What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

HF Radio and Antenna

Roger

Member
Hi everyone, I hold a ham extra radio license, and would like to put an HF radio and antenna in my plane. I have searched the forum, but cannot find any info as to has anyone done it, and what is their antenna configuration.

I was thinking about putting a so called screwdriver antenna in, instead of a trailing wire.

Any suggestions?

Thanks!

Roger
 
What I have seen and used is a long wire from the top of the fuselage to an insulator at the top of the tail, then back to one side of the fuselage. Basically an inverted "V" antenna.

invertedVantenna.jpg


:cool:
 
One solution

When Bill Randolph circled the planet in his 8, he ran his HF antenna from the left side of the cockpit to the left wing tip and then back to the left horizontal stab. Worked for him. Others have used a flu fishing reel to pay out the trailing wire in flight.
 
Hmmm the term screwdriver antenna was a new one to me until I did a little searching around and found it to be a ferrite base-loaded whip. The short answer is yes, they will work (I maintained a fleet of about 80 helicopters equipped with this type of antenna). They aren't particularly well-suited to a fixed wing platform like the RV because we've got that spinny thingy on the front end that would slice and dice an antenna pretty handily. Sticking one out on a wingtip or similar location would result in lots of broken antennas and poked out eyeballs.

As Galin pointed out, many aircraft run wire antennas. Because they are short one needs an antenna coupler unit inside the aircraft to properly tune for the antenna length. Of course this antenna coupler unit could be simple, just like the base of the screwdriver antenna, with the wire acting like the flexible whip of the screwdriver.

While most folks don't like to give it much thought, antennas in this frequency range tend to be pretty draggy, even at their most compact size. A trailing wire is one of the least draggy ones, but then again you're trailing a wire that can be a pain in the backside for a number of reasons, mostly to do with forgetting to reel in the antenna before getting close to the ground..

If you're thinking about having the HF permanently installed, unless you're doing remote/over-water flight I'm not sure why you would bother as there are much better means of communications available. Since you're a HAM I'm guessing you likely want to have an HF just to have an HF. Fill yer boots!
 
If you're thinking about having the HF permanently installed, unless you're doing remote/over-water flight I'm not sure why you would bother as there are much better means of communications available.

This got my attention - I'm wanting to do some international transoceanic flights and having difficulty finding information about comms out over the ocean. What other options exist other than HF? Is SatComm a viable option now? VHF relay through overhead airliners? That seems problematic - but I have not yet found a source willing to talk about it. It's like this is a club secret that you have to know the secret handshake to get in. If you haven't done it the hard way nobody will tell you how to do it.

A fishing-reel style trailing antenna with a small HF rig would work for scheduled position reports I suppose - but it's not practical for monitoring a frequency between reports. Can it be deployed just for hourly checkins and stowed in between for reduced drag? What are the requirements for VFR/IFR transoceanic reporting points here?
 
Last edited:
I have done a bunch of relays over the Pacific from single engine guys down low on delivery flights etc and the occasional C-130 down in the 20s. They have an HF radio and can usually hear Radio but Radio cannot hear the aircraft. I would not plan on the ability to relay as my primary means of communication though. Satcom works great but if you are thinking about using it in a small piston powered airplane I would figure out a way to use it through a headset. Also, your handheld satcom system will not recognize the 6 digit number so you will need to get the full phone number. They are buried on the charts but they are there and don't forget a satcom call is an international call so you need to start wth 00 and then the country code.

In general you are supposed to maintain a listening watch at all times but unless you have SELCAL that is not really practical. Usually what happens is you make your position report and then go off the HF but monitor oceanic air to air. If Radio wants you they will find somebody near you and get them to call you to call Radio.

- Thread drift and a slight rant- What is the oceanic air to air freq? 123.45. That's right. everybody on the costal states doing formation flying and chatting on fingers is stepping all over oceanic air to air for the first 300 miles or so. I dread going out to sea on a bright weekend morning because I know the first 30 minutes of the flight is going to be nothing but "I'm about a mile behind you Fred" "I see you Bob" Please, stop using 123.45. - Rant over-

You are supposed to report your position every 10 degrees if you can travel than in under 1+30 (I think, I don't have a chart with me. Somebody jump in here and correct me if I remember it incorrectly). If you can't cross 10 degrees in 1+30 then they want you to report every 5 degrees. In a nutshell they want to hear from you about every hour or so.

Are you a member at NBAA? They have an excellent international ops group and can point you in the right direction for what is required. I would think AOPA would also probably have something along those lines. If you are talking about flying over the Atlantic then everything you could possibly want to know is contained in the ICAO NAT Doc. The rules for other oceans are very similar and they continue working on making the rules and contingencies for all the oceans the same or similar so there is less confusion.

If I were doing the Atlantic in a single engine I would get in touch with the guy on the board here who just crossed and wrote about it in the last couple weeks to get his gouge.
 
Trailing wire

Bill Harrelson did a lot of experimenting to find the right set up for his trailing wire antenna. He is the guy that flew his Lancair IV over both the north and south poles.

He used an iCom IC7100 type transceiver with the remote automatic antenna tuner mounted in the tail near the antenna tow point. The tow point was just forward of the empennage on the bottom of the plane and carefully faired with a bolt to attach the trailing wire. The wire length was adjusted to get a good match at the typical HF frequencies of interest. What took the most time was finding just the right size plastic funnel to add to the end of the trailing wire as a "drag chute" - I think he ended up with one perhaps 1.5" in diameter. This kept the wire from whipping around and also help it not get snagged as he dragged the wire on the ground for taxi, takeoff and landing. He kept a spare replacement antenna wire in the plane but never needed it.

Have fun.
Carl
KV4U
 
Random data point

I wired a 2 meter rig into the audio panel of my 6A 20 years ago. Talked on it ONE TIME on 146.52. (Repeaters not practical at altitude because you bring up an unknown number of them at once).

While fun and unique, the FM rig was the first thing to be removed during subsequent iterations of the panel.

I've had fantasies of HF aero mobile operation many times (I'm the kind of guy whose Honda Accord would practically do a wheelie on the interstate from drag on the rear bumper due to 13 feet of Texas Bug Catcher antenna mounted there in the 1980's. The HW-101 and inverter supply made the back seat kinda heavy, too :p) At the end of the day, even in X/C on autopilot, I've come to believe I have much more important things to do as PIC than call CQ on 20 meters or check into the 40 meter mobile nets, cool as that might be the first time. For me it's just a fantasy that would never be worth the hassle and distraction - and I already have the IC-7000 and autotuner...

Your mileage will undoubtedly vary; these are just my musings. But I've mused them many, many times. Think it over carefully, and I'd vote to leave it out unless it's mission-critical.

73 de N4DLN
 
Ive been fantasizing about this myself lately. Would be fun, but a lot of trouble to go through. Wouldnt need much power, so the rig could be small, but the antenna is the issue. Drilling holes for external insulators and such is not something I would like to do. Trailing wire? Maybe, but one would need a retraction mechanism. Pretty impractical, but fun to think about!

73 DE K2GOC
 
Modern airliners don't use trailing antennae or long wireline antennae from a wing to a tail, and they cross the oceans regularly - how do they do it? Satcomm?
 
I've worked 80m /M a couple of times checking into MARS on USB about 20,000 over Chicago. Just happened to be in an old Citation with the old Collins USB radio.

I'm planning to put an HF transceiver in my E-LSA Flight Design CTSW. It's carbon fiber so the antenna and ground plane is an issue. Carbon fiber is quite lossy. My top speed is about 120 kph.

I've toyed with the idea of a trailing wire antenna so I could work 80m. I've looked at all the WWII scout planes with the trailing wire setup. A bit complicated, maybe. As a glider tow pilot, I have some appreciation for the foibles of a piece of rope hanging behind a landing airplane.

A more practical idea might be a V from both wing tips to the top of the vertical stab. A tuner in the tail. It will handle up to 20m. Both are draggy, as was mentioned.

Here's the radio I'm hoping will work. CommAir transceiver.
http://www.universal-radio.com/catalog/hamhf/6010.html

I have a PS Engineering 8000C and an adapter to handle the mismatch of microphone impedance. The 8000C handles 3 coms, so I'll be using my regular headset. It's often used by agencies that need to use a non-aviation radio.

(I bought 2 by mistake, so I have an unused PS8000C for sale). :)

My setup is in the incipient install phase. I bought all the gear except the HF radio which is pending FCC approval. I hope to start the install right after Labor Day. I've received considerable help from local Rockwell Collins aviation radio engineers and from Stein Bruch of Steinair.

I make some long trips in the CT and thought that it might be fun to pass the time by making a few contacts. I agree it is essentially impractical. That, of course, is neither here nor there and I find no need to apologize for or defend it. :)

Jim NO0B
 
A buddy installed an HF radio on his Aerostar. The antenna goes from nose to tail and back to mid body. Now, that plane is longer then most discussed here; but he did not see an noticeable impact on cruise speed. In addition, a few engineers said having the antenna parallel to the flight path is the least draggy, and maintains a very small but constant wet area.
No idea if on smaller planes this gives enough length though.

Tim
 
HF

Greg-
Go to 220kts.com, this will tell you all the options if you are considering the North Atlantic.
The problem is Gander Oceanic. They require HF for VFR or IFR. Further north can be done without HF.
Gander apparently does not offer any options such as sitcom.
For those considering the NA, St Johns to Shannon is only 9 hours at approximately 160 kts. This is far more practical than Greenland-Iceland or the further north route.
 
Greg-
Go to 220kts.com, this will tell you all the options if you are considering the North Atlantic.
The problem is Gander Oceanic. They require HF for VFR or IFR. Further north can be done without HF.
Gander apparently does not offer any options such as sitcom.
For those considering the NA, St Johns to Shannon is only 9 hours at approximately 160 kts. This is far more practical than Greenland-Iceland or the further north route.

Thanks - I'll definitely check that out. Any knowledge of the Pacific? I'm thinking of going west first...
 
HF

Greg-
All I know is that the Pacific involves very long distances and avgas MAY be a problem at some of the islands.
A good starting point would be to read the article about Ann Pelligrino and crew recreating the Earhart flight, IIRC 50 years ago. The article is in recent Sport Aviation.
I will also see if I can find the information about a earthrounder flight in a V tail Bonanza a few years ago. He carried at least 280 gallons of fuel for the longer legs.
I believe at least one RV has done west coast to Hawaii and return.
AOPA Pilot had a recent article about another Bonanza around the world.
The late Marion Hart flew solo around the world in her Bonanza, I think she was around 80 at the time. Her airplane is at Davis Monthan.
The standard route in the old days was Hawaii, Wake Island, Guam and the Phillipines.(I may have the order wrong).
Aleutians to Japan may be more practical, Peter Garrison used that route with Melmouth One.
 
Pacific

Greg-
My friend's routing in the Bonanza was Hawaii-Pago Pago-Figi-Papao-Phillipines-Saigon.
Hawaii to Pago is 2200 nautical.
Take a look at earthrounders.org
 
Thanks everyone, really great answers. I think that the best solution for me is an inverted v type antenna from top of the cockpit to tail and back. As far as radio, I have several SDR type radios, the newest of which is a QRP rig (low power - 5W) that needs a Windows based laptop or tablet, is cheap, small and might be perfect for the plane. (https://www.hobbypcb.com/rs-hfiq).

My desire to do this is not for transoceanic travel, but rather for those long cross country flights, and trying to make contacts with other hams from the plane. Should be very cool!

73,
Roger, W2REO
 
Greg-
My friend's routing in the Bonanza was Hawaii-Pago Pago-Figi-Papao-Phillipines-Saigon.
Hawaii to Pago is 2200 nautical.
Take a look at earthrounders.org

That part I've (mostly) got handled - I've had it in my mind since I bought the tail kit that this airplane was intended for RTW flight, I've got sufficient endurance planned for 2200 miles with a constant 15-knot headwind and 2 hours reserve. Now that the plane is flying and proven, and navigation questions have been answered, I'm looking at oceanic/international comms. That still remains outstanding and is what I'm trying to address.

The inverted-V antenna is a possibility, I'm also a fan of the retractable trailing wire if it can be 1/4 wave or less with a good matching autotuner, though I'm worried about the drag and will have to do some testing. I have a lot of homework left to do. I greatly appreciate the information being handed out here, I don't mind chasing leads but I need some trail to sniff out...

I'll definitely keep all here posted as things take off...
 
Last edited:
I greatly appreciate the information being handed out here, I don't mind chasing leads but I need some trail to sniff out...

AC 91-70B is another good place to start. As I said, the ICAO NAT Doc is the bible for the North Atlantic but if you look at the AC and the NAT Doc you will see many many similarities.

The leg between the west coast and Hawaii is the longest overwater leg in the world where there are zero other available alternates. The leg from Hawaii down to Samoa might be a tick longer but there are at least bail out fields. I have done Hawaii to Fiji and Samoa before, in long range jets so it doesn't really count.
 
Roger, if you're anticipating SSB ops on 5 watts, you won't want a compromise antenna. I recall a Lighthouse Hunter QSO I made once on 20m with about 100mW SSB just for grins, but it was from a full-size dipole. If you're going to have paddles on your thigh and work CW, then of course 5 watts is ample, almost cheating :D

Greg, for efficiency in both radiated power and (airframe drag x time in flight), I believe you'll be best served by a longish wire that is only hanging out when you need it to be and not all the time.

Both of you gents are wanting a retractable trailing 1/4-wave longwire, IMO.

The inverted-V with that kind of included angle is not really going to work as an inverted-v is meant to, but will look more like a short random wire (the part from fuselage to tip of vertical stab) with a capacity hat (the shorter return part from the vertical stab to the fuselage). Current in the latter will largely cancel radiation from current in the former, IMO, so it's better to conceptualize it that way. Maybe someone with Mini-NEC can model it for us. I'd be very interested to know if the models prove I know what I'm babbling about. This is not to say that a good tuner can't provide a decent match and radiated power with such an antenna, especially running 100 watts input, and especially on 14 MHz and higher. But it's constant airframe drag...
 
Last edited:
Back
Top