View Full Version : Dutch Long Wire
OK I've used the search function so hopefully this isn't posted somewhere or I'll drop and do 50....
I'm currently an RTO with a LRSC and next month I'm doing a pretty long commo shot (about 2,000 K). I've have had great guidance from teammates and the LRS manual, but I've never done a shot more than 20 K so this makes me somewhat apprehensive. My questions is this: will a dutch long wire work out to that range? And if so, will standard commo wire work or should I 'liberate' something better from the commo tent? Im using the 150 for HF comms...
I've got the LRS manual, some ancient text on commo (circa 1984 but still useful), and slideshows from LRSC.... but nothing on the long wire. Any experience with it?
Ret10Echo
08-21-2010, 05:08
OK I've used the search function so hopefully this isn't posted somewhere or I'll drop and do 50....
I'm currently an RTO with a LRSC and next month I'm doing a pretty long commo shot (about 2,000 K). I've have had great guidance from teammates and the LRS manual, but I've never done a shot more than 20 K so this makes me somewhat apprehensive. My questions is this: will a dutch long wire work out to that range? And if so, will standard commo wire work or should I 'liberate' something better from the commo tent? Im using the 150 for HF comms...
I've got the LRS manual, some ancient text on commo (circa 1984 but still useful), and slideshows from LRSC.... but nothing on the long wire. Any experience with it?
1984....ANCIENT....???
Ok, I'll skip that for now...but we'll come back to the whole "Ancient" thing. I'm just glad you were able to translate the hieroglyphs... ;)
Antenna selection is key only in the respect that certain designs will provide you with the correct direction (primary lobe) and the correct take-off-angle (based on the installation and height above "ground"). Frequency selection has more to do with the success or failure of a sky-wave shot. If you have been working in-close at 20k or so, this could actually be an easier link to establish, but if your frequencies are not compatible then life will become immediately frustrating.
It appears you have some time to do deliberate planning. Given that luxury the slicks on your antenna should provide you with the primary lobe and take-off angle based upon height above ground. Take some time to become familiar with those characteristics.
In the "ancient" past I have used long wires or terminated, sloping-V antennas to a great deal of success. These were "cut wire" antennas as opposed to kits, but building a resonant antenna increases your efficiency.
Summary: Do your homeowork (sounds like you started) and get with your spectrum manager on how the propogation models worked out.
Any more of you "ancient' HF guys have a nickle for the machine? :D
Albeham, I know you are out there...
R10
bravo22b
08-21-2010, 07:31
Well it's nice to see one our RTO's doing their homework.
Just to add some information, this HF shot between AP Hill, VA, and Indiana will be done using ALE (and maybe 3G ALE), and it is unclear what control we may or may not have over frequency selection.
To be tactful, we have had varying degrees of success with the frequencies selected in the past by whoever it is that is supposedly doing this for us (the S-6, I suppose).
That said, there is a lot of effort being put into this to make it successful.
To the original poster, keep doing your homework, try searching on this site for "PRC-150", check with your TL as to what materials may be available to make your antennas, since that may affect your choice of what to build. If time and materials allow, my suggestion would be to be prepared to build several different antennas, as Ret10Echo suggested, that should include a long wire and terminated sloping vee. Plan on conducting an LQA with each antenna and recording all the relevant information to include the LQA scores on each freq, time of day, antenna type used, etc.
Recording all this information will allow you to look at what frequencies worked best, which antennas worked better, etc., and start to build your toolkit of what works.
Green Light
08-21-2010, 10:39
Ah . . . The old days with half-rohmbics, dipoles, 17% off-centers, etc.
I'm not sure that I've ever heard of a "Dutch Long Wire." We didn't use it with the old AN/GRC-109. I know it looks "ancient" but it was a great radio (unless you were the LT who was cranking the generator. :D
Ret10Echo
08-21-2010, 10:43
Well it's nice to see one our RTO's doing their homework.
Just to add some information, this HF shot between AP Hill, VA, and Indiana will be done using ALE (and maybe 3G ALE), and it is unclear what control we may or may not have over frequency selection.
To be tactful, we have had varying degrees of success with the frequencies selected in the past by whoever it is that is supposedly doing this for us (the S-6, I suppose).
That said, there is a lot of effort being put into this to make it successful.
To the original poster, keep doing your homework, try searching on this site for "PRC-150", check with your TL as to what materials may be available to make your antennas, since that may affect your choice of what to build. If time and materials allow, my suggestion would be to be prepared to build several different antennas, as Ret10Echo suggested, that should include a long wire and terminated sloping vee. Plan on conducting an LQA with each antenna and recording all the relevant information to include the LQA scores on each freq, time of day, antenna type used, etc.
Recording all this information will allow you to look at what frequencies worked best, which antennas worked better, etc., and start to build your toolkit of what works.
A definite challenge having an ALE net that has stations at varying distances. It becomes a challenge to build an antenna that will meet multiple frequency requirements. Most of those fixed stations will have a multiband array of some size. Not so easily reproduced by the tactical operator.
bravo22b
08-22-2010, 06:49
A definite challenge having an ALE net that has stations at varying distances. It becomes a challenge to build an antenna that will meet multiple frequency requirements. Most of those fixed stations will have a multiband array of some size. Not so easily reproduced by the tactical operator.
I'm pretty sure I understand what you are saying here... at least the basic gist.
As it applies to the COMMEX that we are planning, this will be an HF link between two fixed stations, both using PRC-150's, and more than likely both using a field expedient antenna system.
MY admittedly limited understanding is that the issue of using a fixed length tactical antenna in a multiple frequency application is at least partially overcome by the internal tuning coupler in the 150. What I have been taught is that the tuning coupler is capable of electronically shortening the antenna length (but not lengthening), so a good compromise expedient antenna is a 1/4 wavelength of your lowest planned frequency (in this case, about 75', 1/4 wavelength for appx. 3 Mhz).
Again, my limited understanding is that the advantages of an ALE net outweigh the possible disadvantages of using one fixed length antenna for multiple frequencies.
I look forward to hearing some corrections or further enlightenment on the subject.
Green Light
08-22-2010, 13:50
Ah . . . The old days with half-rohmbics, dipoles, 17% off-centers, etc.
I'm not sure that I've ever heard of a "Dutch Long Wire." We didn't use it with the old AN/GRC-109. I know it looks "ancient" but it was a great radio (unless you were the LT who was cranking the generator. :D
What is a Dutch Long Wire?
1984....ANCIENT....???
Well when you are born in '87, anything prior seems that way ;)
MY admittedly limited understanding is that the issue of using a fixed length tactical antenna in a multiple frequency application is at least partially overcome by the internal tuning coupler in the 150.
This is what I have been taught as well. Using a long wire during insertion would be much more preferable to a long whip or cut-wire antenna, due to the time factor. Throwing out a piece of wire and rolling it back up is just plain easier.
In the hide site I will definitely try constructing different types of antennas and doing an LQA on each. Thanks for the tips, I look forward to any more advice. Good to see some C Troop guys on here as well.
Hello, here is what I think...
Get with your S-6 shop and talk to your Spectrum Manager. See if you can see or find out what freqs you are going to load in the rig for the ALE group.
Then like the one gent said, but to add, have a good dipole designed for the lowest freq. And get it up about 30 to 45 foot above. I know I am going to get told it should be a 1/4 wave up, I know but, do you have trees like that?
I also would try a end-feed-long wire. It will need to have at least a 1/2 wave cut for the lowest freq. The long wire is good for multi-band work by using harmonics, you can get the radio to use it in a efficient manner. Between the tuner in the radio and the wire it should give you a good usable antenna.
ARRL antenna handbook. Please look it up.
The long wire has no feed line, coax ,ect. It is feed strait from the radios antenna jack, and then pointed about 10 to 20 degrees off center, the direction you are going to shot this hf signal. Ground your radio with a small ground rod, 8" to 9" . Remember strait form the antenna jack, the little small middle point at the BNC jack. A small run of coax, 5", cut and strip it so there is a braid and a center conductor exposed. tie, wrap, etc, the center conductor on the wire, and the braid to the ground rod. The antenna is going to be long and it will need to be supported by a tree / pole etc and the end. Go up from the radio about 10 to 20 feet, then the rest strait out to the world. You could also add a ground wire to this, by running it along the ground under the other wire, this will help the antenna system. Be mind full here, you don't want to have the radio holding the weight of the antenna, you might want to use 550 cord tied to the antenna wire, then tie it to a good solid point so there is no tension on the radio.
Now if I loss you please ask.
Hope the Commo Gods smile on you. Remember Ground the radio!!!!!
:munchin
BT AR
Hello, here is what I think...
Get with your S-6 shop and talk to your Spectrum Manager. See if you can see or find out what freqs you are going to load in the rig for the ALE group.
Hope the Commo Gods smile on you. Remember Ground the radio!!!!!
:munchin
BT AR
Not much about a Long wire that I don't know - used it almost exclusivly with the 109 - but one thing I don't, apparently, know about is S-6. When did that function come to be? I assume that that it is "Signal." So is the Signal Officer now called the S6?
Just learning something new everyday.
Use to call it the C&E Shop, then the S-6 thing came to play due to the other S-shops.
Al
69harley
08-23-2010, 07:52
Google VOACAP, it is a very good HF propagation program. Input the locations of where you think you will be and where you think the other end will be. The software will also ask for current solar flux, transmitter power, and some other variables. After running the program, look at the MUF, LUF and FOT lines.
The frequencies that the S-6 gives you should be near the FOT line for the time periods that you plan to communicate on. If the frequency plan is not executable, then no amount of dutch longwire stuff will work.
The freq plan must be workable. Unfortunately, most freq managers are bean counters.
Electron
08-24-2010, 08:03
The text may be old, but the math doesn't change. You can have the best transmitter in the world, but if your antenna isn't cut right, you just ain't talkin' to no one, Especially with dipoles and inverted vees. Not sure about the Dutch Long Wire, though.
I was in before Gore-Tex too.
LongWire
08-24-2010, 08:21
Trail and error. Figure out what works and what doesn't. Whats the goal here, to conduct a commex or a hide with comms?
Given time and materials it should not be that hard. When we went to Ft Smith for the 18E commex my partner and I took plenty of claymore wire with us to augment the gra-50 that we had. We ended up building a 150' Half Rhombic antenna. Another buddy had a General Ham license and we worked the whole eastern seaboard and as far west as Hawaii with a PRC -104.
Sloping V-s were my favorite to use and made hitting Bragg easy. When we set that monster antenna up though, The guys at Bragg's ears were ringing!!!!
Training should be training, work with what you have and try as many configurations as time permits. Take good notes. Apply the math and make adjustments as necessary. Sometimes small adjustments to the angle will pay off huge dividends. As long as you know the principles you should be okay.
bravo22b
08-24-2010, 10:57
Google VOACAP, it is a very good HF propagation program. Input the locations of where you think you will be and where you think the other end will be. The software will also ask for current solar flux, transmitter power, and some other variables. After running the program, look at the MUF, LUF and FOT lines.
The frequencies that the S-6 gives you should be near the FOT line for the time periods that you plan to communicate on. If the frequency plan is not executable, then no amount of dutch longwire stuff will work.
The freq plan must be workable. Unfortunately, most freq managers are bean counters.
I think this may be our biggest challenge. I'll reserve judgment on whether we will get a workable freq plan for now, but I am not optimistic.
Whats the goal here, to conduct a commex or a hide with comms?
This is meant to be a COMMEX. The PRC-150 is still relatively new to our unit, and I believe that this is the first time we are attempting a skywave shot with them. With the right preparation and planning, this could be a great way to introduce our younger and more inexperienced soldiers to building antennas and getting good HF comms. Without good preparation and planning, well...:munchin
As an aside, I believe the "Dutch" long wire is just some strange nomenclature specific to this unit. Who knows how these things get started.
What is a Dutch Long Wire?
It's a Dutchman with a long wire, ha ha. Revome the word "Dutch" and it's just a long wire trying to not over-shoot a target 2000K away. I like the Vee best, or maybe a 1/4 wave length broad side, low take off, wide path.
Always have extra wire and a good supply of insulators. After the antenna is up, (cut to freq. length), regardless of type, and commo seems to be happening, have another team member or two raise a couple of other types. Nothing like having an antenna fail, for no known reason, and you're letting the "stupid, I've got a good idea" bug take over.
When is AIMC coming back?
WD
I'm sure it's just a label, a longwire is a longwire is a long wire, unless it's got a beard and long hair....like the Dutch (well they used to anyway).
Plenty of good info on here, and as most have stated, it's all about the freqs, antenna selection and take-off angle. Since you're doing the 150, is it with MIL STD ALE??? If ya load those up with freq's around the FOT you should be ok.
I would also add, if using any type of ALE, being it SOF ALE (with the 137) or MIL STD with the 150, I would use a non-resonant antenna (terminating it with resistors, not to insult your intelligence, just clarifying), therefore you can operate on several freq's without re-cutting your antenna to make it resonant. Word of note though, as the freq's change on the certain length of wire, the take off angle will also change IAW how many wavelengths of the operating frequency the wire is cut for.
Also.....get that anenna OFF THE FRICKIN GROUND, I've seen the good 'ol IRING, and several others that you just throw on the ground, with the low wattage man-pack radios, your just absorbing energy into the ground, not radiating it in the desired direction. Those were also primarily made for shortrange/NVIS shots anyway. It DOES NOT MATTER if the wire is insulated or not, EM energy travels on the outside of the wire (skin effect)....unlike electricity which travels through.
However, in antenna selection, with only 2k distance, a good 1/2 wave may work if you can get it elevated enough (for low take off angle), and the freq selection is propping, however it's on the fringe of it's range, but it may work. Only thing is, ya can't terminate a half wave, it's gotta be a multi-wave ant, so you would have to cut for each freq if a resonant 1/2 wave....which makes it not user freindly for any type of ALE stuff.
Anyway, my .05 worth....hope it helps
"When is AIMC coming back?"
haaa, prolly when all the satellites melt....then everyone will be wondering.....WTF now PL:rolleyes:
Thanks for all the responses, I'm learning alot more than I expected. This is my current understanding: Freq selection and antenna selection are equally important, however bad freqs will almost certainly eliminate the advantage of a great antenna setup. On the other hand, good freqs may compensate somewhat for a poor antenna. Am I correct in this (basic) understanding?
this could be a great way to introduce our younger and more inexperienced soldiers to building antennas and getting good HF comms.
This is what I'm hoping as well. It will be a great learning experience no matter what.
Green Light
08-27-2010, 14:25
I'm sure it's just a label, a longwire is a longwire is a long wire, unless it's got a beard and long hair....like the Dutch (well they used to anyway).
That's what I thought. I was wondering if it was something exotic like a 1.667 wavelength antenna with a terminating resistor. :D
Outside of school, I think I used a long wire once. I used the old 17% (or was it 19) off center a couple of times, but mostly we used dipoles of different descriptions. My TS in Germany was a former commo guy and taught me a couple of REALLY exotic antennas that he and his former senior commo came up with years ago. Hard to get the hang of but once you got it and learned the take off angles for the different freqs, it was really something. I still have the notes somewhere. . .
Thanks for all the responses, I'm learning alot more than I expected. This is my current understanding: Freq selection and antenna selection are equally important, however bad freqs will almost certainly eliminate the advantage of a great antenna setup. On the other hand, good freqs may compensate somewhat for a poor antenna. Am I correct in this (basic) understanding?
This is what I'm hoping as well. It will be a great learning experience no matter what.
I've seen more often then not, the other way. A good antenna will compensate for poor freqs. Even the most Sr. C&E officers and NCO's are limited by NSA guidelines. Some are saying the Sunspot game is coming back in 2012, nothing we've seen since the 1850's.
Nonetheless, keep the antenna high, the ground wave low. Maybe you'll hit your target. Energy waves may bounce every 20-60 miles.
FYI - A few us here belong to the 1/2 Watt club, (fictional) - reaching a HAMM operator while overseas to make a call to our families is kinda cool.
I see alot changing in the coming years.
bravo22b
09-13-2010, 06:24
In the FWIW category, the COMMEX that our unit conducted last weekend was successful.
The frequency set that we were given was not great, but there were about 3 freq's that were in the right neighborhood based on the VOACAP propagation model. Only one frequency was successful, all the others were straight zeros across the board. We ended up using MIL STD ALE, and were able to get pretty good LQA scores and send voice traffic.
The commo section BRS used the Harris 1944 dipole antenna kit, and was able to get scores in the 60's. My team set up a field expedient half wave dipole, appx. 5' off the ground, cut to length for the lowest frequency in the ALE channel group. We got comms on the first try and got an LQA score of 57. We then tried setting up a counterpoise, and got worse scores (my guess is that it changed the takeoff angle for the worse). We also set up a long wire, and inverted L, but due to time constraints were not able to test them on the distant station.
I know that most of the teams were also able to establish some type of comms, so I consider it a success considering the experience level of the guys on the teams. The end state (at least for my team) is that my soldiers now have some confidence in the equipment, have exposure to setting up several different field expedient antennas, and have a better understanding of HF theory.
Also, as a side note, the actual distance of the transmission was not 2000 kilometers, more like about 725.
Well, glad you stuck with the 1/2 waves if it was only 725 k's away. Longwire would have over shot, I'm sure.
But, yup, it's all about the freq's. If you have a good proping freq from point a to b, you'll make it on a watt, or 1k watts.
Definitely a great learning experience. Had a chance to use the half wave dipole (first time) . As bravo22b said, very much a confidence booster. Thanks for all the great info, to those who contributed.