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How to simplify logging?
Forum: Digital Modes
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28-04-2024, 02:43 PM
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7285kHz AM?
Forum: Off Topic!
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25-04-2024, 01:16 PM
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VK3XPD 23cm 65W modules
Forum: 1296MHz, Microwave & Opto
Last Post: VK2AZ
22-04-2024, 09:34 PM
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Dud Headphone Jack on Yae...
Forum: Transceivers, Transmitters & Receivers
Last Post: VK2CSW
20-04-2024, 07:53 AM
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23-on-23: Tuesday April 2...
Forum: 1296MHz, Microwave & Opto
Last Post: VK4CZ
19-04-2024, 01:22 PM
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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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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
» Replies: 3
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FT8 vs AGC |
Posted by: VK4ADC - 24-09-2018, 10:36 AM - Forum: Digital Modes
- Replies (1)
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I have been finding that when (mainly) VK, ZL and FK8 stations are working on the same band, the IC-7400(/746Pro) AGC is depressing the gain as it should and the FT8 signals I am trying to work drop down to the point that WSJT-X does not decode them. Slow, Medium or Fast setting makes no difference, still depressed receive gain. The 'local area' signals are often +3dB SNR or higher, sometimes up in the +10 to +15dB SNR range.
If I notice this effect, I usually try to transmit in the same 15 second block (ie First 00,30 or Second 15,45) as they do but that isn't possible when answering someone who is calling CQ on the 'wrong' timing segment.
What I didn't know is that the AGC functions are adjustable in this radio. You can set each recovery time from the front panel in 0.1 second increments but there is also an AGC OFF selection available. I have changed my settings so that I have 0.5S for Fast, OFF for Medium, 6.0S for Slow. Only takes seconds to alter once you know that the setting is available.
The result : Just saw a VK3 and a YB7 both at +7dB on 14.074 and the weaker signals remained un-depressed.
You still have to remember to manually put it back to Fast or Slow AGC for SSB use but it certainly seems the right setting for FT8.
I have only had this radio 12 years or so, been using it on FT8 since March '18, and only just found the AGC OFF setting.
Makes me wonder what else is hidden in the instruction manual.
P.S. AGC OFF = no S-Meter display/readings !!
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ACMA Spectrum Outlook : 5MHz / 60 metres |
Posted by: VK4ADC - 23-09-2018, 07:26 AM - Forum: LF, HF, MF
- Replies (6)
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From text edition for SEP 23 2018 - VK NATIONAL NEWS BROADCAST ON VK1WIA : http://www.wia.org.au/members/broadcast/wianews/
Also in MP3 edition of news available at: http://www.wia-files.com/podcast/wianews-2018-09-23.mp3
"The ACMA released their five year spectrum outlook, and unfortunately, due to a high demand for spectrum, Australian amateurs will not have access to 60m in the near future.
Overall, no spectrum was added, and more importantly, no spectrum was lost.
This has been a great outcome for our bands with pressure from 5G and internet of things, so make sure you get out there and use it!"
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Telecommand transmission |
Posted by: VK2FAK - 21-09-2018, 10:10 AM - Forum: Satellites & Balloons
- Replies (2)
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Hi All..
How do you go about sending command signals to a LEO satellite. using 9k6 ax.25 gfsk .
What radio is required, and software to do the job......?
Never done it here, and at this stage don't have a radio that would do 9k6 baud.
The reason I ask, the problem came up again yesterday with a LEO satellite, which needed a reset, it fixed itself as far as I know, But that's about 3 times now, so may be an idea to set-up for it...
John
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Ladder line Quick connections |
Posted by: VK4AQJ - 20-09-2018, 06:16 AM - Forum: Towers, Masts & Transmission Lines, Antennas
- Replies (13)
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I'm trying to find something that probably doesn't exist. I use 450Ohm Ladder line for my MF ATU, and I use the same line for 160metres. I have to make and break the connection every time I switch from one to the other.
At the moment, I'm using MC4 solar power connectors. They are weatherproof, will withstand movement of the ladder line due to wind, and you can make and break the connection using a special MC4 spanner. I use male and female connectors on the two terminals so that I can only connect them one way.
The MC4 connectors are ok, but they are a bit fiddly to disconnect, especially in the dark, (OK, I could install a light) and they seem like overkill in terms of size, rating etc.
The question is - Is there something already available for make and break connections on 450 Ohm ladder line? THey have to be robust and weatherproof. I've tried searching with no luck, but maybe it has a special name that I'm unaware of. (or it doesn't exist)
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Bernards & Babani Books |
Posted by: VK5TM - 19-09-2018, 01:52 PM - Forum: General Discussion
- Replies (1)
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Some of us will well remember the old Bernards and Babani books from years gone by.
While a lot of the information is well out of date these days, there is still a lot of useful information applicable to todays homebrewer/tinkerer as well as being a useful reference to bits and pieces from years past that may turn up in ones junk box.
There is a sizeable collection of them here: https://www.americanradiohistory.com/Arc...Babani.htm with more being added almost daily at the moment (and some make interesting reading of what life used to be like, for instance no's 12 & 13 on the linked page).
For those that haven't seen or know of this site, have a dig around, lots of interesting stuff there.
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Microwave Activity Day (MAD) Sunday 23rd September |
Posted by: VK4OE - 18-09-2018, 07:23 PM - Forum: Contests, Field Days, Portable Operation, JOTA, SOTA
- Replies (1)
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Greetings to all readers!
This coming Sunday is the 23rd of the month so the usual evening "23 on 23" activity is transposed into a daytime microwave activity day.
For about four hours from around 12:00 noon, there should be several stations around greater South-East Queensland operating from various locations on various microwave bands. 1296 MHz is a starting band, with use of 2403 MHz, 3398 MHz, 5760 MHz, 10.3 GHz, 24 GHz and possibly some higher frequencies during the afternoon.
"Talk back" is most helpful for setting up contacts and organisational liaison and on this occasion the focus of activity will be on the Redcliffe and District Radio Club's 147.00 MHz FM repeater on Mt Glorious. Some folk alternatively will use iChat via the on-line VK-Logger, and the 'spotting' facility that is also on the Logger. Personally I will also have 439 MHz FM simplex available for 'talk back'.
The weather for Sunday is looking rather good at this stage, so it should be a great afternoon! So even if you only have 1296 MHz, get on air and enjoy what amateur radio is all about - having enjoyable radio contacts! You may even become inspired to go further!
Cheers and 73,
--Doug Friend, VK4OE.
p.s. I plan to be active from North Stradbroke Island with all microwave bands from 1296 MHz to 76 GHz inclusive.
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