Tim N3QE was on the money regarding the Wallops Island (VA) Dynasonde,
although the 160 version sounds lower in pitch and is longer in duration.
That's probably because at lower frequencies the pulses need to be
proportionally longer to get the required resolution. It's definitely
wideband as seen on a spectrum display. It's also easily strong enough to
cover DX signals (I'd estimate S7 here). I had several instances this
weekend of needing call or exchange repeats due to its untimely appearance
(e.g. W4ZV TU 599 *****)
Here's the graphical output of the sounder:
Your tax dollars at work generating QRM on Topband!
73, Bill W4ZV
On Thu, Feb 22, 2018 at 1:50 PM, Tim Shoppa <tsho...@gmail.com> wrote:
> Here is a recording (made on 80M a few years ago but sounds substantially
> the same on 160M) of what I'm told is the Wallops Island Ionosonde:
> Here is the waveform showing 4 louder cycles followed by three softer
> If you look at the second panel of the waveform, you see a 20Hz
> substructure in the pulses.
> Even though I'm sitting in once place with a 2.4kHz filter making this
> recording, I understand that the actual spectrum occupied is wider and it
> cycles through the bands repeating on a several minute cycle.
> Tim N3QE
> On Thu, Feb 22, 2018 at 12:56 PM, Jim - WS6X <ws6x....@gmail.com> wrote:
>> I too, am curious as to the source. I heard it for many years in Central
>> California; hear it at my current QTH in Central Shenandoah Valley; and
>> heard it last weekend at NR4M.
>> I describe it as a scratchy sound, sometimes with a bit of tonality.
>> Always 4 pulses (although I don't think I've ever heard the 4 followed by 3
>> as Bill describes.). I've never timed the interval between the groups of 4,
>> but it is fairly infrequent. I'll hear it throughout the evening when I'm
>> at the radio for long periods. It is loud enough on 160 here in VA that it
>> will wipe out all but the strongest signals. I will have to pay more
>> attention to details and record when I hear it.
>> I wish I was better at phonics, but what I hear has distinct articulation:
>> "Gugghk gugghk gugghk gugghk". 😊
>> Jim, WS6X
>> 1. Speaking of noises... (Bill Tippett)
>> Message: 1
>> Date: Wed, 21 Feb 2018 12:48:20 -0500
>> From: Bill Tippett <btipp...@alum.mit.edu>
>> To: topband <firstname.lastname@example.org>
>> Subject: Topband: Speaking of noises...
>> Does anyone know the source of periodic wideband buzzes that sound like
>> buzzz..buzzz..buzzz..buzzz (i.e. 4X then pause) buz..buz..buz (3X ~10 dB
>> I believe this may be some sort of ionospheric sounder but I've heard
>> this for decades, including when I was in Colorado. Hopefully someone
>> knows what's generating this.
>> 73, Bill W4ZV
>> Topband Reflector Archives - http://www.contesting.com/_topband
Topband Reflector Archives - http://www.contesting.com/_topband