[Lowfer] Fw: Mini Whip (Roelof Bakker)

[Howell, Laurence (Shanghai/Singapore)]

Suck eggs time - 

Lee et al - here's one trick - if you do get a high Z eprobe/whip or other antenne earth the coax cable to a ground rod using a very short strap before it enters the shack - - or if you are lucky and living in a house that has concrete and rebar construction  - and older metal windows or louvered patio doors - often by design or chance  are "bonded"  to the rebar in the house, which often is grounded by design or luck at various points around the property - earthing the coax to this window, sill, door (via a screw/bolt), if available will and can knock some N dBs of common mode noise off your Lf reception (up to 40dB I've seen)  - if can also improve hf sn too in some cases. Trouble is most new construction are wooden framed and pvc, but tap around the various metal object  with the coax looking and listening on LF with the rx on AM with the NB off and see if any of the connections to the structure improve things. Akin to a leaky Faraday cage - but hotels and apartments have proved the best in noise resolution.  Ensuring the psu is clean from pushing noise up towards the antennae or via other means to the rx. I favor rechargeable batteries isloated from any AC source at the time of listening , but that's just me.

Laurence in Southern Mexico today.

----- Original Message -----
From: lowfer-bounces at mailman.qth.net <lowfer-bounces at mailman.qth.net>
To: Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands <lowfer at mailman.qth.net>
Sent: Sun Nov 01 13:47:35 2009
Subject: [Lowfer] Fw: Mini Whip  (Roelof Bakker)

Andy and Howell:

The noise I have with a ham antenna not grounded and acting as a long wire 
is deafening.  It is man made coming from everywhere.  I need to tune the 
antenna whatever it is and get shielded line to outside the house.  I did 
turn off my computer but that didn't reduce any noise.  I hear some birdies 
and beat notes that are being created internally within my radio.  (Was 
using a FT-890 transceiver).  I have a new FT-950 and will try that tomorrow 
and see what birdies it has internally.

I just wrote, see below, the following to Steve Ratzaff on the same topic 
for the AMRAD antenna:



> Steve:
>
> I wrote Crystalonics about minimum orders.  I can't find anything listed 
> on their web site regarding minimums.  What is interesting is they have 
> the Sept, 2001 QST article on building the AMRAD Antenna on their web 
> site. They say add $5.00 for shipping within the US.  I suspect there 
> won't be any problem getting a CP-666  FET transistor.  The thing is made 
> by them and it has extremely low noise characteristics.  I am sure much 
> better then a J-310.  The CP-666 is $17.50 plus $5.00 shipping if they 
> will sell one.  I'm inclined to go with it if available.  The two FAR 
> Circuit boards for the AMRAD are $9.95 for both boards.  The special low 
> power line coupling power transformer is around $12.00 to $17.00 depending 
> on brand.  The article is worried about AC line coupling and like a 
> particular brand of transformer.  I am thinking of installing a line 
> filter before the supply.  I happen to have a couple around here someone 
> gave me.  They have three toroids and some caps in them and are in a box 
> around2 1/2 inches square.  This should also help reduce line coupling.  I 
> know I know.  The noise I have here right now is deafening and is coming 
> in on the unshielded feed line. AC line filtering is the least of my 
> present woes.  I am hoping up at my lake house, things will be much 
> better.
>
> Lee, w0vt
>
>
> 
______________________________________________________________
Lowfer mailing list
Home: http://mailman.qth.net/mailman/listinfo/lowfer
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Lowfer at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html