Topband: Band Open - But No Sunrise Peak

[Wes Stewart]

Although my first ever top-band QSO was in 1959 and was a DX station (VE7) it's 
only been in the last year or so that I've been semi-seriously working the 
band.  The impetus being a 9th band DXCC.  At the moment, I have 82 entities 
worked, 52 of them in the last 12 months.  I'm clearly not an expert. That said, 
my observations from the desert of southern Arizona are that I've never noted 
any peaking at my SS but up until maybe a month ago I was noting a peak at my SR.

The caveats are: 1) I'm using my ground-mounted 55' high Inverted-L TX antenna 
on RX, 2) there is a lot more noisy land mass to the north and east of me than 
to the west.  A peak at my SS, if any, when I'm looking for stations in darkness 
(EU, AF), brings up noise as well as signals and offers no SNR improvement. The 
other downside is the increased QRM and the extra hops to any DX.  To the west 
at my SR, the usual activity is from JA, HL, BY and sometimes UA9/UA0.  All of 
these are ~6,000+ mile paths. Noise from the east naturally subsides but there 
is "usually" also a definite peak in received signals.

"Usually" is the operative word.  A couple of surgeries and disconnected 
antennas due to a passing storm had me QRT for the last ten or so days, but this 
AM I was back on.  At 1230Z, the band was loaded with JAs and one HL, most of 
whom I've worked before.  In deference to the W4s I heard calling them I only 
worked the pleading ones.  (I wish I got the same deference in the other 
direction).  Signals were above average, S5-S7.  I decided to hit the shower and 
come back at SR which was 1425Z today.  I returned at about 1400Z and the band 
was totally quiet, with the exception of one station in CO, calling CQ.  I don't 
know whether conditions suddenly changed or all dozen JAs decided to go to bed 
at the same time.

Wes  N7WS


On 1/12/2018 10:23 AM, Nick Hall-Patch wrote:
> Wasn't some of the apparent peaking of signals at sunrise due to improved 
> signal to noise levels as noise levels drop at sunrise?
>
> 20 years ago for many of us, noise levels did actually drop at sunrise.   For 
> many DXers now, (man-made) noise levels stay the same after sunrise, so, no 
> apparent increase in signal strength (actually increase in S/N ratio).
>
> This is not to say that there was  no "real" increase in signal levels at 
> sunrise 20 years ago, just that it was perhaps less frequent than was thought 
> at the time.    If someone has recorded signal strength levels from that 
> period, I'd be happy to be proved wrong.
>
> This morning, in western Canada, a medium-wave broadcaster, HLAZ-1566kHz from 
> South Korea was audible until after 1700UT,  an hour past local sunrise, with 
> a reasonable sunrise peak. Yesterday, there wasn't much of a sunrise peak, 
> and  local noise conditions haven't changed that much over 24 hours.
>
> Was any west coaster on 160m on those two mornings?
>
> 73,
>
> Nick
> VE7DXR
>
>