.edu/pulsar/k1jt/wsjtx-1.8.0-win32.exe

(Edited)
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Ned K1NJ

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   [Above is from yesterday on 80 meters]

                Don't be too concerned.  I downloaded the latest version (post RC3)
  this afternoon and let it sit for a few hours on a dying 10 meter band. I would
  be sure to have gotten some weak signals on a band with a low noise level.
  I only got one signal at -21 and no lower.  Perhaps the method that computes
  signal level was refined or otherwise changed in some way.  You may be detecting
  signals just fine, yet getting different numbers nevertheless.
               Ned,  K1NJ
 
(Edited)
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Ned K1NJ

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                    Well, it's probably not a calculation change.  Above is using
the latest version.  When I set up to actually "work", I set to receive
"on the knee".  When I set up for 10 the other day, I may have just
plunked it down.  Tim has instructions elsewhere on how to do this.

                Ned,  K1NJ
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KB4AAA

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Yeah I had to run 65 watts yesterday propagation was bad. At 50watts nobody would respond at 65 I was working a pile-up calling cq LOL   I had 3 lined up at the same time and worked all 3 in less time then 1 exchange on jt65. It keeps you on your toes trying to keep up.
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John - K3MA

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As much power as you need to make a reliable contact.  Same as any other mode.  What is more important is to ensure your TX signal is clean.  Ensure your TX level out of the Flex never exceeds 0 db (Scale above compression) and your amplifier (if used) is properly tuned and clean.  To lower TX level you need to adjust TX Gain slider on the TX DAX Control panel if you did not already know.
(Edited)
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Ken - NM9P, Elmer

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There is definitely a difference between a "weak signal" mode and a "low power" mode.
Low power modes are designed to 1) save electricity, 2) reduce RFI, 3) be undetectable for covert operations, or 4) give hobbyists something to do in their excess spare time.  (I jest...I love QRP ops, too.)

But weak signal modes are designed to: 1) maintain communications when band conditions are poor, 2) enable communications via meteor scatter, moon bounce, or during times of wide and rapid signal facing.  3) enable communications at the extreme ends of the radio spectrum when power and/or antenna construction is technically difficult or expensive, 4) extend communications at the beginning and end of normal band openings when signal strengths are weak.

There are additional comments that could or will be made, I am sure.

I also add a third category to the mix -- Narrow bandwidth modes.....
These are modes that may be either low power or weak signal modes, but one of their attributes is also that they take up much less bandwidth than some other modes....

e.g. JT9 takes up about 10% of the bandwidth as JT65 or JTDX, without sacrificing much of the weak signal performance.  Both of the modes take a long time to transmit, and have a limited message length - a trade-off for weak signal performance.  

PSK31 and its cousins ave very narrow bandwidth, with unlimited transmission and message length.  PSK31 used to be seen as a weak signal mode, until the JT's came along.  But it is one of the best weak-er signal modes for general conversation.

MSK144 is a great weak-signal mode, but takes more bandwidth than either JT65 or JTDX.  

FT8 is a sort of compromise - 4-6 times faster than JT9/65, but still with limited message length.  It is a little wider than JT9, but about 9 dB less sensitive than JT9/65 or JTDX.  (-20 vs. -29 dB)

But it is a lot of fun.

The first requirement is to make sure you have a CLEAN signal...i.e. check that you are not overdriving the TX audio input.  If you are overdriving either the TX input or your amplifier, you will get poor results.

Then gauge the band conditions...use all the power you need to make the contact, but not more, so you won't cover up other weaker stations.  That is common courtesy.  But if you need more...turn up the wick!
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Ria - N2RJ, Elmer

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50 watts on 6 meters.
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Ernest - W4EG

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As someone said already: As much as it take to communicate with the station you are interested in working.
However, for me, my maximum is 100 watts out of the F-6700 and a Hy-Gain-18HT in the midst of very tall bamboo trees in a HOA and CC&R's.
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Andrew O'Brien

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There is no need to be concerned with "power" level for this Joe Taylor mode , no more than you would for any other digital mode. Set your Flex transmit levels the same as you do for other digital modes and tailor your output power for sufficient power to make the contact.  Obviously, keep transmit DSP OFF.
Andy K3UK
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Ria - N2RJ, Elmer

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Use DIGU and all audio DSP is turned off.
(Edited)
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Carlos Styl

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5 - 10 W 10m
10 - 5 W 15m
10 - 20 W 20m
20 - 50 W 40 m
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W5XZ - dan

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1kw on 160m...just saying

73, w5xz
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Mark WS7M

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Like Howard as much as I need to.  Start low, add as required.

There are a number of ops that seem to think they are signal monitors and will send you little snippets like "wide signal" or "dirty signal" when actually you are just very strong to them.

I was running 120W one day and kept getting this "dirty signal" from a guy.  I checked the mod and it was all looking good.  So I asked him for a screen shot.  He emailed me something from a generic SDR program that looked normal.

I emailed his signal image back side-by-side with mine so show that they looked the same.

Anyway everyone is now an FCC monitor I guess.
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Ria - N2RJ, Elmer

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Sometimes even running 5 watts I would get the occasional "25W DIP" message. People don't understand that I run large high gain antennas and as such I will be loud at any power level. But sometimes I get that some want to knock you down because they view gain or power as being "unfair." When these people are hanging off a tower with a crane and 200lb weight hanging over their head they can talk...
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KY6LA - Howard, Elmer

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Many beginners still misunderstand that JT and FT modes are weak signal modes NOT LOW POWER MODES. Sure you may seem strong to the guy next door but to work that -24 signal you need all the power and gain so he or she can copy you.

As I said. Look at PSKReporter.info to see how far your signal is being heard and adjust your power accordingly
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Bill W2PKY

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A few years back when propagation was better 34mw was spotted all over the continental US and 1W could get me to EU on 15M.  But usually run much more to make Qs more reliably. 
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K1UO - Larry

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Right now it appears that -17 is about the level that is the turning point of a Q or not (usually not) and that is with my 6700 at 80 watts , a long coax run and vertical antennas for any of the HF Bands is all the hardware at the remote site..  At this point I can either give up or turn on the new PGXL.  (NOPE..  its still not here!)  You can bet on 160 I will use more than 80 watts as China is the last Zone needed...  just saying....
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George Molnar, KF2T, Elmer

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1.21 Gigawatts. Anything less and my time sync is messd up.
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Tim - W4TME, Customer Experience Manager

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ha ha
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mikeatthebeach .

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500 meter Parabolic Dish for 20meters Hi ! Hi

< 0.001beamwidth 
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Mark

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This is a low power mode. Simply, it is a "wideband" audio mode. The radio IF has to  be "wide" open to gather data across the "channel". Those running high power will normally desense other lower level signals in receivers. More power, more adjacent interfering signals being created. You can't have wideband audio in a mode like this and think that using a narrow IF filter or audio filter scheme to reject interfering high power stations will work.
I live near many hams that destroy great 6M openings, as they turn on at least 100W or higher "kickers" to burn out a signal and unknowingly (intentionally?) wipe out any chance most of us have to hear anything.
But, if you just jump (hog?) on a single frequency, narrow down your receive audio and IF on your "claimed spot" and then use with high levels of RF, then you can own it and at the same time lose the admiration of other Hams in your area.
In short, PLEASE TURN DOWN THE POWER! The mode handles signal to noise beautifully!!!!!!! just not QRM using the same mode in the same bandwidth.
(Edited)
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KY6LA - Howard, Elmer

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NONSENSE...


This is a WEAK SIGNAL MODE... NOT A LOW POWER MODE

Please do not confuse JT or FT modes with a low power modes like PSK which are easily overwhelmed by 3rd order IMD.


If you are trying to work a very weak signal (-24dB on FT8) you will LIKELY need all the power you can put out so that they can hear you. 

That said, I have no issue with reducing your power output to a level so that you do not overwhelm nearby legacy radios...

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mikeatthebeach .

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Usually the Bandwidth is < 50Hz and agree it is weak signal 
When I text message those in Europe I never get back to from
North America (here). Some are running > 1Kw and Big Beams 
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Ria - N2RJ, Elmer

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I run high power all the time and nobody complains. I also struggle running low power because the other end of the QSO may be low power and indoor antenna... which usually doesn't work unless you have outstanding solar conditions. 

Right now running on 30m 200 watts FT8 into 3 elements beaming europe...
(Edited)
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Mark - WS7M

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Like Howard.... I run as much as I need to for the conditions. Yesterday I snagged Netherlands Scotland England and Indonesia on 20 using 75 watts.

Today I worked Ria N2RJ on 5 watts but right after that for me things died and I needed 100 to reach CA and none of the Europeans I was seeing were hearing me.

There is a mexican station I see sometime and I was able to measure his signal at 45 over. Probably running 50 kw LOL.
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Ria - N2RJ, Elmer

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I think I was using 500 watts when I worked you. I also worked Japan and a bunch of other DX. 
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Mark WS7M

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Well your signal was huge.  I was playing with different powers to see what worked.  I was surprised you came back so quickly
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Ria - N2RJ, Elmer

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Auto seq and call 1st. Skynet called you, not me.
(Edited)
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KM6CQ - Dan

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Joe Taylor has already defined this mode for us.  Here is what he has said about it. "These modes were all designed for making reliable, confirmed QSOs under extreme weak-signal conditions." This is taken from the WSJT webpage. When we read the whole description in context, we discover that there is no mention of ERP, Watts or even transmitter adjustments. We then learn the WSJT suite is comprised of many modes and they are referred to as weak signal modes. The definitive answer to this discussion is W (Weak) S (Signal) J (Joe) T (Taylor). It's all in the name.

Let's not lose sight of how much fun these modes are. Thank you Joe Taylor for many, many, many, enjoyable Q's. 

73, Dan KM6CQ
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Mark WS7M

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Goodly put Dan!   Long time no talk!
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Ria - N2RJ, Elmer

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Dan this is very true, especially since the JT modes were originally invented for MS and EME. Low power is NOT used in those activities!!!
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Alsawadi Telecom

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Low power transmitter will produce weak signal at the other end. So, what is the difference !
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Jim KJ7S

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Short and sweet thought on Power levels with WSJT-X, or any other "weak signal" mode:
Although the statement reads "weak signal" copyable, it works out with the rx station. If the rx station cannot hear you at your 30 wt signal tx level, and cannot hear you at 70 or 100 watt tx level, but can hear you at the threshhold of say -20db at a 275 wt tx level, that is "weak signal" on the rx station, is that not reasonable?
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Mark WS7M

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Well said Jim.

I personally start at 20w.  If I don't get the contact I go to 65w.  The move up from there.  

Usually I can look at the snr of the station I want and get a reasonable idea of the power I should try.  If the station I'm trying is -12 or so I can usually reach them with 65w or maybe 100w.

As soon as the remote station starts to get down around -18 or so I almost always need to crank things up to like 300w to get through.
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mikeatthebeach .

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See a couple of stations, one in Vietnam & one in China on 17meters running 1Kw on FT8 and never can get back to them with my little 30Watts of Power Out !

Texted them via JTAlert messaging and asked what their Power Out was on FT8  !!

They would call CQ forever and no one would get back to them !!

Oh Well !! 
(Edited)
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KY6LA - Howard, Elmer

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Easy to work them with 1KW+
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Mike W1BFA in Maine

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I typically run 45-50 watts on FT9 and other digital modes.  I think as FT8 has gotten more popular and busy I am seeing a saturation of the spectrum slice we are using and QSO success dropping off.  I tend to migrate onto the marginal propagation bands for that reason and have better luck.  It is fun to operate but I find myself going up into the phone band for a little human contact.  :-)
Mike  W1BFA
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mikeatthebeach .

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Well, maybe it time to go back to CW !

73 Mike
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KY6LA - Howard, Elmer

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Typically my 6700 hears Legacy DX about 3-6 dB better than they hear me if I am running the same power as they are. So to compensate for their poor reception I find it necessary to increase power.

Further by the time I hear the DX itself below about -18dB I find that I need at least a KW for them to hear me.

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