Yagi Insulators - Suggestions ?

[VK2XTC]

Hello,

Can anyone point me towards a good source of Yagi element Insulators ?

Struggling to find anything.

VHF / UHF beams.



Thank in advance.



Brian

VK2XTC

[VK5TM]

Have a look at the catalogue:

http://www.stauff.com.au/index.php?id=3 ... =3897-5448

Look at the Stauff1 series

For 12mm tubing you need the 112aPP type number. I ordered direct from Stauff and from memory they were $1.20 per pair

Rex

From this post in January: viewtopic.php?f=11&t=12867&p=52275&hili ... tor#p52290

[VK3AV]

That is what I used on my 2m yagi. Purchasing just the "shells" is quite low cost and they come in a range of sizes.

I purchased SS screws and nylock nuts from my local bolt shop.

Regards
Bernard

[VK3ZAZ]

Hello,

Can anyone point me towards a good source of Yagi element Insulators ?

Struggling to find anything.

VHF / UHF beams.



Thank in advance.



Brian

VK2XTC

http://www.m2inc.com/

[VK1KW]

Black plastic irrigation hose joiners cut the ends off and feed thru the boom - almost zero dollars.

[VK5ALX]

I'm using these for 2mtr and 70cm antennas. Available for either round or square boom

https://shop.nuxcom.de/product_info.php ... 025a590cb1

edit:

For 23cm I use these Paraclips from the UK.

http://www.powabeamantennas.co.uk/G6HKS/parts.htm

The picture shows the clips on my 23cm yagi (at right)
The 70cm phased array for ATV reception has insulators made from irrigation fittings

Alex

[VK2XTC]

Thanks to all who responded. Enough to get me started..

The black plastic irrigation hose joiners sounds interesting.

Can someone expand on the concept there ?



Thanks


Brian

[VK7HH]

Just recently built a YU7EF EF0606 yagi on 6m.

http://hh.vk7.com.au:82/blog/index.php? ... id_post=16

I used Pirtek clamps
http://www.pirtek.com.au/
http://www.pirtek.com.au/catalogues/Sec ... rlink.html

Page 7-8 of the catalogue. $2 per clamp for the 10mm ones. When ordering make sure you specify the plastic bits only as they do normally come with a metal bit which you don't need and drives up the price dramatically. Part number for 10mm is CC2-10.

Use 1/4 inch roofing screws to attach to the boom.

[VK5APN]

Built a number of YU7EF yagis for 2m. All 6 of them I have used glue lined heatshrink. Obviously adjusted element length to reflect the mounting method. Details for the dimension difference is found on Pops website.

How I constructed the yagis is found here

http://members.iinet.net.au/~pearsons@a ... /Yagi.html

Very cheap and very effective

Regards

Wayne

[VK2ZIW]

Hi,
You make it all way too hard. Just use small pieces of 6mm thick PVC sheet.
Stainless (304) self tappers are, a dime a dozen. Nuts and Bolts supplier.
Put one through your element, file the screw head and solder to the stainless.
(Flux: CHEMTOOLS VIOFLUX )

Need a "U" bolt, 4mm x 0.6m threaded rod stainless (304) $6
6mm $8
Pixture:
http://www.unixservice.com.au/hamradio/ ... index.html

"Pixture": Image rendered by "X".

Alan VK2ZIW

[VK2XTC]

Just recently built a YU7EF EF0606 yagi on 6m.

http://hh.vk7.com.au:82/blog/index.php? ... id_post=16

I used Pirtek clamps
http://www.pirtek.com.au/
http://www.pirtek.com.au/catalogues/Sec ... rlink.html

Page 7-8 of the catalogue. $2 per clamp for the 10mm ones. When ordering make sure you specify the plastic bits only as they do normally come with a metal bit which you don't need and drives up the price dramatically. Part number for 10mm is CC2-10.

Use 1/4 inch roofing screws to attach to the boom.

Hayden,

How big is that boom Square Hollow Section ? , from the data you provided in the Pirtek catalogue it looks like the clamps are 30mm wide.
I called and confirm the price as $1.97 each ex GST. which makes them very cheap and a robust solution. Boom needs to be wider to accomidate.

Problem is I'm trying to keep this to a "Bunnings" type solution. And they don't stock anything greater than 25.4mm Square Hollow Section. (3M length = about $30).
Taking it to a 40mm wide will double the cost. And I'm only planing on making a 6 element 2m beam as a starting point. Mainly because it fits into a boom length under 3 meters.

I like the concept of the glue lined heat shrink but still intrigued by the concept of the Irrigation hose pipe joiners suggestion.
I can find a 13mm joiner, are they 10mm internal diameter ? How are they cut and fitted.

Anyone ?



Brian

[VK4TI]

Go to your local cheap shop and source a white cutting board , test a bit in the micro just in case and cut it to your needed size , some ss screws and your done , the bunnings boom will be fine , I have glued and screwed white cutting board up to large 6m beams with good success

[VK7HH]

Hayden,

How big is that boom Square Hollow Section ? , from the data you provided in the Pirtek catalogue it looks like the clamps are 30mm wide.

Brian

Not sure how we are all "making it all too hard" as someone earlier posted, but the method I (when I say I, I actually learned how to build these by another local amateur) used worked for me, and the forum is a method of sharing these ideas, not writing everyone else's methods off. Not saying it is the best, but my 6 element 6m yagi was knocked up in 30mins to an 1 hour with basic tools.

The SHS boom is 40mm x 3mm wall thickness from Ullrich Aluminium. I bought it in a 6.5m length. The clamps are indeed 30mm wide.
The reason for the large boom is you can make an antenna 6.5m long with as little flex as possible (no joining boom sections, no weakness ). I did not document the mounting method of the mast clamp to the boom. Piece of angle iron, bolt a square plate however large you need (150mm x 150mm square IIRC on mine) and drill holes for your U bolts. Attachment to the boom is made with two (or more hose clamps, again no drilling of the boom) I need to get photos of that.

Bunnings is good, but as you have found out, they are relatively limited on what they stock. I paid around $85 from memory for a 6.5m length. 10mm tubing was $6? a length in the same lengths of 6.5m.
http://www.ullrich.com.au/contact_Au_Sales.php

I have in the past built beams using plastic hose/heatshrink methods as described by Wayne 5APN, and they have worked quite well.

Regards
Hayden

[VK7HH]

Hi again Brian,
See photos attached, the clamps will go onto a 25mm boom, with 2.5mm of overhang on each side. Still plenty of room to drive the screws in if you are careful.

Regards
Hayden

[VK7DX]

Looks like Hayden forgot,

remove rubber washer off roof screw and fit a flat steel washer,this stops the roof screw from forcing into the clamp.

The best angle iron for making the boom to mount is old bed angle,its spring steel and very light

good luck

Frank

[ZL2UCI]

Insulators from an old analogue TV aerial perhaps?

[VK7HH]

Looks like Hayden forgot,

remove rubber washer off roof screw and fit a flat steel washer,this stops the roof screw from forcing into the clamp.

The best angle iron for making the boom to mount is old bed angle,its spring steel and very light

good luck

Frank

Yes I did forget... when I did the 6m one Frank, the clamp tightened up enough without the screw going into the clamp. Element wouldn't budge.

Hayden

[VK2XTC]

I like the pirtek clamp option as I no longer have a a bench drill and drilling accurate holes that align correctly in a boom with a hand held drill is problematic.

I got under the house today and found an old TV antenna (forgot it was there) and stripped it for parts and it raises a number of issues.
I cut down one of the elements and used the old insulator, and fed it with some old RG-58 I had in the junk box via a 5 turns on a 38 mm electrical conduit to form a choke.
Power by a H/H the VSWR was about 1.5:1 across the entire 2M band.

This has raised some questions.

1. The gap between the driven element seems quite large using the TV antenna insulator. Too large really.
I've been measuring the end the end length of the element (999mm). Is there a factor to take into account the gap between the two elements on a split dipole?

2. Am I really reading the antenna VSWR or just reading the choke? I don't have an analyser for 2M so have to rely on VSWR meter and a H/H. (I have a Mini 60 for HF so would have tested the Choke with known 50 Ohm load. cannot do that with the Hand Held as it will burn little resistors)

3. Can you substitute a Folded dipole DE with a Split Dipole DE in the same antenna design? The folded Dipole DE seems difficult at present with no pipe bender.



Thanks


Brian

[VK2XTC]

I like the pirtek clamp option as I no longer have a a bench drill and drilling accurate holes that align correctly in a boom with a hand held drill is problematic.

I got under the house today and found an old TV antenna (forgot it was there) and stripped it for parts and it raises a number of issues.
I cut down one of the elements and used the old insulator, and fed it with some old RG-58 I had in the junk box via a 5 turns on a 38 mm electrical conduit to form a choke.
Power by a H/H the VSWR was about 1.5:1 across the entire 2M band.

This has raised some questions.

1. The gap between the driven element seems quite large using the TV antenna insulator. Too large really.
I've been measuring the end the end length of the element (999mm). Is there a factor to take into account the gap between the two elements on a split dipole?

2. Am I really reading the antenna VSWR or just reading the choke? I don't have an analyser for 2M so have to rely on VSWR meter and a H/H. (I have a Mini 60 for HF so would have tested the Choke with known 50 Ohm load. cannot do that with the Hand Held as it will burn little resistors)

3. Can you substitute a Folded dipole DE with a Split Dipole DE in the same antenna design? The folded Dipole DE seems difficult at present with no pipe bender.



Thanks


Brian

[ZL1RS]

Brian,

1. The gap is taken up by the coax tails going from the RG-58 to the DE connection points. The aluminium and the coax tails all forms part of the driven element, so the tip to tip dimension is near enough. Likely the TV antenna element material is 3/8" or 10mm diameter aluminium tube, so 999mm for a 2m dipole seems too long to be resonant ... 970mm will more likely be resonant near the bottom end of the 2m band. (That may change when the dipole is within a Yagi structure, so don't expect a 970mm long dipole driven element will be right for any particular Yagi).

2. Not sure if that choke will effect the SWR much. The SWR on 50 ohm coax cable of a 10mm diameter dipole at 2m will be about 1.5:1 ... and change a little bit according to height above ground or proximity to objects.

3. Yes ... assuming the Yagi design is a "50 ohm" one. The driven element length for a folded dipole and a split dipole will probably be different though. If it is not an 'industrial secret', tell us what 6 element 2m band Yagi you are looking at building and we can give you a better idea.

73,