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Thursday, December 10, 2020
Pete Juliano's Presentation to the 2020 G-QRP Club Convention -- Building SSB Transceivers
Saturday, December 5, 2020
Adding 10 kHz of Coverage to My BITX 17
"Radio, Radio" By Elvis Costello and The Attractions
Friday, December 4, 2020
The Terrible Collapse of the Arecibo Dish: Climate Change, Hurricane Maria, and Funding Cuts. Also: China's New Dish
From https://www.thewrap.com/watch-crazy-footage-of-the-arecibo-observatory-collapse-goldeneye-video/ :
"Alas, over the 2010s it was battered by a series of severe, climate change-linked tropical storms and hurricanes, culminating in terrible damage inflicted by Hurricane Maria in 2017. Unfortunately the 2016 election led to a government unwilling to fund repairs. Though new sources of funding were cobbled together late in 2018, in late Nov. 2020 it was determined there was no way to safely repair the telescope and the National Science Foundation announced it would be decommissioned.
The decommissioning was supposed to proceed after NSF determined the safest possible method, but physics had other plans. So it is that on Dec. 4, the whole thing up and collapsed with almost no warning."
More info (from NSF):
https://www.nsf.gov/news/special_reports/arecibo/index.jsp
Here is a good 2017 article that discusses the electronic and mechanical arrangements at Arecibo, and the budget cuts it was facing. The article seems to almost predict the collapse:
Here is a comment from someone who worked there and heard the collapse:
Jonathan Friedman, who worked for 26 years as a senior research associate at the observatory and still lives near it, told the Associated Press news agency of the moment the telescope collapsed on Tuesday.
"It sounded like a rumble. I knew exactly what it was," he said. "I was screaming. Personally, I was out of control... I don't have words to express it. It's a very deep, terrible feeling." https://www.bbc.com/news/world-us-canada-55147973?fbclid=IwAR3RuwzTfJmqInrOOFB-nctknDzyB_VSr_qdNrjg9LbbxUnAbynKBv9stPQ
Here is an interesting WIKIpedia article on China's FAST dish, with comparisons to Arecibo:
Thursday, December 3, 2020
Receiving Signals from China's Chang'e-5 Lunar Sample-Return Mission
Background info:
A great report from Daniel Estevez EA4GPZ on radio amateurs receiving telemetry from Chang'e-5:
Wednesday, December 2, 2020
Radioactive Regulator Tubes -- OA2s! Who knew?
Monday, November 30, 2020
Adam N0ZIB's Direct Conversion Transceiver
This is obviously very cool, but looking ahead I think Adam should think about adding one more mixer, changing the bias on the TX amps, and adding a mic amp. Boom: A Double Sideband Transceiver.
Pete wrote: When I was in the US Navy and a particular unit did something outstanding – the Command ship would raise the Bravo Zulu Flag for a job well. Don’t know if you can see it there in MO but I have raised the BZ flag to you. Outstanding and congratulations.
Bill and Pete:
Just finished a DC transceiver using Arduino nano, SI5351 (my sincerest apologies, Bill), diode ring mixer and lm386 audio amp. The transmit portion is a two-stage class AB pre-amp (from EMRFD page 2.32), which is driving an IRF510 final (biased at 2.08 volts) from Pete’s design. Output is about 5watts into a CWAZ low pass filter, based on the design from here: https://www.arrl.org/files/file/Technology/tis/info/pdf/9902044.pdf
I’m using a manual TX/RX switch which is doing multiple things. It brings the Nano A1 LOW, offsetting the transmit frequency 600 Hz for CW, grounds the audio input to prevent deafness (learned that one the hard way), and it engages a relay that switches the antenna from the receiver to the transmit, and also turns on the transmitter stages. Keying is through the first stage of the pre-amp.
I still have some tidying up to do, and I’m not sure the LPF works so well using two component inductors instead of all toroids, but I finished it today and made my first QSO into Ontario almost 1000 miles away. It’s been great fun!
73,
Adam
N0ZIB
Missouri
Sunday, November 29, 2020
Rocket Knack
Friday, November 27, 2020
6EQUJ5 -- SNR, the Big Ear Radio Telescope, and the "Wow" Signal
This Hack-A-Day article explains the significance of 6EQUJ5 on the paper readout of the Big Ear radio telescope. It is a signal-to-noise readout.
The article also has interesting information about the radio telescope that was used.
I have on my shelf John Kraus W8JK's wonderful book "Big Ear Two -- Listening for Other Worlds." John Kraus is the guy who built the Big Ear. In a reminder of how new radio technology really is, Kraus got his start in radio as a ten year-old boy in 1920. He ripped the wire out of the ignition coil of a Model T Ford to make a tuning coil for a crystal radio. He took the earpiece out of the family telephone. His father gave him a chunk of Galena. He used the crystal radio to listen to the early broadcasts of WWJ in Detroit.