Quadrifilar helicoidal antenna - Photos of Ivan's version

Pictures of Ivan's 137 MHz version

Even though the face of the builder doesn't exactly reflect it, these were his words after a test:

    It works *AMAZINGLY* !

    First of all it's really omnidirectional, no more "point and follow"
    the satellite any more, second .. "I don't know how it does it" but 
    the noise/signal ratio gets almost zero when the satellite is 
    "close enough", the doppler effect is almost totally cancelled, 
    you can pick the satellite "from when it appears at the horizon  
    until it gets down".                                            

    The difference between the QFH and a simple "stilus antenna" is 
    *HUGE*.

Have a look at Ivan's blog...

Even though the face of the builder doesn't exactly reflect it, these are his words after a test:
It works *AMAZINGLY* !

Here it begins, plastic pipes, tools, lot of paper with drill templates printed on, ruler (in MILLIMITERS), tape, etc. etc. ..

Here the drilling technique, templates printed on paper "glued" to the surface, mini holes then cut all and file/sandpaper/etc. ..

Some finished holes (still to clean a bit), the smaller holes are for the coax cable.

The "outer loop" completed, we were testing how the loop has to be made and the wire lenght with a "fake wire".

At 9.45 PM we had to stop, pub time, the antenna is 90% completed, it only misses to pass the wire and do a couple of solderings and is done, here with just one loop on (we were testing the thing).

Another view of it.

NOAA-15 image... Signal is clearly quite strong - the noise in the white areas (clouds and white telemetry bands at the left) is due to the insufficient bandwidth of the receiver (note from the 'editor' jc)

NOAA-15

mail

	Even though the face of the builder doesn't exactly reflect it, these are his words after a test: It works AMAZINGLY !
	Here it begins, plastic pipes, tools, lot of paper with drill templates printed on, ruler (in MILLIMITERS), tape, etc. etc. ..
	Here the drilling technique, templates printed on paper "glued" to the surface, mini holes then cut all and file/sandpaper/etc. ..
	Some finished holes (still to clean a bit), the smaller holes are for the coax cable.
	The "outer loop" completed, we were testing how the loop has to be made and the wire lenght with a "fake wire".
	At 9.45 PM we had to stop, pub time, the antenna is 90% completed, it only misses to pass the wire and do a couple of solderings and is done, here with just one loop on (we were testing the thing).
	Another view of it.
	NOAA-15 image... Signal is clearly quite strong - the noise in the white areas (clouds and white telemetry bands at the left) is due to the insufficient bandwidth of the receiver (note from the 'editor' jc)
	NOAA-15