@Aussie_Andy it is interesting some GA opt for a fixed antenna arrangement, while others (and most ferry pilots) go for a retractable antenna they reel out from the storm window. I am thinking this is more straightforward assuming it doesn’t tangle with the tail plane!
The Turtle PAC ferry tank (collapsible) is a simple 337 on an N-reg. Aluminium internal tanks are a more challenging engineering job: appropriate venting, plumbing and pump.
Yeah, I thought about the reel-out type but being a ham-radio enthusiast I also kinda liked the idea of having a proper HF installation. And I also know, from ferry pilot friends, that there can be reliability issues with the reel-out-the-window antenna: not su much the antenna itself, but the clips and leads used to join it all together… the last thing you want to be pissing about with in IMC over an ocean maybe ;) And as an electronic engineer, I can also tell you that, depending on how the ATU is setup vs the antenna wavelength on a given frequency, you can get VERY HIGH VOLTAGES at the end of what is technically and “end fed random wire” antenna – right next to the ferry tank installation: no thanks ;)
I used a Turtle PAC (made in my native Australia!) and yes, under FAA or Australian or even pre-EASA UK CAA (or Danish CAA where mine was installed) regulations, there’s nothing to it. But EASA wanted a FULL STC including a DROP TEST – so I pulled out of that process and “flew the route without using the ferry tank”…
Aussie_Andy wrote:
The easy part in fact was the HF transceiver and ATU installation: the HF is NOT installed in the panel, it is in the rear fuselage and has a small lightweight control head which sites ON not IN the panel. This massively reduces the paperwork requirements..!
But even in the rear fuselage, does it not count as “installed” and therefore need a mountain of paperwork (especially as it’s non-certified) — or can you work around that by velcroing it in and calling it “luggage”?
Yes there was paperwork (as I said above) but NOT integrating into the panel and avionics (it’s electrically and regulatory separate!) saves a lot of cost and process..! Other than the mechanical aspects (eg W&B) it’s from a Reg perspective just like putting the transceiver on your knee.
I can also tell you that, depending on how the ATU is setup vs the antenna wavelength on a given frequency, you can get VERY HIGH VOLTAGES at the end of what is technically and “end fed random wire” antenna
@Aussie_Andy this always reminds me of the GPS overlay vs NDB approach regulation. Let’s regulate for the system that wouldn’t pass safety certification today.
While CAT uses HF, the use of HF for puddle jumpers (albeit a very big puddle), is mainly a SAR issue as there is no other traffic at the typical GA cruising level. So GA uses ham radio HF and is expected to make position reports and monitor HF in IFR in convective weather, when a much more reliable system is available in a satellite telephone, without the added frisson of playing either cockpit fire or Kentucky fried chicken bingo!
Well said Robert..!
RobertL18C wrote:
this always reminds me of the GPS overlay vs NDB approach regulation
And the general mistaking of merely burdensome regulation for “quality regulation”. The press did it with Sala (‘the N reg plane, because European regs are stricter, read better’, or indeed Grant Shapps’ plane being N reg), when in reality, the European regulations aren’t higher quality, they are just merely burdensome. The case cited here with the antenna insulator is another example of burdensome and disproportionate rules, not quality rules.
alioth wrote:
in reality, the European regulations aren’t higher quality, they are just merely burdensome
I agree completely. I know of many examples of ferry crossings in EASA registered aircraft where the ferry tank installation is uncertified BECAUSE GAINING THE CERT IS UNREALISTICALLY BURDENSOME – so the effect is not great safety, it is greater avoidance.
That porcelain insulator looks good for about 1 megawatt 
It’s big enough for the Voice of America transmitter
Surely one could have just run a coax through a hole in the hull, via a rubber grommet?
Installing that feedthrough is also a big job, because the aerodynamic forces will be such that it will need a hefty doubler plate.
Yeah there’s a reinforcing plate etc – a mod that’s been done a thousand times before under US, Aus and UK CAA regs – but EASA required a bespoke structural engineers report..!!
Coax via grommet would’ve been great but that was not on the Piper approved mods list ;)
