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(Members: 3, Guests: 330) on 06 Jun : 15:15

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Support 4hv.org!
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.

Special Thanks To:
  • Aaron Holmes
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The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Featured Project
Another week, another featured project. This week, we have Uzzors' Coolidge X-ray Machine, a fascinating foray into the world of x-rays. He's managed to capture some very fascinating images in a very well-done thread. If something about the project strikes your fancy, please stop by Uzzors' project thread, and let him know what you think.

As always, feel free to PM me if you have a suggestion for the next featured project.

Uzzors wrote ...

It's about time I tried using a Coolidge X-ray tube I bought on Ebay last summer. I was given no information on it other than it's a dentist tube, so everything will need to be determined empirically. The x-ray tube is 30cm long and 6cm in diameter. The filament has a resistance of about 0.2 - 0.3 Ohms, and is wound "Benson" style, or as a helical coil. So where do I start? I'll need to know an approximate power rating of the tube, and maximum voltage. Since the x-ray intensity is proportional to the filament temperature, I thought I could measure the anode current at very low filament temps, and assuming the anode current rises linearly with filament current plot a graph. A suitable filament current range can then be determined.

I don't even have ballpark figures for this tube, so your guess is as good as mine! Tube power and tube voltage.

Additional pictures:

Ipod nano and k750i:

TV flyback multiplier, digital watch and dosimeter:

Posted by Chris Russell on Thursday 14 May 2009 - 21:20:49 |Comments are turned off for this item |printer friendly create pdf of this news item
Featured Project
Back by popular demand, it's the featured project of the week! I've picked the first one myself, but if you have any suggestions for next week's featured project, please feel free to send me a PM.

This week, Cesiumsponge has a great project going with his Tesla Thermionic Valve Wireless Energy Transmitting Apparatus. In an act of showmanship that Tesla himself would no doubt approve, the project is not yet fully unveiled. Details are still sketchy, but it looks great so far. He's obviously paying a lot of attention to small details.

Feel free to stop by Cesiumsponge's project thread and let him know what you think.

Cesiumsponge wrote ...

Gather around and witness the fruits of Tesla's lifelong work! Expeditiously, I shall be unveiling an unrealized dream of his, a masterful thermionic valve apparatus of superlative wonder and whimsy after many a sleepless night of scheming and laborious toil.

A mechanism of excessively high potential and very considerable frequency.
A contraption to capture the wild possibilities of a dawning age of industrialism.
A device to astound and mystify the youth,
A machine to bewilder and confound the old!
Fascination and fear,
Stupor and surprise!

More lively than an electrotherapy session and twice as delicious as a cool radium tonic, guaranteed!

Before the grand unveiling, verification, and tuning takes place scant weeks from now with all notes, I will tantalize this kind audience with some previews.

Posted by Chris Russell on Thursday 07 May 2009 - 15:54:17 |Comments are turned off for this item |printer friendly create pdf of this news item
Our very own Dave Marshall, AB3I, will be on the air on Friday, March 20th, 2009, looking to make contact with fellow hams -- 4hv.org hams in particular. The great news is that he'll be aeronautical mobile from a military aircraft, meaning he'll have a huge height advantage. He'll be over the southeastern US from approximately 0930 EDT to 1200 EDT (1330z to 1600z), operating at 14.240MHz, perhaps moving up or down a bit to minimize interference.

Edit: If 20m is completely dead, Dave will move down to 40m, 7.175Mhz, up or down for QRM.

He should have a great signal just about anywhere with active 20m propagation. Anyone who'd like to contact him is encouraged to give it a try; it will be great fun, and a rare opportunity to work an aeronautical mobile station on HF. If you can't bust through the pileup, do not despair. He will call for 4hv.org members specifically from time to time.

If you're looking for him, be patient, as he does have a job to do that may take him away from the radio here and there. Just be patient; he should be pretty hard to miss once he's on the air.

Discussion will be on this thread: . Please direct any questions there.
Posted by Chris Russell on Thursday 19 March 2009 - 19:34:50 |Comments are turned off for this item |printer friendly create pdf of this news item
Remote Exploit'd!
Hello all,

My apologies, but we've lost the last week's worth of posts due to a server vulnerability. Some script kiddie's worm was able to get into the server. The server may be slow for a few more hours as I restore all the other accounts on the server from the latest backup. I've tracked down the security hole to ensure that it can't happen again.

Again, I'm terribly sorry about the mess. I'll be glued to the computer for most of the night restoring data. Feel free to drop me a PM on the forum, or contact me on AIM, username OMJamal. Any comments, questions, or concerns are appreciated.

Posted by Chris Russell on Friday 23 January 2009 - 21:42:19 |Comments are turned off for this item |printer friendly create pdf of this news item
Progress Report
I just wanted to let everyone know that work on the new site is progressing slowly but surely. I appreciate everyone's patience. In related news, both of the main computers in my household died this week, so I am stuck with my file server box. I guess it never rains, but it pours! Things may slow down for a bit until I can save up for a replacement, but I'll try to keep the impact to a minimum. As always, feel free to PM me with any questions or comments.
Posted by Chris Russell on Saturday 12 July 2008 - 18:26:42 |Comments are turned off for this item |printer friendly create pdf of this news item
4hv Migratory Junk Box
For anyone who is interested, we're starting a migratory junk box. Please see the details at .
Posted by Chris Russell on Wednesday 02 July 2008 - 20:17:47 |Comments are turned off for this item |printer friendly create pdf of this news item
Changes and Feedback
I'd like to offer a huge thanks to everyone who has contacted me and pitched in to help with the big changes planned for 4hv.org. Everything is still in the process of being planned out, but I will do my best to keep everyone updated via regular announcements here on the front page.

One of the best suggestions that I've had recently is that we organize some sort of group chat so that we can all get together in the same informal setting and toss thoughts and ideas around. I think that's a great idea, and I'd enjoy the chance to interact with everyone. To that end, I'd like to invite anyone and everyone to the 4hv.org chat room, #hvcomm, on the shadowworld irc network, this Sunday, June 29th. The chat will be held between 5pm and 7pm EDT (2100-2300 UTC). During that time, the chat room will be moderated and dedicated to the sole purpose of discussing the future of 4hv.org. Anyone and everyone is encouraged to participate. It will be fun, honest! Logs will be made available in real time so that people who come in late will not be lost. If there's interest, we can extend the chat beyond this time. Of course, you're welcome to show up early or stay late.

Here are the best ways to get into the chat room:

* Download an IRC client such as mIRC or XChat, connect to the ShadowWorld network, and join #hvcomm. Note that you may need to add shadowworld.net to the server list. This link may work for you if you have an IRC client installed: irc://irc.shadowworld.net/hvcomm

* Use the chat room link on the left side of every page here on 4hv.org to access the Java client.

* Go to http://shadowworld.net/cgi/ . #hvcomm is now listed on the drop down channel list.

Hope to see you all there!
Posted by Chris Russell on Thursday 26 June 2008 - 05:26:34 |Comments are turned off for this item |printer friendly create pdf of this news item
4hv.org Poll Results
Here are the results of the 4hv.org poll . Thanks for your patience while I tallied the results. Overall, there were 102 responses to the poll. The numbers you see may not be exactly what you'd expect, as some people skipped questions, and some people answered the same question with multiple points. Once again, a big thanks to everyone who took the time to respond.

As you can see, there was a lot of helpful feedback about the way things are going here. There were also a lot of helpful comments that just can't be included in such a simple summary. Some people went to really great lengths to make their opinions known. Now that I have the feedback I needed, I'd like to address what I plan to do to improve 4hv.org.

Planned changes to 4hv.org:

Better forum software: First, and foremost, we need better software running the site. e107 is fine for what it is, but clearly, there are a lot of needs that just aren't being met with the current software. After a lot of looking around, taking into consideration the things below that I plan in implementing, there's really only one option: phpBB.

Wiki integration: One interesting thing uncovered by the poll is that we could more than double our current base of wiki contributors, if the wiki simply weren't so darn easy to ignore. Probably the best solution here is to integrate the wiki more with the site. Its purpose needs to be made clear, it needs to be easier to use and log into, and it should be prominent enough that people realize it is there and what it does.

Revamped forum rules: Some of the rules we have are unclear. Some of the rules we have are old. In any case, there are an awful lot of them to remember. Better forum software will allow us to automate many of the rules, and thus remove them from the list. Example: automatic image resizing and double post prevention would allow us to remove those rules from the list.

Careful selection of users: The general consensus seems to be that we are having a problem with our signal-to-noise ratio, and that I need to re-introduce some sort of screening process for potential members. I know from experience that open registrations can lead to a lot of "noise" in the forum. I also know that an application system can frighten good people off, while still allowing potentially bad members in. I also know that an application system is costly in terms of time and effort to maintain. The best solution that I've seen is to allow users a "trial period," wherein new users will be able to make an arbitrary number of posts. At that point, the user can't make any more posts unless they have a high enough rating through the site's feedback system. This is the system I want to implement here at 4hv.org.

Streamlined design: 4hv.org's layout needs to be streamlined to allow easier access from a variety of browsers and devices. People with mobile devices or low bandwidth need a better way to access the site. We also need better implementations of things like RSS feeds, that make the site more convenient to use.

New forum structure: Some parts of the forum are not very active, while others can be almost too active at times. We all need to re-evaluate the current topic structure and decide what can go, and what needs to be expanded.

Moderator transparency: A few notable conflicts on the board have pointed to the need for greater transparency in the moderating process. Again, the new software proves itself to be useful here: a public log of all actions taken by moderators or administrators will be available for anyone to read. The hope is that this will foster a greater understanding of what moderators do, and also prevent any possible misunderstandings over their actions.

A new front page: The front page of the site can get awfully stale at times. It also does not do a whole lot to explain what 4hv.org is, or what it does. While announcements are certainly important, it might also be nice to include some information about who we are, what we do here, and why we do it. Not only do I want to re-write the front page, but I also want to let our members submit items for inclusion on the front page, such as featured images or projects, in a simple manner -- possibly without moderator intervention, for trusted members.

Make use of what we've done: This forum, as well as the two archives, contains massive amounts of information. All three, as well as the new software, must implement a much better search function, so that information can be found. This will help in keeping the same questions from popping up over and over, as well as draw new people to the site, possibly via Google searches.

Increase activity: Once the majority of these changes are in place, we will be in a much better position to start attracting new members to 4hv.org. This can be done in a variety of ways. I'd like to make simple banners and buttons available for linking, as well as possibly investing in placing ads in relevant locations. Several members kindly offered their assistance with recruiting people at their workplace, or at their university. Efforts like that will go a long way to ensuring that we are reaching our highest potential.

Other tweaks: I've already disabled the CAPTCHA on login, since it turns out a lot of people were annoyed by that. Hopefully the potential for password brute-forcing is minimal. Note that completing the CAPTCHA will still be required in order to register or reset your password. Many of the other suggestions made can be implemented on new software: math rendering tools, user image galleries, user video / youtube galleries, and more.

How you can help:

Donations: Every dollar helps. The less I have to work to pay for 4hv, the more time I have to work on 4hv. I understand that not everyone can donate, and that not everyone wants to -- but if you are able, it would help me a great deal to be able to get this undertaking completed sooner, rather than later.

Feedback: Any feedback on the planned changes would be helpful -- maybe I left something out, maybe something just seems wrong. You can leave a comment on this news item, drop a note in the suggestion box, or contact me directly via private message. Any contact at all is always welcome and appreciated.

Moderation: If everything goes as planned, we will probably also need a few more moderators to round out the team. I realize this goes against the poll, but the general feeling amongst the moderators is that we need more help. The public moderator log should help people understand what is going on "behind the scenes." If you've thought about moderating, this might be a good time to join the team.

I apologize for the length of this news item, but I feel this is an important matter. 4hv.org turns seven years old this July, and I'd like very much for the site to continue to be a useful resource for another seven years, and beyond.

Again, let me emphasize, any feedback at all is welcomed. Please feel free to drop me a note with anything you might have to say.

Your Humble Administrator,
Posted by Chris Russell on Wednesday 11 June 2008 - 04:19:17 |Comments are turned off for this item |printer friendly create pdf of this news item
Multilingual Members, Your Help is Needed
If you speak any language other than english, we need your help! Please see this thread: for more information.

Any help with this matter would be greatly appreciated. I can't discuss the nature of the project at the moment, but I can assure everyone that it will be of interest to many of our members. Contributions will, of course, be properly credited.

In other news, I'd like to thank everyone for their participation in the 4hv.org poll. Having feedback from users is a very important part of making sure 4hv.org continues to meet the needs of its membership for many years to come. So far, I have received many helpful responses, and I look forward to implementing many of the suggested changes. It looks like results have stopped trickling in, so the data is going to be compiled in the near future. However, if you have not yet answered the poll, there's still time -- just not very much of it. For those who expressed an interest in the poll's results, I plan on making the results available for everyone very soon.

Posted by Chris Russell on Saturday 17 May 2008 - 18:47:51 |Comments are turned off for this item |printer friendly create pdf of this news item
Hello all,

I apologize for the recent downtime. Everything should be pretty much back to normal now. If you notice anything that seems wrong, please contact me via PM or use the Moderator/Admin Contact board.

Posted by Chris Russell on Sunday 10 February 2008 - 18:01:39 |Comments are turned off for this item |printer friendly create pdf of this news item
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