Portable HF Radio: Issues and Options

when it comes to using hf radio in the real world things can become a lot more challenging than we might think hf radio is a whole other animal compared to vhf or uhf radios that we might be used to and despite the benefits that hf radio brings to the table there are also downsides or obstacles we have to get around one major series of disadvantages lies within the field of portability so today let's get into the nitty-gritty details of some problems you might face when trying to make your hf radio setup a lot more portable with every radio setup there are compromises and one of the biggest compromises all radio operators make is their antenna and that is also by far the biggest barrier to portability hf radio antennas by their very nature are usually quite large you aren't going to be screwing in a microwhip antenna to your hf rig and making any contacts whatsoever the antennas that function and are resonant at lower frequencies are usually dozens of feet long this is our main challenge and spoiler there isn't really any good solution for this there are many ways of shortening an hf antenna to function in a more compact space and we will definitely be talking about that in the fut n for this there are many ways of shortening an hf antenna to function in a more compact space and we will definitely be talking about that in the future what i really mean is we want ultra portability most ham radio operators are content with something like a long wire antenna or a dipole or an in-fed half-wave antenna basically a long piece of wire that gets strung up in a tree or with a mast or something like that and that's perfectly fine obviously this is preferred if we have the time and space for it but many times we don't have the time or the space for it and this is where we start to notice that we might be asking too much from our radio systems or at least for the technology that we have at the moment we want to be hiking along a trail take a knee for a second and get a message out or even better be able to fling up a whip antenna really quickly and get a message out if we are in a less than friendly situation unfortunately when it comes to civilian hf radio this isn't going to be possible at the moment but we can get close and to do that we must first understand a bit of basic radio theory at the very simplest level a transceiver a radio capable of transmitting and recei and to do that we must first understand a bit of basic radio theory at the very simplest level a transceiver a radio capable of transmitting and receiving needs a few things to work at the very minimum we need the radio itself a power source an antenna and some cabling and adapters to connect everything together now hf frequencies are not like the frequencies you might be used to if you have a history with vhf or uhf radio with high frequencies despite the somewhat misleading name the wavelength of transmissions on hf bands is actually quite long a good rule of thumb is that the lower the frequency the longer the wavelength so what does this mean for us with our antenna well you know that foot long whip antenna or rubber ducky antenna that you have when you're handheld yeah that's not going to work on hf frequencies longer wavelength lower frequency bigger antenna in fact the frequencies or bands that you want to operate on will dictate exactly how long your antenna has to be for instance let's take a look at one of the oldest antenna designs in the book and arguably one of the most efficient ones the dipole dipole antennas are pretty simple and they are usually the benchmark that designs in the book and arguably one of the most efficient ones the dipole dipole antennas are pretty simple and they are usually the benchmark that people use when comparing new antenna designs a dipole antenna is nothing more than two strands of wire connected by an insulating connector in the middle which sometimes includes a balance or balancing unit to keep the impedance matched across the system but hold on here we're getting ahead of ourselves if we understand a bit about basic radio theory we know that the length of the dipole legs is dependent on what frequency we want to transmit on in a perfect world where thermodynamics don't exist we would all be running full wavelength dipole antennas this would mean that the antenna is the exact wavelength of whatever wavelength we want if we wanted to operate on 40 meters for instance a full wavelength antenna would be a little over 130 feet or 40 meters long in total however as hopefully some of you have noticed full wavelength antennas are almost never used because they lose their efficiency to heat dissipation pesky laws of thermodynamics and such and also due to diminishing returns using a piece of wire that's longer than half fficiency to heat dissipation pesky laws of thermodynamics and such and also due to diminishing returns using a piece of wire that's longer than half a wavelength doesn't really do much for you as a result most people use half wavelength dipoles which if we're sticking with 40 meters would be a total length of 66 feet so in our quest to shorten our antennas as much as we can we can see that the job just got a lot easier but 66 feet is still quite large this is perfectly fine for setting up at a base camp for the night or something like that but it's not really feasible for taking a quick knee beside a trail to make a transmission so what can we do to shorten this 66 feet length well one answer is loading coils the idea of loading coils is pretty simple we take some of that 66 feet of line scrunch it up into a tightly wound coil and by coiling that wire we are effectively shortening it but electrically the wire is still the same length this can greatly reduce the length of your antenna especially at lower frequencies when antennas can be quite long now you might say why don't you just make the whole antenna a coil and indeed you technically could in fact there are a lot of companies be quite long now you might say why don't you just make the whole antenna a coil and indeed you technically could in fact there are a lot of companies that sell ultra compact antennas like this one that market that very capability very thick coils combined with a very short telescopic whip so all good right well not really as you will hear time and time again throughout the radio world there are a lot of trade-offs with doing this generally speaking the longer your coil or the larger your coil is in proportion to the rest of the wire the more inefficient the system is so with a loaded coil system we can see that there is a balance that must be maintained having a whip that's the right length and a coil that's also the right size as well now all of what i have mentioned is really just describing how resonant antennas work there are other ways of getting to the same goal we will be talking about matching transformers and antenna tuners another day and of course there are other antenna designs too end fed half wave is another popular choice vertical half wave slopers jungle antennas aka quarter wave ground plane antennas you get the point there are a lot of ways of skinning this parti ice vertical half wave slopers jungle antennas aka quarter wave ground plane antennas you get the point there are a lot of ways of skinning this particular cat so to recap if we want to stick with resident antennas of a dipole-esque design we can use loading coils and collapsible whips to get us where we want to be one of the most widely known and one of the only companies that has taken this idea and commercialized it is buddy pole buddy pole has been around for a long time and many of their main products are essentially what are loaded coil dipoles there are a couple of other companies that also make these but i only have personal experience with buddypol specifically the buddy's stick this is a somewhat new product that they recently came out with that caters to very specific users this antenna has been extremely popular throughout the summit on the air or sota crowd and for good reason for us though we can take advantage of this loaded dipole design to meet our goals as well what i have been experimenting with here is pre-assembling the critical parts of the antenna and placing these down inside a backpack this allows us to get really close to our goal because we can hook up al ng the critical parts of the antenna and placing these down inside a backpack this allows us to get really close to our goal because we can hook up all the wires and have everything pre-connected then when we take a five-minute break all we have to do is screw in our vertical element our collapsible whip and extend our radial now a note about the radial you might think that this whole system the tripod and the buddy stick vertical and the loaded coil that you might think that's all you need not so stringing out this radial here is required if you do not string out this radial you will not make any contacts or even hear anyone at all on most of the lower frequency hand bands that's why i mentioned that the buddy stick is essentially a loaded coil dipole because this radial is more or less one half of that dipole that's why technically calling this a counter poise is not quite right it's really one of the radials in our dipole system this radial is why we can't use this system while on the move you need to have it elevated off the ground we might be in open terrain and perfectly fine with a super long whip on our back but trailing 20 feet of wire behind us while we walk is just not p d we might be in open terrain and perfectly fine with a super long whip on our back but trailing 20 feet of wire behind us while we walk is just not possible and that's why i said we can get close to our goal but we still have a lot of work and a lot of testing left to do with this system you can take off the ruck set it directly on the ground extend the radial and screw on the whip and now you're deployed pre-assembling the buddy pole antenna might seem like it's not worth it especially considering you're potentially increasing the risk of damaging the system you might say that pre-assembling part of the buddy pole system is kind of diminishing returns right it's a lot of risk for not a lot of gain it doesn't take that long to screw these pieces together when you get to a site and you can just leave the whole thing together and it's in its carrying case however the real benefit to pre-assembling much of the buddy stick system is that you don't have to worry about a lot of small pieces getting lost and you can do this in the dark under total blackout conditions it's not hard to extend the radial and screw on the whip by feel so that's one major benefit is this system a compromise y r total blackout conditions it's not hard to extend the radial and screw on the whip by feel so that's one major benefit is this system a compromise yes absolutely but does it work also yes the biggest downside to the system is that it's not really feasible to be used in an invis role which is a bummer but in that case a regular dipole will work just fine so let's take a look at what this might look like in an actual backpack setup so to show more clearly what a complete system might look like here is an example that i've thrown together of mostly what i use so as we can see here we have the buddy stick pro basically all the way inside the backpack pre-assembled and as we can see this backpack being longer than your standard assault pack this is more of a more of a rug than anything else we have less of the buddy stick sticking out at the top to get caught on stuff again i would not recommend walking around with this hanging out of the top of your backpack unless you're in an area where there are no snag hazards but trust me if you're you know a klutz like me you will you will snag and bump this on stuff and this is again really a really important part of your system taking a look you know a klutz like me you will you will snag and bump this on stuff and this is again really a really important part of your system taking a look at the side of the bag we can see that we have our telescopic or collapsible antenna here of course ready to go at a moment's notice and we also have threaded through the inside of the bag since this buddy stick is uh pushed all the way down inside the bag here the actual radial here is in this pocket so i poked a small hole through the eberly stock bag here to the inside in a place where it's not going to fray too bad and threaded this through to the inside so that you now have your radial quick and easy to get to so all you have to do in the middle of the night in the dark where you're working with light discipline you can get to this by feel and you can stretch it out by feel so you don't need to to have a super great motor skills to do that which is always handy so you can tighten that back up to make sure it doesn't fall out you can also put it in a pouch or one it doesn't really matter too much so taking a look at the top of the bag here we can unzip this to find our ic705 nestled very nicely in there we could add padding if we tter too much so taking a look at the top of the bag here we can unzip this to find our ic705 nestled very nicely in there we could add padding if we wanted to we could put some padding or clothing behind that whatever you wanted to do for that i find that this works really really well just as is but if you're super concerned about your radio getting damaged obviously make sure that you take care of that before anything else because this is a very very expensive system right all the cabling is routed down inside the bag using multiple holes for routing cables which is very very handy and we can take advantage of a small admin pouch on the top here to hold our antenna analyzer and some extra batteries for various stuff either the icom ic705 or an extra tablet battery which we can talk about in a later video up here up top we can unzip the top of the bag here to reveal a solar panel on the inside it fits very nicely on top of there and as you can see kind of peeking out there from the main part of the bag we have an entire laptop so if you wanted to bring with you an entire laptop you could do that i tend to not go very far with these because they're super heavy and you get a lot of you wanted to bring with you an entire laptop you could do that i tend to not go very far with these because they're super heavy and you get a lot of the same capabilities with a smaller windows tablet but i just wanted to show you this will fit with this entire system from inside here i went with a smaller battery just to save weight uh and save a little bit of space but we've got our coax here just in case we want to run a dipole of some kind um moving down inside the bag here i don't know if you can see it very clearly or not but we have a sleeping bag mat we've got some food and other kinds of sundries that you might need out on the trail for a couple of days of operating and we have our dipole down here at the bottom and as we can see peeking out here from the side the rest of our system now i don't know if you can see this or not very clearly but the versa hub doesn't actually go all the way to the bottom of the bag i have my tent right here so this adds another layer of protection for this somewhat or comparatively delicate coaxial connection right here as well as we're wanting to make sure that we keep things uh impact resistant because because again we want to make sure th xial connection right here as well as we're wanting to make sure that we keep things uh impact resistant because because again we want to make sure that we have some kind of impact protection for setting this thing on the ground making sure we get a nice level platform to work from and this works out really well any tint will work but yeah you can get this versa hub further down inside the bag obviously if you were to push it down further but i find that this works really really well and the amount of space you'd gain by uh putting this further down inside the bag is not worth it in my opinion because then you're experiencing a very critical part of your system to impacts from the ground so again again this takes into account some of the fragility of some of these radio antenna systems and again we can see our uh green radial wire here going all the way up through here out through the corner there and back down to the outside pocket so all in all this is a pretty complete system uh you don't really need much more uh anything else for for operating uh out in the woods for at least a couple of days obviously this pack is you know just one of many that you can use and obviously we can for operating uh out in the woods for at least a couple of days obviously this pack is you know just one of many that you can use and obviously we can put molly pouches on the side and uh on the front here to hold various items of clothing food you name it all the kind of general stuff you need out in the woods right so yeah i thought that might be a helpful way to kind of visualize how the system comes together so hopefully this was helpful in understanding some of the challenges we face when trying to be ultra portable with our systems there is no one answer to any of this stuff in fact there are so many answers that it's oftentimes overwhelming a lot of people would probably prefer to just be told go out and buy this or that i know i myself would prefer that as it's much simpler but unfortunately that's not how it works in the radio world and your own needs will dictate which radically divergent path you will take so thanks again for watching everyone and we will be on to the next one soon and as always fight in the shade