Regarding the question of QRM on 50.276, it's pretty much non-existent
unless you have a strong station nearby that is causing overload/de-sensing.
The mode is narrowband in that the audio tones are shifted only about 175
Hz. The JT-65 software is capable of decoding signals as close as 1 Hz away
from each other (and sometimes less), meaning if one station is using an
offset of 1,000 Hz and another is using 1,001 Hz, the decoder is still quite
capable of decoding both. It's quite amazing actually.
Because the software can also decode signals well below 0 dB S/N (down to
-28 actually), contesters, DXers, and casual operators alike can work other
stations when even CW can't get through. Typically barefoot and with smaller
antennas. Sure, there are big guns on the band like any other band, but most
are running modest stations.
It's an amazing mode, and during the contest last weekend, 50.276 was filled
with stations. The week prior, stations in the mid-west were working both
Europe and Japan at the same time. Crazy wild conditions! JT9 actually steps
it up a notch with a more narrow shift and the ability to decode still
deeper.
The down side is that these QSOs take four minutes. You're not going to work
60 an hour but you may be working stations when the other modes are
resulting in endless, unanswered CQs.
--Dennis NE6I
-----Original Message-----
From: CQ-Contest [mailto:cq-contest-bounces@contesting.com] On Behalf Of Ria
Jairam
Sent: Thursday, June 15, 2017 2:51 PM
To: Zack Widup; CQ Contest
Subject: Re: [CQ-Contest] Can you not hear me now?
The world above 50MHz is well ahead of the curve when it comes to
assistance, weak signal modes and other technology. For example in some
contests you can use chat rooms and telephone to solicit contacts, a
definite no-no in HF contesting.
But there are different challenges on the UHF/SHF bands and I'm only now
getting into that.
73
Ria, N2RJ
On Thu, Jun 15, 2017 at 5:25 PM Zack Widup <w9sz.zack@gmail.com> wrote:
> I was curious about the same things. I have not yet used JT65 but I
> got very interested in it after a presentation at the VHF Weak-Signal
> Forum at Dayton this year. I have downloaded the software and want to
> play with it.
>
> Would I use it in a VHF contest? I don't know yet. So far I have
> entered most VHF contests as a Single-Op QRP Portable. I don't take a
> computer along. I log on paper and then enter the log into the
> computer when I get home. A computer running JT65 would be something
> else to drain my battery, and I am usually trying to conserve battery
> power as much as possible. I've been on a pretty tight budget the
> last couple years and don't want to buy another battery. But I do want
> to experiment with JT65 at home and see how I like it.
>
> 73, Zack W9SZ
>
>
> On Thu, Jun 15, 2017 at 12:15 PM, John Geiger <af5cc2@gmail.com> wrote:
> > You bring up a good point about digital modes Tor. From watching
> > the DX cluster, it seemed that quite a few stations probably spent
> > most of the contest on 50.276 running JT65. Also, how do you keep
> > from QRMing each other when several stations are all on 50.276?
> >
> > 73 John AF5CC
> >
> > On Thu, Jun 15, 2017 at 2:45 PM, RT Clay <rt_clay@bellsouth.net> wrote:
> >
> >> Somewhat off-topic, but with meteor scatter (even when using
> >> MSK144),
> you
> >> usually CAN hear the other signals. The advantage of MSK144 over
> >> ear
> copy
> >> is that it can send information in very short meteor bursts that
> >> are not long enough for SSB.
> >> An equal problem on VHF seems to be that many people are going to
> digital
> >> modes by default, even when signals might be very strong. This
> >> makes
> qsos
> >> take much much longer than necessary (one transmission on JT65 for
> example
> >> takes 1 minute). I made one MSK144 qso during the contest with a
> >> station
> >> 800 miles away on 2m. He was 56-57 (via tropo) and the qso would
> >> have
> been
> >> much easier and faster on SSB. He could have probably worked many
> >> more stations by calling cq using SSB.
> >>
> >> Similarly, 50.276 is now jammed with JT65 during 6m openings.
> >> Nearly all of the qsos I have made there have been with signals
> >> strong enough for
> easy
> >> CW/SSB copy, but using JT65 forces each qso to take several minutes
> just to
> >> exchange a report and grid.
> >>
> >> Tor
> >> N4OGW
> >>
> >> On Thursday, June 15, 2017 7:16 AM, James Cain <
> >> jamesdavidcain@gmail.com> wrote:
> >>
> >>
> >> The latest ARRL Contest Update newsletter summarized some 3830
> >> ARRL
> June
> >> VHF Contest comments as follows:
> >>
> >> "In the soapbox comments from the most recent June ARRL VHF
> >> Contest
> many
> >> stations were reporting the use of the MSK144 digital mode for
> >> making
> QSOs
> >> where a SSB or CW path did not appear to exist. MSK144 can be sent
> >> and received using the WSJT-X program by Joe Taylor, K1JT. MSK144
> >> uses exchange sequences as fast a five seconds to take advantage
> >> of
> propagation
> >> that might
> >> occur due to meteor scatter."
> >>
> >> Way back in the ancient days of radio there was a saying:
> >>
> >> "You can't work them if you can't hear them."
> >>
> >> Maybe we need an updated saying:
> >>
> >> "You can work them even if you can't hear them."
> >>
> >> K1TN
> >> _______________________________________________
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> >> CQ-Contest@contesting.com
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> >>
> >>
> >>
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