[AMRadio] 40 m SWBC


D. Chester k4kyv at charter.net
Wed Mar 11 14:20:09 EDT 2009


Early Tuesday evening, at about 2400 GMT I worked Steve HUZ on 7160 kHz 
until the band went long and I lost him at 0030 right in the middle of a 
transmission - just as if he had flipped a power switch and dropped from 1 
kw down to a few milliwatts.  All in about 5 seconds. But the whole time, no 
broadcast QRM. My antenna is an 80m dipole, fed with open wire tuned 
feeders, average height 110' off the ground.

At 0630 GMT I ran my automated CQ on 7160, and had Sergio, IT9QJM come back 
to me on slopbucket.  He said I was S7 to S9 and perfectly readable, 
although there was a language barrier.  I should have tried out my rusty 
Italian!  He did understand that I was on AM.  He said he was using a 
homebrew transceiver.

He also said he was running only 10 watts to a half wave dipole!  He was not 
pinning my S-meter by any means, but he was perfectly readable, well above 
the background noise.  There had been an English-speaking Bible Beater on 
frequency earlier (from South Africa, I believe), but it had shut down and I 
didn't hear any other broadcast on the frequency. No amateur slopbucket QRM 
either.

Hearing a 10 watt SSB station that well, and being heard at up to S9 with 
approximately 300 watts carrier output,  leads me to believe that 
transatlantic AM should be a breeze whenever band conditions are half way 
decent.  I would say the best time to try would be between 0430 and 0630 
GMT.  Maybe earlier as the days get longer.

If most of the broadcast stations really do go away, T/A QSO's should be 
possible all evening long.  As Tom, K1JJ pointed out, as long as it's dark 
or within an hour of darkness in both locations, the USA-EuropeDX can be 
worked. The Euros on 40M should be workable any time from OUR own local 
sunset to perhaps two hours before our own local sunrise, depending on 
season. USA stations can be heard working them throughout that time, which 
varies depending on  the season. Tom says  he has worked Europeans even 
though they are a couple hours past their sunrise. The problem is on both 
sides of the pond, people tend to sleep between 12 midnight and 4AM local 
time. But this could be a window of opportunity for the night-owls who are 
still up at the bewitching hour of 3 AM  local time, because of the lack of 
QRM.

I predict a reduction in broadcast QRM, but that it won't go away entirely. 
Already, there are big holes in the broadcast QRM, below and above 7200. 
The most significant change is that amateurs outside Region 2 (the Americas) 
will once again have use of 7100-7200 after more than a half century. 
European and American hams will have exclusive or at least primary use of 
the segment, while those in other parts of the world will have access at 
least on a shared basis.  British, Spanish and Italian hams are already 
active on the new frequencies, and Ireland, Netherlands and France are 
supposed to gain access on the 29th (supposedly along with the rest of 
Europe).

PE1MPH reported vacant broadcast channels on the following frequencies:
7130
7145
7155
7160
7185
7190
7195
He suggests maybe 7160 and 7185-7195, although the broadcasters change 
frequencies all the time.

One of the significant aspects of the 29 March date is that's about the time 
of the normal seasonal shift in international broadcast frequencies anyway, 
so mandating the changes on this daty may enhance compliance.

On this side of the Atlantic, here is a quick snapshot of what I heard on 
40m on the 1st of March, listening with the 900' beverage that is generally 
directional towards Europe.  I started to scan the band a few minutes before 
0300 GMT.  Between 7100 and 7200 I heard broadcast carriers on the following 
frequencies:

7120
7125
7150
7155
7165
7175
7190
7200

At 0300 on the dot, the 7200 station closed down.  I continued to scan above 
7200.
Broadcast carriers were on the following frequencies:

7205
7225
7235
7245
7250
7255
7260
7265
7275
7280
7290
7295

Then I re-scanned 7100-7200, because stations often start up or close down 
at the top of the hour.  BC stations were heard on:

7105
7110
7130 (very weak)
7150
7165

Amateur SSB was heard on only a couple of frequencies between 7200-7300. 
Dozens of slopbuckets were audible on vacant frequencies between 7100-7200. 
A few Europeans, mostly Italians were heard amongst them, some quite 
strapping.

No amateur AM was heard at all.

On the 9th of March, Steve WB3HUZ reported:

Freq (kHz)     BC Station     Signal Strength

7125               Y              5/9+20
7130               Y             Very Weak
7135               N
7140               Y             Very Weak
7145               N
7150               N
7155               N
7160               N
7165               Y             Very Weak
7170               N
7175               N
7180               Y             Very Weak
7185               Y             Very Weak
7190               N
7195               Y             Very Weak
7200               Y              5/9+10



Don k4kyv

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