Shortwave Antenna OverLoad - Urban Legend or a sad reality for some . . . What Do I Do ?
RHF
Shortwave Antenna OverLoad
- Urban Legend or a sad reality for some
. . . What Do I Do ?
The focus of the claim about OverLoading a Radio is most often directed
to 'portable' AM/FM Shortwave Radios that are designed
to work very well using their built-in Whip Antennas.
These Radios can be OverLoaded by using a very long {LongWire}
Random Wire Antenna; especially in an Urban Area where nearby
High Powered AM/MW and FM Transmitters are already causing
problems for the Radio; when only the Whip Antenna is being
used. The Urban Legend has a 'basis' in the modern highly
charged Urban RF Environment.
FOR 'PORTABLE' AM/FM SHORTWAVE RADIOS :
Many 'portable' AM/FM Shortwave Radios their manufactures
recommend using a Shortwave Reel {Roll-Up} Antenna with their
Radios. These are about 23 Feet Long and can be used as a Fixed
Shortwave Antenna or Un-Rolled and Rolled-Up for temporary and portable
use with the Radio.
READ - Try a Compact 'portable' Shortwave Reel {Roll-Up} Antenna
for Mobility
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1687
Also - Sangean ANT-60 Antenna : Clip to the Whip Antenna
-=V=- External Antenna Jack
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1843
ABOUT THE RIGHT SIZE SHORTWAVE ANTENNA :
IMHO - Most 'portable' AM/FM Shortwave Radios a Shortwave
Antenna that is about 35 Feet Long is adequate to provide
good signal levels (better audio quality) that are more
consistent (less fade) and significantly improve the
Listening Enjoyment of the Radio by the Radio Listener.
LONGER SHORTWAVE ANTENNAS :
For Longer Shortwave Antennas that are used with 'portable'
AM/FM Shortwave Radios; I would suggest that the Radio
Listener consider using a Portable Wire Antenna.
READ - "Portable Wire Antenna" (PWA) for your 'portable'
AM/FM/Shortwave Radio
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1728
"Portable Wire Antenna" (PWA) by Tom Sevart [N2UHC]
PROTECTING THE "PORTABLE" AM/FM SHORTWAVE RADIO FROM THE ANTENNA :
If the Radio Listener has their 'portable' AM/FM Shortwave Radio
permanently connected to an Out-Side External Shortwave Antenna.
I recommend that they consider building and using a "GIZMO"
Connector Box between the Antenna and the Radio.
READ - Portable Radio Antenna "GIZMOE" Connector Box
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1489
THREE RADIO BANDS -AND- THREE ANTENNAS :
With 'portable' AM/FM Shortwave Radios the Radio Listener is
often trying to receive and listen to three different Radio
Bands : the AM/MW Broadcast Radio Band; the Shortwave Radio
Bands; and the FM Broadcast Radio Band. Each of these Radio
Bands can require a 'separate' Receiving Antenna for the Radio
Listener to 'get' the Stations that they want to "Hear".
READ - Three 'different' Radio Bands
and two to three 'different' Antennas
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1809
.
.
iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
<http://groups.yahoo.com/group/Shortwave-SWL-Antenna/>
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/502
.
I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
With a Shortwave Listener SWL Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
.
.
= = = In Shortwave-...@yahoogroups.com,
= = = "Mark - AA6DX" <aa6dx@a...> wrote:
> Hi All ... just wondering, where did this urban myth about
"overloading"
> your shortwave radio start?
> Pure MALARKY. Put up the very best antenna you can ... the bigger
the
> better, the higher the even more better. A resonant antenna works
best, but
> not necessary to log some real DX reception! A resonant antenna is
> relatively simple for a single frequency, or band, but gets
complicated when
> trying to resonate on all the shortwave broadcast allocated
frequencies.
> True, a radio CAN be overloaded, usually by an adjacent broadcast
facility.
> Not to worry ... put up a piece of wire ... ANY KIND ... nice to have
the
> fancy connectors, but not necessary .. all sorts of plastic items can
be
> used for insulator(s) for the end of your wire aerial, and you can
use
> insulated wire, bare wire, electric fence wire, speaker wire (split
it to
> get 2wice the bang for your buck!), picture hanging wire, etc. The
local
> Dollar store has many items that will work fine for hanging your
short wave
> aerial to a tree, and the Web is a very good source for lengths,
etc....
> and connecting a long wire to your telescoping portable antenna works
swell.
> Just use an alligator clip .. available at any hardware, automotive,
or
> electronic, etc. store. Other types of clamps come to mind, like the
paper
> clips with levers, the big plastic ones used for keeping your potato
chips
> fresh, clothes pins ..... you get the idea...just make sure the wire
is
> bared and shiny at the end you are connecting to the whip.
> Wires inside are fine ... but in almost all instances, getting the
wire ..
> now known as YOUR antenna .. outside in the clear will produce
better
> results. I use small magnet wire for receiving antennas, and larger
of the
> same for making my dipoles, loops, etc .. but ANY wire will work!
> Scrounging is part of the fun.
> Most antennas for shortwave offered for sale are quite simple, and
YOU can
> make one, save the bucks towards getting hardware for raising the
height of
> YOUR home brew antenna(s) above ground level.
> I have several shortwave receivers, although most of my rigs are
> transceivers, used in my Amateur Radio hobby, as well as short wave
> listening. My Grundig Yacht Boy 4ØØ is my constant companion .. I
am
> continually amazed at its capabilities. Even hook it up to my
killer
> stereo computer speakers and get excellent STEREO on FM! An aside
.. if
> you are out by your car -- parking lot, picnicking, camping, etc...
raise
> the
> collapsible antenna, get tuned in to where you want, and set the
radio on
> the middle of your metal car roof (or close) -- amazing! Not
recommended
> for rag tops .. Hah..
> I bumped into an aerial yesterday I forgot I had, and not going to
put it
> up ... it's an Eavesdropper, a trapped dipole antenna ... I could
probably
> be talked into parting with it for $50 shipped ... has a feedline ..
> here's scoop
>
> http://www.universal-radio.com/catalog/sw_ant/0680.html
>
> Been keeping it for when going camping, but have not done that for a
couple
> years.
>
> I have a small lot these days, and my wires for ham radio endeavors
claim my
> airspace! It is fun to experiment and wire antennas are quite cheap
to
> build, perhaps FREE if you can find some junk wire! If you want to
get a
> lot of it, stop by your local electric motor winding shop ... they
buy
> enameled wire by the pound, and usually have spools that have been
used and
> not enough left on them for a winding job, but absolutely GREAT for
your
> antenna farm!
>
> Glad to answer any questions that I can, and if I don't know, WE will
find
> out!
> Ex mgr .. Electronic Equipment Bank -- Commercial Sales Mgr . EGE --
Chief
> Engineer (radio) -- Hammin' for 4Ø+ years.
>
> Cheers .... Mark, in Eureka, Far Northern California
> http://h*me.p*cb*ll.n*t/aa*dx
> aa6dx@p...
>
>
>
> overload a Grundig s350? I acquired this as
> a second radio for the upstairs. Which, BTW is working pretty good on
it's
> own. Just patchy at times.
>
> I
> Your Radio Shack random wire antenna will probably overload your
> > Yacht Boy, or so I've been told. I have used one of these
>
>
> Rachel
> a.k.a. Mommabird
>
> .
> Regards ~ RHF
.
r2000...@hotmail.com
danamic range. I use a ~70' wire antenna, with a 9:1 tranformer,
(with another 1:1 for ground noise isolation) and I have very little
problem with overload. A ham who operates at(or beyond) legal
power lives about 2 miles form me and when he fires up, I do
have to leave the band he is operating on. But I used to own a
R390/URR and a R392/URR and both suffered the same problem.
I borrowed a R5000, and a PCR1000 and the R5000 was
slightly better. The PCR1000 was a POS joke. The DSP was nice,
but I guess I'm a "horse drawn man", and a radio must have knobs.
My Heath GR64 doesn't have any overload issuses, but given it
is a deaf as a post, I am not shocked.
I supect that with a decent antenna, a good matching overload
maybe on over blown issue.
Terry
RHF
.
The RadioShack DX-398 / Sangean ATS-909 is 'noted' for being the
exception to the rule; that most 'portable' AM/FM Shortwave Radios
have a tendancy to OverLoad with a very long (+100) Wire Antenna.
.
Conversely, some complain that the RadioShack DX-398 / Sangean
ATS-909 is some what deaf on it's Whip Antenna when compaired
to other 'portable' AM/FM Shortwave Radios.
.
jm2cw ~ RHF
.
.
r2000...@hotmail.com
I thought that I had read somewher that it was fairly prone to
overload.
I have used my R2000 with about 800' of wire up in a nature
preserve and had no noticable problems. We camped out,
in a VW transporter, and I listened on and off for 2 days.
BTW your antenna site if a very well organised place and
full of interesting info.
Terry
running dogg
As I understand it, it is the front end transistor(s) that are being
overloaded when somebody talks about "antenna overload". This problem
occurs mostly with cheap portables. Since they are built cheaply, the
front ends are also cheap and do not have the selectivity of a better
quality receiver. Clipping a length of wire to the whip of one of these
portables will pick up images mostly of AM and FM stations that are in
the vicinity of the receiver. For example, I have a cheap Radio Shack
AM/FM radio that is easily overloaded. Just pointing the whip antenna in
the direction of the nearest FM station (about two miles away) is
sufficient to produce images of that station all over the dial. The
problem is not with the whip, it is the front end.
RHF
.
Replace "front end transistor(s)" with Front End RF Circuitry.
.
YES - You are right many low cost 'portable' AM/FM and Shortwave
Radios are poorly designed and have various images and signal
products that can be hear all over their tuning range. As much
as nearby AM/MW Radio Stations can be a problem. So too, as
you point out nearby FM Radio Stations can be a very real signal
'overload' problem for these cheap portable and table top Radios.
.
Fortunately for Us as Radio Enthusiast for every dozen or so of
these low cost poorly designed Radios. There are a few well
designed Radios that are 'quality built' like the: Sony ICF-2010,
Sangean ATS-909, Grundig Yacht Boy 400 PE, to name a few.
.
CHECK-OUT - DXing.Com's "Modern Shortwave Receiver Survey List"
DXING COM => http://www.dxing.com/rx/rxindex.htm
For some of the better 'portable' AM/FM Shortwave Radios
and some outstanding Table Top Shortwave Receivers.
Mark Zenier
When you've got a quarter of a million watts of medium wave transmitters
blinking their tower lights on your horizon, it's a problem. And I'm
5-7 miles away.
Especially with a Kenwood R-1000 which uses diode switched bandpass
filters in the front end. Since I got a portable to tote around,
I found that If I want to use another receiver in the house, I have
to turn on the R-1000 to bias the diodes on or off, (or disconnect the
antenna), otherwise the spectrum is filled with intermod reradiated from
the antenna.
[Diety] help any radio buff who lives in Federal Way/Vashon Island or near
any other large metro area's medium wave transmitter patch. I heard a
story about a MARS operator/ham there who was having problems with
an on frequency harmonic on a MARS channel around 4 MHz. The FCC guy he
talked to said (words to the effect), Yup, it's right on your frequency,
a couple of miles away, 100 milliwatts, and within the legal limits. Sorry.
Mark Zenier mze...@eskimo.com Washington State resident
starman
>
> As I understand it, it is the front end transistor(s) that are being
> overloaded when somebody talks about "antenna overload". This problem
> occurs mostly with cheap portables. Since they are built cheaply, the
> front ends are also cheap and do not have the selectivity of a better
> quality receiver. Clipping a length of wire to the whip of one of these
> portables will pick up images mostly of AM and FM stations that are in
> the vicinity of the receiver. For example, I have a cheap Radio Shack
> AM/FM radio that is easily overloaded. Just pointing the whip antenna in
> the direction of the nearest FM station (about two miles away) is
> sufficient to produce images of that station all over the dial. The
> problem is not with the whip, it is the front end.
Correct, which includes the first mixer too. Either the front end needs
better preselection using some kind of LC circuits and/or the active
componants (transistors) need to be operated at higher voltages to
provide more 'headroom' from overloading. A good receiver uses both
methods in conjunction with well designed RF amp's and mixers'.
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starman
>
> When you've got a quarter of a million watts of medium wave transmitters
> blinking their tower lights on your horizon, it's a problem. And I'm
> 5-7 miles away.
>
> Especially with a Kenwood R-1000 which uses diode switched bandpass
> filters in the front end. Since I got a portable to tote around,
> I found that If I want to use another receiver in the house, I have
> to turn on the R-1000 to bias the diodes on or off, (or disconnect the
> antenna), otherwise the spectrum is filled with intermod reradiated from
> the antenna.
You could try replacing the standard switching diodes with a hot carrier
PIN type like the 1N5711.