Recent posts
#12
General Radio Discussions / High school students contact I...
Last post by DU2XXR - Feb 02, 2024, 09:08 AM #13
HF and Propagation / EFHW modeling
Last post by DU2XXR - Feb 01, 2024, 09:37 PMhttps://sz1a.org/en/featured-articles/end-fed-half-wave-efhw-antenna-modeling-with-mmana-gal/
QuoteGenerally speaking, EFHW antennas seem to be a good compromise antenna due to their increased practicality of feeding at the wire-end, which is their significant advantage. However expect performance similar to (or slightly worse than) an OCFD/Windom, nothing more. There is no pot of gold at the end of this rainbow! 😀
#14
General Radio Discussions / The most hackable radio
Last post by DU2XXR - Feb 01, 2024, 08:44 AM #15
HF and Propagation / Re: USDR+ inexpensive QRP port...
Last post by DU2XXR - Feb 01, 2024, 08:36 AM #16
HF and Propagation / USDR+ inexpensive QRP portable...
Last post by DU2XXR - Dec 26, 2023, 03:05 AMFor this Christmas, my ham son and daughters pitched in to get me a pre-owned uSDR+ radio, which cost PhP 4,000 or the equivalent of $72, and it's been exceeding my expectations, so far. The Seller even included a free QRP guys endfed antenna un-un (which I believe is not the original one but a copy, but should work OK nonetheless). This still sells for around PhP 8,000 new or around $145. A quick search on Amazon got me this radio for $138. You may also find official sellers of the latest (tr)uSDX here.
I was quite sad to have to put up my mobile all-bander radio for sale, so this would be a good alternative for the occasional portable and even mobile HF operations.
Note that this is one of the derivatives/clones of the open-source USDX radio, and while the creators of the original project have expressed their disapproval of the numerous unofficial builds due to profiteering and differences in quality, I have decided to graciously accept this item and share my experiences with it with fellow hams.
Some details and observations:
https://n2rac.com/usdr-qrp-software-defined-radio-review-2c675521524f
I was quite sad to have to put up my mobile all-bander radio for sale, so this would be a good alternative for the occasional portable and even mobile HF operations.
Note that this is one of the derivatives/clones of the open-source USDX radio, and while the creators of the original project have expressed their disapproval of the numerous unofficial builds due to profiteering and differences in quality, I have decided to graciously accept this item and share my experiences with it with fellow hams.
Some details and observations:
https://n2rac.com/usdr-qrp-software-defined-radio-review-2c675521524f
#17
The Prepper Channel / Solar Superstorms: Planning fo...
Last post by DU2XXR - Dec 06, 2023, 01:10 PMSolar Superstorms: Planning for an Internet Apocalypse
by Sangeetha Abdu Jyothi
University of California, Irvine and VMware Research
https://www.ics.uci.edu/~sabdujyo/papers/sigcomm21-cme.pdf
by Sangeetha Abdu Jyothi
University of California, Irvine and VMware Research
QuoteIn this paper, we show that a powerful solar superstorm has the potential to cause massive disruption of the Internet. Astrophysicists estimate the likelihood of a solar storm of sufficient strength to cause catastrophic disruption occurring within the next decade to be 1.6 to 12%. Paying attention to this threat and planning defenses against it, like our preliminary effort in this paper, is critical for the long-term resilience of the Internet. Several challenges remain open in this space. How can we model infrastructure failures more accurately? How do we factor in solar threat during Internet in- frastructure and systems design? How can we help operators in making disaster preparation and recovery plans? We anticipate that this paper will provide an initial impetus towards answering these important questions.#Digital #SpaceWeather #CME #Communications
https://www.ics.uci.edu/~sabdujyo/papers/sigcomm21-cme.pdf
#18
Public Announcements / A Guide to Joining the DX1ARM ...
Last post by DU2XXR - Nov 29, 2023, 06:51 PMAs this is a traffic net, the net controller directs stations who have
traffic/messages/announcements to transmit to the net or to another station.
Schedules
VHF 144.880 MHz
M,W,Sat 2000H-2100H (1200Z-1300Z)
UHF 431.600 MHz C4FM
M,W,Sat 0930H-1000H (0130Z-2000Z), Sat 1930H-2000H (1130Z-1200Z)
UHF 431.600 Analog FM
(No net schedule)
For more information, you may also visit our website at https://dx1arm.com or email us at digital@dx1arm.net .
traffic/messages/announcements to transmit to the net or to another station.
- The order of priority for the net is as follows: Emergency, priority, digital/network, portable, mobile, and fixed stations.
- If you have traffic for the net or for a station, state your CALLSIGN "with traffic" when checking in. The Net Controller will ask you to stand by and will pull you out to deliver the traffic when it's your turn.
- If you have traffic for the net, you may transmit/deliver it once the Net Controller instructs you to do so.
- If you have traffic for another specific station, Net Controller will call that station so that they can receive it. If you have many items of traffic or a longer message, Net Controller may direct you to an alternative frequency or channel to make your message exchange.
- If that station is unavaialble, Net Controller may record the traffic for later relay, or ask another station to do so.
- If you don't have traffic for the net, simply state your CALLSIGN when checking in. The Net Controller will acknowledge and log your callsign. You will be asked to stand by for any possible traffic, announcements, or relay. You may be pulled out if the NCS needs to update the DX1ARM database with your details if we don't have it yet.
- You may ask to be excused from the net when you are leaving by saying CALLSIGN "checkout" or CALLSIGN "checking out". Net controller will mark the time you have been excused and no longer available to receive traffic.
- Announcements are made toward the middle of the Traffic Net, when a certain number of DX1ARM members are in attendance to ensure effective dissemination of information.
- Priority or emergency calls and traffic are acknowledged at any time during the net. If you have priority traffic, say CALLSIGN "priority". If you have emergency traffic, say CALLSIGN "emergency". Net control will ask all stations to stand by and will immediately pull you out for your traffic.
- Please leave a 2-second gap between transmissions to accommodate possible emergency or priority traffic or weak, distant, or network stations.
- The net will close on time having fulfilled the purpose of traffic exchange. Only priority traffic is allowed for late check-ins.
Schedules
VHF 144.880 MHz
M,W,Sat 2000H-2100H (1200Z-1300Z)
- BM DMR TG515044
- YSF 72170 DX1ARM-VHF-RPT
- ASL 50763
- HH 94119
- Echolink DX1ARM-R
UHF 431.600 MHz C4FM
M,W,Sat 0930H-1000H (0130Z-2000Z), Sat 1930H-2000H (1130Z-1200Z)
- WIRES-X DX1ARM-RPT-LINK 89934
- BM DMR TG51518
- YSF 78427 DX1ARM-RPT
- ASL 50763
- HH 94015
- Echolink DX1ARM-L
UHF 431.600 Analog FM
(No net schedule)
- BM DMR TG 515100
- YSF 11096 DX1ARM-UHF
- ASL 518254
For more information, you may also visit our website at https://dx1arm.com or email us at digital@dx1arm.net .
#19
Public Announcements / Re: DX1ARM Traffic Net
Last post by DU2XXR - Nov 15, 2023, 09:18 PMUpdate: 2023-11-15
DX1ARM Traffic Net
On behalf of the net manager, 4I1FCI, I would like to share some changes we have been working on with the aim of improving the DX1ARM Net.
You may have noticed a different format in the recent week's net calls, as we are focusing on effective delivery of traffic, e.g., facilitating traffic exchange between net members (by "net members" we mean anyone who checks into the net). The goal is to establish the net as an effective means to exchange traffic, and also to make it an efficient way of checking in for both club members and friends of DX1ARM.
Thank you for your cooperation and support.
A summary:
Notes:
As we are continuously working on improvements, we appreciate feedback. This is actually just the first phase, as we intend to incorporate elements of the radiogram or additional relay mechanisms (e.g., delivering traffic outside of the net or via other nets) in the future.
You may check out our net schedules at https://dx1arm.com .
DX1ARM Traffic Net
On behalf of the net manager, 4I1FCI, I would like to share some changes we have been working on with the aim of improving the DX1ARM Net.
You may have noticed a different format in the recent week's net calls, as we are focusing on effective delivery of traffic, e.g., facilitating traffic exchange between net members (by "net members" we mean anyone who checks into the net). The goal is to establish the net as an effective means to exchange traffic, and also to make it an efficient way of checking in for both club members and friends of DX1ARM.
Thank you for your cooperation and support.
A summary:
- Net members are called to check-in and share traffic/messages.
- Net controller takes note of "attendance" of club members. Club announcements are made once a good number of club members are checked-in and in-attendance.
- Guests are welcome to check-in at any time. However, everyone is expected to listen carefully to net controller's instructions and wait for their turn.
- For no-traffic checkins, the net controller immediately acknowledges their callsign as logged and cleared, with no need for further pull-out, except if they need to clarify information such as name and location (to update the DX1ARM database).
- Priority or emergency calls and traffic are acknowledged at any time during the net.
- Net ends on time having fulfilled the purpose of traffic exchange. Only priority traffic is allowed for late checkins.
Notes:
- Priority or emergency calls and traffic are acknowledged at any time during the net.
- DX1ARM maintains a list/database of stations with their info (name, location, etc). The NCS may pull out stations to ask about their information if they are new to the net, a new ham, or not yet in the database.
- Net participants are asked to listen for the entire duration of the net or after they have checked in for the purpose of relays or receiving traffic. A station may ask to be excused or "checked out", and the NCS will mark that station as checked out after a particular time.
As we are continuously working on improvements, we appreciate feedback. This is actually just the first phase, as we intend to incorporate elements of the radiogram or additional relay mechanisms (e.g., delivering traffic outside of the net or via other nets) in the future.
You may check out our net schedules at https://dx1arm.com .
#20
Public Announcements / DX1ARM Traffic Net
Last post by DU2XXR - Nov 14, 2023, 05:40 AMDX1ARM Traffic Net
On behalf of the net manager, 4I1FCI, I would like to share some changes we have been working on with the aim of improving the DX1ARM Net.
You may have noticed a different format in the recent week's net calls, as we are experimenting with a new purpose and format of the DX1ARM Net. We are now prioritizing club members, and we are facilitating traffic exchange between net members. The goal is to establish the net as an effective means to exchange traffic, and also to make it an efficient way of checking in for both club members and guests.
Thank you for your cooperation and support.
A summary:
As we are continuously working on improvements, we appreciate feedback. This is actually just the first phase, as we intend to incorporate elements of the radiogram or additional relay mechanisms (e.g., delivering traffic outside of the net or via other nets) in the future.
You may check out our net schedules at https://dx1arm.com .
On behalf of the net manager, 4I1FCI, I would like to share some changes we have been working on with the aim of improving the DX1ARM Net.
You may have noticed a different format in the recent week's net calls, as we are experimenting with a new purpose and format of the DX1ARM Net. We are now prioritizing club members, and we are facilitating traffic exchange between net members. The goal is to establish the net as an effective means to exchange traffic, and also to make it an efficient way of checking in for both club members and guests.
Thank you for your cooperation and support.
A summary:
- During the first 30-40 minutes of the net, only Club Members are called to check-in and share traffic/messages. Guests are advised they will be called during the latter part.
- Club announcements are made once club members are checked-in and in-attendance. This is to ensure maximum reach of the club announcements.
- Guests are invited to check-in after the members' traffic and announcements proper.
- For no-traffic checkins, the net controller immediately acknowledges their callsign as logged and cleared, with no need for further pull-out. Net controller will only pull out stations who say "with traffic". The traffic can either be directed to the net or directed/relayed to a fellow net member.
- Priority or emergency calls and traffic are acknowledged at any time during the net.
- DX1ARM maintains a list/database of stations with their info (name, location, etc). The NCS may pull out stations to ask about their information if they are new to the net, a new ham, or not yet in the database.
- Net participants are asked to listen for the entire duration of the net or after they have checked in for the purpose of relays or receiving traffic. A station may ask to be excused or "checked out", and the NCS will mark that station as checked out after a particular time.
- Net ends on time having fulfilled the purpose of traffic exchange. Only priority traffic is allowed for late checkins.
As we are continuously working on improvements, we appreciate feedback. This is actually just the first phase, as we intend to incorporate elements of the radiogram or additional relay mechanisms (e.g., delivering traffic outside of the net or via other nets) in the future.
You may check out our net schedules at https://dx1arm.com .