Hey guys.

Still working on antenna knowledge and have a question for short range communication.

I need a portable antenna solution that can be used to communicate with stations from a few miles out from my station and covering that skip zone. I was thinking about putting together an inverted V dipole on a 30 foot telescoping mast and playing with the wire angles. I could potentially mount this in the back of my truck or on a trailer roof as well.

Better choices?

You know what I'm going to say...

Pay ZERO attention to any post that has "NVIS" in it. Put up a ladder line fed doublet at 50 ft or higher and you'll be GTG.

Mic drop.

Ok, the rest of you go ahead and confuse him...

Thank you for the reply.

I am going to have a tough time doing 50 plus feet on a portable antenna. I figure the highest I am getting is 30 feet if on the ground, plus five feet in the back of the truck and plus 10 feet if on the trailer.


To phrase it another way. I am trying to figure the best way to communicate with friends within the state as close as 10 miles and as far as 500 miles away.

LOL, I did.




Op, if you want close range HF comms you need band flexibility and weak signal digital modes, and even then there's no guarantees. It's going to have more to do with the mode employed and luck than the antenna you use.

A spider beam 18m mast isn't really that expensive in the grand scheme of radio and would support a ladder line doublet easily at 50ft (assuming you left out the top coupe of sticks.) You mentioned deploying from a truck so it isn't like you have to hike around with it.

My solution to your problem is a mobile screwdriver antenna with extra radials and clipping the whip to an extension when possible.

http://www.wolfrivercoils.com/TIA.html
I have one of these I use portable, well I guess at non-home locations? I used it here until I got a wire up in the air, literally 12ga THNN from a vent pipe, over a tree, back down to a rope off the fence..

Not much better that you could do as a practical matter. Fan dipole for 80, 60, and 40, maybe 20 also. Maybe traps to reduce the number of wires and overall length.

Durrrdurrrdurrr  straight lines go round a curved surface best durrrdurrrdurrrr.

80m full size loop installed horizontal in the trees 40-80 feet up. ~265 feet of wire in total. Can be a triangle, circle or square. There are daily nets that cover Alaska and they guys that have the sky loops consistently have the best signal in state then they talk up and down the west coast on the same antenna. 80m dipole same height would be my runner up, but a sky loop can’t be beat IMO.

ETA, I participate on the loop on end fed antennas currently.

Somehow I missed portable in my first reading of the OP lol. A low loop is still good, he could do a horizontal delta loop off his mast and 2 ground attachment points.

Packing around and setting up a fan dipole with a bunch of traps isn't exactly a portable operators dream either...

For portability I can recommend this one as I've been using it for over a month now with good results. Will be easy to set up with your pole as a sloper, flat top or invered V or L. Small, cheap, light, works.

https://www.ebay.com/itm/203307858012

20~25 foot mast, two dipoles used as 4 guys, easy. Staple of both amateur as well as mil ("AS-2259/GR") HF operation.

OP What time of day are you wanting to operate, and most importantly on what HF bands?

That I like, I might have to make one someday soon.

This.   And by the way, it excels at NVIS, which is what .mil needs more than anything else for regional HF comms.

This clone version has coils for better swr on 40 and 80.


Link

a simple dipole, 2 pieces of wire connected to the end of the coax, with or without a balun, usually called an inverted vee since only the feed point is on the top of your portable pole and the ends are lower.

Maybe make it into a "tap" dipole you can have 20m for longer distance in the day, add a few feet of extra wires to each end and 30m during the day, a few more feet and 40m day or night, a few more feet of wire to get on 60m then maybe even 80m. you can use banana plugs/jacks or alligator clips or whatever to attach the extra wire to the existing wire

if you just need 2 bands, then put both dipoles on the same coax, it almost always works just fine.

get on 40m during contest weekends or work SOTA guys, and see who you can hear or work, or just watch the FT8 screen and fill in the grid square blocks you see printed and eventually you'll figure out what band gives what coverage what time of day.

.- .- ....- --.-

By going lower, it will still work, but the antenna will be less efficient especially on 160-40. It will still work, it will just radiate less power because of higher ground losses and you will be more dependent on better propagation. You can compensate by using more power. If portable, then a  solid state mobile HF amp will help make up for the ground losses.

If you are portable with trees, you can support 2 ends of the antenna with trees and easily get 50 feet if the trees are available.

20~25 foot mast, two dipoles used as 4 guys, easy. Staple of both amateur as well as mil AS-2259/GR HF operation.


That is pretty slick. I wonder if I can reduce the overall foot print by raising the feed point without affecting operation too much. I am still not sure on how much room we will be given to work with.

I found a whole list of parts and instructions put together from DXE (it looks like they sell the whole thing if you wanted to go that route) as well as a lot of guidance on the antenna. Either way, this looks like something I should do for my next project.

Operating times would vary based on need but, we are to assume that there are no other means of communication in the immediate area and the goal is to be able communicate with areas where normal services are available.

For HF propagation, the tough nut to crack is that zone from 25 to 250 miles from you.  It's usually going to require use of the lower bands (160, 80, or sometimes 60 meters) in the US because of our relation to Ionosphere in this part of the globe.  And even then, performance on those bands is poor during the daylight hours much of the year.  The solution to these problems is to get a really great antenna up as high as you can and run as much power as possible, but none of that is very conducive to portable setup and use for most.

I operate portable about 90% of the time when I play radio, and I like to get on 80M a lot when I can to grab local-ish stations, but it's not always reliable and the results will vary throughout the time of day and the part of the year you're in.  So as many said above, just put up the best antenna you can for those bands and cross your fingers that propagation is on your side.

Now for longer ranges, then you can rely on higher bands, mostly 40 and 20 meters to go further, and those are usually more dependable for favorable conditions and easier to manage antenna wise since they can be physically smaller/shorter.

No. The only way to reduce the size is to use some loading on the elements: coils, traps, linear loading etc. Antennas for low frequencies tend to be big.


No it's not. The general solution to short range HF is a simple antenna relatively low to the ground. The hard part is whether the ionosphere will support that propagation path and if you have a suitable frequency available for that path.

Play around with various antennas and find one that works for you.

For portable stuff I personally like end feds - either something homemade or like the Par End Fedz offerings, or the MFJ-1982. I can usually find a tree to throw it up in, or lift one end up with a telescoping pole.

Doublets/dipoles work really well, but usually take a little more setup time, but not always. An inverted-V like you mentioned would be a very simple setup for portable ops.

For the higher bands a vertical can be a really simple option, but not ideal for close range contacts. This weekend I built a super simple "up and outer" antenna for 20m and made a handful of QRP contacts with it from coast to coast.

There is no perfect antenna - so you need to find where you're willing to compromise and go from there. Short antennas are easy to setup, but suffer from inefficiency. Long antennas are great for efficiency, but take up more real estate and take longer to put up. Unless you operate from somewhere with lots of 100ft trees getting an antenna up really high can be difficult and/or expensive. Etc, etc.

This is my personal experience so YMMV, but I live in northern Colorado and I have a buddy in southern Colorado (roughly 275 miles between us). Last year we had a weekly scheduled contact at 7pm local time on 80m using JS8call. We typically used 10-30 watts. I was running an MFJ-1982MP in an inverted-v configuration at 30ft, and my buddy was using a Hustler 6BTV (24ft vertical antenna). Neither of these antennas are what anyone would consider a good choice for short range 80m contacts. Nonetheless we never missed a week and always had 100% communications between us. If you want armchair copy, long winded SSB conversation you'll probably want more power and better antennas to deal with noise and fading, but this just shows that even less than perfect setups can get the job done.

Interesting... I just started using my Hustler 5BTV last night.   On 40m I was talking to Michigan and Montana but could not hear the NJ station from my upstate NY QTH,  probably around 300 miles to the NJ station.  Then again I had the same with my MFJ OCFD. on 40m.

My guess is that 40m at whatever time that was went "long" and the ionosphere wasn't supporting any short range links. I would venture to say that you would have had better luck with 80m.

Funny you say that.......Having just tuned the antenna and having 80m was a new thing for me........all I could find on 80m was the usual megawatt bloviators camping on 80m frequencies.  They’re an odd bunch of personalities. I only tried to talk once to them and wasn’t heard or was ignored.  Granted the 80m on my Hustler is rather narrow.   I can go from about 3.850-3.895 and stay under 3 SWR.

I for sure haven’t developed the knowing of good propagation times.

I understand that, but in this situation being a portable/temporary setup and likely limited in how high it can be, and that for those lower bands even a dipole at 40-50 feet would be considered "low" for the wavelength and favor higher-angle takeoff, "as high as reasonable possible" will probably still be optimal.  

A half-wave dipole about a quarter-wave above ground is said to be pretty optimal for "NVIS" work, and for an 80 meter band dipole, that's about 60 feet high.  I don't usually put much higher than that in the realm of a temporary or portable setup.

Now if reliable short-skip propagation were more common on the higher bands, that'd be a different story.

Coax fed 40/20 Meter fan dipole hung as an inverted vee.
The 40 Meter element will load as a 3/2 wave dipole on 15 Meters. SWR can be improved on the upper end (SSB) portion of 15 by using capacitance "hats".
Since the coax run will be short, RG-8X or even RG-58U can be used. The 1:1 current balun in the center can be eliminated if desired.

Alternately, a 40/20 Meter trap dipole such as the MFJ-17754 can also be used. As with all trap dipoles, the bandwidth on the lower frequency band (40 Meters in this case) will be narrow.
If you want 80/40 instead, consider the MFJ-17758. A 20 meter dipole could be slung below it as in the above.

Those are good antenna solutions for the money, but I think an insulated radiator would be better for the off situations where you might throw the wire in the bushes for quick deployment or the ends might be low where someone could come in contact in a campground or something. Also not sure how that bare copper behaves when being coiled and uncoiled multiple times and then stowed in the back of a Jeep.

I'm going to make something similar with an Alpha Delta center insulator and some more supple wire.

This is the way I think, in one configuration or another. It's hard to beat a wire antenna for the money. I looked a couple of verticals like the super antenna, buddipole and alpha delta but, that is a lot of money I could spend on other things.

NVIS for the win!!!!
Well, kind of but I couldn't resist to bring this up

NVIS isn't an antenna but rather an antenna radiation pattern/propagation and it only works on the lower bands (usually 80 and 40m). Don't bother trying to build a 10m "NVIS antenna". Believe me, I know many people who did and swore that it worked like a champ. LOL. All were newbies. Just forget about it, ok?
Yes, NVIS is a good thing for close contacts on the appropriate frequencies that support that kind of propagation. Most 80m horizontal dipoles and alike, are NVIS because they are relatively close to the ground, in relation to the wavelength.

80 and 40 meters will most likely be your best choices on HF. I would choose 2 meters for contacts out to about 15 - 20 miles.

Practice, practice, practice! It's the only way to find out what will work for you. Check into regional, 80 meter nets, late in the evenings. This will give you a good idea of what can be done on that band.