recommendations for a vertical FM omnidirectional aerial that canbe mounted at the bottom?

On Mon, 09 Jul 2012 23:08:46 +0100, Stephen H
wrote:

Am shortly going to put up my metallic tree up against the gable end of
my new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as
it will sit on top of a pole.

Search for J-pole or Slim Jim.
--
Roger

On 10/07/12 07:39, David Woolley wrote:
Stephen H wrote:
Am shortly going to put up my metallic tree up against the gable end of my
new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as

Vertical dipoles are always omni-directional in the horizontal plane.
However, FM (band 2) broadcast stations are horizontally polarized, so a
vertical dipole is of no use for them. I might just believe that a single
relay was vertically polarised, but you wouldn't want an omni-directional
aerial for that.

Eh? What year are you in? 1975?

Band 2 broadcast stations have been mixed or circular polarisation for years.
They have to be with so many listening in cars.

2BSur2Bsur wrote:
On 10/07/12 07:39, David Woolley wrote:
Stephen H wrote:
Am shortly going to put up my metallic tree up against the gable end of my
new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as

Vertical dipoles are always omni-directional in the horizontal plane.
However, FM (band 2) broadcast stations are horizontally polarized, so a
vertical dipole is of no use for them. I might just believe that a single
relay was vertically polarised, but you wouldn't want an omni-directional
aerial for that.

Eh? What year are you in? 1975?

Band 2 broadcast stations have been mixed or circular polarisation for years.
They have to be with so many listening in cars.

In article , Roger
scribeth thus
On Mon, 09 Jul 2012 23:08:46 +0100, Stephen H
wrote:

Am shortly going to put up my metallic tree up against the gable end of
my new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as
it will sit on top of a pole.

Search for J-pole or Slim Jim.

Would be a good idea except I don't know of anyone who makes them for FM .

You'll find some on the top's of London towers blocks tho;!...

--
Tony Sayer

2BSur2Bsur wrote:
On 10/07/12 07:39, David Woolley wrote:
Stephen H wrote:
Am shortly going to put up my metallic tree up against the gable end of my
new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as

Vertical dipoles are always omni-directional in the horizontal plane.
However, FM (band 2) broadcast stations are horizontally polarized, so a
vertical dipole is of no use for them. I might just believe that a single
relay was vertically polarised, but you wouldn't want an omni-directional
aerial for that.

Eh? What year are you in? 1975?

Band 2 broadcast stations have been mixed or circular polarisation for years.
They have to be with so many listening in cars.

They should have abandoned the horizontal component
years ago and gone for a straight VP system.
Apart from anything else it would probably save more leccy
In a day than gets generated all the UKs PVPs in a year

In article
,
Graham wrote:

[Snip]

They should have abandoned the horizontal component
years ago and gone for a straight VP system.
Apart from anything else it would probably save more leccy
In a day than gets generated all the UKs PVPs in a year

what about all of us who had installed decent HP aerials? the cost of
replacing those would be peanuts and we'd all end up with multipath ....

--
From KT24

Using a RISC OS computer running v5.18

In article ,
charles wrote:
In article
,
Graham wrote:

[Snip]

They should have abandoned the horizontal component
years ago and gone for a straight VP system.
Apart from anything else it would probably save more leccy
In a day than gets generated all the UKs PVPs in a year

what about all of us who had installed decent HP aerials? the cost of
replacing those would be peanuts and we'd all end up with multipath ....

I should have written: "Wouldn't cost peanuts"

--
From KT24

Using a RISC OS computer running v5.18

On 10/07/2012 16:14, tony sayer wrote:
In , Roger
scribeth thus
On Mon, 09 Jul 2012 23:08:46 +0100, Stephen H
wrote:

Am shortly going to put up my metallic tree up against the gable end of
my new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as
it will sit on top of a pole.

Search for J-pole or Slim Jim.

Would be a good idea except I don't know of anyone who makes them for FM .

You'll find some on the top's of London towers blocks tho;!...



I have found plans on the net for both the FM and DAB versions of the
Slim Jim using "common every day materials" such as copper tube, copper
wire, plastic waster pipe etc with the claim that they can be built for
less than 10 quid worth of materials.

In message , Stephen H
writes
On 10/07/2012 16:14, tony sayer wrote:
In , Roger
scribeth thus
On Mon, 09 Jul 2012 23:08:46 +0100, Stephen H
wrote:

Am shortly going to put up my metallic tree up against the gable end of
my new house.

I'd like recommendations for a good quality vertical omnidirectional FM
dipole that can be mounted from the bottom rather than in the middle as
it will sit on top of a pole.

Search for J-pole or Slim Jim.

Would be a good idea except I don't know of anyone who makes them for FM .

You'll find some on the top's of London towers blocks tho;!...



I have found plans on the net for both the FM and DAB versions of the
Slim Jim using "common every day materials" such as copper tube, copper
wire, plastic waster pipe etc with the claim that they can be built for
less than 10 quid worth of materials.

Indeed, a quick Google on 'FM radio vertical aerial antenna' brings up a
few designs specifically for the FM band.

However, for sheer simplicity, I reckon that a quarterwave whip or rod
(possibly a modified CB aerial and mount) fixed on top of the pole -
with the coax screen connected to the pole at the aerial mounting point
- will probably suffice. As the FM band is centred on around 100MHz
(3m), a quarterwave will be around 1.m.
--
Ian

In message , Ian Jackson
writes


As the FM band is centred on around 100MHz (3m), a quarterwave will be
around 1.m.

Someone nicked my 'point five'.

It should be, of course, 1.5m.
--
Ian