Ideas for an FT8 Radio

[Jim Brown-10]

On 1/2/2019 2:56 PM, Carl J. Denbow wrote:
> While it's legal to run maximum power on FT8, or any other weak signal
> mode, it's certainly not in the spirit of the weak signal mode ethos
> Most weak-signal mode enthusiasts pride themselves on the worldwide
> contacts they can make with low wattage.

You are confusing "weak signal" with QRP. "Weak signal" means signals
are weak thanks to the mode of propagation and/or because it's a
difficult path. WSJT-X modes like FT8, JT65, and JT9 are designed for
that sort of communications -- long distances on 160M (4,000 miles and
up); E-skip, long distance tropo and moonbounce on 6M, and so on. These
modes are also useful if the station on the other end has a lot of
receive noise, and most of us do nowadays.

The moderate power levels you are espousing ARE appropriate on the HF
bands with decent antennas and moderate noise levels. BUT -- when I'm
trying to work 6,000+ miles on 160M, I run legal limit into very good
antennas, because that's a difficult path. AND -- even with that, I
often get much weaker signal reports than I transmit, often in the range
of -20 to -24, which means that I'm certainly not using too much power!
Last night on 160M, I tried for most of an hour to work an SV2, who was
6,600 miles from my QTH near San Francisco. For most of that time his
signal was weaker than -20.

73, Jim K9YC



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[Bill Frantz]

I thought I would look through the high power QSOs in my log for
Los Gatos, CA to find what I do, instead of what I think I do. I
found that I use high power for:

   The Elecraft SSB net: I frequently need a relay to reach Chicago.
   DXpeditions: Minimizing the time for my QSO lets others make
their QSOs
   Contests: Particularly when entering the contest to work DXCCs
   FT8: I have a number of Rx -24 DB contacts. My only 3W QSO
has -17dB from @800W.

At the other end of the power spectrum, I have a QSO with a V3
at 1.4W and 5W contacts around the world. (Many of these were
back when there were sun spots.) All my contacts from New
Hampshire were with 10W or less, most 5 or less. These contacts
include a useful number of DXCCs. I do play QRP as well as QRO.

I also admit that when I got my amp, I was a kid in a candy
store. I used it, perhaps at times when I didn't strictly need it.

It is obvious from this data that I clearly think that all's
fair in love and DX. Also, I should take a careful look at my
transmit antennas. I also act as if I believe that using enough
power to make the QSO is a valid way for a ham to operate.

I will close with the thought that working EME is certainly a
weak signal mode, and that it frequently takes a kilowatt to
play in that league.

73 Bill AE6JV

On 1/2/19 at 2:56 PM, [hidden email] (Carl J. Denbow) wrote:

>While it's legal to run maximum power on FT8, or any other weak
>signal mode, it's certainly not in the spirit of the weak
>signal mode ethos  Most weak-signal mode enthusiasts pride
>themselves on the worldwide contacts they can make with low
>wattage.  Many feel that 100 watts is QRO on these modes.
>Personally, I usually run about 35 watts, but I've had QSOs
>with stations in far-flung regions running power in the
>milliwatt range with a dipole up 20 feet.  That's the real
>attraction of these modes to many. And, until the advent of
>FT8, you heard very few stations running more than 100 watts on
>these modes.  FT8 seems to have attracted a whole different
>crowd.  Some of these, I think, view FT8 as a "the new RTTY"
>and operate according to the accepted operating procedures of
>that mode.  I view this trend as very unfortunate.

-----------------------------------------------------------------------
Bill Frantz        | I don't have high-speed      | Periwinkle
[phone]      | internet. I have DSL.        | 16345
Englewood Ave
www.pwpconsult.com |                              | Los Gatos,
CA 95032

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[Ed Muns]

+1

Thanks for clarifying this common myth.

Another common myth is that QRPers must use compromised antennas.  Many
times QRP and marginal antennas and marginal locations are common but its
not a requirement.  There are a number of QRP enthusiasts who use big
antenna farms.

The JT and FT modes simply allow another level of participants to operate
because decoding is reliable at many times lower signal levels than CW and
SSB.  Power is only one of many factors that contribute to signal strength.
If FT8 combined with one's QTH, antennas and path require more than QRP,
even 1500 watts, so be it.

The FCC got this right many decades ago when they set the amateur rule that
we use only as much power as necessary for reliable communication ... up to
a maximum of 1500 watts.

Ed W0YK

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Jim Brown
Sent: Wednesday, 02 January, 2019 15:19
To: [hidden email]
Subject: Re: [Elecraft] Ideas for an FT8 Radio

On 1/2/2019 2:56 PM, Carl J. Denbow wrote:
> While it's legal to run maximum power on FT8, or any other weak signal
> mode, it's certainly not in the spirit of the weak signal mode ethos
> Most weak-signal mode enthusiasts pride themselves on the worldwide
> contacts they can make with low wattage.

You are confusing "weak signal" with QRP. "Weak signal" means signals are
weak thanks to the mode of propagation and/or because it's a difficult path.
WSJT-X modes like FT8, JT65, and JT9 are designed for that sort of
communications -- long distances on 160M (4,000 miles and up); E-skip, long
distance tropo and moonbounce on 6M, and so on. These modes are also useful
if the station on the other end has a lot of receive noise, and most of us
do nowadays.

The moderate power levels you are espousing ARE appropriate on the HF bands
with decent antennas and moderate noise levels. BUT -- when I'm trying to
work 6,000+ miles on 160M, I run legal limit into very good antennas,
because that's a difficult path. AND -- even with that, I often get much
weaker signal reports than I transmit, often in the range of -20 to -24,
which means that I'm certainly not using too much power!
Last night on 160M, I tried for most of an hour to work an SV2, who was
6,600 miles from my QTH near San Francisco. For most of that time his signal
was weaker than -20.

73, Jim K9YC



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[Neil Zampella]

Carl,

you tell that to Joe Taylor, who himself has said he uses the power it
takes to make the contact, especially on EME and Meteor Scatter. It is
not a low power mode.  For some people using 500w from California
results in a - 19 report from  Israel.    That is a weak signal.

You use what it takes to make the contact.

Neil, KN3ILZ

On 1/2/2019 5:56 PM, Carl J. Denbow wrote:

> While it's legal to run maximum power on FT8, or any other weak signal
> mode, it's certainly not in the spirit of the weak signal mode ethos 
> Most weak-signal mode enthusiasts pride themselves on the worldwide
> contacts they can make with low wattage.  Many feel that 100 watts is
> QRO on these modes. Personally, I usually run about 35 watts, but I've
> had QSOs with stations in far-flung regions running power in the
> milliwatt range with a dipole up 20 feet. That's the real attraction
> of these modes to many. And, until the advent of FT8, you heard very
> few stations running more than 100 watts on these modes.  FT8 seems to
> have attracted a whole different crowd.  Some of these, I think, view
> FT8 as a "the new RTTY" and operate according to the accepted
> operating procedures of that mode.  I view this trend as very
> unfortunate.
>
> 73,
>
> Carl
>
> ======================================
> *Carl Jón Denbow, N8VZ*
> 17 Coventry Lane Athens, Ohio 45701-3718
> <mailto:[hidden email]>[hidden email] <mailto:[hidden email]>
> www.n8vz.com <http://www.n8vz.com/>
>
> EM89wh
> IRLP 4533 Echolink 116070
>
> PSK and JT65 Forever!
> ======================================
>

---
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[Edward R Cole]

I've been using JT since its advent in early 2000's (I began with
JT44 in 2003 using my HB psk-31 computer interface).

I only had 110w on 2m using a MOT repeater PA so lucky to get 80w to
antennas.  But I was using four 10-element yagis, which was
considered minimum for CW eme in 1998 if using 600w.  JT modes
allowed me to make contacts with a 10-dB weaker signal.

I was at about the bare minimum of ERP for doing eme back
then.  About 2007 I started running 600w with an 8877 powered by HVPS
of an old Swan HF amp that ran 2500v at 400ma.  About 2011 I upgraded
to a 4kV 750ma PS to run 1500w, which produced a big signal using my
array on JT65.  It took 55w drive to reach that.

Just finishing a new sspa from W6PQL that will run about 1200w that
requires 2w drive and using a 50v PS.  I installed a 30w 10-dB
attenuator so my 20w 2m transverter could run full power.

But the main issue is that one uses the RF power needed to make the
contact.  I understand that FT8 is less sensitive than JT65, about
-24 vs -28 dB.

I may try it on 6m where I have 1kW and two 7-element yagis (not
quite yet QRV - rotator issues).

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   [hidden email]

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