Add antenna with no antenna jack?
Randon Loeb
years old now. It does not have any antenna jack, like a scanner
would. It has one jack port, about 3.5mm size labeled AM ext. The unit
has a extending vertical antenna. I think there might be a tiny screw
to remove the antenna, but otherwise its not designed to come off. I
would like to add on a good antenna (or build one myself ;-) in the
back yard, but I'm not sure how far I'll get without an antenna jack.
Can I simply solder the new antenna feeds to the extending vertical
one? My guess is no? The AM jack is for AM bands only (and shortwave
is usally FM?)? Should I remove the existing antenna? The manual on
this unit is long gone. Unit still seems to work well, no shortage of
variety programming on a good evening. However, tends to have static,
and who knows what I'm missing. I guess I should mention that I'm
primarily interested in short wave bands used for international
broadcast. I plan to upgrade the unit in a year or so, but until then I
thought a good antenna would help, but I'm at a loss as to where to feed
it into the unit.
BTW, if you don't think the unit would benefit from a better antenna
anyway, let me know and I'll save myself the trouble. But since I'm
studdying for Technician Liscense anyway, I though this would also be a
low expense way of jumping into the world of antenna building/setup,
before things get 'serious'.
P.S. If the above answer is affirmative, if you'd also like to suggest
some sites for info on simple SW band antennas that would complement the
receiver well (particularly homemade) for backyard use, I'd appreciate
that too.
Thanks
Doug Smith
<rloeb...@cticonsulting.net> wrote:
>Hi, I have a Realistic DX-390 (short wave receiver), must be around 10
>years old now. It does not have any antenna jack, like a scanner
>would. It has one jack port, about 3.5mm size labeled AM ext. The unit
>has a extending vertical antenna. I think there might be a tiny screw
>to remove the antenna, but otherwise its not designed to come off. I
>would like to add on a good antenna (or build one myself ;-) in the
>back yard, but I'm not sure how far I'll get without an antenna jack.
The "AM ext." jack may well be for an external antenna.
But an alternative is to simply wrap the leadin wire from whatever external
antenna you use around the builtin antenna.
>(and shortwave is usally FM?)?
No, shortwave is usually AM.
> If the above answer is affirmative, if you'd also like to suggest some
>sites for info on simple SW band antennas that would complement the
>receiver well (particularly homemade) for backyard use, I'd appreciate that
>too. Thanks
A good general rule is as much wire as possible, as high in the air as
possible, and as far from obstructions as possible. Really, you don't have
to worry about much more than that.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com
Due to excessive spam, messages from uu.net are deleted unread.
Gray Shockley
> Hi, I have a Realistic DX-390 (short wave receiver), must be around 10
> years old now. It does not have any antenna jack, like a scanner
> would. It has one jack port, about 3.5mm size labeled AM ext.
Bingo! That's the antenna jack for shortwave. My /guess/ as to why it's
labeled "AM" is to keep people from thinking it's for the 88-108 mHz "FM
Band".
> The unit
> has a extending vertical antenna. I think there might be a tiny screw
> to remove the antenna, but otherwise its not designed to come off. I
> would like to add on a good antenna (or build one myself ;-) in the
> back yard, but I'm not sure how far I'll get without an antenna jack.
> Can I simply solder the new antenna feeds to the extending vertical
> one? My guess is no? The AM jack is for AM bands only (and shortwave
> is usally FM?)?
No, shortwave is generally AM or one of its variants "Single Side Band"
(SSB). SSB - this is really simplified but it should do - is obtained by
suppressing the carrier and leaving a "sideband" on either "side" of what
would have been a "normal" AM signal.
SSB is divided into Upper Sideband (USB) and Lower Sideband (LSB). On the
your 390, you would tune onto a station that's broadcasting sideband, turnh
on your "BFO" (front panel - lower right if it's the same place as on my
DX-392).
Others here can explain SSB much better than I and explain "zero-beating" and
such.
> Should I remove the existing antenna? The manual on
> this unit is long gone.
You can get one from RadioShack. Also, you can get most (all?) of the manual
at www.radioshack.com (last time I was up there, the site was still being
"renewed" and it was difficult to navigate).
> Unit still seems to work well, no shortage of
> variety programming on a good evening. However, tends to have static,
> and who knows what I'm missing. I guess I should mention that I'm
> primarily interested in short wave bands used for international
> broadcast.
Ah! So - for the most part - AM is all you need.
> I plan to upgrade the unit in a year or so, but until then I
> thought a good antenna would help, but I'm at a loss as to where to feed
> it into the unit.
As above.
Btw, you may well find it very difficult to upgrade without spending quite a
bit of $$$. The DX-390 is a very good SW receiver.
> BTW, if you don't think the unit would benefit from a better antenna
> anyway, let me know and I'll save myself the trouble.
$9.95 at RadioShack. Seventy feet of copper stranded wire and the necessary
insulators and lead in. Add a 6 to 8 foot ground rod (do NOT buy at
RadioShack - this is one of the things they charge WAY too much - usually
about half RS's price at a local hardware store). Rub the wire from the end
of the seventy foot longwire to the "tip" of an 1/8" plug (so-called "Sony
Plug"). Just a mono mini-phone plug. Run the ground wire to the sleeve.
> But since I'm
> studdying for Technician Liscense anyway, I though this would also be a
> low expense way of jumping into the world of antenna building/setup,
> before things get 'serious'.
> P.S. If the above answer is affirmative, if you'd also like to suggest
> some sites for info on simple SW band antennas that would complement the
> receiver well (particularly homemade) for backyard use, I'd appreciate
> that too.
> Thanks
Hope this helps.
Gray
--------------------------
Gray Shockley
Entropy Maintenance Technician
Tao Chemical Company
--------------------------
gr...@compcomm.com
http://www.compcomm.com/
Vicksburg, Mississippi US
The Johnsons
where you would connect an SW antenna. In fact, I am listening to mine right
now on the 75mtr band. I am using a small table top SW loop (by Ed. W / Edek
Electronics) with an assist by a little amp. Works really well. The DX-390,
like nearly all Sangean radios, have poor sensitivity off the whip and need some
kind of external boost.
Russ K3PI
Dwight Stewart
>
> Hi, I have a Realistic DX-390 (short
> wave receiver), must be around 10
> years old now. It does not have
> any antenna jack, like a scanner
> would. It has one jack port, about
> 3.5mm size labeled AM ext.
The green "AM EXT ANT" jack is the antenna input jack. You can plug
any external shortwave antenna (amplified or non-amplified) into this
jack, assuming the antenna feedline has a 3.5mm mono plug. If your
antenna feedline doesn't have this plug, simply replace the connector
on that feedline, or use an adapter to convert the existing connector
to a 3.5mm plug. If you intend to use heavy coax as a feedline, make
a short jumper, using lighter coax (RG-174U for example), from the
radio to the floor to take the weight of the heavy coax off the small
jack on the radio.
By the way, as Doug has already said, most shortwave activity is AM,
not FM. FM reception on this radio is handled by the telescoping whip
(the AM antenna is inside the radio). And, yes, an external antenna
will be a great improvement (especially if you're using nothing more
than the internal antenna now).
Dwight Stewart (W5NET)
Ron or Midgie Bardo
old Rat Shack active antenna, model mumber 20-280. I have had my 390
for about 8 years and the said antenna for about as long. Both work
quite fine for me.
For BCB stuff, you could use the Select-a-tenna, whith I do not have,
or the Rat Shack AM loop, #15-1853. That sells for $29.95, at lest
that is what paid for it, The amplified antenna I believe has been
discontinued.
As a side note, the Rat shack loop has a significant effect on the
390 (greatly increases gain), but little effect on GE SR III, other to
null out noise, which also does have it benefits.
Hope this helps.
Ron Bardo <rmb...@chartermi.net>
In article <slrn9cdcj...@linux1.localdomain>, Doug Smith
CW
--
CW
KC7NOD
www.kc7nod.20m.com
"Randon Loeb" <rloeb...@cticonsulting.net> wrote in message
news:3AC6B001...@cticonsulting.net...
Randon Loeb
1. DX-390, despite its age, is a still a decent unit.
2. The jack is indeed for an external antenna!
3. With $10 from RS I can increase the reception (I saw this at RS the
other day, but wanted to wait for resonses on this list first)
A few more questions though:
1. With wire like the one from RS, does orientation matter?
2. Is there also a relatively inexpensive amplifier that would also
help?
3. Grounding rod- if it's 8', how much of that sticks out of the
ground--iow how much is burried? And can several antennas share the
same grounding rod?
Bill Meacham
>
> A few more questions though:
> 1. With wire like the one from RS, does orientation matter?
Very unlikely that you would notice any difference.
> 2. Is there also a relatively inexpensive amplifier that would also
> help?
I'm not a fan of receiving pre-amplifiers for SW bands...I'll let
somebody with more experience using them elaborate.
> 3. Grounding rod- if it's 8', how much of that sticks out of the
> ground--iow how much is burried? And can several antennas share the
> same grounding rod?
Ideally, all 8 feet should be in the ground. Thats not always
easy. But if you can only drive a rod 5 feet in your soil, then
save a buck and buy a 5 foot rod and eliminate 3 feet of ugly rod
sticking out of the dirt. Yes, it SHOULD BE a common ground for
all of your antennas and whatever equipment grounds you may have.
Good luck,
Bill
NEWS
has 3 large windows facing west in Chicago. I bought a spool of thin coated
wire of about 100 ft. I soldered the approriate size connector to one end
and then draped the wire on my blinds going back and forth until it was all
used up. Everything is inernal.I attached the wires with alligator clips.
I'm impressed with the reception. I don't know if more distance on the wire
would improve reception or not. The whole thing was pretty inexpensive.
$10. I was cautioned about amplifying the sound in terms of damaging
circuitry. I had used a RS amplifier for SW before, but the current setup
seems to work best. I only have a western exposure and wonder what would
happen if I could lay wire NS. Also, I'm assuming this is as safe as an
internal TV antenna.
CW
need no further amplification. As a matter of fact, overload may be a
problem under some circumstances. An attenuator would be a good idea. You
probably won't need it most of the time, but when you do you will be glad
you have it. One can be found on my site.
--
CW
KC7NOD
www.kc7nod.20m.com
"Bill Meacham" <NOSPA...@coqui.net> wrote in message
news:3AC8C34C...@coqui.net...