Question on antenna power dividers

[K1JJ]

So the double wilkenson.
2 volts into the first divider the output of the first divider would be 1.41v and the second divider outputs would be 1 volt each.
So you would get 8V, 11.3V, 8V.
Then you need to add a quarter wave section to the 11.3 to line up the phase so the voltage will drop a tad. Is that close enough?

Frank,

Yep, that's sounds pretty close.

I did a search for Wilkenson power dividers and came up with nothing other than microwave strips, etc.

Do you have any info that applies to HF (7mhz) and using coaxial cable to make up a pair of them?

T

[W1VD]

T

Late 70s and early 80s Handbooks - 40 meter 4 square. Wilkinsons were used as the power dividers. The relay/phasing setup is still in the shed...

On super optimization for F/B and unwanted lobes...helped out K1FO a number of years ago when he was optimizing 2 meter yagi antennnas for an EME array. He was able to get tremendous F/B and unwanted lobe rejections but the pattern fell apart with even light rain on the antenna. Obviously water droplets are bigger in terms of wavelength at 2 meters than 40 meters, but I see tuning changes on the 40 meter dipole here when it rains. Will be curious how your pattern behaves under wet conditions. Keep us posted.     

[K1JJ]

T

Late 70s and early 80s Handbooks - 40 meter 4 square. Wilkinsons were used as the power dividers. The relay/phasing setup is still in the shed...

On super optimization for F/B and unwanted lobes...helped out K1FO a number of years ago when he was optimizing 2 meter yagi antennnas for an EME array. He was able to get tremendous F/B and unwanted lobe rejections but the pattern fell apart with even light rain on the antenna. Obviously water droplets are bigger in terms of wavelength at 2 meters than 40 meters, but I see tuning changes on the 40 meter dipole here when it rains. Will be curious how your pattern behaves under wet conditions. Keep us posted.     

Good points about the rain, Jay.

Yes, I see the f-b go back to a "normal" Yagi when it rains. It may also be the sheeting over the end insulators (dust contamination) AND the rope gets wet and saturated on the end supports.  Rain has always had an effect on my critically tuned antennas, so I live with it.

Yes, I've seen the 4-square guys using the Wilk dividers. I'll keep looking around for info, but if you come across something, please post it.


I've already made the three booms for the new 2X2X2 stacked 40M Yagis, so I'm at the point of no return...   I'm using surplus 5" diameter, 3/16" wall aluminum, so no overhead guy supports needed. Nice and clean that way.   (Lord save me from myself) 

T

[WA1GFZ]

well a true Wilkenson has a resistor across the ports but you don't need it.
The  Two lines are 1/4 wave electrical of 75 ohm line.  (remember velocity factor will make it just over 20 feet) Any way think think of transforming 2 50 ohm ports to 100 ohms with quarter wave 75 ohm lines then connecting them in parallel to a 50 ohm source. In your case you will need one more 50 ohm section of 1/4 wave / 90 degrees to get the higher power center element to the same phase delay as the the outputs of the second wilkensen. 75 meter array I think I use 42 feet of RG11

[KD6VXI]

Yes, I've seen the 4-square guys using the Wilk dividers. I'll keep looking around for info, but if you come across something, please post it.

I seem to recall in the ARRL handbooks, under solid state amp design, they go into at least some detail of the Wilk's.

If not in the handbook, it's in the Solid State Design for the Radio Amateur by DeMaw, I think.


--Shane

[WA1GFZ]

Tom,
The divider does not need to be at the antenna it can be in the shack.

[Gito]

hallo


Reading about this topic,something cross my mind,reading the old ARRL hand book,there's a way to couple transmitter power to the Antenna using ling coupling ,
the tighter the coupling the more power we can deliver to the antenna,thinking of that ,can we use this method to deliver ,by coupling the transmitter power output to  3 antenna input using link coupling .

By choosing the coupling  of each antenna ,
the looser coupling get less power ,
the tighter one get more power.
Here's a picture of what i'm trying to explain,can it be done.

Sorry for my English

Thanks

Gito

[KA2QFX]

You know, Gito may have a good solution there.  The link coupling certainly doesn't need to be an integer ratio, can be used as a match for the three to one split and with one link adjustable (rotatable) you should get exactly the differential power you need. I'm willing to bet phase response won't be an issue either.

[K1JJ]

The loose-coupled inductor idea sounds interesting, Gito!  Looks like you're thinking out of the box, which is good.


I do wonder if there will be a phase shift as one of the coil is TURNED to reduce coupling.... unless we simply move the coil away from the main one to keep the phase constant and reduce coupling power.

ie, If we turn a coil so it is 180 degrees flipped, the phase will shift 180 degrees. I wonder if this is a slow change in phase as the coil is turned around its poles.  Will a 10 degree turn from the main coil produce a 10 degree phase shift, just as a 180 degree coil turn will make a 180 degree phase shift?

So, what might work - maybe a setup with the two outer coils fixed - and the inner on variable to and fro asssembly to get more or less coupling will work without turning it with respect to the main coil.

Thanks for the idea.

Tom, K1JJ

[Gito]

Halo Tom

it's only an Idea that cross my mind,I hoped it may work,
I used to read the old ARRL handbook,because in there you can find articles about grounded cathode circuit(I used to build small M.W transmitter),all the output coupling they used is link coupling ,so there's the Idea came from,Why not used it as a "power splitter".

 So can it be used as a power splitter? I hoped it can.
I think moving to and fro is a good Idea Tom

Regards


Gito.

[WBear2GCR]

I kinda like the idea of trifilar wound secondary on a core...

But there the problem is that if you use a few more turns (symmetrically) to make the higher voltage, then the impedances don't match!

So, that brings up the issue of what the actual power to the ant is and what the actual pattern ends up being...

It does eliminate the phase issue, but substitues the power/impedance problem.

But I would think you can dork that empirically to make it work.

Dunno. I nowe bee un tenner ekspurt.

                _-_-bear

[Gito]

Hi Bear

It's an air wound coil,not a "ferrit/Iron ballun " so coil turns does not change  It's reactance is 50 Ohm at the operating frequency.

What we  do is moving the coupling of the coil  to and fro so the coupling is tighter or looser,not by adding  more turns (the impedance is still the same) so it's an issue of coupling between coils, using air wound coil.
tighter coupling --- more power output
less coupling------- less power output.


Regads


Gito.