Dear Madhukar ji,
I do not want to sound pessimistic, but when a powerful broadband noise source (from an really looong HT line, especially) is so close, I doubt if a loop would be rejecting the noise to any great extent.
Unfortunately, I face a similar problem myself, noise emanating from the elevators of my highrise. I tried a 3 element yagi directed opposite to the source of QRM/N, it did not quite work. I tried mag loops, it was very directional, did cut the noise a bit, but was too cumbersome to use.
Finally I settled for two seperate antennae: the main antenna for Tx, and a remote small broadband loop in my balcony for Rx. Now at least it is workable, but rx levels are about 20-30dB lower than a full sized dipole (but readable at least)!
My point is, with broadband noise sources very close by, the loop geometry "rejecting noise" is probably more of a myth than a performer, unless you have actually s.
I would be only more than happy if you are successful: will try it myself following your reports.
On the other hand, a veteran ham in his own right, in Gurgaon, has successfully used active phasing type noise cancellers to combat the same problem that you and I have. (Now this is one ham whose findings and results can be blindly relied on!)
Best regards,
73
Ron
VU2ORO, Indirapuram, NCR
From: Madhukar VU2MUD <vu2mud@yahoo.co.uk>
To: HAMBREWERS Group <HamBrewers@yahoogroups.com>
Sent: Thursday, November 15, 2012 3:48 PM
Subject: [HamBrewers] Question on Loop/ Delta Loop
I face a very high level of electrical noise at my new Permanent QTH - being just about 300 Mtrs from HT Lines - becoming a Permanent QRM too!!
This is present at unacceptable levels - s-9 + most of the times. This made me consider a Loop/Delta Loop Antenna for 7 Mhz to handle the noise issue.
Planning for a Horizontal installation - I understand that this gives me only Ground Waves - OK for now.
I need clarifications on the following issues.
1. Most of the Links that I see on the web is for a full wave design. What limits the use of a Half Wave Delta Loop??
2. Where should bthe feedpoint be?
3. What will be feedline impedence??
4. What kind of Balun is required to feed to a 50 Ohm cable?
5. What else is to be considered??
I have a LDG - Z-100 Plus antenna tuner.
Madhukar – VU2MUD
Yahoo Mail: vu2mud@yahoo.co.uk
Gmail: vu2mud@gmail.com
General Blog: http://vu2mud.blogspot.com
Satellite Blog: http://workingtheoscars.blogspot.com
Location: Lat: 13° 0' 6'' N; Long: 77° 32' 10'' E;
Grid Loc: MK83SA
Yahoo Mail: vu2mud@yahoo.co.uk
Gmail: vu2mud@gmail.com
General Blog: http://vu2mud.blogspot.com
Satellite Blog: http://workingtheoscars.blogspot.com
Location: Lat: 13° 0' 6'' N; Long: 77° 32' 10'' E;
Grid Loc: MK83SA
__._,_.___
| Reply via web post | Reply to sender | Reply to group | Start a New Topic | Messages in this topic (8) |
.
__,_._,___
No comments:
Post a Comment