There are a very interesting series of loops and amplifiers coming out of
Cross Country Wireless, in particular the latest uses an aluminium bicycle
wheel rim, note just the rim which can be bought at a modest price. On a
suitable base it is self-supporting and needs to be simply cut with a hack
s
Steel mesh is good. From distant memory a nylon mesh of 0.8mm square is
used in the food industry. This turns out to be the stuff ladies use to
fluff out their ballroom gowns and is very cheap. Perhaps you could snip a
piece without it being noticed ? I also found the fibreglass net used for
p
You might look at Cross Country Wireless for a high performance multicoupler:
http://www.crosscountrywireless.net/multicoupler.htm
Look at the IP3
David G3UNA-G6CP
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of vk2wf
Sent: 01 February 2019 22:03
To:
It's the shared receive-only site that I will build for my club. I can't
think of a better application of subs for members who live in high density
housing as we do. LF is now completely out of the question for all but a
privileged few.
David G3UNA/G6CP
-Original Message-
From: Topband [
A few UK clubs are doing this or have it in mind, including my own. I think
it is the best thing a club can do for its members.
David G3UNA/G6CP
" I also think that building and maintaining a shared Community Low Noise RX
Receiver Site would make a great DX Club project and service."
-Orig
, melts or breaks out in flames at QRO,
that the now-demonstrated large dB loss will also be present running QRP and
LP.
73 and good luck,
Guy K2AV
On Tue, Nov 13, 2018 at 5:25 PM David Cutter via Topband <
topband@contesting.com> wrote:
> I am planning an inverted L over a folded count
I am planning an inverted L over a folded counterpoise as K2AV.
My power levels will likely be about one third of the design levels for the
K2AV design. I can imagine during tune up or adjustments that I might hit
half the power level for short periods, so my component values need not be
so extre
Cross Country Wireless pre-amp have exceptionally high IP3 using FEMPT
transistors. He is also developing units for contesters. Contact owner Chris
Moulding.
David G3UNA /G6CP
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Rune Øye
Sent: 13 Novem
If you don't have plastic pipe, select a plastic beaker from the kitchen
cupboard.
David G3UNA-G6CP
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Don Kirk
Sent: 30 August 2018 12:53
To: Tim Shoppa
Cc: Trevor; topband
Subject: Re: Topband: Air Wound C
tnx I'll look at that
David G3UNA
From: Carl Luetzelschwab [mailto:carlluetzelsch...@gmail.com]
Sent: 02 August 2018 12:29
To: David Cutter
Cc: Joe Subich, W4TV; topBand List
Subject: Re: Topband: WB6RSE Flag type loop question
David,
The NEC-4.2 engine appears to give very good resul
I am at a loss to know how to model it with any confidence, for wires close
to or on the ground.
David G3UNA
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Luetzelschwab
Sent: 01 August 2018 23:02
To: Joe Subich, W4TV; topBand List
Subject: Re:
Roger
I wondered if you'd considered the inverted L with a folded counterpoise ala
K2AV. I'm seriously considering this with the 80m option for my very
limited garden and another site.
When doing your comparisons, do you use the RBN?
Sorry, can't comment on your soil conductivity query.
Davi
>From what I have read on K2AV, avoiding foliage is extremely useful.
BTW Mike, G4IUF has only ever used dipoles (very bent and much lower than
yours) on 160 and 80 and has done well with both, then again, he's been
chasing dx for 25 years or so to accumulate his scores.
David G3UNA
-Origina
There is an item in an old ARRL antenna book showing an 80m dipole residing
in clay pipes just under the surface.
David
G3UNA
- Original Message -
From: "Dick Grolleman"
To:
Sent: Wednesday, January 10, 2018 6:09 PM
Subject: Re: Topband: Bury beverage wire?
Hi All,
That was Neil
From a relay hold-on point of view, this will perform very similarly to the
diode across the relay.
David
G3UNA
- Original Message -
From: "Brian Pease"
To:
Sent: Sunday, December 24, 2017 5:18 PM
Subject: Re: Topband: Detuning Relay Flyback Diode
I am sure that some rigs use an
Jim
I agree with your idea about the zener and a diode but I disagree about
using signal diodes on their own. In my early career I recall changing a
few 1N4148/1N914s on small cradle relays. Changing to 1N4000 series stopped
the failures. I also agree, that for small relays there is no need
The back emf diode slows the relay a lot and you can improve that with a
resistor in series, fudge as required.
Here's another method:
in the drive transistor circuit, fit a small capacitor between collector and
base. As the back emf builds up, a current will be fed back to the base
which will
Elan
I see from your QRZ page that you already have several towers and Yagi.
Have you considered using one as a top-loaded vertical? Do a Google search.
David
G3UNA
- Original Message -
From: "Elan Paim"
To: "Topband"
Sent: Thursday, December 07, 2017 8:11 AM
Subject: Topband: A
Trevor
That circuit works well if you only have a 13V typical radio supply. You
can string several relays from the T/R line but remember to fit a 1N4000
type diode across the relay, + end to supply, -end to the T/R line.
It's important to take into account your linear amplifier (if you are u
Having just done another weekend of Jamboree On The Air, I'd like to suggest
that presenting several modes at an event such as this is the way to go.
None of the scouts had any history of amateur radio and didn't know what to
expect, but they saw the wires we strung up and they had first hand
e
To get the best performance from your choke, K9YC recommends you make a coil
of about 7" diameter from memory. His document has lots of curves to choose
the best assembly.
David
G3UNA
- Original Message -
From: "MR TREVOR DUNNE"
To: "topband List"
Sent: Saturday, September 16, 201
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