[TenTec] Carrier sliding across bands

Carlos carlos.peco at gmail.com
Fri Nov 9 18:08:48 EST 2018


Hi Bob,
Yes, ionosounders appear as a moving clean carrier, they can sweep the band
you are working in 3 or 4 seconds.

What you describe looks to me like a harmonic of a switched-mode power
supply where the fundamental frequency is set by an RC oscillator.
Sometimes you can see several harmonics spaced by the switching frequency
(for example, some noise every 60 kHz or so).

73,
Carlos VK1EA



On Saturday, November 10, 2018, Bwana Bob <wb2vuf at verizon.net> wrote:
> An ionosonde, I think, would be a clean signal. I get switching power
supplies sweeping across the bands in my neighborhood, but they drift very
slowly and usually have a rough AC modulation on them.  The buzz is often
found across the band at 20-30 kHz intervals.  Noise blankers won't wake
them out.  I hate 'em!
>
> 73,
>
> Bob WB2VUF
>
> On 10/24/2018 12:22 PM, MadScientist wrote:
>>
>> Ionosonde sounds like the most plausible source. I read the description
and it looks very much like what I am hearing.
>>
>> Thanks!
>>
>> Gary
>>
>>> On Oct 24, 2018, at 11:16 AM, Mike Bryce <prosolar at sssnet.com> wrote:
>>>
>>> that could well be nothing more than a switching power supply (think
wall wart here) and that’ s the oscillator singing away.
>>>
>>> if you can, run the 7300 on a battery and pull the main breaker in the
house. If the carrier goes away, start looking
>>> if it’s still there, as your neighbors about pulling wall warts one at
a time (good luck with that!)
>>>
>>>
>>> Mike, WB8VGE
>>> www.theheathkitshop.com
>>>
>>>
>>>
>>>> On Oct 24, 2018, at 12:07 PM, MadScientist <dukeshifi at comcast.net>
wrote:
>>>>
>>>> Well, I entered the SDR world with my new IC-7300! That’s off topic
but what I have observed with it is very much on topic.
>>>>
>>>> Over the past year I have heard, on all rigs, a carrier sweeping
across the band (all bands). It is fairy strong.
>>>>
>>>> The landscape ,on the 7300 is fast enough to observe the nature of
this. The signal consists of actually three peaks that typically start on
the low end of a given band and sweep the range of 200 KHz in about 2
seconds, with the speed being nearly constant, as evidenced by the sloping
line that the signal makes on the waterfall display.
>>>>
>>>> That line is almost perfectly monotonic across the entire scope window.
>>>>
>>>> In addition, I sometimes see a carrier that makes a back-hand-forth
movement on the waterfall display.
>>>>
>>>> Does anyone have any idea what be the origin of this signal??
>>>>
>>>> I know it’s not a radio artifact as I have herd this on a dozen
different radios. Also, if I disconnect the antenna, this is never heard.
>>>>
>>>> Gary
>>>> _______________________________________________
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>>>> TenTec at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
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