Are all skew plane ant equal?

[forest]

 hello chaps a bit of advice please if i may
are all skew plane antennas equal? i ask cos i bought some cheapish short ones from hobby king  and they have the same range as the rubber ducks now i thought the ducks we sth like 2 db gain and the skews 5 db or have i go that all wrong? i have a cb radio back ground so do understand the electical lenghts for ant and the need for swr  and such things

you can get skews for 7 quid a pair and then gavs skews are 28 quid a pair is there any diff has any one done a side by side?

cheers for any advice  ;D

[quadfather]

hello chaps a bit of advice please if i may
are all skew plane antennas equal? i ask cos i bought some cheapish short ones from hobby king  and they have the same range as the rubber ducks now i thought the ducks we sth like 2 db gain and the skews 5 db or have i go that all wrong? i have a cb radio back ground so do understand the electical lenghts for ant and the need for swr  and such things

you can get skews for 7 quid a pair and then gavs skews are 28 quid a pair is there any diff has any one done a side by side?

cheers for any advice  ;D

They';re definitely not all equal.  For starters, the materals used.  The cheap ones use copper wire without coating.  They will arrive at your doorstep pre-oxidised.    Not sure what Gav is using for the lobes, but it';s not copper, at least the wire surface is not copper.

Then it';s the precision of the manufacture.  As you know the length is important, but for skews the angles are also important.  The cheap ones I have are just 90 degrees horizontally and flush at the top, whereas Gav';s are about 105 degrees horizontally and 45 degrees offset at the top.

It';s the little details like this that make all the difference.

[forest]

ok i see , these one i have here are 45 out the top and look to be 90 out to the curve an back in at 90 as i said no better than the ducks  i just went flying and i get about 150 yards and get flickering from a 250 mw fs vtx and overhead  20 ft they flicker quite badly that must be the signal not going through the carbon mix frame?  the range on this 250mw fs set up is quite poor

what sort of distance should i be getting with 250mw just a  average? and what do you recommend for ant? at the mo i fly out in the open but as i improve i plan to fly in the woods with the 250 and out in the open with my 450diy

thanks 

[quadfather]

I took a couple of pictures of my cheapos compared to my new set from Gav.  When I said 45 degrees offset earlier, it';s actually not 45 degrees, but around 107 from the lobe leaving the shield at the bottom to arriving at the centre in the top.

Gav';s on the left, cheapos on the right



In terms of range, I';m not sure.  It depends on the position of the antennas, the quality of the VTX/VRX and a few environmental factors.  I have not range tested them yet, but I would expect with clear line of sight to go a kilometer with Gav';s, perhaps even further.  Certainly a lot further than 150 yards.

[forest]

thanks for taking the time to do the pics and i see the diff

heres mine





these have three leafs so are they still skew ? or are these called clover , so much to learn ! they dont work very well at all  but they were cheap

[quadfather]

thanks for taking the time to do the pics and i see the diff

heres mine

...

these have three leafs so are they still skew ? or are these called clover , so much to learn ! they dont work very well at all  but they were cheap

Three lobes are cloverleafs, four lobes are skew planar wheels.

I asked Gav if he could make me a couple of those you have and he advised against it.  You need some clearance between the lobes and the frame, in particular if you have CF plates.  Otherwise the frame acts as a shield and any downwards radiation is blocked.  Cloverleafs and skew planars have a radiation pattern similar to an apple.  They';re weakest when your quad is above you, and even worse when you block that signal with CF plates.

I still like the idea of the stubbies, but I';d need to be able to position them correctly so the airframe doesn';t block half the radiation pattern.  They would have to go on a mast which defeats the purpose of having the stubby.  On a foamie they might just work, but then their build quality will still let you down.

[forest]

i bought them  cos i too liked the idea of a stuby ant,  i wonder if there is a simple swr meter for 5.8, must look in to that i used to love making cb radio twigs and it   be nice to know the swr of the ant we are using
it looks like im going to have to bite the bullet and invest in a pair of gavs twigs  sory cb speak there "antennas"

it was the ducks that didnt behave over head  ive not tried the clovers over head,

ok many thanks qf you have been most helpful as always have a great evening   

[quadfather]

it was the ducks that didnt behave over head  ive not tried the clovers over head,

ok many thanks qf you have been most helpful as always have a great evening

Ducks are worse. Their pattern is more like a donut, so you have a nice void up top. 

No worries, have a good one yourself.

[bazzerh]

Make some yourself, it';s not that hard and its quite rewarding. I';ve just made a couple of jigs so I can bang them out for friends nice and quickly.

[forest]

ah that explains the poor reception  ducks were never any good back in the cb radio days as well

bazzerh ive been thinking about that, i do like to make every thing that  i can my self  do you swr yours? or are you working from a known electrical length? and if you do what do you use for swring?

[bazzerh]

No I don';t swr them, you need a microwave coupler thingy for that which go for big bucks. I do try and follow precise measurements and angles though and a couple of Alex greves'; tips for antenna length like cable longer than 1 wavelength and not a multiple of half a wavelength. I make all mine 13cm long. Job done. I also use pre made double ended pigtails of rg402 cable cut in two.

I had one of my antennas on my diy goggles on a passenger ride on a penguin fpv plane a week ago. Was still getting good reception at 2.5km so was quite emotional about that :)

[forest]

wow i would be emotional as well if one of mine did that , is alex greves on youtube?  you are getting my juices flowing with all this talk of diy antenna

[Tango21Delta]

is alex greves on youtube?

You can find him here https://www.youtube.com/user/CAGreve1231

[forest]

thank you tango very kind of you

[forest]

ok watched a few vids and ill make them in future its seems easy enough   with the online calcs 

tell me please  is it the clover leaf  the tx fitment and the skew on the rx? does it mater i guess it must , i didnt realize mine were diff, i was wondering why most adverts said one of each rx and tx ,doh! could this be why mine were poor? i might of had them round the other way