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Author Topic: The Desert Whooper  (Read 1617 times)

Offline Desert Whooper

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The Desert Whooper
« on: August 14, 2021, 0051 UTC »
This is the QSL card that will be available soon to confirm your reception reports.



The elusive Desert Whooper used to inhabit the shores of ancient Lake Mojave and is harder to spot than the more common Bigfoot creatures.  DW's lonely whoop modulates the electric charge stored in its tail and pulses an electromagnetic wave outwards.


In honor of the Desert Whoopers, the beacon was built from scratch and has a hybrid analog/Nano controller so that it can continue to whoop if the Nano fails. The transmitter is crystal controlled and features a varactor diode circuit for the upward frequency sweep.

Telemetry is as follows:

BAT is in volts DC
oTMP is in degrees F with a calibrated thermistor
iTMP is in degrees F using a digital two wire sensor within the weather tight box
PV is in milliAmps to monitor solar panel performance

The antenna is a 1/2 wave dipole oriented North/South but .15 wavelength above the desert soil to create a more vertical but omni-like pattern. The 1:1 balun is home made and measured VSWR is close to 1.1 to 1

Thank you to all who have posted logs. They are very useful!

Offline ChrisSmolinski

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Re: The Desert Whooper
« Reply #1 on: August 14, 2021, 1240 UTC »
Awesome!  :)

And thanks for running the beacon, it's a fun DX catch.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline Teotwaki

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Re: The Desert Whooper
« Reply #2 on: August 14, 2021, 1330 UTC »
I want a QSL card....   8)
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Desert Whooper

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Re: The Desert Whooper
« Reply #3 on: August 16, 2021, 2328 UTC »
For the eQSL please send a detailed reception report to Desert_Whooper at protonmail.com


Please include the time, date, DW's telemetry readout, signal strength/quality, your approximate receive location, radio receiver and antenna used.

Am still searching for a deal for printed QSL postcards.
« Last Edit: September 12, 2021, 2216 UTC by Desert Whooper »

Offline Heathkit

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Re: The Desert Whooper
« Reply #4 on: August 17, 2021, 0152 UTC »
Howdy!

Your beacon is keister kickin' for a peanut! She's a regular at >S5 in Prince George, BC and on SDR's all over western Canada. Your north signal is far better than your E-W-S, according to online SDR's.

Thank you!

73's

Offline Teotwaki

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Re: The Desert Whooper
« Reply #5 on: August 17, 2021, 1432 UTC »
Your north signal is far better than your E-W-S, according to online SDR's.

I agree the DW beacon kicks keister, lol.

SDRs have many different antennas and noise floors that factor into the indicated S level. Time of day propagation is a big factor too.

Right now VE7GL is indicating S3 while Maui (3800 Km away to SE) and SoCal kiwis show S5. The KFS SE kiwi is indicating S9+ with its gain antenna. Sometimes I try the other KFS receivers with directional antennas and am guessing the strong S signals are due to a NVIS like signal coming down on top of the array.
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Teotwaki

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Re: The Desert Whooper
« Reply #6 on: August 17, 2021, 2101 UTC »
For some near real time propagation data related to the western desert beacons try selecting point Arguello, Calif from this list
https://www.ngdc.noaa.gov/stp/IONO/rt-iono/realtime/RealTime_foF2.html

A sample plot as of this hour



If DW's antenna has the pattern mentioned earlier such as this


....then based on time of day there will be reflections of near vertical and angular radiation energy


Some good antenna references for longwire antennas
https://www.qsl.net/aa3rl/ant2.html
https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1993/10/page41/index.html
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline syfr

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Re: The Desert Whooper
« Reply #7 on: August 20, 2021, 0007 UTC »
Great posting, and I'm really glad to hear that DW is back to making serious RF! Very strong on the usual Kiwis tonight
Kiwsdr x 2. TenTec Paragon/NRD535

Offline canswl

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Re: The Desert Whooper
« Reply #8 on: August 21, 2021, 0431 UTC »
Fair reception into Masset, BC at 04:30 UTC tonight.
Listening to the amazing world of radio since 1967
Victoria, BC CANADA
Perseus SDR with ALA 100LN and Flag antennae
eQSLs always appreciated to CANSWL@GMail.com

Offline Teotwaki

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Re: The Desert Whooper
« Reply #9 on: August 21, 2021, 0503 UTC »
Fair reception into Masset, BC at 04:30 UTC tonight.

Holy moly!  Your receive setup is great! Is it a remote SDR?
« Last Edit: August 21, 2021, 1721 UTC by Teotwaki »
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Desert Whooper

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Re: The Desert Whooper
« Reply #10 on: August 22, 2021, 2146 UTC »
Please post up here if you requested an eQSL but did not receive it.

Offline Desert Whooper

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Re: The Desert Whooper
« Reply #11 on: August 22, 2021, 2154 UTC »
https://www.bclnews.it/2021/08/21/the-desert-whooper-beacon-4095-65-khz/

The Desert Whooper Beacon 4095.65 KHz
In your August 4th logs a person offered some incorrect information about DW’s transmit format. For your readers’ interest, here are some technical details of the one watt beacon that provides fascinating propagation performance.

The beacon started development in November of 2020. It was built from scratch and has a hybrid controller consisting of two 555 CMOS timers to key the transmitter along with an Arduino Nano controller to generate Morse code and collect data for performance telemetry. The 555 timers will independently key the transmitter if the Nano fails for any reason. (Fortunately the Nano has functioned for 10 months without issue.) The 4.09565 MHz transmitter is crystal controlled and features a MV1403 varactor diode circuit for the upward frequency sweeps of 150 Hertz. The sweeps provide distinctive audio for the SWL’er as well as an easy to spot visual pattern on the waterfall display of Kiwi SDRs. The transmitter has 4 transistors and the final amplifier is a IRF510 MosFet followed by a low pass filter, all inside a shielded box.

The beacon is powered by a sealed lead acid battery which is kept charged with a solar panel. The battery is protected from over discharge by a low voltage disconnect (LVD) circuit that is independent of the Nano. Time has shown that the solar panel size provides good charge current even in cloudy weather and the beacon does not draw much battery power overnight.

The antenna is a 111 foot long, 1/2 wave dipole oriented North/South and it’s about 0.1 wavelength above the dry desert soil to create a more vertical but omni-like pattern. The 1:1 balun is home made and the antenna’s measured VSWR is close to 1.1 to 1

There are six cycles of DW in Morse along with 29-30 “whoops”; then the DW identification is sent along with four different telemetry numbers.

Telemetry is in slow Morse code as follows:

BAT is the battery’s voltage to tenths of a volt using a precision resistor divider and the Nano’s A2D function. Normal values range from 12.8 to 14.4 volts
OTMP is in degrees F with a calibrated 10k NTC thermistor located outdoors, about 100′ from the beacon.
ITMP is in degrees F provided by a digital one-wire DS18B20 microLAN sensor located within the weathertight equipment box. The reading runs 5 to 10 deg warmer than OTMP.
PV is given in milliAmps to monitor solar panel performance and battery charge current. Measurements are based on an INA219 current sensor board. The values of the current can range from 0 to 2000. Note that a value of 4 or 5 is just the idle current consumed by the solar controller because the battery is fully charged.

In case the Nano fails, the number of whoops can decrease from 30 down to 29 as a crude measure of rising temperatures. On some recent days the internal temperature has peaked at 120 degrees F when outside air temperature was measured at 112 degrees! The box is in shade but the electronic circuitry generates waste heat that causes the temperature rise. Monitoring the temperatures during night and day provides for some interesting deltas..

DW was officially deployed to the Western desert on February 21, 2021. It has been heard in Canada, California, Hawaii, Maryland, Utah, Arizona and many other locations. Some SWL logs can be seen here: https://www.hfunderground.com/board/index.php?board=9.0 and eQSLs are being provided.

The DW Team


Offline Heathkit

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Re: The Desert Whooper
« Reply #12 on: August 23, 2021, 0254 UTC »
Thank you for the info, the beacon and the lovely e-QSL card!

73's

Offline Teotwaki

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Re: The Desert Whooper
« Reply #13 on: August 23, 2021, 1622 UTC »
https://www.bclnews.it/2021/08/21/the-desert-whooper-beacon-4095-65-khz/

------ SNIP------

In case the Nano fails, the number of whoops can decrease from 30 down to 29 as a crude measure of rising temperatures.


The decreasing length of the 30th whoop had been noticed by a few of us.  The box's internal temperature effects on the analog circuitry timing makes sense.
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Exo

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Re: The Desert Whooper
« Reply #14 on: August 24, 2021, 2313 UTC »
"The Desert Whooper HF Beacon"
RECEPTION REPORT by Exo.

Frequency: 4095.65 kHz
Mode: CW
Date Time: 2021AUG23 2206UTC
Signal level: -102 dBm, good readable.
Copy: DW  BAT 13.6  OTMP 98  ITMP 114  PV 4  DW
Notes: Upward frequency chirp signature whoop only on repetitive dash intervals.

AUDIO RECORDING:
PLAY MP3 audio recording of Desert Whooper HF Beacon reception

WATERFALL IMAGE:
Waterfall display image on my kiwiSDR receiving Desert Whooper HF Beacon

Receiver: my home kiwiSDR on the coast of Northern California.
Antenna: Broadband dipole at 30ft.
« Last Edit: August 25, 2021, 0056 UTC by Exo »
Exo
HF aficionado. On the coast of northern California.
Various receivers, transceivers, and broadband antennas.
kiwiSDR receiver on private LAN for multi-freq HF monitoring.