NVIS techniques, Part 3

Keypounder, a name a few folks may remember, is writing updates to his articles on NVIS that NC Scout published almost 5 years ago at the Brushbeater site.  He has continued his research and study of NVIS, and wants to update  and expand upon his earlier articles on the subject.  This article is being posted as the third of what looks to be now  at least 4 articles on NVIS.

As NC Scout stated 5 years ago-
“…. I will re-iterate that these skills, along with Land Navigation, are among the most perishable and most difficult to learn- under duress, near impossible. So for those of you who feel you’ll do it when ‘the time comes’, you’ll be sadly mistaken.  Please folks, try this at home.”

 

Part one of this series on NVIS operation focused primarily on the basics of NVIS; what it is, why it is, how it works, and listed some of the major factors involved in successful NVIS operation, briefly touching on these factors. Link here: https://www.americanpartisan.org/2021/05/nvis-techniques-part-one

Part two of this series on NVIS operation looked at HF listening and transmitting techniques, some specific to NVIS. Link here: https://www.americanpartisan.org/2021/05/nvis-techniques-part-2

Part Three discusses how to decide which HF radio to purchase. Several common civilian amateur radios will be reviewed in some detail, and general characteristics desirable in an NVIS station specifically will be discussed.

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So, we’ve discussed at some length a few operating skills, some basic and and some more advanced that radio operators will find useful and we’ll get into non-permissive environments operation and antennas in part four, but right now, I’d like to talk a bit about radios, in particular, HF transceivers whose primary use will be in support of local and regional communications using NVIS. We’ll discuss fixed operation transceivers, and radios for both portable operation and man-portable operation.

When you first take a look at what is on the market with regard to amateur HF transceivers, there is a multitude of equipment out there from all over the world, new, used and surplus. My knowledge base for surplus equipment is pretty low once you get past Korean War era Collins tube rigs, so I will not get into that; NC Scout may have some thoughts on surplus gear. My focus will be on civilian amateur gear available in the USA, and specifically, what is appropriate for NVIS operation.

NVIS operators are by definition interested in lower frequency HF, notably on the 160, 80, and 40 meter amateur bands and possibly including 60 and 30 meters, too, but the three main NVIS bands in the US are these three. Any radio intended to be used for NVIS should include those three bands. Some good transceivers do not cover 160 and that rules them out. There are multiple reasons for this:

• It is extremely rare that one cannot communicate with NVIS on 160 meters- NVIS is possible 24-7 on 160;
• 160 meters especially in North America specifically, because of the location of the magnetic north Pole, has odd propagation on 160. Signals get twisted in odd ways on 160 and this complicates DF efforts.  This is a Good Thing for FreeFor, and lacking this capability is a Bad Thing.
• The more places that bad people have to look for your comms, the better. Right now, with enforcement still a consideration, General class licensees using digital or CW operating on 80 and 40 meters have only 200 kHz of bandwidth, 75 kHz on 80 and 125 kHz on 40. All 200 kHz of bandwidth on 160 is available for a General to use for CW, SSB or digital, so that doubles the available bandwidth.
• Even if band restrictions were to became moot, having another 200 kHz of available frequencies on which to operate on another band entirely is a non-trivial advantage.

Civilian operators are usually interested in NVIS as a means to provide emergency communications, during a disaster or other such event. Unless you have enough money to buy a radio for every occasion, (and there are folks like that out there,) what this means is that the radio you buy may have to serve in a variety of potential circumstances, including but not limited to one or more of the following:

• HF operation from your home or base, including short wave monitoring, long haul HF comms, and local and regional HF comms using NVIS.
• VHF and/or UHF operation in support of local LOS communications from your home or base camp.
• Mobile HF operation from a vehicle, including short wave monitoring, long haul HF comms, and local and regional HF comms using NVIS, and VHF/UHF LOS comms, should you have to travel during an emergency, or simulations thereof, or if you elect to use a vehicle as a readily relocatable comm center;
• Portable operation under more or less normal conditions, using vehicular or other transport, operating on some combination of NVIS, long-haul skywave or LOS comms;
• Portable operation in a non-permissive environment using vehicular or other transport support during an emergency,  in the event that you have to evacuate, or if you are involved with providing comms for a community or team doing long range patrolling during an extended disaster such as an EMP, a nuclear war, or a wholesale breakdown of civil order.
• Man-portable operation on HF, VHF, and UHF either during normal times or an emergency.

The above are some examples of different scenarios with different operational requirements.  Each person reading this article may have different requirements, which would drive you toward a different selection of radio. Although there may be some individual differences, most folks interested in emergency communication generally and NVIS specifically are more likely to want a radio that is suited to portable or mobile use as well as fixed location use.

So how do you pick? What are the things to look for when looking for something to use on HF, especially NVIS?  It’s going to be a free country again, so you are free to do as you choose, but these are my standards based on my experience-

My “have to haves” for an HF radio used for NVIS are:

• frequency coverage- MUST cover 160, as discussed above;
• reliable  and durable- must work and keep working. “shop queens” are ‘right out’;
• Must allow CW, digital and voice communication; ( some CW-only radios or SSB-only radios are very good, but in the context of NVIS operation are not acceptable.)
• 100 watt output.  (QRP is great fun, but right now on 160 daylight NVIS, SSB requires about 25 or 30 watts.  When the SFI increases as we move toward solar max for cycle 25, 100 watts may be required to operate on 160 sideband around local noon(LAN) )
• Serviceable here in the US, with documentation and parts support from the manufacturer. Accidents happen; dropping a 25 dollar UV-5r is an annoyance, but getting your $500 Chinese HF rig repaired when you drop it will be another matter altogether. On the civilian side, Elecraft is a US company, and Yaesu, Kenwood, and Icom have a robust maintenance and repair presence presently in the USA.

My strong preferences for an HF radio used for NVIS are:

• Low power draw.  Power for portable ops, especially man-portable ops, becomes one of the big constraints on such operation.
• Weather resistance.  One thing I really like about the IC-7200 is the water resistant front panel.  Most civilian HF radios have little to no moisture proofing and are designed for air conditioned indoor environments, another constraint on portable operation.  If I lived in the coastal Pacific NW, this would be a must-have and the IC-7200 would be my go-to rig.  Same with the SE USA and other semitropical areas, where the morning dew is a potent destructive force when it comes to electronics in the field. These locations are where Pelican cases and dessicant packets become essential accessories.
• Good to excellent receive filtration.  This makes a big difference in what your station can do.  You can get by with less, so this is not essential. Once you try a rig with really good filters, however, you may decide this is a ‘have to have.’
• Internal sound card for digital operation.  (this borders on a “must have”.  Digital is going to be the preferred operating mode for FreeFor.  Those who cannot use it will be at a significant disadvantage especially in a non-permissive environment, and while you can run a Signalink on the Yaesus, if you lose or damage that box, you are SOL WRT digital.)
• internal tuner;  most will tune 3:1, some do better, notably Elecraft and Kenwood.
• Good clean transmit.  Again, Elecraft and Kenwood lead the rest;  Icom is acceptable, and Yaesu is marginal.
• Ability to see what is going on on the bands (internal or external band-scope/pan-adaptor)
• Compact and light enough to move around without a block and tackle- suitable for portable use.

Nice to haves include:

• internal panadaptor.  I like being able to quickly see signals;  it is more convenient to have this built right into the radio;
• low weight- the 9 pound 857D is about as heavy as I’d want to go for a man-portable radio, and there are lighter radios available.
• Receive antenna jack-  NVIS does not require a listening antenna, but they come in handy, as noted in my earlier example.  Having that capability built in is a plus, although there are outboard antenna switches and noise cancelling boxes that do the same thing. Nice, but not essential.
• Multiple transmit jacks- having the ability to quickly change antennas is another nice, but not essential feature.  Coax switches work well, or you can label the transmission line and put some reflective tape on it so you can find it in the dark.

Notice that I did not talk about price; perhaps I should have brought that up first, because budget drives everything. Most folks have constraints on spending, and good radio equipment is not cheap, even older used equipment. Figure out what your budget is, and figure out what features you are willing to give up to make your budget. Entry level HF radios as of May 2021 are around $600 to $900 new. Next tier radios run around $1000 up to about $1500 new. Used prices for late model radios are usually around 2/3 to ¾ original retail, maybe more depending on demand, condition, and accessories included. I paid about $900 for my IC 7200 new, and used ones are running around 600-700 dollars. Same for the 857D; new was around $900, used around 600 to 700; more with accessories (filters, outboard autotuners, etc.) Older equipment pricing is more dependent on condition and options and accessories that come with it- headsets, keys or paddles, Signalink, power supplies, etc.

When you are budgeting for your station, don’t forget things like antenna wire, rope, transmission line, baluns, insulators connectors, adaptors, and all the other miscellaneous things you’ll need to get on the air. Whatever you plan to spend on a radio, add a few hundred to the cost of the radio itself for the other stuff you have to have, or take the total budget and deduct, say, $300 to $400 for your initial buy for antenna wire, coax and accessories.

Once you have your budget, the next decision to make is whether or not your HF radio will also be required to operate on VHF and UHF all-mode. This is a key decision point as it drives what sort of HF operating you will be capable of doing, what your station capability will be. Let’s look at a comparison of two good but very different radios that serve as an example of this decision, the most important decision you will make with respect to NVIS operation.  These two radios, with which I am thoroughly familiar, are  the Yaesu 857D  and the Icom 7200.

The Yaesu 857D is one popular example of the “DC to daylight” HF, VHF and UHF rig. Recently discontinued, this radio will run on 160, 80 and 40,  a basic requirement for NVIS, and also runs all the other HF bands as well as 6 meters, 2 meters and 70 cm (50, 144 and 440 mHz).

Pluses include: Very compact; reliable; reasonably rugged; midweight (9 pounds); can be set up to operate with the head detached (a plus for mobile operation). Provides MF, HF, VHF and UHF coverage. Sometimes referred to as a “Shack in a box”.

Drawbacks include: the menus, which are complicated and require many, me among them, to purchase a book to tell you how to use the menu system; no internal sound card for digital operation, a distinct negative; fair to poor transmit audio in stock form, with inferior spurious suppression; inferior receive filtration- (improvements require expensive  now-discontinued supplemental Collins filters;) like most mass-market amateur radios it is not designed to be at all weather resistant; it does not have an internal tuner; it has only one antenna jack.

With all of those drawbacks, I own one and like it within its limitations; it is an excellent choice for mobile or portable voice operation when the need for a single unit that runs 160 meters to 70 cm exists, and it is about as heavy a 100 watt rig as I’d consider for man-portable NVIS operation. Newer lighter DC-daylight rigs are available, including the new Yaesu 991.

The 857D is emphatically not my first choice when considering operation on multiple bands, CW, digital work, weak signal work, or the need to cope with noise or interference. The 857D is not alone in possessing these limitations; radios of similar size with similar functions have similar limitations (IC-7100, FT-991, etc) because WRT software and hardware there is only so much capability that can be crammed into a small package and sold for anywhere close to a reasonable price.

If I wanted a reasonably priced modern entry level rig more suited to portable, not mobile, NVIS operation with emphasis on digital modes or CW and I wanted to maximize durability and ruggedness, I’d probably look to the Icom 7200, also discontinued. This radio covers 160 through 6 meters, and is one of the few civilian amateur radios with any sort of weather resistance. Icom selected components used in its line of marine radios for the front panel controls and it is built to resist abuse, with an excellent cooling system, rear bumpers and optional front handles that help protect the front panel. For digital operation it has a USB jack and internal sound card, a plus. Although the IC-7200 lacks 2 meters and 70 cm, the receiver is superior to the 857D, with easy to use notch filters, digital signal processing, adjustable IF filters, and dual passband tuning all of which provide improved selectivity, and allows more advanced operating.

Pluses include: rugged, reliable and engineered to protect both the front and rear panels; dual cooling fans; a USB jack and an internal sound card to make digital operation easy; acceptable receiver, especially in its price class; compact; good for SSB and CW as well as digital, with average to better than average transmit quality, and decent audio from a water resistant speaker;  easy to navigate menu system.

Drawbacks include: 1/3 heavier than the 857D (12 pounds); somewhat larger; uses a bit more power than other rigs in the same class; like the 857 ( and most other entry level rigs) it does not have an internal autotuner and it has only one antenna jack.

I also own one of these, and use it primarily for portable operations where I transport equipment by vehicle. It sees action on Field Day, Winter Field Day, and other field operations my friends and I participate in and it would be a primary rig for emergency response.  It lives in its own EMP resistant 20mm ammo can. It works well for NVIS operation or other HF operation, has usefulreceive filtration and sensitivity, but if I want to operate on 2 meters or 70 cm I have to use another radio. I have multimode VHF/UHF transceivers, but that is another radio to deploy if I must meet that requirement, and another power drain, part of the price I pay for improved HF performance.

This is an example of the “DC to Daylight” versus “HF only” decision for entry level radios at about the same price point. You must decide whether having the ability to do LOS VHF/UHF comms with the same radio you’ll use for NVIS is worth the decrease in HF operating capability, or whether you’d have improved HF capability with one radio and use another for LOS- VHF/UHF.

If you decide on the “DC to daylight” option then your choices in new 100 watt rigs are limited. Last I checked, Kenwood was still selling the TS-2000X, which covers 1.8 mHz through 1296. It is an old design, and a bit beefy at 17 pounds. I would not call it a portable rig, but you can carry it around and it is satellite capable, if that matters to you. It is also reputedly a bit deaf compared to other HF rigs and to other dedicated multimode VHF/UHF radios. I have not operated one extensively so cannot comment from my own experience. Right now, Yaesu has the 991, a new design, and Icom is still selling the IC-7100, another older design which is portable or mobile capable.

There really isn’t anything superior to these radios in the 100 watt DC to daylight class at least at any sort of reasonable price point that I am aware of. The design compromises inherent in packing this much functionality into any sort of remotely portable radio cannot be overcome, given the present state of the art. If we are granted another 10 years of technological innovation, perhaps we’ll see the functionality of an Elecraft K3S or K4 in a DC to daylight rig that weighs only 10 pounds and costs only ½ ounce of gold. Or perhaps not. We’ll have to wait and see what happens.

If you go for the HF only option, then your choices in new current production radios are broader, depending on your budget. We’ve already talked about the IC-7200, which you would have to get used. In new rigs, you could choose the Yaesu 891 or the IC 718, both serviceable entry level rigs. A step above these rigs are the IC-7300 and the Kenwood Ts-590SG; until 2019, Yaesu had the FTDX1200, a decent radio, but that has also been discontinued.

Both the 590 and the 7300 are outstanding radios for the money and both are excellent choices for NVIS. Both have very good to excellent receivers; both have good transmit quality, with the edge on transmit quality to the Kenwood. If you want to see the results of Sherwood Engineering’s tests on these two radio’s receivers, and many others, here is the link:

http://sherweng.com/table.html

Apart from minor differences in receive performance giving the 7300 a slight edge in dynamic range, it has some things going for it that the Kenwood does not. First off, it is lighter and smaller, and second, the 7300 has an internal panadaptor, a big advantage if you are doing CW or voice NVIS, as it allows you to see where other stations are operating, a plus. I have no personal experience with the 7300, but I do use my Elecraft panadaptor extensively and it is very handy. Most folks are not going to try the sort of weak signal work I described earlier, so the panadaptor is more likely to be used a lot to quickly pin down other folks signals. Going back to budget, the 7300 is less expensive than the 590SG these days, another bonus.  The 7300 does not have as much receive filtration adjustment as the 590 does, however;  its primary filtration adjustment is a dual passband arrangement similar to the 7200.

The flip side of this is that the Kenwood is a brute when it comes to CW and digital, with two cooling fans like the IC7200, and while the panadaptor is useful, most folks operating digital NVIS, as most FreeFor will be doing (at least the survivors, )will use a laptop or tablet to drive the radio. The Kenwood also has an outstanding general coverage receiver with receive filtration almost equal to the Elecraft K3 built into it. If you are using Fldigi for digital, which I recommend, then you’ll have a waterfall on the computer and the need for an internal panadaptor is less. The Kenwood also has two transmit antenna jacks and a receive antenna jack, all nice to have. I know only a few folks who are hardcore enough to deploy listening antennas in the field, although it is very useful to be able to do, especially in non-permissive environments. The 590SG has IF out, allowing you to use an SDR Play with the computer to set up a true panadaptor.

Toe-MAY-toe, tah-mah-TOE.  At the end of the day, it really comes down to personal preference and operating style. I have some friends who are thrilled with their 590SG, and others who sing the praises of the 7300. If you want a modern touch-screen radio, the 7300 may be a good choice; if you want a more traditional and rugged radio looking rig with knobs and buttons, then look hard at the 590SG. Underneath the veneer, both are essentially SDR rigs.

In the HF/6m only class, there are a lot of higher end radios that provide even better performance and operator convenience. I am partial to Elecraft and I own and take any of several Elecraft QRP rigs, both CW only and multimode,  into the field (during good weather!) , but given the cost of the K3S (or for that matter the new Kenwood 890S, an incredible radio I’ve been casting envious eyes on), not to mention the weight and bulk, I would be very reluctant to take a radio like that into the field, although a number of DXpeditions have done so. Usually those radios are donated or bought by the expedition and written off; 2 or 3 weeks and they’re history. The new K4 is Elecraft’s response to Flex Radio’s 6400 and 6600 radios, but regrettably Elecraft was affected by a big forest fire last year and has struggled to complete and ship this new rig.

Speaking of the Flex radios,  they are US made, state of the art SDR equipment, with breathtaking capability, but I would not take them into the field either. They are big, heavy rigs and they are not cheap. They have amazing capability and allow easier operation, but although I have been interested in and involved with radios since I was a child in the 1960s, I have other interests and other demands on my time and money besides amateur radio. I need to balance communications with other things I also need to be able to do. The high end Flex Radios start at around $5,000; I could buy an IC-7300, an IC-9700, a Home Patrol 2 scanner, a 40’ tower and VHF beam antennas for that price and still have money left over for coax and wire. With the capability of the 7300 it is unlikely that it will limit my operating capability, and it is light enough and compact enough that I can take it out of the shack and run it portable if needs be.

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There is much to be said for used equipment; as noted previously, there are some very good radios that have been discontinued that are only available used, and they cost less than new equipment. Modern solid state gear is engineered to last if not abused; I have 40 year old discrete component through-hole PCB radios (IOW- user serviceable) that are still in good shape after decades of use.

If we are talking used rigs, then here are some to consider when gently treated and in good condition; note that there are no guarantees for used equipment bought in private sales, and most used equipment dealers offer only a 30 day warranty at best. I have marked radios that I either have used and like or that I can recommend based on trusted recommendations from others with an asterisk*:

For DC to daylight 100 watt used rigs, consider these:

*IC 706, especially the MkIIG. Suitable for mobile operation and man-portable. It is getting old, however;

*FT-857 plain or D model. As discussed, especially suited for mobile or portable ops.  If you can get one with the optional filters installed, it is a better radio;

*IC-7100; likewise good for mobile and light enough for man-portable, although I wonder about the durability of the screen;

TS-2000X; one of the few DC-daylight radios to cover 1296, a plus if you intend operation on that band and full duplex capable. NOT recommended for use in unsheltered field environments.

FT-897, the predecessor to the 991. Can be had with on-board battery, a plus; noted for problems with the readout screen, a negative. Aftermarket tuners can be had for this rig but it does not have an internal autotuner. Notably heavier than the 857D, especially with the battery.

If you are considering HF only (or HF plus 6 meters) take a look at these:

*IC-718. Basic entry level rig, HF only.

(IC-78. Similar to the 718, but for .gov use. HF only. Grab one if you see one.)

FT-450. Yaesu’s older entry level rig- no receive filters; the newer 450D had filters and was a significant improvement. HF + 6 meters.

Alinco’s DX-70. I’ve heard good things about Alinco, and I like the engineering of their 220 mobile FM rigs, but I have no experience with this one.

*IC-7200. A brute of an HF rig as discussed  above.

*TS-590S. Predecessor to the 590 SG, also an excellent radio and available for less than the cost of a much inferior new entry level rig. I’ve seen these go for under $500 gently used in good shape.

There are lots of other choices in older gear, but once you get past about 10 to 15 year old designs, the weight and size increase, and the available features and reliability start to decrease. I enjoy using older radios, especially the very last of the solid state analog radios like the Ten Tec Corsair which have low noise floors (I can hear things on my Corsair 1 I have trouble hearing on my Elecraft), but for use in the field or when communications are essential, I cannot recommend them. Likewise with tube rigs- tubes are what I grew up with in radio and I enjoy putting old tube rigs back into service and puttering around with them, but tubes are getting increasingly hard to find, expensive and have always been fragile. For field use, they are not suitable and many of them lack 160, a damning disqualification.

So, there are my thoughts on radios for NVIS.   I must reluctantly put down my goose quill and send this off for editing and publication. I hope you have found this of use. The next installment, Part 4, will talk about advanced NVIS antennas and how to best employ them in non-permissive environments. I realize this has been a bit dry but will have lots of graphs and diagrams for this next article.

Keypounder.