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 decis