Internal antenna or whip?
 

I have been flying with a whip antenna in my F-16, and never had a glitch while airborne...

However, it would look much cooler with the antenna inside the plane - there is not a lot of carbon
in the nose of my plane, and I was thinking about routing the antenna all the way forward....

Anyone had any experience with this? I fly all my other planes with internal antennas, but the jet has more
metallic components, so I don't know if it's a good idea?

Take a look at the pictures - it does look better without the whip, right?? :D

Tor/Norway

RE: Internal antenna or whip?
 

i agree...without a whip he looks better..[8D]
but i prefer a safe way than a better looking...:eek:

and for ground photos the whip can be removed!:D

RE: Internal antenna or whip?
 

I really hate the whip antennas. You spend hundreds, sometimes thousands of hours perfecting details, and then you have that big old ugly antenna coming out that makes everything look like a toy from Toys'R'Us (just look at Wolfgang Klührs MiG.......perfect, except.......).
I had my sabre with an internal antenna without any range problems, and it looked great. My F-15 will have it internally as well, running up inside the stab.
Just get it away and clear of carbon components, they severely shield off any signals that are coming in. Another thing that really helps: make sure you can "see" about 50% of the antenna no matter what angle you are looking at it. That way you will get consistent range from all angles without "dead spots" and "unlimited range spots". (My main worry with whip antennas is that when looking straight from the top you get almost 0 projected antenna area, thus least range.....yet you usually have exactly that attitude when you are furthest away, turning back inbound!!! Range checks on the ground hardly ever feature "top view").
So much to the theory.....i'll post some pics of the new sabres antenna setup as soon as i get it installed and range checked.

RE: Internal antenna or whip?
 

Or you can edit the picture in PhotoShop and remove it!!:D

I will do extensive range checks, but if I have any doubts, I will go with the good(?) old whip!!

RE: Internal antenna or whip?
 

I would never remove the whip from my jet. I don't see it in the air, and I can remove it on the ground.
icepilot is right, there is always Photoshop for the pics...

RE: Internal antenna or whip?
 

We've mounted the revolution whip antennas inside several jets and had no range problems at all. Just be sure the antenna is clear of metal, CF, and leads.

RE: Internal antenna or whip?
 

These antennas are nothing else that high gain antennas. It allows then to be shorter,
but does not increase the range or noise reduction of reception. A "hole" for a regular
whip remains the same hole for the so called revolution.
As long as Frequency Modulation is used, for ANY rx antenna,
it does not matter to have it standing horizontally or vertically.
The only problem with the high gain antennas is they are shorter, therefore make
the Tx "holes" bigger compared to their size.
They are then more likely to be blanked out.
The main advantage is you can fit them almost anywhere.
They would be the perfect solution if we had aiming Tx antennas, always pointing at the plane... ;)
Until then, I stick to my whip... :)

RE: Internal antenna or whip?
 

If you do a good valid range check, determining the Baseline comparing that distance with full power you'll know what difference internal, external, full whip, or loaded whip makes before you ever go airborne!

During the design phase, and possibly with a little more work after construction, you can route the factory wire antenna out the leading edge of a wing like BV does in the BobCat. Bob may do this in other Jets he produces, but I can tell you the leading edge of the wing is a great location for the antenna!

If that's not an option, rather than a full length whip antenna standing straight up (which does look toyish), route the wire antenna to the rudder like we all used to do for many years. To me that looks much better and more like what you might find on an aircraft. Shoot I've got two external antenna's on my MIG and over the years I've gotten to like the way they look.
Lee H. DeMary
AMA 36099

RE: Internal antenna or whip?
 

Hi Tor

I do not think that any of us like external antennae on any model but they work. I flew a friends CARF Eurosport this weekend with his aerial routed through the fuse. My Euro runs a whip. We flew his far away with no glitches or lock-ups that we could notice. You also need to take into account which turbine controller you are using. His Euro has a Jetcat 120 in it. I know that not all controllers are as friendly to our receivers! Remember the ECU is a speed controller varying the voltage to the pump and the pump is a normal brushed motor causing sparks and therefore noise-yes they do have suppressors(capacitors) on them to reduce the arcing.

Would I consider running my aerial inside a turbine jet - NEVER!!!!!!!!!!!!!!!! I lost my first Hotspot without any good reason. Cannot afford to take any chances with these wonderful beasts!

Good luck

Zane

RE: Internal antenna or whip?
 

As usual, seems like everyone has his view and is willing to stick to it...
I think it would be crazy not to have an aerial if there is carbon fiber in the plane.
High gain antenna is not even a solution for me.
The best I've seen so far is the two antenna on the Mig15...
How are they hooked up on the receiver ?

RE: Internal antenna or whip?
 

I would not dare to run my antenna backwards to the rudder because of the steel pipe blocking the signal all the way to the rear of the plane!

I guess after losing my last F-16 to an unexplainable radio (?) error I will take the safe way and go with the whip...:eek:

T

RE: Internal antenna or whip?
 

icepilot,

That's the safest way to go. That is wy way too actually... :)

Yann

RE: Internal antenna or whip?
 

I have done a "dry check" with my radio, running only a 5 cell pack, receiver and a few servos on a ply plate. Now i will set up my plane with the internal routing, and run the same check again, from all angles, turbine on and off, lights on and off, all flight conditions basically.
If i do not get close to the original range i will re-work and maybe even switch to whip, but if i get great range results i see no reason to arificially make my plane unattractive......

RE: Internal antenna or whip?
 

Like it's been said before, you can't check from every angle and every configuration from any distance...
The laws of physics say how things work. It is up to you and only you to take whatever risk you want.
We do the range check test to check if the transmition works at least in the present configuration.
It cannot mean it will work the same up in the air.

RE: Internal antenna or whip?
 

You can't check every angle, but you can check the 360 degrees in the horizontal plane, plus top and bottom.
When thinking a bit about the HF technology, you can also become pretty good at "predicting" weak angles.

Theory and experience shows: the more projected antenna there is (the length that you can "see" from that angle), the better the range from that angle. You will have optimum flight conditions with around 50% from all angles.
(A straight line will have optimum range with the antenna 90° towards the antenna-receiver line, but just a few yards with the antenna in line, with you only seeing the antenna as a "dot").
As you said, the laws op physics can't be tricked, but they do not state that a wisely installed internal antenna cannot reach as far (or further) than an external whip....

RE: Internal antenna or whip?
 

It won't if you have carbon fiber laid in the fuse.

RE: Internal antenna or whip?
 

Why carbon fiber? Has the fuselage ever broke first while in the air. The use of Carbon fiber is to spend more for the same thing. If you run it into the ground it all brakes. With the radio concerns, why do it.
Darryl

RE: Internal antenna or whip?
 

Yann, carbon fiber only shields in the immediate area behind it. It is like wind around a house....standind downwind right next to the house gets you shielded, but once you get some steps away the wind will come up again. HF radiation behaves just like that, at least it seems the same, because of the wavelength and amplitude we are running (now its getting more complicated, i'm trying to draw up a basic picture).
Of course a full carbon fuse will shield off everything inside, but carbon stringers and local enforcements have no effect if you stay away a couple of inches/decimeters.

RE: Internal antenna or whip?
 

Well, Daryl , many jets are made of carbon fiber nowadays... And carbon fiber tend to blank the antenna, if standing in between...
So if your fuselage is not mode of carbon fiber (which is not my case), then you can use internal or whip antenna.

RE: Internal antenna or whip?
 

Tor,

I fly four different turbine powered models and all my RX aerials are routed inside my models. I havn't moved to wards the whip antenna because I have had NO reason to do so, besides whip antennas are ugly. Although if they were the only option I would use one, but like I said, no reason to.

All I do is route the RX aerial in a series of small !QUOT!S!QUOT! bends.

Good luck.


Darryl

RE: Internal antenna or whip?
 

Can't the aerial be routed from underneath the fuselage and have a full antenna wire underneath the fuselage were it will not upset an otherwise beautiful model?

Reuben

RE: Internal antenna or whip?
 

F-86: You could, but then you would have very very poor range when flying straight towards or away from you....

Darryl, glad to see someone else routiung internally...i thought i was on my own ;)

RE: Internal antenna or whip?
 

On the advice of Graupner/JR engineers at the Austrian Jet World masters many of us changed to half whips some years ago (half the normal aerial with the other half a vertical whip at 90 degrees) which is suggested as an excellent configuration for best RF reception at all flight attitudes. There is an excellent article on range testing JR Transmitters on the new JR web site (www.JRradios.com) Well worth a look.

Regards,

David Gladwin.

RE: Internal antenna or whip?
 

I would be interested in seeing such a setup...

RE: Internal antenna or whip?
 

Hei Tor,
I would NEVER fly my jets on an internal or parallell to the fuse antennae on 35 MHz. I know from experience and testing that you can do this on 72MHz, but here in Norway where 35 mHz and 40 mHz are the allowed freqs, whip is in my opinion the only option. The funny thing is you can have an installation with a hidden antennae giving you reasonable range and everything looking swell, but on the 20th( or whatever) flight - PCM lock or PPM shakes. I only know that after we started with the whips, the number of radio troubles were reduced to almost nothing.