Discone versus Amateur white stick..

[phillmobile]

I thought I read somewhere once that a discone is horizontally polarised (i.e. from the disc rather than the cone) so that might account for dramatic differences?

yes i think your right, i too always thought they where horizontally polarised

[JohnUK]

I use my wire for HF up to 40MHz

The Discone for 40MHz up to 140MHz

And a Ham white stick 2m/70 for 140 to 470MHz

The Ham white stick has good gain for VHF and UHF but fails on UHF low so the discone covers that area. My wire is homebrew.

[dcwuk]

Make one of these shove it in the loft and Bobs your uncle

[pete_uk]

Are there any details on that antenna?

[bigbassman]

Make one of these shove it in the loft and Bobs your uncle

Looks good.Can you just verify that (a) C is the longest element and (b) the downward facing elements are connected to the centre core of the co-ax? I'm not questioning your methods,just want to be sure.

[dcwuk]

This was made by my late father, I haven't verified the length of the elements for frequency but the measurements are accurate. Element C is the longest and yes the downward elements are connected to the coax centre.
Whether or not its upside down I couldn't say, I will try and find the original instructions that I expect are among dads paperwork ( he kept everything)
I tried the aerial in my shack and found it worked well, the elements are made from small bore copper heating pipe.
I imagine with a bit of tweaking this could be adapted for external use.
regards
dcw

[bigpimp347]

on a centerfed dipole it makes no difference where the inner coax is, up or down, makes no difference.
an looking at the measurements 610 is the bigger number than the other four

another way to make these is cut each wire for the band you want to listen to.
so 6" for 70chs 18" for 2mtrs (although pointless as 18" is a 3/4 wave on 70cms )
you don't need five wires, you can use two, three, ten..!!

[bigbassman]

Quick (and maybe daft) question.Am I compromising anything signal-wise by wrapping my X30 in BLACK self amalgamating tape??.I want to mount it outdoors,but being very..well..white,it could/will attract unwanted attention.It's virtually invisible when it's black.The antenna is only used for listening.Thanx.

[RadioPixie]

Quick (and maybe daft) question.Am I compromising anything signal-wise by wrapping my X30 in BLACK self amalgamating tape??.I want to mount it outdoors,but being very..well..white,it could/will attract unwanted attention.It's virtually invisible when it's black.The antenna is only used for listening.Thanx.

Wrapping it up with black tape is fine and shouldn't disturb the performance

[bigbassman]

OK RP,thanx for that.

[bigpimp347]

after all it's already wrapped in white fibreglass.. !!
tape, paint, plastic bags won't lower any performance, metal, water, metallic paint will.

[troffasky]

Some advice I was given for improvising radomes for outdoor wifi stuff was...stick it in a microwave oven, if it warms up then it's attenuating radio and isn't suitable. Not sure if it applies at lower frequencies.

[bigpimp347]

stick it in a microwave oven,

stick what in ???
and nothing metallic or you'll see a nice few sparks and bangs..!!

i wouldn't advise putting anything into a microwave oven thats not food stuffs or recommended by a manufacturer.!!

[Monsta]

Lets do some Math!

Microwave oven ...average Diameter 15-18 inches
average 2/70 White stick antenna ....when disassembled sections about 40 inches



...of course you could chop your Diamond up into small chunks with a junior hacksaw
and THEN ,microwaving it before "gaffer-taping" it together and mounting it outside
...that should do the trick!

troff ..do me a favour ...if you are ever flogging one of your antennas on eBay let me know ..
...just in case!

[troffasky]

Lets do some Math!

Let's do some Reading!:

improvising radomes for outdoor wifi stuff was...stick it in a microwave oven

I've highlighted the key word, now after reading it again, do you still think I was suggesting putting an antenna in the microwave? Or is there possibly a different, more plausible, explanation?