Radio direction finding, Fu.NP.E a/c

[LA6NCA]

I am currently working on three new Youtube videos on radio direction finding.
I will use Fu.NP.E.a / c
I don't understand how it works.
The yellow loop works well for radio direction finding.
But what is the blue / red loop for?
There are also some controllers.
"Seite", "Seiteregler", "Enttrubeng".
How should these be used?
LA6NCA

 

[Funksammler]

The yellow loop is the main direction finding loop, it has a figure of 8 antenna diagram, you use it to find the minimum signal. This still gives you two possible directions, 180 degrees apart. The blue and red loops are sense antenna's, they each have opposing cardioid antenna diagrams. So if your main loop is at the minimum, one of the sense loops will be at its maximum, while the other is also at its minimum. So by switching between the red and blue loops you can immediately hear from which side the signal comes and read the bearing from either the red or blue scale (which are 180 degree apart).

Because of reflections from metal objects in the surrounding area, the antenna may pick up some weak secondary signals. You know that you have reflections if you can not get a clear minimum on the main loop. This is where the Entrübung comes in, it uses a small amount of signal from the sense antennas to counter the reflections; you adjust it so you hear zero (or the lowest possible) signal at the minimum. 

hope this explains it a bit,

Funksammler

 

[LA6NCA]

Thanks for the fantastic response. You know everything.  :-)
Then I'll practice what you say.
I did not know that it was possible to find the exact direction.
There are two buttons on the same shaft. One is "Entrübung" which is a dual capacitor and the other is "Seitenregler" which is a pot meter.
Certainly also works to get the deepest possible zero. ??

I am also going to make a video in which I am aiming directionfinder towards north wheat using Fu30a.
I will also measure the Magnetic declination wheat using the star Polaris.
LA6NCA

[Funksammler]

Like the "Entrübung" the "Seitenregler" allows reflections to be dialled out of the sense antennas so that the difference between the red and blue sides becomes clearer.
The same principles are used in the EP2 direction finder...

regards,

Funksammler

 

[LA6NCA]

Thanks for the good response.
I'm going to test out today.

I'm helping a museum restore an EP2.
I have the steering wheel itself, but we have to make the antenna itself.
How big is the antenna?
How long are the tubes?

regards LA6NCA

[Funksammler]

I have my EP2 antenna stored away at the moment, a bit difficult to access. Next time I have a chance to access it I will take some measurements. Maybe I can find the answer in the manual, if I can find it. I have some vague memory of the antenna loop being 1 m2, so all sides would be 1m long...

regards,

Funksammler

[Funksammler]

I dug out the manual, although it does not contain the exact sizes of the antenna, it does confirm that 1m2 area, to the lengths of the a rods in the antenna are all 1m. I didn't get the description of the antenna 100% right though. In fact the red/blue rods form another loop antenna, 90 degrees to the main yellow loop antenna. The red/blue loop is switched in phase or in opposite phase to the sense antenna (the rod running in the centre and on top of the loops), this phase switching forms the two opposing cardiod diagrams of the combined antenna . The "Seitenregler" is actually a double resistor in the red/blue loop which causes a variable phase shift in relation to the sense antenna which can be adjusted to create the maximum difference between the red and blue sides.

[tornfuté]

For EP2 they are 2 types of antennas , the PR4 or PR6, one is a little bit

heigher then other , i guess PR4 is equal to PR58N , i own   a box 

in which you can store an antenna and a tripod Z7N , i  have measured  my side rod it’s around 98 cm , so what FS writes is correct around one meter, they are  4 times 2   articulated rods 

pierre

 

[tornfuté]

PR4 and Pr6:description