High Frequency, or HF, is the method used to communicate over long distances with no infrastructure other than you, your radio, and an antenna. HF signals travel beyond Line of Sight (LOS) where Very High Frequency (VHF) and Ultra High Frequency (UHF) quit working. For a lot of people just getting into the communications arena of preparedness or looking to upgrade their capabilities for regional networking, the most common question that comes my way is justifying the cost of equipment. Usually this revolves around two very different areas- QRP, meaning low power but generally ~5W and QRO, or ~100W rigs. Since the communications in the field is not a one-size-fits-all affair, there’s very different considerations from what an operator expects in a base station to what can be run for a long period of time out of a pack. It’s not only important to know the difference in Signal Strength between the QRP and QRO but to know the basics about the rig itself, specifically power efficiency, and what affects that strength. Each have a purpose, and with knowledge and experience a good field operator can make the same contacts running much less power than many would consider possible. While running a rig in the field for a EMCOMM, summer or winter Field Day, National Parks On The Air (NPOTA), or Summits On The Air (SOTA) activation, power consumption and antenna efficiency can become the difference between having a successful day or a big waste of time and may mean the difference between passing critical information or becoming part of the problem. Selecting a field rig is a bit different animal from what you’d run in a base station or mobile rig, and there’s a few pointers we’re going to cover to make the selection a bit easier for your needs.
QRO: 100W and a Wire
The first rig you should buy when getting into HF is a QRO, or ~100w transceiver. Why? Because having a higher amount of power available to you can compensate for a less efficient antenna system, poor or dynamic solar conditions, and operator inexperience. Yeah, QRP looks cool but you gotta start somewhere. Making contacts is the important part. With 100w you can always decrease power but having that extra output may make the difference between a solid but readable contact or simply fading into the noise floor. With the generally bad solar conditions we’re currently experiencing on HF, having that extra power in a base of operations comes in handy.
But running a full-powered rig in the field becomes tricky. While it’s possible, and I’ve done it more than a few times, a QRO radio is power hungry and requires large capacity batteries for extended operations. If you’re only out for a short trip, such as a SOTA activation or an afternoon in a park, the needed batteries aren’t that big of an issue. There’s many compact HF rigs that offer 100w also, including the very popular FT-857 among Preppers, so size or weight is not exactly a problem in a pack. But the current draw, 1.2A on receive, is a problem if you’re working out of that same pack for more than a day. 1.2A on receive becomes 4A of consumption for 5w of transmitted power out of that same 857. 5A for 10w, 8A at 25w, and 21A at 100w. So if we’re working with an inexpensive Sealed Lead Acid (SLA) Battery, commonly in a 7 Amp-Hour (Ah) size, our 4A for 5W only gets us 1.75 hours of transmitting time. So while 100w in the field is nice, the power consumption tradeoff forces us to look elsewhere.
Low powered rigs can be every bit as polarizing among hams as a caliber debate among gun nuts. “Life’s just too short for QRP!” Which is every bit as equivalent a statement to “the only useful calibers begin with a 4 and end with a 5!” or “.223 is a poodle shooter!”. A lot of huff with little fact and in both cases shouted by a curmudgeon. If you’re planning on working off-grid for an extended period of time, power consumption rapidly becomes a QRP operator’s most important number.
Compared to our FT-857 example from above, a dedicated QRP rig really begins to shine with its efficient use of power. The ubiquitous FT-817 consumes a mere 450mA on receive with the backlight on and squelch off, and around 300mA with the light off, squelch up and volume down. On transmit it consumes 2A for 5w output, being twice as efficient at the same power level as the FT-857 with a smaller footprint. Other rigs have similar numbers, like the excellent Icom 703’s 300mA and 3A at 10w or the ideal Elecraft KX2’s 150mA and 2A at 10w.
Aside from power consumption, a QRP rig will allow you t get more use out of your battery. By design, most are able to run at lower supply voltage. For a 100w rig, almost all of them will stop running at 11v. If they still power up, the audio will sound garbled and those of us who’ve experienced this call it ‘motorboating’. Many of the all-mode QRP rigs on the market run down to at least 10v, with the 703 pictured above bottoming out at 9v. So not only can you run more efficiently, you can run longer off the same batteries, which equates less weight, which means more room for other important stuff if planning on long term field operating.
But what’s the REAL difference where it matters- getting through?
Decibel (dB) levels are the measurement of received signal volume and an indication of signal strength. All things being equal, meaning the same antenna, same transmission line, same ground, same atmosphere conditions, etc, 100w will have 13dB gain in strength over a 5w signal. The general rule of thumb is that 3dB difference is twice the power output and 10dB being ten times the output. Since 6dB is roughly 1 S-Unit, we’d get a little more than twice the signal gain over our 5w QRP signal. Looking at our current consumption figures, it’s starting to look more logical to have that QRP rig over lugging twice the battery capacity to the field, especially if part of our job as RTOs is monitoring.
Conversely we know that not all things are equal. The current solar conditions are pretty rough on average, with occasional great openings on 20 down through 160, and having that extra signal strength could come in handy. Since most of the newer QRP rigs can run up to 10w, giving us 3dB extra with the same superior efficiency, some of the potential problems are overcome. But this leaves other issues to address, such as the transmitting mode itself, the feedline, and the antenna.
Single Side Band (SSB) or more commonly known as “phone” operating is simply talking into the mic while transmitting. While it’s the easiest to copy for beginners, it’s also the most susceptible to interference and signal loss. Continuous Wave (CW), the propagation mode for Morse Code, holds a 13dB gain in strength at the same power level as SSB, meaning that 5w CW signal will be equivalent to a 100w SSB transmission. So while the digital modes also possess quite a bit of signal superiority over SSB, CW only requires a key and your time and patience to learn. Due to its simplicity, its a worthwhile skill to learn as an RTO.
The last piece of the efficiency puzzle is the antenna system itself, with the feedline and radiating elements being of equal importance. On HF, loss figures are not that big of an issue, so you can get away with running cheaper coax such as RG-58 or RG-8X and have little issues. But keeping as short a transmission line as possible IS important, for efficiency’s sake. The radiating element itself should be cut to as close a resonant length as possible providing as close to a 1:1 Standing Wave Ratio (SWR) as you can get. SWR is the measurement of your antenna’s efficiency given in as a ratio between power reflected back and power sent forward, with 1:1 being a perfect 100% efficient and 2:1 being 50% efficient, and so on and so forth. For a basic dipole, where each leg is quarter wavelength long on HF, we can calculate our necessary antenna length for each of the two dipole legs by using the formula:
234 / Frequency= Length in Feet
So since we planned out our transmission schedule and frequencies using our Signals Operating Index (you planned that, right?) we can create the antennas we need as close to resonance as possible and making us that much more efficient, meaning a much higher probability of success.
So where does this leave us? For those new of upgrading their capabilities, 100w is the way to go. It has the least learning curve getting you on the air and overcoming many of the more technical factors that inhibit efficient communications. But if you’re planning on working in the field in any capacity, be it recreational or more of a preparedness stance, a QRP rig provides a level of efficiency that the higher-wattage rigs cannot match. Both are very important, offering regional capability networking other operators in a way no other conventional means can match. While success includes learning quite a bit about the art of communications, its a worthwhile goal going far beyond simply having stuff. Further, simply having the radio or the license is not enough- get the training and get on the air. It’s the only way.
60 thoughts on “High Frequency Ops: A Dedicated QRP Rig vs. Full Power in the Field”
Reblogged this on FOR GOD AND COUNTRY.
Pubs to reference on antennas? Any out there you would direct one too? You preferred?
A couple of important .pdf downloads: https://brushbeater.wordpress.com/2016/07/30/an-additional-resources-for-field-antennas/
While more suited to VHF/UHF, this post contains the important antenna calculation: https://brushbeater.wordpress.com/2015/10/15/the-jungle-antenna/
Hard to beat a dipole for simplicity’s sake on HF.
You’re gonna want a copy of the ARRL Handbook also.
Check out the 4 NVIS articles NC Scout has posted here, both his beginner article and the three part post on NVIS he graciously posted here. Short response:
A dipole IS hard to beat, quick, easy and cheap. You can arrange it as a flat-top, an inverted vee or a Vee, depending on your support options and the time and manpower available.
Get a copy of the Antenna Book, too; used is fine. It doesn’t need to be the latest version, anything for Ed 21 up will have useful information that is reasonable up-to-date for anything short of EME antenna design, which has been evolving quickly. If you can, try to get the CD which will have a version of EZNEC and other useful programs on it.
That first section, on NVIS, represents 90% of what you’ll need for HF capabilities – both for a ‘base station’ and for field deployment – so that should be your first focus in growing your capabilities. This means a radio and antenna system that are efficient on 80M and 40M (3.5Mhz and 7.0Mhz) should be your very first priority.
Once you have 80M and 40M nailed down, you should work on an efficient antenna system for 160 Meters, because as we move closer to the solar minimum the NVIS windows (presently early morning and early evening) for 80M operation will become smaller, and 40M may lose it’s NVIS window all together – making 160M the primary NVIS band for much of the 24-hour comms cycle.
For 30 Meters (10.1Mhz) and above, NVIS isn’t a real possibility, and so should take a back seat to optimizing your NVIS capabilities both at ‘base’ and for field portable operations.
Above 10Mhz it becomes far easier to make contacts out beyond the NVIS circle, with much smaller antennas, including expedient/compromise antennas common to mobile and field-portable operations, so not only is 90% of the utility of an HF station to be obtained on 40/80/160 Meters using NVIS, but that is where 90% of the time and effort has to be spent to optimize your station(s), too.
Spot on, Loderunner. At this point in the solar cycle, in the MidAtlantic area, and across the central united States, the FoF2 rarely rises above 7 mhz during the day, usually only as a result of solar wind or a flare providing some brief added ionization. This will continue to get worse as the cycle progresses to the solar minimum; 40 meters will be open for longer haul communications, but not for NVIS. Further South, in South FL and South Texas, the FoF2 will be somewhat higher, but relying on 40 for NVIS for the next several years would be a mistake.
OTOH, 40 will work nicely for contacts out to 1000+ miles away, and farther as the ionization of the D layer decreases. Frank, W3LPL, is expecting that this cycle will see more daytime long haul openings on 40 than any living amateur has ever experienced during the next several years. In his words, 40 will become what 20 has been, the premier long-haul communication band.
Even 80 meters can ‘Go Long’ especially before dawn, and NVIS in the predawn hours will be 160 meters only. As stated elsewhere, despite the length of a full-sized 160 meter dipole, I am a fan of QRP radios that offer 160 meters.
I have been giving serious thought to getting another board for my K1, which presently has a 40/20 board, for 80 and 30 meters. 80 will give me daylight NVIS and 30 will give me long haul capability. A linked dipole, or an 80/30 cross dipole set up as an inverted Vee, would be a simple and easy way to cover these two bands. I’d cut the 80 meter part of the cross for 3550, and maybe add a link to give me something on the upper end of 80, say 3850, if my rig was sideband capable. You could do something similar for an 80/40 cross dipole.
80M has indeed been “going long”. It has been doing so very early (2300Z ~ 0200Z) on a substantial percentage of days in the last few months, which has severely impacted quite a number of evening nets in the ‘Carolinas, Ohio River valley, New England, and beyond.
Right now, in the Mid-Atlantic region, the best window for NVIS on 80M has tightened up to about 90~120 minutes each evening – roughly 1/2 hour before sunset until 1 hour after sunset. By Sunset+2hrs conditions very often will not support NVIS (phone) at the 100 watt level with typical fixed-station antennas, and QRP/Field stations with improvised antennas would have only a very minimal chance of making contact within 300 miles — unless using a digital mode optimized for high-noise, weak signal paths, such as Olivia, MTxx, or one of the JTmodes. Even employing an optimized digital mode, QRP/Field stations will likely have some difficulty moving their traffic.
At the end of January each year, an even called Winter Field Day is held. I strongly urge folks to participate this year from portable/improvised stations and use the event as a learning experience, to familiarize yourselves with where the bands are headed for the next 3 to 5 years as we pass through the Solar Minimum. At the 5 watt level, expect to make most contacts with CW and Digital modes, not voice – so please take this opportunity to do a shake-down cruise of your portable gear…including laptop and software.
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Great article & kudos for the advice to, initially, go 100w. “Learning” can be an elusive & frustrating thing starting with QRP, particularly for someone in a surburban “RF hell.” Ditto, the full-featured 100w box in the field. Having a power supply that measures current draw, I did some brief testing awhile back. Your article prompted me to look at that spreadsheet again. I tested my KX3 against my Yaesu 450D, a rig that could be described as “average 100w full-featured transceiver” and the 450’s current draw curve was quite an eye-opener. The modern 100w transceivers are great & do some neat stuff – but running all those features in the background draws current whether you’re running at 100w or 5w, where the 450’s draw on 5w (key-down) is still 6.5A. KX3 was 1/6 of that and only 10% of 450’s receive draw.
If someone is just getting into it, they’d do well to heed your advice and get a basic 100w rig. Oh, and learn Morse so you can do stuff even when the solar cycle is in the toilet.
Nice write-up. 🙂
Spot on! QRP radio should be considered as the equivalent of a snub nosed revolver – for experts not beginners, and useful after you learn on the full sized article.
While times permit free association and easy travel, getting help from the more experienced is a great way to get started. With that in mind, if any of the readers are near Riverton, Wyoming, there is a new group organizing: https://wyomingadventureradioclub.wordpress.com/. I think Sparks31 is putting it together.
For the rest, the ARRL site arrl.org has an area index of ham radio clubs.
Yeah that’s his club.
For those seeking field training east of the Mississippi, I offer an RTO course. More on this to follow very soon.
It’s my club. Hope to see some of you from the Rockies that Saturday.
It’s mine. If you’re within driving distance come on down.
It is. Come visit.
Similar to what you wrote NCScout, I started out with a QRO radio and a simple G5RV dipole antenna. Once I felt I had mastered that radio I picked up a Yaesu 817nd at the Dayton/Xenia Ham Fest this year. I wanted a BOR (Bug Out Radio) that was sturdy, light, simple, covered basically all of the bands from UHF to 160 meters and ran on a battery. Ham Radio Outlet had a special on them during the ham fest for $599-.
My first try with my new 817 was frustrating. One of the reasons was the operating manual for the radio was what I would describe as vague. Next was the antenna I built which was a nice kit that came from a Club in Hawaii called, “The End Fed 6-40 meter Matchbox Antenna”. Although I did make ‘some contacts’ with that antenna, overall I was frustrated with the performance of the 817. Then one day due to CFS ( contact frustration syndrome) I connected the 817 to my G5RV antenna and voila – I made contacts using 5 watts. This prompted me to build a QRP antenna of my own design.
My QRP antenna basically is a dipole with a QRP 1:1 balun from Balun Designs and pre-cut lengths of wire hooked together using Anderson Power Pole connectors. The wires lengths if hooked together in the correct order would be resonant on 10, 15, 17, 20, 30, and 40 meters.
Just attach a rock to a messenger line and tossed it up over a tree limb as high as I could go. Then took the bitter end of the messenger line and attached it to the balun. Next I fastened the correct wire lengths to make up the band I wanted to work, and the coax and hoist the antenna to as high as it would go, pulled each length of the dipole wire ends out into an inverted ‘V’ configuration. Hooked the coax up to the radio and VOILA made connections without the need of a tuner.
My respect for the 817 radio has grown immensely as well as my radio skills over the seven months I have owned it. As a matter of fact my first contact on a 160 meter antenna I just hoisted was made on this radio. The contact lectured me for using a QRP rig on 160 meters. I let him rant on and on about “you people that clog up the bands with QRP radios” as I was so stoked that I made a contact. I will have to admit I egged him on a bit so I could continue to TX/RX. LOL
Another great article NCScout! Please kep ’em coming.
Many thanks my Brother 😉 Your article is next up-
End fed antennas can be frustrating to say the least. I have one, and have found that the key has been to keep my coaxial cable as short as possible (18 inches or less). This runs counter-intuitive, as traditionally the coax has been kept long to create a ground in the antenna system. Think of traditional military NVIS antennas, where the antenna wires are plugged directly into the back of the radio or tuner, and try to match that setup. That being said, matchbook-style multi-band antennas are far from ideal. As with all antennas, especially QRP antennas, you will find that compromises are made for multi-band capability. By far my best multi-band antenna for NVIS and long haul communications has been a homebrewed off center-fed dipole. OCFDs have advantages and disadvantages all of their own, but I would strongly urge anyone trying QRP out, especially QRP NVIS operations, to shy away from compact matchbox-style multiband antennas for their initial experimentation. As Loderunner, Keypounder, and NCScout have stated here and in other comments, 40m NVIS is going to be increasingly difficult, so for NVIS experiments get down into 80m and 160m and I suspect you will be much happier with your experience.
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How much of this can be integrated into an infantry outfit? Can it be operated / transported without trucks? Can it be adapted to nonstandard / improvised power supply’s? Can it be set up/torn down and moved quickly after each broadcast? What is the total mass/bulk of the entire system with power generation? Can it be repaired with salvaged / improvised parts? Is it -OR CAN IT BE MADE “weather proof” without fixed structures or extensive tenting?
All of it can. In fact, one of the original goals of this blog was applying skills I learned from my time in a LRS Company to communications skills for preppers, EMCOMM and anyone else looking to make their gear work in less-that-ideal circumstances. I have an upcoming course that covers doing just that, in a Small Unit Environment. If you want to take what you read and put it into praxis, email me for a date.
Some great comments here; I will add one more to touch on a few things.
As noted, more power can compensate somewhat for a poor antenna, one of several reasons I agree with NC Scout’s recommendations to buy a 100W rig when starting out on HF operations, but when you get into QRP, decent antennas are essential, and every DB of loss or even a fraction thereof can be the difference between being ‘weak, just over the noise’, but contact made, and ‘QRZ?’ ( meaning, “was someone calling me?”) i.e. contact *not* made. When doing this as a hobby, this is frustrating and discouraging, but not life-threatening. When lives may depend on signals getting through, that’s another kettle of fish. Everything that goes between the output connector of the radio and the actual radiating elements of the antenna has loss, and one of the big reasons I like building my own baluns and transformers is that I know what those losses are. (N.B., low SWR does not necessarily mean low loss!) Transmission lines have loss, so as NC Scout has already said, keep the line as short as feasible, both for weight and for minimizing loss.
In the context of man-portable operation the less stuff you have to carry the better, which is why cross dipoles and linked dipoles resonant at the frequencies you intend to operate on are a good idea. Antennas like that mean you don’t need a transmatch, one less thing to carry and hook up. This is also a powerful incentive to master Morse Code; keys and paddles are made today which are extremely small and light. Using manual CW avoids the need to carry (and power) a [fragile] laptop, a sound card interface (I use the SignaLink for my Yaesu radios), but there are others), and the assorted cables to connect everything.
We’ve talked about frequency bands already; If I were going to have only one or two radios I’d be reluctant to pick a radio that did not have 160 meters, primarily because of the NVIS capability that bestows.
What we really have not touched upon, however, are receive capabilities. Most modern radios, and even most 50 year old radios, are acceptably sensitive; what separates the fair from the excellent are the dynamic range figures, and the ability to filter out nearby signals. The ability to narrow down your received bandwidth is useful not only to allow you to exclude unwanted signals, and listen only to the ones you want to hear, but also, and just as important, to improve the signal to noise ratio. If you are listening to a PSK 31 signal that is in and out, with a filter passband of, say 2.6 khz, you will be amazed at how much improvement in S/N ratio you will get by going to a 300hz filter. Best to filter in the IF, but even an outboard audio filter will help.
The ongoing development of SDR and DSP technology has made this filtration much more affordable. I have an acquaintance who had to send his FTDX5000 (One of Yaesu’s high end HF rigs) in for repairs. He sought my advice on a backup, and I suggested a Kenwood 590SG. He was so impressed with the performance of his “backup” 590 that he sold his FTDX5000 shortly after it came back from Yaesu. He said he could see the writing on the wall.
The point is that SDR technology is making good receive performance much more affordable; the 590 rivals the performance of the Elecraft K3 for 1/3 the price, and is compact and portable enough for Field Day. Deciding what radio to buy can be a tough choice, and much depends upon your budget.
For a first 100 watt HF radio, I’d look at any of the following three radios:
-the Yaesu 857D new around 850 USD (has vhf and uhf, a distinct plus)
-the ICOM 7200 new around 850 USD (better receive filtration than the Yaesu, and easier to navigate)
-The Kenwood 590SG, new around 1250 USD ( used 590S is a good used option, and street price is about the same as the 857 or the 7200, maybe less)
All of these have 160 capability.
For QRP it is hard to beat the versatility of the Yaesu FT-817ND. If you can find one with the W4RT One Board Filter, grab it! The factory stock filters are mediocre and need to be upgraded, but both Collins and W4RT are no longer making the upgrades.
You can find them out there today, but the prices are going up.
I’ve heard that the IC-703 is a great radio, but I have no experience with it.
If you have manual CW capability, the now discontinued Elecraft K1 gave any two bands from 80 to 10 meters, and sipped power. Common band choices were 40/20, 80/40 and 80/20. If your primary selector is power budget, the K1 is an excellent choice. AFAIK, however, 160 was not an option, at least not from Elecraft.
The K2 is an interesting alternate to the KX3, but by the time you’ve bought the 160 option and the SSB option, it would be cheaper to get the KX3. However, Elecraft does apparently still offer a k2 compatible transverter for 220.
And now we get to the Mercedes of QRP rigs, the KX3. With roofing filters, the KX3 on holiday special will run over a thousand dollars. If you want to spend more, you can add all sorts of other options, including all mode 2 meter capability. Expensive? Yes. Capable? Yes. Weatherproof? Oh HELL no!
If my budget for two rigs was limited to, say 1300 dollars, I’d look for a used FT-857 or a used IC-7200 and a used FT-817.
If I had the budget, I’d go for the 590-SG and the KX3. The receive performance difference is substantial. I do not think I will ever outgrow the capability of either radio.
So, there you have Keypounder’s New Years ruminations on this subject
Y’all stay warm out there!
Outstanding from Keypounder. Another +1 for Morse, if you really want to be able to say you can make comms with little power when the band is in the toilet. Have done KX3 as well has 817ND, both excellent choices, although apples/oranges in their class (pricepoint). And, yes, if you can get one of the 817’s that someone has installed the W4RT (Collins) filters in, snag it! You have no idea how wonderful it is to throw a really GOOD filter on CW and literally wall off the world (without attenuating your receive signal, like many factory digital filters do now) for a good conversation with your distant end. Great topic.
I can personally attest to the quality and utility of the Elecraft KX3, the Yaesu FT857D, Icom IC-706MkII-G, and the Icom IC-7200. I never liked the receiver of the Yaesu FT817, but I never got to use one with custom filters (i.e. W4RT) either. Still, the FT817 would rate as a [C]ontingency at best in my book due to other objections I have with it.
For a field-portable radio I would (and did) choose the IC-7200 because of its DSP filtered receiver and overall durability. Before that I ran an IC-706MkII-G for over a decade. Neither of these does the best w/r/t power budget, but I have several kit radios – NORCAL Sierra and Webber Dual-Bander – which beat *anything* factory made where battery conservation is a factor. They are both very compact, CW only rigs
I would also point out that there are some very interesting radio kits being produced these days which I expect to change the portable-radio landscape substantially. Three which come to mind are QRP-Labs, McHF, and uBitX – each of which promises to provide a lot of functionality for not a lot of money, but these are not pre-packaged, ready-to-use radios – they’re kits that will require you to do some ‘maker’ work, particularly in providing a rugged, weatherproof enclosure.
I recently ordered a uBitX multi-band radio kit, and will be evaluating it as soon as it arrives. NCScout and I have already discussed providing a review of it here, once we’ve spent some time with it, in the field as well as on the bench.
Happy new year and 73
I have been trying to learn CW and also built one of those cheap Chinese QRP 40m kits to practice and experiment with. I also ordered and it’s in transit, a QRP labs QCX kit to build, again for 40m. I’m looking forward to it’s arrival so I can begin construction. It should a few levels above the first kit.
Back to the cheap kit. I had 15 spots on 30 Dec on the Reverse Beacon Network. Of those spots, the best signal was 158.8 miles from me at 15dB SNR in NC. The best DX was 672.23 miles in MA, 7 dB SNR. That’s in my back yard, battery power, about 1.5W or less, LnR trail friendly antenna, cheap kit radio, from 2039z – 2229z. banging on a straight key. I have been out 2 other times with that same configuration and was shut out (as recent as yesterday – cold!!).
I can put this configuration up in about 15 minutes and be on the air sending code down range. I’m using a MFJ -971 to tune. I would like to cut the deployment time to under 10 minutes.
I’m going to continue to do this to become more proficient. Would a vertical like the Super Antennas MP1 (their latest offering – I can’t remember the model) be something to consider??? (The 2 longest poles in this tent are putting up the trail friendly and tuning it)
BTW, I have an 817, but just experimenting with minimal gear and trying to learn code. I do not have an auto tuner.
Also, I’m not trying to talk to the world, just the region (SC, NC, VA, GA etc.).
S6cnrdude: Just throwing this out there, as I’ve done a fair portion of what you seem to be doing. Portable tuners that don’t need power are a great thing but you can go smaller & just leave the rig configured with some jumpers using something like the little Elecraft T-1 tuner. It does take a 9v battery, but only uses the battery during a tuning cycle, passive otherwise. It will not just give you a match on the mop bucket – it will do it on the wooden mop handle.
Best little tuner on the planet (imo). Also available as an easy kit. If you don’t go to something with a really good built-in tuner, that T-1 will stand you in good stead with any little QRP rig you desire.
My personal go-to field antenna is a sloping end-fed wire, with a small 9:1 UNUN. 52.5′ of wire, ’bout a 14′ counterpoise at right angle to the radiator (tied off on branch, whatever) or laid on the ground. Toss up in tree; rotate yourself depending upon max directionality desired. Superb on 40/20/17/15; not the most efficient on 80 but will load up just fine anyway – for nearby stuff very workable. The whole things goes in a ziploc.
Kudos for the CW effort.
I agree, the Elecraft autotuner is sweet, light, and uses next to no power. I carry one with my 817 wherever I go.
If budget is an issue, though, not cheap. I’ve found good 100 watt manual MFJ tuners for $10 at hamfests. While more bulky they don’t weight much more than the T-1.
Badger: Tnx! I have seen the T-1 on Radio Preppers you tube channel. I’ll definitely look into it. If I can shave 3 minutes or more off of the tuning process, that will almost get me under 10 minutes time from dropping the ruck to being on the air.
I take it that your sloping end feed is home brew? Tnx again.
3 minutes? The T-1 will do that, easily. 😉
A sloping end fed is very easy to build.
Badger, great idea with the 9:1 balun and 52.5′ antenna you describe. Would you share how long your coax is?
I am assuming this is a sloped antenna – Corret?
Also, a good auto tuner is the LDG Z-81. It takes four AA batteries and like the Elecraft T-1 only uses the battery power for tunning up 1-5 seconds.
Having first hand experience with both tuners, I’ll say the T-1 is hands down better, and I love LDG as a company. But the T-1 is better in both size and tuning range (although you should have a close to 1:1 antenna anyway, but I digress). Neither’s battery consumption is an issue- both only consume power while tuning, and a minuscule amount at that. You’ll likely rarely change the battery in either.
Whoops Badger, that is the LDG Z-817 auto tuner. Thinking faster than I can type. LOL
Go take a look at the three-part set of articles I wrote that NC Scout posted on NVIS, in particular the third one which talks about antennas for NVIS. In that article, you will find a graph of the pattern of a vertical compared with a low dipole.
As stated in my comment above, low power and high antenna loss do not make for happy QRP operation. Cut a dipole for the lower end of 80, hang it as an inverted vee with the apex at 25 or 30 feet, and ENJOY making contacts. Once you have gained some skills *then* set the bar higher with a compact double dipole SuperAntenna or a Hustler compact dipole. I’d suggest one challenge at a time.
One of the better CW ops I know has an NVIS setup with a tripod, mast, and a pair of Hamstick 80 meter antennas set up as a dipole about 15 or 20 feet up. Several years ago, he drove about from location to location, setting up his NVIS dipole and running QRP CW for Field Day. He’s a professional RF engineer who designs antennas for a living, and he’s been licensed since the 70s. He did not do this because it was easy or a good way to make contacts, he did it because it was HARD, and he wanted the challenge.
In the two or three hours he was at our Field Day location, I think he made 8 or 10 contacts. On Field Day. And he was happy! The same guy with 100 watts and full sized antennas runs at rates of 120 to 180 Qs an hour. For hours on end. Non-stop. That FD he wanted to do something different.
Now, it is supposed to be a free country, and you’ll do what you like, but there are multiple reasons that NC Scout and those that have been there and smelled the elephant are suggesting a good full size antenna. If you want the most difficult challenge possible, go for it! But if you want to learn how to operate and add skills, eat your elephant one bite at a time. I’ve been known to hack off more than I can chew a time or two myself, and you do grow from the experience, but you may find it a better use of your time to learn from my mistakes.
Tnx Keypounder. In some ways I’m kinda like that RF engineer you spoke of. That’s why I’m experimenting with a QRP CW kit and just started construction of another one this afternoon (snow day off work!). I’m trying to learn some radio theory, CW ops, rapid deployment techniques, propagation, different antennas, etc along the way. I’m compiling notes and findings in a notebook for future reference. I’m sure there will be some fails along the way and it is a challenge but one that is fun and interesting.
The information presented here is a great help. I hope to learn all I can from various sources and my own experience before the lights go out one of these days.
I have the T-1 in my sites and will purchase one very soon.
Thanks again for the info, the NVIS articles are excellent!
One e clearest definitions I have read in a while. Now the quest is for an efficient feed line and radiator that will operate. From 30 trough 80 meters.
1) I use low loss RG8x as the best compromise feedline.
2) Linked dipole for 80, (60?) 40 and 30.
S6cnrdude: RE your question above about the end-fed. I’ve done home-brew, with just some speaker wire and an adaptor that breaks out RG-58 to to BNC/screw posts, coax maybe no more than 25′. That was with T-1 & 817 – was a favorite setup in a small pack for awhile. But it wasn’t as efficient on multiple bands as I use now & described above.
These days I (rig & coax immaterial) I use a 9:1 UNUN from Bob at Balun Designs to terminate & breakout the signal. With a properly proportioned counterpoise it “behaves” like a dipole, although not polarized the same way. It will also propagate right off the end of the wire directionally. The big advantage is more flexibility to your tuner & a quantum leap in multi-band functionality. I have a small version in a commo pack that I keep ready to go, and a home version (fed with 100′ of RG-8, bigger wx-proofed UNUN) is my main antenna. The smaller version of the UNUN is about 2x all dimensions of a Zippo. A good UNUN really seems to take an end-fed where people hope an end-fed will get them (but seldom does)
It’s also a great antenna for someone who is lot-limited in a residential area. And wire antennas seem to disappear in trees to people who didn’t see you put it up in the first place, as well as taking the wind well. There are lots of good antenna solutions out there; having your ticket is about learning so try several, but you get to ruck it & set it up… 🙂 I like my ziplocs.
Badger, something you can do to run multiple lengths of wire on that UNUN, terminated by a Anderson Power Pole. That way if you need 20, you have 20, then connect another length for 40, 80, and so on.
I have one of Bob’s UNUN’s that I use primarily for a receiving antenna but it’s cut for 40m. You can make them just as easily as buying them (if you don’t mind winding torroids). The key to it all is having a good ground coming from the UNUN- for a QRP setup you can use a steel tent stake with a soldered wire running to the ground screw on the UNUN. This is also where you can run a counterpoise under the radiating line (the antenna wire itself) for a tighter NVIS pattern if desired, but I’ve found the best results with a standard dipole.
The whole purpose of an UNUN is to maintain UNblanced line in to an UNbalanced radiating element. A BALUN takes an UNbalanced feedline (coax) and transforms it for a BALanced antenna (a Dipole). 😉
ncscout, quite correct. Good return for the end-fed (whichever way works best) is essential. I like the narrowing with the reflector; that’s a great technique you point out there. FTR when I mentioned dipole in same breath as an end-fed, I only meant that it can propagate similarly to one, depending on layout.
On the cheap for winding toroids, salute. However, I have more time behind me than ahead & am lazy in that regard when doing an “economy of time” analysis that takes a couple sips of coffee. 🙂
Have any off you checked into the LiFePo4 batteries? Don’t confuse them with the other non-SLAB’s out there. Bioenno power makes some very high quality ones, and you can have over three times the available power for the same weight compared to a SLAB. They recently had 17Ah batteries on clearance for $100, and it weighed about 4.5 pound with a 20A max output. More than enough AH to run a 100W rig at 25-50 watts for quite awhile. I recently choose to go three QRO route with an IC-7200 versus the QRP route with an FT-817. Mind you, I had to sell my old radio to fund this purchase, so I didn’t want to be stuck with only 5 watts out. If they made the 7200 only 50 watts max and a few pounds lighter I’d be happy as a pig in poo. The next radio will be a lighter rig, maybe an 817. Keep up the good articles, and good job on the spearhead transmission.
I thought you had quit the internet, Marine 😉 Great to hear from you my friend.
I have a good friend who’s all about them. They have a HUGE advantage in the weight savings category, but they’re more expensive (although getting cheaper).
As for a pack-friendly 7200, look into a 703 plus with a set of portablezero’s aluminum rails. The one I use in photos from time to time is great and has an on-board tuner. No idea why Icom quit making those rigs- excellent radios.
I am in the process of gathering the items needed to make an ocfd down to 80m for my home antenna. I’m thinking now I need to include 160m as well. I found the link below quite helpful. Lately 40m had been almost useless for nvis and 80m less than reliable. After reading the posts above now I know why. Getting reliable local Comms using hf nvis has been the most difficult skill to master in my ham radio journey.
I regularly check the NOAA real-time FOF2 site to keep up with what the ionosphere is doing; it helps prevent disappointments when setting skeds with new friends and acquaintances.
Including 160 in an OCFD will make the dipole about twice as long. If limited in space, there are a variety of options, including folding the outer ends, up to 1/8 of each element. Inductive and capacitive loading can help reduce the length required, too. The Antenna Book has a good section on this.
Luckily space is not an issue at my qth. What would be the dimensions of each leg for 160m? In my post above I should have stated very close nvis has been frustrating. I have a friend who is 40 miles away with an obstruction in our line of sight so VHF simplex does not work. Hence the emphasis on nvis. Also looking into a simplex repeater as an option.
234/f= quarter-wave length in feet
Thanks but it’s an ocfd. I already have the measurements for each leg of the 80m version but wasn’t sure how much to add on each side to get 160m
Ah I gotcha. OCFs are dipoles with the short end being 1/6 wavelength and the long being 1/3, together making that halfwave dipole. Make sure you have a 4:1 Balun center (which you probably already do).
Yes, I have one from Balun Designs made for ocfd that is used in the article I linked to above. This is for my home station so I want to do this right. This will also be the first antenna I’ve made myself. So essentially if I double the measurements for the 80m ocfd It would be a 160m ocfd correct? Will this mess with the harmonics for any of the other bands? I’m only interested in 20/40/80/160.
Do the calculations. It’ll make every band that was quarterwave at least halfwave. So it won’t mess with the harmonics so much.
Also, My icom 718 started powering off and on quickly when the ldg autotuner was trying to tune. Short story is the problem was caused by corrosion on the powerpoles on the deep cycle battery used to power the radio. Kudos to LDG electronics for excellent customer service and figuring out the problem.
While frustrating, it provided some valuable lessons. I have brand specific tuners for both of my icom and Kenwood hf rigs. If the problem had been with the tuner for some reason I could not have swapped tuners between radios. From now on I will buy the generic tuners instead. I have also removed all the wiring from my deep cycle batteries when not in use. I suspect gasses from battery charging caused the corrosion in the first place. If the tuner itself had been the cause of the problem I have exactly zero electronics knowledge and would have had no clue where to start. Hth someone, Homer
Judicious use of No-Ox conductive grease will help manage your problem, which is not unique to you! You do need to be careful not to slather the stuff around, because, well, it is CONDUCTIVE! but a light coating on surfaces subject to corrosion will help keep you on the air.
That’s GREAT stuff to have on hand.
For long term outdoor connections I also use self-sealing electrical tape to weatherproof.
That’s an easy solution. Thanks!
Homer, good luck super-sizing your 80m OCFD; had one using that exact config (incl the 4:1 current balun from Bob) – overall probably the most versatile antena I had till losing a “mast” from an old maple branch that came down. Nice choice. Lengthening to a 1/2-wave for 160 should be interesting; probably challenge seems to lie in getting it high & properly supported. I hope your LDG is up to the challenge in the multiple band role; there can be a lot of inductance to account for “way out there” at the end of that wire. A quick EZNEC look says it should probably do you well although, oddly, 20m can be an odd duck at times. Good luck – oh, to have the luxury of the real-estate to do that. 🙂
I’ve got the real estate and the trees. Lol
Worst case I suppose I could make a separate dipole just for 20m.
I would encourage you to separate your 20 meter requirements from this antenna, and focus on fulfilling your NVIS needs as well as possible with this OCF.
For 20M, a dipole would probably do just fine; and if not, there are several antenna designs, not much larger or more complex, which could give you several dB better performance.
Newbie here. Learning a huge amount from this website – both from articles and comments which are always refreshingly courteous – thank you all. NY resolution now firmly to get my CW to an acceptable level – not touched Morse since spending my formative years using flashing light between ships N Atlantic in the 80s. Perhaps if I dress up in foul weather gear and throw a bucket of cold water over myself it might all come back !
Have dabbled a little in SOTA and the RADAR concept has caught my interest but, interesting as this is, it doesn’t quite hit the spot for me. My focus is now on making pre-arranged HF contact specifically with people I want to speak to ‘within state/country’ when I want to speak to them which the structure of those activities doesn’t really champion. Traditional DX to me is just a bit too much like standing on a bridge over the freeway waving to strangers !
A North Atlantic Sailor! A mentor and great friend of mine had a lot of sea stories from the 80s…I’ve lived pretty rugged in Iraq and Afghanistan but I want no part of that.
Thanks for reading and feel free to jump in any time, and if there’s anything you wanna see, feel free to ask.
@Deeps – Welcome! “Traditional DX to me is just a bit too much like standing on a bridge over the freeway waving to strangers” I agree, there’s not much utility in ‘paper chasing’ (although I do enjoy working DXpeditions when the opportunity arises). As for keeping ‘skeds’, that’s the essence of preparedness radio – being able to maintain regular communications with a selected set of known stations, using a minimum or resources is at the heart of that purpose.
@ncscout – “if there’s anything you wanna see, feel free to ask.” Yep, there’s an excellent collection of knowledgeable and friendly folks here. I hope you enjoy and benefit from NCScout’s oasis as much as I do.
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