A fellow Ham sent me the link to this video and I am speechless! The examples you give in illustration, and the verifiable references you provide, demonstrate you really are putting out concrete and useable information. Super-easy to follow and understand. You don’t talk over heads. Not only military/vet friendly, but beneficial to anyone who cares to learn. Finally, without question, you impart in a number of minutes, what it takes many folks years to learn. Thank you for sharing and keep up the great work! -AI6AM
Ditto! I spent 22 years in the Army, the last 16 years as an Air Traffic Controller including 2 tours in VietNam, and never learned this much about HF communications. Now, at 83, I'm a beginning Ham operator, and this is the best instruction I've received - ever - on NVIS. Blessings & 73, - KJ5APR
Magnificent presentation. I wish I could give you two thumbs up. I am very intrigued by the "Terminated Folded Dipole". It looks like a good choice for ALE work given the broadband nature. Well, done!
Great video!!!! I have noticed that the terminated folded dipole antenna mention is on top every Army National Guard building in Oregon. Thanks for your hard work putting this information together. 73
Yeah...you always...and I mean ALWAYS inventory aka SL-3 list, your gear before you left for the field. ran into what you are saying numerous times. made more field expedient antennas more often than we liked to.
I only recently found this channel. The content is brilliant and you have inspired thoughts on NVIS usage for my mobile HF plans. I hope you find the opportunity to complete Episodes 7-9 and beyond. Thank you. VE1PS
Brilliant video and very informative. Well done. I run (for now) a 65' T2FD (Terminated Folded Dipole) and to be honest it is the greatest thing since sliced bread 😀. With 100 watts I have no difficulty working into the U.S., VE, VK on 40m and receive reasonable reports. I plan to upgrade the T2FD with a high power terminating resistor to run a bit more power, also to increase the length to 90'. Feeding it with 450Ω is also something I am considering. I find it an exceptionally quiet antenna QRN wise, even if a station is weak you can still work him/her without and difficulty.
I would like to review Dave's paper but I cant find it at the link provided. Could you send it to me or possibly share a new link? Great videos, thanks for taking the time!
Hello Matthew - That was a really great and informative video. I am a big fan of the T2FD and I'm wondering if you could give a short talk on the T2FD regarding its operation in the 30/35 degree setup. I have my T2FD for quite a while now in the sloped position (35 degrees) and to be honest I wouldn't use any other wire dipole. Over the years I have used the usual Trapped Dipole (W3DZZ) and the G8KW Trapped Dipole and a Doublett but the T2FD beats them hands down for being a super QRN free (almost) in comparison to a Dipole. Even running QRP I have had contacts into the US. Thank you for uploading such a great series ov videos and information. 73's de Ger EI6DP
Ger, thanks for the kind feedback. You have quite the setup on your end. My experience with T2FD has been the Tennedyne TD-90HP800 in use at West Point. Before we installed a JK Mid-Tri 40 this past summer, the T2FD was the quickest we could set up between two ends of Bartlett Hall. We could only install at level with top of roof and yet we were able to get California (and a station in Vancouver) and as far as Slovenia as our west and east limits. I will add to my list of follow-on vids one on T2FD specifically and thank you for recommending.
What about the end fed half wave antenna? Only one support necessary. Resonant, often on several bands. No counterpoise. Great antenna for portable work.
If I wanted to add another wire to cover the 60 m band is that doable or would it create too much interference with the existing two wires that are already there
When using an inverted V does the center support and side stakes need to be in a strait line on the ground or is it ok that form more of a triangle pattern to save space?
Your mismatch of 7.1 efficiency would depend on your type of feeder as any mismatch loss is nagated by reflection gain, if balanced feeder is used you have vertually no loss no matter what size of mismatch or swr is
I'll be doing some training with some special forces guys in a couple months (I'm not special forces) as their radio operator. We will be getting jammed, and hunted and need to stay constantly on the move and also keep our radio signature small. I'm planning to only use tacchat (instant message) and only transmit every 12 hours. We will be in a heavily forested and mountainous environment. I feel confident in my ability as a communicator to get a NVIS shot the normal way but am looking for some more creative ideas to keep my radiation signal small and to keep my load light, specifically in antenna design.. Any help will be welcome.
Depends on freq and time of day. Check out the voacap analysis video in the series to learn how to simulate HF shots. If you bend back the whip so it is horizontal, it can also assist. Just depends on strength of ground wave vs. what is refracting back down from ionosphere
I commend you for putting such a good presentation together, however I urge you to reconsider your evaluation of the T2FD. the T2FD had a very specific mission and therefore it is not a universal antenna, it is by no means "broadband' because it functions well on only two harmonically related frequencies (determined by its physical dimensions and installation), and it is much more difficult to install than the inverted V vertical, the AS-2259. Also its inherant losses are far higher than you project due to the extremem balun ration and the dissipation resistor. It is not a braodband antenna, it only shows a very narrow range of impedance load to the transmitter, this was to provide protection to the early transistor outputs of the early military radios. tube outputs were far more tolerant of reflected power versus the fragility of the early transistor outputs. Also you seem to have skipped over the Fan-Lite antenna which is far superior to many of your presented types, however it requires a significant area for erection and several persons to erect it. Ther is a much more affordable and smaller antenna similar in construction, the Whiskey antenna from White Wolf. Teh best NVIS antenna is that one designed by Bonnie Crystal, it is an inverted V driven by an auto tuner. Works superbly.
Hey Jim, appreciate your comments. This overview was of antennas already widely available to units and then a small sample of others. The T2FD at West Point's W2KGY/AAM2P MARS station has been amazing with a 2:1 or better across all frequencies (verified with an Agilent Field Fox). It was also easy to setup. Feel free to contact me on enterprise email.
@@BoominLikeThunder it isnt just the antenna but the frequency you use. A dipole can work for both nvis and for long range. Use VOACAP to see which frequencies work best to reach location and for which time of day. You can switch between antenna types to simulate the shot as well. A simple dipole is all west point used for last two years and reached stations well into europe.
T2fd 90 is vswr 3:1 for below 3 hmz to get to 2:1 or better you need 180 ft version but the 4:1 balum is not going to be that good www.bwantennas.com/bwds.html
The TFD antenna is really just like any other dipole except it provides 2:1 SWR or better, generally, to across the entire HF band. That alone will not answer your question. Additionally it is not relevant which radio you are using....just the power level AND mode of communication AND frequency/time of day are key factors in figuring out whether you can make a shot between point A and point B. But backing up, most TFDs can handle up to 100watts and more expensive TFDs are designing to handle multiple kW. Next, to fully answer your question, I can't without fully understanding what you mean by "work". Work as in handling 20 watt input power? Work as in successfully making contact between an undisclosed point A and undisclosed point B? With the sunspot count as high as it is, 20 watts will get you pretty far using digital modes and pretty good distance in SSB voice.
@@militaryhfradio244 until I seen this video, I hadn't heard of a TFD. Previous HF Experience was done with a dipole, and inverted V. I am prepping for Noble Skywave, but so far the only kit I have is PRC 138, NVIS and a Harris Diapole Kit. No Amplifier, UPS or Coupler like I have used in the pass. I have enough spare heavy gage copper wire I believe to make a TFD. Going to buy some PFC pipe tomorrow and see what I can conjure up. Your video's are great and better then previous training I have done. Cheers!
@@davidpowelson4817 you cant get any more realistic training than that. You will be surprised by how well you can do with that. Just make sure you get your antenna high, run voacap analysis to figure out best freqs to hit certain areas at different times of day and switch between antennas that are oriented in different directions
