"Guy Atkins" schreef in bericht
. ..
I think you're 100% right, Wavetrapper. Craig and I have been good friends
since the late 1980s, and I'm very familiar with his approach to Kiwa
products. Like with the Kiwa MAP unit, the MW Loop was labor-intensive to
build (but not quite as bad a situation as with the MAP). The major
products
at Kiwa have been a labor of love for a dwindling hobby crowd. He kept the
parts costs as low as possible by doing most of the work himself (you
should
have seen the ingenious, screw-driven device he cobbled together to cut
the
spiral grooves for the wire in the PVC pipe core of the MW Loop!). Craig
also built his own flow-solder table for soldering PCBs, if I recall, and
a
number of other clever tools and construction aids.

Craig is more of an inventor/engineer than he is a business person who has
all the expenses and profits figured out to the last penny. He had a very
good career before Kiwa as a broadcast station engineer, and gained quite
a
reputation for modifying expensive pro-recording consoles to produce
better
sound. He still does some consulting on the side, but his heart is in the
Kiwa Electronics business.

Unfortunately, as the hobby slowly decline, we lose some of the quality
accessories and peripherals like the Kiwa MAP and the Kiwa MW Loop. I'm
aware of an amazing prototype replacement for the MW loop that Craig was
working on a few years back, but now I don't think he'll be producing it.


It should be nice when he stops production of these succesfull items, to put
the schematics/drawings on Internet, open to the interested hobby-builder.

MRe

Brenda Ann is looking for the schematics of a Spice Chest Radio.Guys and
gals,lets help her.Get on the stick.
cuhulin

It's a great device and I'm happy to own one ; but you can do better
receptionwise with a couple DA100E active whips combined in an ANC-4
(total new, about $600) ; or substitute a Wellbrook ALA1530 for one of the
whips and you can co-locate the whip and the loop, still combining them
in the ANC-4. The British pound though makes that more expensive today.

Just in case somebody is pining for great MW reception and cursing the luck
that you can't get the Kiwa MW loop any longer.

Separate the whips by 125' or so.

The ANC-4 lets you steer the pair of antennas from one endfire to the other,
with a null that starts in a closed V at endfire (= in the plane of the loop,
in the case of the loop+whip ; and = the line of the whips, in the case of
two whips ) to an opened-V line at broadside, to a closed-V line at the other
endfire.

The phase alone would do it except you have to keep rebalancing the gain
at each angle, so it's really a two dimensional adjustment to null something ;
just as, with the Kiwa loop, you have to adjust azimuth and elevation both.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

Just a guess, but is the bandwidth big enough with the Kiwa? I'm
guessing you need 40Khz BW.

IBOC should work with a wellbrook, since they are untuned.

Byung Myung Sying wrote:
I actually have my Kiwa Air-Core Loop (bought years ago when they were
actually still being made) connected to my Yamaha RX-V4600 Home
Theatre receiver which happens to be able to tune AM IBOC. It
actually has a pretty good AM section. There are 3 local Detroit AM
stations transmitting IBOC during the daylight hours. Two of them
actually sound pretty good, the other one doesn't quite have their
IBOC encoding working all that well and has lots of digital artifacts.

The big problem, which kind of defeats the whole purpose is that, even
with the help of the Kiwa Loop, AM IBOC cannot be received in "IBOC
Mode" except for extremely strong local stations. Thus, even if I
want to listen to "clear channel" digital stations at sunset or
sunrise from other cities, the IBOC mode doesn't have enough digital
signal to "latch on" to the digital broadcast. Thus, all the DX IBOC
listener gets is a noisier, inferior AM DX signal, much worse sounding
than it would have been without IBOC. I've tried tuning WBZ in Boston
(an IBOC station) at sunrise, since they turn on their IBOC earlier
than in Detroit (we're on the western edge of the Eastern Time Zone).
They have an excellent analogue signal, but there's no hint of any
detection of their IBOC signal.

I also have DRM capabilities (a TenTec RX-350 receiver and computer
sound card based software). As DXAce reports, the QRN from DRM
transmissions to adjacent stations is JUST AS BAD OR WORSE than IBOC.
However, since DRM doesn't share "bandwidth" with an analogue signal
(as IBOC does), the sound quality of the received broadcasts are
vastly superior -- truly FM table radio comparable. In addition, DRM
is receivable over DX skywave conditions. I enjoy broadcasts from
Radio Luxembourg in the early morning hours in true high fidelity
stereo sound. DRM also allows vastly superior coverage with lower
transmitter power. Listening to the late-afternoon DRM transmission
of Radio Nederland from Bonaire with 5 kW, I get no dropouts and
excellent audio quality.

I doubt that shortwave broadcasting has much of a future, even with
DRM. Antenna real-estate is just too expensive and environmental laws
are stricter. However, those who complain about the QRN from DRM
broadcasts should consider that all forms of digital transmission
(RTTY, the Russian Woodpecker etc etc) produce horrible levels of
interference, and DRM is really no worse.

Fred E.
N8UC -- Detroit



wavetrapper wrote:

IBOC is not authorized currently for night use. It is ok to turn it on
at sunrise and have it run til sunset, I believe. Sunrise and sunset
are the two prime DX times on MW.