[Lowfer] 33.950

[Dexter McIntyre W4DEX]

Michael Sapp wrote:
> Dex, nothing observed on 33.950 last nite....
Mike,

I did a 25 hours transmission on 33.950 on Tuesday night.  Neither you 
or Garry saw the signal.  However just to prove I was transmitting I 
received a report from Paul Nicholson in Todmorden, UK.  But of course 
Paul is doing much longer term signal processing.  Also what puzzles me 
is that on the night before I was transmitting OP2H and got no decodes 
but Paul noticed a signal on 29.500 while analyzing Bob's transmission.  
When I told Paul I was transmitting OP2H he used the recording and was 
able to decode my OP2H signal using deep search.

I remain puzzled therefor all is normal.

Below is what Paul posted on the rsgb_lf_group reflector:

"I can report reception of some VLF signals from Dex
W4DEX as WH2XBA/4 during the previous two nights.

Sending OP-2H with 100W at 29500 Hz from 2014-03-11 03:00
onwards produced a signal in Todmorden which averaged 0.135 fT

  http://abelian.org/vlf/tmp/29500_140311a.gif
  http://abelian.org/vlf/tmp/29500_140311b.gif

and S/N was 16.2dB in 125uHz.

The transmission began at 23:00 UT with 50W carrier until
02:00 when it switched to 100W of OP-2H.

The signal is only slightly weaker than WH2XBA/1 transmitting
at the same time on 29499 Hz. /1 was averaging 0.146 fT over
the same period.

I sent the signal data to Markus DF6NM who was able to get a
good deep search detection out of it:

 2014-03-11 05:14:00 WH4XBA ... -55.0dBOp 100% 15.7dB

Measurements ended before the signal vanished because of the
appearance of military signals on a nearby frequency.

Interestingly, the phase of Dex's transmission was almost
constant throughout the night:

 http://abelian.org/vlf/tmp/29500_140311c.gif

Phase bounces around ± 25 degrees but there is no significant
trend of the phase between 00:00 and 05:30.  What variation there
is can be attributed to noise in the 1.66mHz measurement band.

Then last night Dex made a transmission at 33950 Hz.  The 50W
carrier appeared at 2014-03-12 03:00 UT and averaged 0.107 fT
between 03:00 and 07:00 and S/N was 20.6dB in 69.4uHz bandwidth.

Here too, the phase was fairly constant:

 http://abelian.org/vlf/tmp/33950_140312a.gif

Path length WH2XBA/4 to Todmorden 53.703N 2.072W: 6194km.

-- 
Paul Nicholson
--