| |
G0FTD > TECH 13.09.04 02:40l 38 Lines 1275 Bytes #999 (0) @ WW
BID : 0F6896G0FTD
Read: GUEST OE7FMI
Subj: Re: Delta Loops
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<ON0AR<IK1ZNW<GB7SXE
Sent: 040912/1317Z @:GB7SXE.#38.GBR.EU #:4919 [Hastings] FBB7.00i $:0F6896G0FTD
From: G0FTD@GB7SXE.#38.GBR.EU
To : TECH@WW
G8MNY quoting G0TEZ:-
>I found that stations that had previously been S3 were 9+ but, they still
>only got me at S3 so I put a reflector 1/10th wavelength inside the loop.
>As it was on the floor of a loft, I could make it free standing from Baco
>Foil (aluminium turkey foil) with 3 supports.
>I know we have a lot more power available on AR but the reflector is well
>worth trying .
I don't get it - a reflector INSIDE the loop -was that AWAY from the loop.
A reflector 1/10th lambda AWAY from the loop will work, giving typically
4dbd gain,maybe 5dbd but obviously at the expense of directivity.
My model results here give 4.12dbd with 11db front to back ratio,
I simply made the reflector 10% large and at 1/10th lamba AWAY, I didn't
attempt any optimisation of the antenna.
This sounds more like what G0TEZ is doing and knowing that CB s-meters
have a very poor dynamic range - I would suggest that the claimed S3 to
S9 improvement is actually only accounting for that same 4db or so.
(I recently tested a few CB s-meters and found that 1 s-point was an
increase of anything from 0.5db - 1.5db).
I don't recommend anyone attempts to put a reflector UNDER a loop
unless you want a "cloud burner" ;-)
- Andy -
Read previous mail | Read next mail
| |
