Dielectric plate ?

***Vipersan*** · 3 Weeks Ago

Originally Posted by Satcom1

If one were to take a piece of PCB material and draw on the pattern with a resist pen such as a Sharpie permanent marker it then could be etched.

A solution of 1 part Muratic Acid to 2 parts Hydrogen Peroxide makes a good and safe agent.

Hi Satcom ...
I had already considered the etching option ....as I still have some Ferric Chloride crystals somewhere in the shed ..
The only thing that put me off ..was the pre etch pcb materials I had ...was copper clad compressed paxolin type stuff ...similar to that used in veroboard..
I suspect it might well be an option if fibreglass pcb material was used instead.
rgds
VS

pride21 · 3 Weeks Ago

hi vipersan the main part of the plate with the 3 large parts i put in lnbf first i tried the other way but ertu on 1w goes,as i posted before i changed the outside strips so its taper to large then taper it seemed to improve on signal,you have to try different things.

**Channel Hopper** · 3 Weeks Ago

Originally Posted by Vipersan

The only thing that put me off ..was the pre etch pcb materials I had ...was copper clad compressed paxolin type stuff ...similar to that used in veroboard..

How do you know paxolin is not a dielectric ? , besides copper plate works very well at these frequencies, foil is not a great contender

The copper parts on a veroboard (last used it in 1980) might be an ideal way of cutting the various tracks to give the best performance at one frequency( or a good performer at all). Use the single dotted 1mm stuff and cut out/replace as necessary.

From the original Doktorofsat plan I can see a transform design that is very efficient at mid-frequency (3.7-3.8GHz), but not over the whole band.

(Then again I was working on focal alignment with deflection coils at college, and getting disheartened, finally submitting designs for some fixed polarity mechanical porting in the early nineties).

***Vipersan*** · 3 Weeks Ago

You may well be right CH ...
As you rightly say the paxolin type board material may well be a suitable dielectric material ..
In reality I simply have no idea of its 'qualities'
I guess experimentation is the only way to find out.
I simply assumed that glass fibre would be more suitable.
As to vero ...would the holes in the tracks not cause problems ?...or are they not a factor at these frequencies..
rgds
VS

**doktorofsat** · 3 Weeks Ago

Channel Hopper

I'll try to find some copper and stick it on the a thin plate

If the plate has 2-3mm the reception is not good at all I try it believe me , and get mad

2-3% amplification...too small

When I use an 0,7-1mm plate always got good results.I hope that using Cu instead of Al , I'll notice some improvments

The distance between the stripes are important.With actual distance it;s a better amplification on 3600-3900 MHz .I write in my early posting , be free "2play" a little with distances between the 2 column of stripes (6 pieces/column)

You can put even more big elements in the middle !I try with succes , playing with an 0,5mm copper wire and making some spirals.

I made 2 spirals like in photo and put them verticaly on the both side of short stripes
I got even an extra 8-10% on certain freq!!Pretty cool, isn't it?!

vipersan, pride21, satcom1 and other fell free to make experiences with the plate and of course post the result.
At my QTH is a bit cold outside even at daytime but I'llmade an another plate for several testing.And I work hard on my next 1,8m pfta dish, and believe my it takes a lot of time

Best Regards

DoktorOfSat

***Vipersan*** · 3 Weeks Ago

Thanks for the extra info Doktor..
Hopefully my adhesive copper should be here within the next few days (assuming no more postal strikes) ...then I too can experiment a bit more..
Also ...do I take it from your last picture that this also is showing the correct direction to insert the plate for maximum gain ?

ie ..the top of the photo towards the lnbf antenna within the throat ..
rgds

**Channel Hopper** · 3 Weeks Ago

Originally Posted by Vipersan

As to vero ...would the holes in the tracks not cause problems ?...or are they not a factor at these frequencies..
rgds
VS

No problem at 4GHz at all, the wave cycle at C-Band is upwards of 7cms, one reason the signals can also breach foil coatings without too much difficulty.

**doktorofsat** · 3 Weeks Ago

It;s a pleasure for me to give infos!

BTW, I made the scheme in Paint

in a hurry

Vipersan and others of course the best position of plate is with short stripes at the entrance of lnbf.Please check the photo

**nelson_b** · 3 Weeks Ago

Originally Posted by pride21

hi vipersan the main part of the plate with the 3 large parts i put in lnbf first i tried the other way but ertu on 1w goes,as i posted before i changed the outside strips so its taper to large then taper it seemed to improve on signal,you have to try different things.

hi - pride21 -- i made another plate tonight -- taper to large then taper -- as in post 44

--- this gave - me also - a slight improvement over original plate
--can now "just" pick up the AFN t.p. 4175 R - 28000 at 1 west --
never had a hint of signal from this transponder before

regards nelson.b .

-- p.s. -- using 1mm perspex -- co-op tinfoil - on double-sided tape

***Vipersan*** · 3 Weeks Ago

Excellent news Nelson..
Congrats on your first taster of AFN
..hopefully further 'tweaking' will get you a full pixel free picture even in bad weather on this particularly difficult mux..
..not that there is a great deal to see except on 'pentagon' ...but still its a bit of a buzz adding another notch to your belt.

really pleased for you..
VS

pride21 · 3 Weeks Ago

hi nelson_b i too played around with the plate,while ago i bought some slug tape from Ebay

its thin copper with sticky back which you peel off,any way i made a plate today waited for the rain to stop a bit rushed outside put in the lbnf then went to see any improvement,well i was surprised there was an increase of quality on most channels across sats,what surprised me more was ortm on 24.5w went from 30% quality to 46%,then i tried 18w before i tried grts which was breaking up,now it shot in with 56% quality,i think copper seems the answer.

***Vipersan*** · 3 Weeks Ago

Originally Posted by pride21

hi nelson_b i too played around with the plate,while ago i bought some slug tape from Ebay its thin copper with sticky back which you peel off,any way i made a plate today waited for the rain to stop a bit rushed outside put in the lbnf then went to see any improvement,well i was surprised there was an increase of quality on most channels across sats,what surprised me more was ortm on 24.5w went from 30% quality to 46%,then i tried 18w before i tried grts which was breaking up,now it shot in with 56% quality,i think copper seems the answer.

Hi Pride ..that slug tape is very similar to the stuff I've ordered ..
Sadly ..nothing in the post today ..
Hopefully I might get it tomorrow ...
Nice to know the adhesive copper is working.
rgds

**doktorofsat** · 3 Weeks Ago

Originally Posted by pride21

hi nelson_b i too played around with the plate,while ago i bought some slug tape from Ebay its thin copper with sticky back which you peel off,any way i made a plate today waited for the rain to stop a bit rushed outside put in the lbnf then went to see any improvement,well i was surprised there was an increase of quality on most channels across sats,what surprised me more was ortm on 24.5w went from 30% quality to 46%,then i tried 18w before i tried grts which was breaking up,now it shot in with 56% quality,i think copper seems the answer.

Congratulation Pride21

I worked very hard on a polarmount today and I have no time at all to to make&test some dieldectric plate!!!

Your results are excelent !!! I know that 24,5W has a very low signal for me QTH , I never catch this bird with my 150cm PFA Dish!

I'll try to get some Cu foil to make a new plate and see the results

***Vipersan*** · 3 Weeks Ago

Hi friends ..
Still playing around with the foil version of the DOS plate..

I tried sandwiching the 54mm DOS plate against another 1mm section of the same material ...but this time cut into the same shape as my origional Polythene T shaped plate..

I'm using the Pentagon channel as my test channel ..

First I tried my origional polythene T ..
Signal 44 Quality 27
Perfect picture

Then I tried the 1mm T cut from a clear DVD case..

Signal 43 Quality unusable
No picture

Next the 54mm DOS foil on 1mm plate
Signal 44 Quality low 20's
No picture

Finally the DOS foil 1mm sandwiched against another the 1mm T shaped piece of plastic (the foil strips are in the centre of the sandwich)
Signal 44 Quality 24 >25 slightly varying

Perfect picture

I expect this design might be best for my setup as it still leaves room for improvement ..
Hopefully the copper strips will gain me a bit more ..when it eventually arrives.

Overall ..it does seem that I _have_ to extend the dielectric outside the lnbf throat in order to collect signal and get maximumum gain..whichever option I choose.
I suspect this might be a quirk of my particular dish as it was _never_ designed to use a feed horn or scalar rings.
rgds
VS

**nelson_b** · 3 Weeks Ago

Originally Posted by pride21

hi nelson_b i too played around with the plate,while ago i bought some slug tape from Ebay its thin copper with sticky back which you peel off,any way i made a plate today waited for the rain to stop a bit rushed outside put in the lbnf then went to see any improvement,well i was surprised there was an increase of quality on most channels across sats,what surprised me more was ortm on 24.5w went from 30% quality to 46%,then i tried 18w before i tried grts which was breaking up,now it shot in with 56% quality,i think copper seems the answer.

thanks for the tips -- pride 21 --
this is getting addictive l.o.l. -- have no copper -- but did have some thin brass so again made another plate --

1 mm perspex -- thin brass sheet - on double sided tape --
same design as yesterday -taper to large then taper--
inserted all the way into the l.n.b.
very pleasing results

-- pentagon channel 1 west up from yesterdays tinfoil result of 40 strength 40 quality
to 55 strength - 82 quality --

not tried other sats as yet -- leave that till tommorow now i think

regards - nelson. b.

***Vipersan*** · 3 Weeks Ago

Originally Posted by nelson_b

thanks for the tips -- pride 21 --
this is getting addictive l.o.l. -- have no copper -- but did have some thin brass so again made another plate --

1 mm perspex -- thin brass sheet - on double sided tape --
same design as yesterday -taper to large then taper--
inserted all the way into the l.n.b.
very pleasing results

-- pentagon channel 1 west up from yesterdays tinfoil result of 40 strength 40 quality
to 55 strength - 82 quality --

not tried other sats as yet -- leave that till tommorow now i think

regards - nelson. b.

Attachment 25417

Attachment 25418

Verrry Nice Work Nelson..
I'm suitably impressed

**doktorofsat** · 3 Weeks Ago

Nice results nelson_b

Please tell us the lenght of the striped from the 2 columns ad the distancw between them

**Channel Hopper** · 3 Weeks Ago

Originally Posted by pride21

hi nelson_b i too played around with the plate,while ago i bought some slug tape from Ebay its thin copper with sticky back which you peel off,

The problem you are going to have is when the weather changes again, the heat of the reflected sunlight will quickly evaporate the adhesive.

Veroboard is the way to go.

**nelson_b** · 3 Weeks Ago

Originally Posted by doktorofsat

Nice results nelson_b

Please tell us the lenght of the striped from the 2 columns ad the distancw between them

hi -- doktorofsat --

length of top stripe 10 mm
second stripe 11.5 mm
all other stripe lengths - as your original -
thickness of all stripes 3.5 mm
distance between stripes 5.5 mm

no time to check signals from other - transponder/ sats - untill tonight -

cheers nelson.b.

pride21 · 3 Weeks Ago

hi nelson_b thats a good result for pentagon channel,btw what is the quality of ertu channel.

pride21 · 3 Weeks Ago

hi doctorofsat we have to keep trying to improve on signal quality,my 1.4 offset is my limit here tho i would like a 1.8cm dish,do you get grts on your 1.5cm dish if so what quality.

***Vipersan*** · 3 Weeks Ago

Originally Posted by Channel Hopper

The problem you are going to have is when the weather changes again, the heat of the reflected sunlight will quickly evaporate the adhesive.

Veroboard is the way to go.

Can't argue with your logic CH ...but I guess during the 'experimental' phase ...its definately the way to go.
So much easier to manipulate...
Once the perfect design emerges ...I would think either vero or better still ..an etched pcb would be the answer.
best rgds
VS

**Channel Hopper** · 2 Weeks Ago

Originally Posted by Channel Hopper

How do you know paxolin is not a dielectric ? , besides copper plate works very well at these frequencies, foil is not a great contender

Just to confirm

_http://www.holbourne.co.uk/index.php?option=com_content&task=view&id=22&Itemi d=48

10G/50: Silicone glass grade with high temperature resistance. Can be used at 200°C. Excellent dielectric properties and low loss tangent. Conforms to BSEN60893 3-6 SIGC202 (BS3953 Type SI4 & SI5

**Satcom1** · 2 Weeks Ago

I'm thinking it is the element array and not the board material. One mentioned 2mm not as good as 1mm. What if thinner?

This is an interesting thread. Experimentation is how Edison solved so many problems.

Sad to say we have no Circular C band in states everything we watch FTA is Linear. With the exception of one or two channels in the clear.

***Vipersan*** · 2 Weeks Ago

..Hi friends ..
I can't help feeling a little dissapointment..
My adhesive copper tape arrived today ..
Spent a few hours making up another plate .
And now have my DOS plate as efficient as i can get it..
It is now providing fairly uniform gain accross the C band spectrum on all sats tested but is only -equal- to my T shaped slab of polyethylene cutting board ..
Nothing I do will make it produce better results.
Both plates are effectively maxed out and equal.
I can only assume I was getting maximum possible results for my dish/lnb/plate combo to start with.
cest la vie..
I'm amazed at Nelsons result with the thin brass on perspex ..and can only assume he achieved resonance at that specific fequency..
Looking forward to seeing his results for other sats and other frequencies.
rgds 2 all
VS

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Dielectric plate ? Discussion of C-Band reception for Europe and beyond

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