Weird HF Antenna - SunAir

[aseanaero]

I bought an old Piper Aztec for parts salvage last week and it has a very unusual HF antenna

It's a SunAir Electronics reel system that uses a small electric winch to feed a copper antenna through a 'stinger' in the base of the fuselage.

Other components are a large antenna coupler box and a reel control system in the cockpit to tell you how many feet of antenna is delpoyed.

I've NEVER seen one in 25 years of being around aircraft , anyone seen one before ?



Antenna reel/winch



Reel system controller



Antenna coupler

[the wizard of auz]

Jeez.... that makes my old 25kg Sunair HF look positively modern. I know mine is a 1969 model, so thats either a flash version or older.

[aseanaero]

Wiz

That is just the antenna coupler !

The SunAir boat anchor HF is another 2 boxes in the nose compartment plus the HF controller in the cockpit.

[the wizard of auz]

Yeah. I have the two boxes in the nose and the brick in the dash as well.
Lucky the C310 has a decent sized nose compartment.
She's old but I love her. It was my first ever airplane.
one day when I win Lotto, I'll do the big restore on her. historical value.

[mendi63]

On the end of the wire should be a drogue (a plastic funnel made a good one). They were often left wound around the perimeter fence when the pilot forgot to wind the antenna back in.

[aseanaero]

On the end of the wire should be a drogue (a plastic funnel made a good one). They were often left wound around the perimeter fence when the pilot forgot to wind the antenna back in.

The drogue is gone and so is the stainless steel extension in the stinger.

Apparently the stainless steel tube got stolen off the aircraft in Irian Jaya , thoughts were it would make a really good blow gun

[tail wheel]

That wind out HF antenna is probably more efficient, particularly at lower frequencies, than more modern electronically tuned HF antennas.

As Mendi63 noted, in the days of DC3's etc, the antenna wire was a regular feature of airport fences!

Sunair HFs were notorious for noise. It can't be too old - I think Australia converted from AM to SSB in the early 1970's? Or is that Sunair HF multi function AM and SSB?

[troppo]

If it got flogged irian jaya it could well be a penis gourd by now...or a bong.

[aseanaero]

That wind out HF antenna is probably more efficient, particularly at lower frequencies, than more modern electronically tuned HF antennas.

I've only read about trailing HF antenna on old WW2 aircraft like Catalinas , never seen one on a GA aircraft.

Whether it's AM and SSB don't know yet , I haven't looked , let you know later.

[bushy]

Yes we did

The first flying job I ever had was flying cherokee sixes out of Port Augusta, one of which was an RFDS aeroplane. The base director insisted that it be fitted with a trailing antenna much like the one in the AZTEC. I think we had to keep running it out until the load meter peaked??? It was also fitted with a fixed antenna,and once it was tested, and everyone had a play with it no-one used it any more. Everyone used the fixed antenna.
Theoretically it is much better than the fixed antenna. We used HF most of the time.

[Checkboard]

Ernest K. Gann's Fate is the Hunter describes a scene in which he is delivering a DC3 to Europe, and in order to let down through cloud over the sea, he lets out the HF antennae, and descends until the antennae hit the water!

You can see the antenna is still useful, even if the radio doesn't work anymore!

[Led Zep]

Highly effective at taking out runway lighting too.

[Capt Fathom]

Yep.

Flown a C175 and an Aztec with those antennas!

The one on the C175 was electric..

The one on the Aztec was manual. You had to count the number of turns on the way out, so you knew when you got it all back!

[aseanaero]

The one on the C175 was electric..

This antenna is electric also

and in order to let down through cloud over the sea, he lets out the HF antennae, and descends until the antennae hit the water!

What ? I guess the antenna load changes or something when it hits the water ?

[Checkboard]

As I remember, the water knocks off the drogue, and the antennae starts whipping around.

[Brian Abraham]

Was a time when HF was the ONLY radio for GA (5 channel Skyranger?). Tower comms were HF at secondary airports. VHF was reserved for airlines and primary airports, GA not permitted at primary airports. Antenna either a clothes line strung from fuselage to tail to wing tip, or the reel as shown. 172 I flew had the clothes line and 180 the reel. Most GA was sans radio in those days, SARTIME being the modus operandi and an AIRFLASH PRIORITY phone call the means of cancellation.

[aseanaero]

Thanks Brian

I have an old filght service guy now charter operator coming to Jakarta from Oz next month so I'll ask him about the pre-VHF days for GA , probably explains his fascination with HF radio , he grew up with it !

I learnt to fly in the mid 80's and probably used the HF for real 2 dozen times.

[triadic]

I learnt to fly in the mid 80's and probably used the HF for real 2 dozen times.

You were lucky (!). I know many GA pilots that were never taught how to use the HF in the aircraft they flew until they day they went bush. For many it was just a gadget in the panel to be left off. Transponders were the same when they started to appear in GA aircraft. Turn it on - then what do you do ???

Great times and the HF trailing antenna was certainly not uncommon. As the electronic tuners got better then they slowly disappeared. Some of the larger GA aircraft started having Collins 618T's fitted which was an airline type HF and they were great. Just had to find a suitable location to fit it!!

The Secondary towers used 3023.5 if I remember correctly.

[aseanaero]

Some of the larger GA aircraft started having Collins 618T's fitted

I've sold a couple of 618T's in core condition for US$1,000 each which we salvaged out of a 727 VIP aircraft, working but needed a shop visit as the aircraft had been parked for 9 years.

They go for around $2,500 to $3,000 outright with a fresh tag in the US now.

You're right they are physically massive (90cm x 40 x 30cm from memory) and they weigh 25-26kg but probably no heavier than a complete older SunAir HF set.

Collins Proline gear out of 727 and 737 classics is going for peanuts in Asia at the moment as there were a lot of older aircraft that came here from the USA (some from the Mojave aircraft storage facility) and operated for a few years until they hit a C check and are now being broken up for salvage

[Capt Fathom]

And who can recall the old VHF's that had to be tuned-in.