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23-on-23: Tuesday April 2...
Forum: 1296MHz, Microwave & Opto
Last Post: VK4CZ
5 hours ago
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Audio Clipping on Sideban...
Forum: LF, HF, MF
Last Post: VK2CSW
17-04-2024, 08:27 PM
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Dud Headphone Jack on Yae...
Forum: Transceivers, Transmitters & Receivers
Last Post: VK4JRH
17-04-2024, 07:48 AM
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FTDX101D & SCU17 ?
Forum: General Discussion
Last Post: VK4TS
16-04-2024, 10:50 AM
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Wiring a microphone for h...
Forum: Homebrew
Last Post: VK2CSW
15-04-2024, 07:47 PM
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Dipole for 6m
Forum: 50MHz
Last Post: VK2CSW
15-04-2024, 07:10 PM
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Toroid Supplier/s
Forum: Ancillary, Test Equipment, Components & Parts
Last Post: VK2CSW
11-04-2024, 06:26 PM
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Non-Resonate End Fed UNUN...
Forum: Homebrew
Last Post: BI1EIH
08-04-2024, 05:06 PM
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I had forgotten...
Forum: General Discussion
Last Post: VK2AZ
07-04-2024, 11:40 PM
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the way the USA has corru...
Forum: Off Topic!
Last Post: OZ2M
07-04-2024, 05:08 PM
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» Views: 2,857
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Wanted |
Posted by: VK3ALB - 10-11-2018, 08:56 AM - Forum: Wanted
- No Replies
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WANTED
10GHz amplifier + 24GHz doubler boards (SU-02) from RF-Microwave.com
One would be nice, two would be better.
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Paul Bittner W0AIH SK |
Posted by: VK4WDM - 03-11-2018, 05:27 PM - Forum: Silent Keys
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According to report in QRZ.COM, well-known contester Reverend Paul Bittner, W0AIH, of Fall Creek, Wisconsin was killed on October 31 in a climbing mishap at his huge "antenna farm." He was 84. He had previously said that he wanted to be buried with a bible, a Morse key and a climbing belt!
I worked Paul many times over many years.
Wayne VK4WDM
[url=http://www.qth.com/w0aih][/url]
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Wanted: The Australian Wireless Review Apr 1923 Article |
Posted by: VK5TM - 03-11-2018, 04:16 PM - Forum: Wanted
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Does anybody, by any chance, have a copy of 'The Australian Wireless Review' Apr 1923 magazine and could scan a two page article please?
Looking for 'Making Condensers' Pages 20 & 21 (for historical interest).
There is a pdf of the magazine on line, but of such bad quality as to be useless.
Thankyou.
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Polish students’ satellite - PW-Sat2 |
Posted by: SWL-PL001 - 03-11-2018, 05:08 AM - Forum: Satellites & Balloons
- Replies (1)
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As soon as 19th November 2018 launch of 4. polish satellite - PW-Sat2 - is scheduled. It’s primary mission is a technological tests of sail-based deorbit system. The PW-Sat2 is one of the payloads in SpaceFlight SSO-A The SmallSat Express mission aboard SpaceX’s Falcon 9 rocket. Please be advised that planned launch date may change since it’s quite common for orbital rockets launches - be prepared and follow our socials!
Radio link
The satellite is equipped with full duplex communication module TRxVU Rev. B from Innovative Solutions in Space BV. It operates in amateur bands UHF (downlink) and VHF (uplink). Antenna module consists of two dipole antenna (for uplink/downlink) with linear polarisation. Downlink power equals to 27 dBm (0.5 W). Downlink signal utilizes BPSK modulation, data scrambling according to G3RUH and AX.25 protocol. By default, the satellite transmits its downlink signal at 1200 bps, however it might be changed on request by the OPERation team (via uplink telecommand) up to 9600 bps. Currently set bitrate will be published on PW-Sat2’s Twitter profile, however determination of actual bitrate should be fairly easy by looking at signal spectrum.
What data will be transmitted?
Every 60 seconds the satellite transmits a beacon frame full of telemetric data. 229-bytes long payload of the beacon frame contains the most important information about satellite’s state - among others - temperatures of main subsystems, battery voltage, solar power, on-board computer mission time and experiments state. Other data, such as historical telemetry, experiments data, photos from cameras will be send on request from PW-Sat2’s OPERation team. There is one exception from this rule - deorbit sail experiment will transmit its results on-line (since after sail deployment random tumbling is expected to occur resulting in signal loses and solar energy decrease).
Downlink signal of PW-Sat2 will be opened for everyone to receive, decode and interpret data!
HAM radio tools to receive PW-Sat2
HAM radio community plays important role in almost every cubesat mission - receiving and sharing acquired signal with satellites’ owners. Our team has prepared set of tools helping in receiving and demodulation of PW-Sat2 radio signal and upload to cloud-based service afterwards. We believe that data shared to us by community will have big impact on our mission.
Prepared desktop application is available on Linux and Windows platforms (however Ubuntu Linux is the main supported OS). It allows for signal reception utilizing software defined radio receivers (SDR): RTL-SDR, FUNcube Dongle Pro+, ADALM-Pluto SDR as well as “traditional” analogue radio receivers with single sideband demodulator (SSB) via computer’s line-in. Acquired signal from radio receiver is demodulated and deframed. Correctly received frames are classified by means of their type and uploaded to cloud-based application (radio.pw-sat.pl) prepared thanks to co-operation with SoftwareMill company. The cloud-based application allows for frames collection, sharing and telemetry decoding (for beacon frames, labeled as “telemetry frame”). There are available additional features like charts presenting the most important telemetry data.
How to start receiving?
Detailed information are available in our Wiki - https://github.com/PW-Sat2/HAMRadio/wiki. A good starting point is to take a look at “Quick start guide”. The wiki pages will be updated as new information (e.g. about orbit, TLE data) will be available.
We encourage to try the software (desktop and cloud parts) right now! In case of any problems - don’t hesitate to mail us (by an e-mail, Messenger, in comment etc.), create an issue on GitHub (https://github.com/PW-Sat2/HAMRadio/issues) or simply ask in this thread!
Mission status information
Up to date information about mission status will be published on our Twitter profile - don’t miss anything, follow us now!
Contests
To encourage you to listen to PW-Sat2 and honour your contribution we would like to issue QSL cards for every HAM radio who will send us (to radio.pw-sat.pl) at least one correct PW-Sat2 frame.
Additionally we’ve prepared contest in three categories:
* the first received and uploaded frame,
* the last received and uploaded frame,
* the most received and uploaded frames.
Shortly after mission we will reveal the winners and honour with packs of PW-Sat2-related gadgets!
For more about contests see (https://pw-sat.pl/en/ham-contest/).
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Image frequency math on Tecsun PL-880 |
Posted by: VK-SWL6002 - 25-10-2018, 05:54 PM - Forum: EMC, Interference
- Replies (6)
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Hello.. this is my first post so if I make any errors of etiquette please let me know.
I am trying to work out the math of inter-modulation frequencies using my Tecsun PL-880 as an example. I have been SWL on my new Tecsun PL-880 (loving it) using a 17.1m random wire antenna with 9:1 unun and getting plenty of signal. Even setting the SW antenna gain to 'local', I seem to still be getting quite strong frequency images of the local AM radio stations.
I have been doing a lot of research, spreadsheeting and math, but can't quite work out the exact math of why the image frequencies are where they are.
I know the PL-880 uses an IF of 45 kHz and 10.7 MHz, but can't quite get the math to replicate why for example, I am receiving images of 720am (station 6WF here in Perth, Australia) on 6525,7675,8155,12870,15590,16070.
One clue is the frequency difference between all images is one third of the frequency difference between the original stations. For example, the difference between original station 720 6WF and 6RN 810 kHz is 90kHz, but the difference between images of those stations (eg 15560 for 810 and 15590 for 720 ) is one third of that .. ie 30kHz. This one third spread is apparent right across the images, ie the 495kHz MW band spread from say 585 6NR to 1080 6IX is three times of that in the image (say 15470 (6IX image) - 15635 (6NR image) = 165kHz or 1/3 of 495kHz!
Another clue. The spread between 720 6WF and one of its images at 16070, is 15530, half of which is 7675 which is also an image of 6WF
Another clue. The mid point between 720 6WF and one if its images at 15590, is 8155, which is also an image (15590 - 720)/2 = 7435, and 7435 + 720 is 8155 (mid way between 720 and 15590).
If any expert with a little time on their hands can decyper the math (ie various integer multiples of IF +/- RF) I would be very interested to know! I have spreadsheeted out all the images and still can't quite get integer multiples happening.
I hope someone can work it out, or point me to the math of an answer somewhere. Thanks for your time!
CP Perth, Australia
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WSPRView for Windows |
Posted by: VK4ADC - 24-10-2018, 03:28 PM - Forum: Digital Modes
- Replies (64)
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WSPRView for Windows
I started writing this software because Leigh VK2KRR has been asking for a few changes for search options of the people at WSPRNET and not getting very far. My thoughts were that if I was able to retrieve (basically) the same bulk data from their web site, maybe a little local processing/filtering might achieve what Leigh wanted. The difference is that the extracted data can be manipulated locally so there is a better chance of obtaining the desired outcomes.. That also means that development will be ongoing for a little while so you will need to check for version updates yourself (at least for now).
The software download link plus some descriptive text is available from :
http://www.vk4adc.com/web/software-proje...or-windows
New versions / bug fixes will be available periodically.
Try it and respond direct by email or PM with any comments..
Doug VK4ADC
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Remote your shack, how do you do it? |
Posted by: VK5PJ - 23-10-2018, 01:10 PM - Forum: General Discussion
- Replies (2)
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Hi
as a keen VHF operator, I am often frustrated by the good openings happening while I am at work. . . maybe you have had similar frustrations, maybe you could add your input to this thread.
What really sparked this up to 'frenzy' level was the opening on 50 MHz across the south pole last December, I would have to come to work knowing that some time mid morning there would be most probably be an opening and I would be at work. Arrrgh
Okay, so my work involves me spending a lot of time in front of a PC, with the occasional slow time where I have to wait for other processes to finish, step one how do I get to connect to my Shack PC from work? For me this step involved creating a free account with TeamViewer which allows me to install their software on the work PC and the home PC. I can then as needed connect to the home PC.
To control the rig, it is connected to the Shack PC via either a mix of USB and serial data, so the WSJT-X and FLdigi software has control over the rig. So now I can at least run JT65, WSPR or FT8 from remote (even from the teamviewer app on my phone).
Next step, how do I control the rotator, hmmm this step has caused me a lot of headaches as to what to use, I eventually settled on an EA4TX rotator controller that plugs up to a USB port on the PC and can be controled a number of different ways.
Okay, I can QSY, change modes, turn the antennas but how do I turn on the 50MHz amp? enter a little box called a RLY-8 purchased from an ebay seller (seller Id is: IOT-HUB) here in Australia just recently for $110. It has an ethernet port and a USB port and can control 8 different devices via its isolated relays. I have not connected this to my system as yet as I am working on the best way to switch the 50MHz amp, 144 MHz amp and a few other accessories in the shack but my initial testing looks good (no birdies found on the bands from this box).
Peter, vk5pj
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9:1 OR 4:1 ?? |
Posted by: VK4CCV - 22-10-2018, 02:52 PM - Forum: LF, HF, MF
- Replies (2)
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I am about to put up a Dipole antenna but unsure what Balun would best suit.
I can only place a wire up that is 88' in length.
At the centre it will be 33' and the ends drop down to 20'.
The Antenna will be fed with 450 Open Wire which will be 33' to the ground where the Balun will sit.
The run back to the shack will be around 40' where I will use LMR195 to the Tuner.
I have purchased a 9:1 but now wondering wether it should have been a 4:1 ??
VK4CCV Pete
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