[TenTec] Carrier sliding across bands

Sat Nov 10 15:48:08 EST 2018

You might be interested In G3PLX's neat exploitation of ionospheric sounders at:

http://jcoppens.com/radio/prop/g3plx/index.en.php

73
Steve
G3XKR 

Sent from my Xperia™ tablet

---- n0dbx via TenTec wrote ----

>"Chirp Sounder" we called those in the navy.  I was in a reserve unit in 
>the early 80's attached to NCS Nea Makri Greece.  It was a 100 watt 
>transmitter on a vertical antenna that resembled the old AEA Isopole 2M 
>vertical.  The control head was 8 miles away with a CRT readout.  It 
>scanned from 2 MHZ and up, but I don't recall if it ran all the time or 
>on demand.  I do recall a toggle switch that panned the display across 
>the HF spectrum and gave you a rough idea of propagation.  Seems there 
>was a readout at the tech control center of the receive site in town and 
>another with the transmitters in the country.  Neat toys, but don't 
>think it was used all that much.  Everybody just knew you went lower 
>down when it got dark.
>
>I can still hear those 100 WPM TTY printers running and smell the oil.  
>Wish we could get fresh caught deep fried baby squid here. Mighty tasty!
>
>Darrel, N0DBX
>
>On 11/10/18 11:29 AM, xanthi wrote:
>> I was given a schedule for these ionosounders way back in the 
>> mid-90's. Using time and frequency on which the sweeping signal was 
>> heard in coordination with the schedule info, one could determine the 
>> location of the sweeping transmitter heard.
>>
>> I have lost that info.  I'm sure it would be too out of date to be of 
>> use  now.  There are lots of these transmitting sites that transmit in 
>> a precise sequence with no overlap in frequency at the instance.  I'm 
>> sure there have been lots of additions and deletions.  I don't know if 
>> this info is available on the internet.  I have forgotten what the 
>> frequency limits for the sweep are.  I seem to recall the bottom was 3 
>> mHz.
>>
>> The engineer who gave me the information worked for a company that 
>> built two-way HF communications equipment that made use of the 
>> sweeping signals to automatically establish the best point to point 
>> communications path frequency at the time.  I expect it was probably 
>> used mainly by the government.
>>
>> I most commonly hear these signals swish by on 40M these days.
>>
>> de KY4P
>>
>> ------------------
>>
>> On 11/9/2018 6:08 PM, Carlos wrote:
>>> 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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>>>>
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