Bitcoin donations to: 1CE9UfWJcHBYkWPns7iqBqZgKhd5xfqEaM thanks!
Buy Bitcoins easily by clicking HERE and get $10 in free bitcoins!

Web hosting in Iceland - OrangeWebsite.com

Recent Posts

Pages: [1] 2 3 ... 10
1
It is a good read. I've never thought of a guitar string as a antenna, but it was good for understanding it.

Joel
N6ALT
2
Antennas / Understanding Your Multiband End-Fed Half-Wave By Daniel Marks, KW4TI.
« Last post by gil on August 18, 2017, 11:37:02 AM »
Great read... File attached.

Gil.

3
General Discussion / Re: U.S. Navy unit discovers HF radio communications
« Last post by gil on August 18, 2017, 11:35:27 AM »
One word comes to mind... Duh!

Gil.
4
General Discussion / Re: U.S. Navy unit discovers HF radio communications
« Last post by htfiremedic on August 18, 2017, 09:53:35 AM »
That's funny!   Didn't they use that "new technology" in Vietnam??  I may be mistaken, but.....


Sent from my iPhone using Tapatalk
5
General Discussion / U.S. Navy unit discovers HF radio communications
« Last post by Sparks on August 17, 2017, 10:26:14 PM »

The Commander of Task Force (CTF) 75, Fleet Combat Camera Pacific (U.S. Navy), has recently discovered that HF Radio across the Pacific actually works …


Commander, Task Force (CTF) 75 successfully completed communications systems tests using high-frequency (HF) radio waves to broadcast voice and data 6,050 miles from Naval Base Guam to Port Hueneme, California, July 27, 2017.


The assessment tested the capabilities of expeditionary forces to use HF waves to deliver data over the Pacific. HF has become a viable alternative for military forces when more common forms of communication, such as satellites, are unavailable.
[…]
Common communication devices used by the U.S. military incorporate satellites. CTF-75 has been testing HF systems in the case of satellite communication failure. HF is a frequency wave broadcast that is transmitted around the curvature of the Earth. Unlike other forms of frequencies, such as very-high frequencies and ultra-high frequencies, the transmission is not distorted by terrain or physical obstructions.


“We may not always have access to operational equipment or the latest assets, but as communicators we should have a backup plan that is ready to be executed,” said Carmon.


Well done, boys! — Next: The Wheel. And then: Gunpowder …
6
New To Radio / Re: Do I need an SWR meter for a backpack rig?
« Last post by SlowBro on August 17, 2017, 12:16:46 PM »
Thanks all! I'll try to remember to report my success or failure later.
7
Antennas / Re: Can you recommend a backpackable 40M QRP homebrew design for my BoB?
« Last post by gil on August 16, 2017, 08:25:37 AM »
Don't forget to post about it, with photos ;-)

Gil

Sent from my SM-G928F using Tapatalk

8
General Discussion / Re: PLEASE READ! Welcome to Radio Preppers.
« Last post by gil on August 16, 2017, 08:22:04 AM »
Hello and welcome aboard :-)

The most reliable band for NVIS is 80m.  Don't ditch the 2m band... Using USB on 2m can greatly increase its range. 2m USB can cover the near-regional range and 80m the far-regional range. Both can work DX under some conditions, especially 80m. Any band works for local, so we might as well use VHF or UHF with shorter antennas.

Gil

Sent from my SM-G928F using Tapatalk

9
Antennas / Re: Can you recommend a backpackable 40M QRP homebrew design for my BoB?
« Last post by SlowBro on August 16, 2017, 07:53:21 AM »
On your advice I picked up the parts to make a tuner with SWR LED indicator. Simple and cheap circuit. For the antenna wire I will solder in spade connectors to alter the config between Windom, end fed, and dipole. Thus I won't have to pick only one configuration. I'll carefully match coax in the New Carolina Windom style having its necessary 10' of coax vertical, and a choke of ferrite snap ons and coiled coax at the end. That choke should only benefit the end fed and dipole configurations so it should make a great three-in-one portable antenna.

The radiator wire and center balun will be loosely taped to a very long fishing line. That line will do all of the load carrying and the wire can thus be thin (lightweight) and use spade connectors that would otherwise disconnect when strung between trees. No stress or load carrying on the radiating components. A rock on both ends, slingshot the ends into trees, pull both sides down, and tie it off.

Testing in a month or so and I'll try to remember to update this thread with my results.

By the way forum notifications don't seem to work. I don't get emails when someone replies.
10
General Discussion / Re: PLEASE READ! Welcome to Radio Preppers.
« Last post by Commsguy on August 16, 2017, 07:29:58 AM »
Hello everyone,

I'm a prepper located in Western Europe and I stumbled upon this forum in the links section of the webpage of OH8STN - awesome to find an entire forum dedicated to ham radio & preparedness, without too much focus on only either of those topics, but the best intersection where both topics meet.

As a prepper I got in to ham radio & comms-gear a few years ago when I picked up a scanner and later a few chinese HT's and I extensively started testing ranges to get a good understanding of communication capabilities. A huge pet-peeve within the prepper communities are people buy a few Baofengs and basically make grotesque assumptions on their capabilities or usefulness, nor not even practice using & operating their radios. Not to mention how little time people spend on finding & evaluating the right or up-to-date frequencies to get news or information from.

I've come to the conclusion that 2m & 70cm is pretty much only useful for short-range, tactical communications for those people in your prepper group that are very near or with whom you are directly working together. For instance the neighborhood watch, on patrol or in vehicle convoys or vehicle to dismounted. Unless Party A and Party B both have Diamond VHF/UHF antennas on their roof, I've kept VHF & UHF prepper communications within 5 Miles tactical range (that is with external DIY antenna's but not in any optimum situation. Better to be conservative with range rather than overestimate). For obvious reasons I do not wish to rely on amateur repeaters.

That brings me to my next and latest research, where I've spent the last year looking into: NVIS. I've already ready a few threads on this forum and I've spend so much time reading all available articles and research into, ranging from the USMC antenna books to the latest research on NVIS from 2015 (http://www.vederfonds.veron.nl/PhD%20Thesis%20B.A.Witvliet%202015.pdf)

A few problems I can't get around are so many articles praising NVIS on 40 meters. Most of the amateur radio articles on NVIS are from the United States, and I have some problems with that:
  • The Unites States is huge compared to Europe, if one makes an international contact 320 kilometers out (200 miles) that would be in the States only the next state over
  • After keeping an eye on ionograms (http://digisonde.oma.be/latestFrames.htm) daily for a year, I've never seen the foF2 frequency above 60 meters, and I hardly ever hear amateurs from my country on 40 meters, and the times I did I suspect it was the groundwave playing a factor.
     I know the solar cycle is currently at a minimum, and foF2 could easily go to 40 meters in a maximum
  • professional or commercial articles on NVIS only give very broad and shallow information in regard to frequency choice which are no help at all

A close friend recently started prepping as well and I want to establish a (for HF very) short-range method of communication. The ranges to think of are 15 to 75 miles. I'm having the hardest time with finding the right frequency band that would provide the highest reliability for daily communication, all-year and preferably solar cycle round.

PS: Saw the CB sub-board, maybe that should/could be expanded to general license-free comms (to include PMR446 for instance) and add an NVIS subboard.
Pages: [1] 2 3 ... 10