[Lowfer] thoughts on PA0RDT "mini whip"

Thu Dec 22 09:44:06 EST 2016

Same here, Jack. I have a 90% completed AMRAD whip that I just need to seal
in PVC pipe and attach the connectors.....

On Thu, Dec 22, 2016 at 9:41 AM, Zack Widup <w9sz.zack at gmail.com> wrote:

> Any idea how it does compared with the AMRAD e-probe antenna? I built an
> AMRAD whip but have yet to put it up. Since I have the next week off from
> work and it might be unseasonably warm, this is probably a good time to do
> it.
>
> 73, Zack W9SZ
>
>
> On Wed, Dec 21, 2016 at 4:50 PM, Howell, Laurence J <
> L.Howell at conocophillips.com> wrote:
>
> > Doug, I have three or four probes up various trees, some just separated
> by
> > 5m or so, but as ever, the selection of the height and location sweet
> spot
> > for best s/n is manifestly important here. A few feet either way can
> make a
> > hooge (hooge) difference  - I ve run various shoot outs on what works
> best
> > and though we get the odd earlier long haul decode on 475 with the
> highest
> > probe (50ft or so), the best here is one at around 35ft or so called
> "Aces
> > high" - slightly higher than RDT states but I do see that curve too in
> s/n
> > using NDB and W&G test set.
> >
> >  It took me a season or two to get just the right tree. Out of all the
> > antennae here the probes tend to work best over active or passive large
> or
> > small loops but that's probably because of the bespoke nature of the E/M
> > interference fields on this acre and related to off site man made
> > electrical noise sources. It will be different elsewhere - what works
> best
> > here wont elsewhere.
> >
> > I figured out that the best type of tree to have one on is the Genus
> > "Acacia" - which is pan-global and typically the worse is the Coconut
> Palm.
> >
> > I see a lot of comments on they are just mickey mouse appliance antenna
> > but Ive been using them in military and commercial situations for over 35
> > years and its horses for courses, and they work best here (and in a lot
> of
> > other countries around the globe) over anything else. Stat. Used to use
> > them in Antarctic for air-to-ground ops when the main wideband or LPA
> were
> > snow static bound....
> >
> > I ground the RG6 where it typically hits ground (boggy ground into a lake
> > typically), large series J common mode choke at that end, another in the
> > shack, keeping the power injector away from noisy mag fields that intrude
> > even metal ali boxes, then Bino isolated transformer which is usable at
> > 1kHz up to 500kHz or more - quite a few turns on 73 material from memory.
> > Power is battery though simple unstab DC from 110VAC is pretty good if
> you
> > decouple well. Playing with the voltage from 9-18VDC can help with iMod -
> > mine appears happy around 15V but my local blow torch on 1430kHz appears
> to
> > have a issue with pins stuck in its coax quite often :-) (joking)
> >
> >
> > Laurence KL7L
> >
> >
> >
> > -----Original Message-----
> > From: Lowfer [mailto:lowfer-bounces at mailman.qth.net] On Behalf Of N8OOU
> > Sent: Wednesday, December 21, 2016 1:32 PM
> > To: Discussion of the Lowfer (US, European, & UK) and MedFer bands <
> > lowfer at mailman.qth.net>
> > Subject: [EXTERNAL]Re: [Lowfer] thoughts on PA0RDT "mini whip"
> >
> > Doug,
> >
> > The mini whip is mounted and grounded to the top of a galvanized steel
> > trellis that I grow hops on. The trellis is about 15 feet tall, and
> > grounded at the base. RG-6 quad shield coax is grounded at the mini
> > whip/trellis, and runs back to the shack. Nothing in the shack is
> > externally grounded. I'm not sure if the DC power supplies ground back
> > to the mains.
> >
> > 73   de   N8OOU - Mike Meek
> >
> > On 12/21/2016 03:55 PM, Douglas Williams wrote:
> > > Mitch & Mike,
> > >
> > > Thanks for the info.
> > >
> > > Mike, did you ground the antenna at the base, halfway point, or at the
> > > house?
> > >
> > > Anyone else have any info, feel free to chime in.
> > >
> > > D. KB4OER
> > >
> > > On Wed, Dec 21, 2016 at 4:48 PM, N8OOU <n8oou at meekfarm.us> wrote:
> > >
> > >> Doug,
> > >>
> > >> A few observations on the mini whip.  I built one from my junk box
> parts
> > >> based on the original design. I had to add a notch filter to block my
> > local
> > >> 500W AM BCB station. Inserted in the whip between the FET and Buffer
> > amp. I
> > >> also must use a 500 Khz low pass filter at the receiver for LF. I have
> > it
> > >> mounted about 15 Ft above ground, away from the house, and grounded
> > >> according to common information found on the web.
> > >>
> > >> It works (all the way up to 10m), better than a long random wire, but
> > not
> > >> as good as the Low Noise Vertical I just finished.
> > >>
> > >> 73   de   N8OOU - Mike Meek
> > >>
> > >>
> > >> On 12/21/2016 03:07 PM, Douglas Williams wrote:
> > >>
> > >>> Have any of you used one of these on VLF/LF? What are your
> experiences?
> > >>> They seem to be everywhere on eBay, from kits to fully assembled, and
> > >>> averaging $12 - $40.
> > >>>
> > >>> D. KB4OER
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