Televes mounting arrangement

The first time I saw the new mounting method for the DAT 75 I seriously
wondered if the installer had assembled the aerial incorrectly. I was
surprised that the mast protruded between the elements and was so close to
them. I took a photograph and put it on my website.

http://www.wrightsaerials.tv/023dat75mastprox.htm

However, it turns out that this is the 'official' method. Presumably Televes
have carried out tests and found that the mast is no detriment to reception.
I've asked the webmistress to remove the item from the Rogues section
because the installer was merely following the instructions, and as regards
the actual design I think we have to assume Televes know what they're doing,
unless and until tests show otherwise.

Anyway, here's an odd thing -- on the picture of the aerial shown here

http://www.turbosattrade.com/tradeup...dateapr07.html

the mounting method is different yet again. The middle boom is clamped. A
short length of mast protrudes above it.

A few days ago I got an email which I reproduce below:

------------------

I think an apology would be in order to the installer & Televes, please see
attached instruction.

Kind Regards
-------------------
There was an attachment showing the Televes assembly leaflet. Incidentally
this showed the cable fixed with cable ties and flying across from the
reflector to the mast.The email was from Shuan Lafferty. I replied as
follows:

-------------------
Hello Shaun,

At the time I honestly didn't know if this was the correct way to assemble
the aerial. Since then I've found out that it is, according to Televes. But
the fact is that by putting that much metal so close to the director
elements the performance must be affected. Maybe the design allows for this
and any detuning is compensated for, I don't know. I'm sure Televes will
have done all the necessary tests and so forth. You must realise that for
many years we have been told that extraneous conductive objects must be kept
well away from the elements of an aerial, so this design does seem very odd.

I notice that the installer of the aerial on the website hasn't followed
Televes's instuctions re the cable fixing.

I will amend the website though next time I do any work on it.

What's your interest in this? Are you an installer? Do you use these
aerials? If so what do you think to them?

Bill
-------------------
Shaun rung me on a 'number withheld' phone a few minutes later. He told me
that he was in close contact with just about everyone who was anyone in the
aerial trade, and that he worked for a very large company. He wouldn't tell
me which company though, which I couldn't understand. I'm really rather
curious about this, so if you're reading this Shaun please reconsider your
decision to remain anonymous. You were very interesting to talk to. If
anyone else knows who Shaun is could they please let me know?

Bill

In article , Bill Wright
writes
The first time I saw the new mounting method for the DAT 75 I seriously
wondered if the installer had assembled the aerial incorrectly. I was
surprised that the mast protruded between the elements and was so close to
them. I took a photograph and put it on my website.

http://www.wrightsaerials.tv/023dat75mastprox.htm

However, it turns out that this is the 'official' method. Presumably Televes
have carried out tests and found that the mast is no detriment to reception.
I've asked the webmistress to remove the item from the Rogues section
because the installer was merely following the instructions, and as regards
the actual design I think we have to assume Televes know what they're doing,
unless and until tests show otherwise.

Anyway, here's an odd thing -- on the picture of the aerial shown here

http://www.turbosattrade.com/tradeup...dateapr07.html

the mounting method is different yet again. The middle boom is clamped. A
short length of mast protrudes above it.

A few days ago I got an email which I reproduce below:

------------------

I think an apology would be in order to the installer & Televes, please see
attached instruction.

Kind Regards
-------------------
There was an attachment showing the Televes assembly leaflet. Incidentally
this showed the cable fixed with cable ties and flying across from the
reflector to the mast.The email was from Shuan Lafferty. I replied as
follows:

-------------------
Hello Shaun,

At the time I honestly didn't know if this was the correct way to assemble
the aerial. Since then I've found out that it is, according to Televes. But
the fact is that by putting that much metal so close to the director
elements the performance must be affected. Maybe the design allows for this
and any detuning is compensated for, I don't know. I'm sure Televes will
have done all the necessary tests and so forth. You must realise that for
many years we have been told that extraneous conductive objects must be kept
well away from the elements of an aerial, so this design does seem very odd.

I notice that the installer of the aerial on the website hasn't followed
Televes's instuctions re the cable fixing.

I will amend the website though next time I do any work on it.

What's your interest in this? Are you an installer? Do you use these
aerials? If so what do you think to them?

Bill
-------------------
Shaun rung me on a 'number withheld' phone a few minutes later. He told me
that he was in close contact with just about everyone who was anyone in the
aerial trade, and that he worked for a very large company. He wouldn't tell
me which company though, which I couldn't understand. I'm really rather
curious about this, so if you're reading this Shaun please reconsider your
decision to remain anonymous. You were very interesting to talk to. If
anyone else knows who Shaun is could they please let me know?

Bill





I bet if you did a NEC model of that thing it would show up some
"interesting" patterns;!....
--
Tony Sayer

"tony sayer" wrote in message
...
I bet if you did a NEC model of that thing it would show up some
"interesting" patterns;!....

It has passed the CAI benchmarking scheme. I don't know what that means . .
..

Bill

In article , Bill Wright
writes

"tony sayer" wrote in message
...
I bet if you did a NEC model of that thing it would show up some
"interesting" patterns;!....

It has passed the CAI benchmarking scheme. I don't know what that means . .
.

Bill



Numerical Electromagnetic Code..

Its a a way of calculating what an aerial will do. You make up a
computer model with wires on an X Y Z axis basis...

Http://www.eznec.com/

http://www.nittany-scientific.com/

http://www.nec2.org/
--
Tony Sayer

"tony sayer" wrote in message
...
In article , Bill Wright
writes

"tony sayer" wrote in message
...
I bet if you did a NEC model of that thing it would show up some
"interesting" patterns;!....

It has passed the CAI benchmarking scheme. I don't know what that means .
.
.

Bill



Numerical Electromagnetic Code..

Its a a way of calculating what an aerial will do. You make up a
computer model with wires on an X Y Z axis basis...

I meant I don't know the validity.

Bill

"Bill Wright" wrote in message
...

"tony sayer" wrote in message
...
In article , Bill Wright
writes

"tony sayer" wrote in message
...
I bet if you did a NEC model of that thing it would show up some
"interesting" patterns;!....

It has passed the CAI benchmarking scheme. I don't know what that means .
.
.

Bill



Numerical Electromagnetic Code..

Its a a way of calculating what an aerial will do. You make up a
computer model with wires on an X Y Z axis basis...

I meant I don't know the validity.


FWIW, you could look he
http://www.dtg.org.uk/retailer/benchmarking_basis.html

JohnT

Bill Wright wrote:
The first time I saw the new mounting method for the DAT 75 I seriously
wondered if the installer had assembled the aerial incorrectly. I was
surprised that the mast protruded between the elements and was so close to
them. I took a photograph and put it on my website.

http://www.wrightsaerials.tv/023dat75mastprox.htm

However, it turns out that this is the 'official' method. Presumably Televes
have carried out tests and found that the mast is no detriment to reception.
I've asked the webmistress to remove the item from the Rogues section
because the installer was merely following the instructions, and as regards
the actual design I think we have to assume Televes know what they're doing,
unless and until tests show otherwise.

Anyway, here's an odd thing -- on the picture of the aerial shown here

http://www.turbosattrade.com/tradeup...dateapr07.html

the mounting method is different yet again. The middle boom is clamped. A
short length of mast protrudes above it.

A few days ago I got an email which I reproduce below:

------------------

I think an apology would be in order to the installer & Televes, please see
attached instruction.

Kind Regards
-------------------
There was an attachment showing the Televes assembly leaflet. Incidentally
this showed the cable fixed with cable ties and flying across from the
reflector to the mast.The email was from Shuan Lafferty. I replied as
follows:

-------------------
Hello Shaun,

At the time I honestly didn't know if this was the correct way to assemble
the aerial. Since then I've found out that it is, according to Televes. But
the fact is that by putting that much metal so close to the director
elements the performance must be affected. Maybe the design allows for this
and any detuning is compensated for, I don't know. I'm sure Televes will
have done all the necessary tests and so forth. You must realise that for
many years we have been told that extraneous conductive objects must be kept
well away from the elements of an aerial, so this design does seem very odd.

I notice that the installer of the aerial on the website hasn't followed
Televes's instuctions re the cable fixing.

I will amend the website though next time I do any work on it.

What's your interest in this? Are you an installer? Do you use these
aerials? If so what do you think to them?

Bill
-------------------
Shaun rung me on a 'number withheld' phone a few minutes later. He told me
that he was in close contact with just about everyone who was anyone in the
aerial trade, and that he worked for a very large company. He wouldn't tell
me which company though, which I couldn't understand. I'm really rather
curious about this, so if you're reading this Shaun please reconsider your
decision to remain anonymous. You were very interesting to talk to. If
anyone else knows who Shaun is could they please let me know?

Bill






Bill, the mounting arrangement where the mast is clamped from top and
bottom for the DAT75 is correct. The other link where the middle boom
and bottom boom bar are used to clamp is the old arrangement no longer used.

There is a further accessory that creates a horizontal mount so the
DAT75 can be mounted for Vertical signals.

The whole arrangement for Vertical mounting seems a bit hap hazard.

Regards
Glenn...

Bill, the mounting arrangement where the mast is clamped from top and
bottom for the DAT75 is correct. The other link where the middle boom and
bottom boom bar are used to clamp is the old arrangement no longer used.

That makes sense from the POV of mechanical stability but it's going to
upset a lot of RF purists, and I for one am going to cringe whenever I
see one just as I cringe whenever I see any yagi with the mast between
the elements, its just wrong. I trust they have re applied for the product
certification.

--

Graham.
%Profound_observation%

Graham wrote:
Bill, the mounting arrangement where the mast is clamped from top and
bottom for the DAT75 is correct. The other link where the middle
boom and bottom boom bar are used to clamp is the old arrangement no
longer used.

That makes sense from the POV of mechanical stability but it's going
to upset a lot of RF purists, and I for one am going to cringe
whenever I see one just as I cringe whenever I see any yagi with the
mast between the elements, its just wrong. I trust they have re
applied for the product certification.

I don't think it is RF purism but just understanding the law of physics. It
would be an interesting exercise on an antenna range to see just how much
difference the different forms of mounting make. In real world situations
the signal from the transmitter is likely to be less than perfect in terms
of polarisation as well as phase so how much difference does it make? I
would be interested to hear what others think.

Peter Crosland

I also notice that Bill's web site is STILL pushing Technology at Home
magazine!

Perhaps he doesn't bother to update it very often?

--
Robert