| |
G0TEZ > TECH 16.09.04 10:13l 68 Lines 2924 Bytes #999 (0) @ WW
BID : E50247G0TEZ
Read: GUEST OE7FMI
Subj: Re: Re; G0TEZ and delte loops
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<ON0AR<EB2BJX<GB7YKS<GB7SYP<GB7MAX<GB7SAM<
GB7OAR<GB7BOB<GB7HVU
Sent: 040916/0805Z @:GB7HVU.#16.GBR.EU #:52494 [Great Harwood] FBB7.00i
From: G0TEZ@GB7HVU.#16.GBR.EU
To : TECH@WW
> I think I now understand what you mean by the reflector,
> which is what I thought in the first place - it's placed
> away from the loop not inside it because the original
> wording is not very clear and can easily be misunderstood.
-------------------------------------------------------------
I don't know if this is a wind up.
If I make a horizontal wire triangle and stand inside it, then I am inside
it,not under it or away from it.
I am assuming here that we are using the ordinary Euclidean geometry we
all did at schhol, not a pseudosherical or any other non - euclidean
geometry.
If I make a wooden box and step into it. I am inside it. If I make a
little
metal box around me, still inside it, we are both inside the wooden box.
If the boxes are both triangular, one is still inside the other.
If the inner box is just sitting there, not powered in any way, it will
reflect radio waves. Yes, there are possible losses through hysterisis but
if you realy needed to, you could make the reflector from a mesh, just as
they do with some reflectors on dipoles and some transmitting parabolic
Aerials, where the driven element is at the focus.
If your outer box is replaced by a wire loop, the inner box will still
reflect the radio waves it emits, outwards and horizontally polarised.
I don't know where you get the 5.5dB gain from but, even that represents a
power gain of 10^0.55 ==3.58 according to my calculator. That would be dBd
I presume, not dBi.
As for the CBs S meter, no one seems quite sure just what an 'S' point
represents in terms of dB. I have to say that i have never met two ham
radio S meters that agreed with each other. We use them just as I used to
use a CB S meter, as an indication of relative signal strength.
On that basis, if a man 20 miles away was getting an average signal from
me of S3 on his meter and I was getting the same, then the next day, with
no change in power, we see S9+20 dispayed on our meters and we know that S
meters are logarithmic, exponential, if you like, i.e. twice the movement
of that needle does not represent twice the power, more like 10^2 times
the power, then that is a big increase!
The bottom line is, I did it. I did it to be devious and because I only
had a 5' high loft. I only remember it because it surprised me.
As for the polar diagram, I have no way of working that out. If I really
cared, I would get a book and find out how to measure it.
I suppose it isn't as simple as walking around it with a field strength
meter.
I can't see any other way in which I can explain the meaning of the word
'inside'. I just don't see the problem.
If I had been able to add a third passive element, a director, then that
would have been 'outside' the driven element.
If it is a joke, you win.
If you're calling me a liar. O.K. I don't care.
They don't do halfpenny numbers any more. I'm gone 10 - 10.
Read previous mail | Read next mail
| |
