Hello,

Not an antenna expert, so thought I'd ask here.
I've gotten some great info. from you folks in the past, which I really
appreciate.

Will be buying a portable sw receiver for a gift.

Many of them seem to come with a built in telescopic antenna.
I guess the intent is to use fully extended, and vertically, although
horiz. use also seems to be doable from the pictures, but would sure be
awkward in a horiz. position I would think.

How "good" can one receive 30 MHz (and the normal fm broadcast bands)
using one of these antenna vertically ?

Aren't most sw signals horiz. polarized, or, by the time they actually
make it here, the polarization has become pretty much randomized ?

Will try with a "lon'wire" of course, but thought I'd ask re how good
the built in antennas, vert. oriented, are as a general question.

BTW: anyone have any strong opinions on a good $ 250 max table top
(preferred)or portable sw receiver for a very non-technical person ?
Would want it to have memories. SSB not necessary.

Thanks,
Bob

On Sun, 08 Aug 2010 08:56:33 -0400, Bob wrote:

How "good" can one receive 30 MHz (and the normal fm broadcast bands)
using one of these antenna vertically ?

Hi Bob,

How good? Not very.

They will pull in the extremely powerful stations, but if you expected
to pick up a particular one, then you have every chance of failing.

Aren't most sw signals horiz. polarized, or, by the time they actually
make it here, the polarization has become pretty much randomized ?

Yes.

Will try with a "lon'wire" of course, but thought I'd ask re how good
the built in antennas, vert. oriented, are as a general question.

I have been a SWLer since the late 50s. Sometimes I was in the middle
of it, sometimes at the margins. Let me explain.

Here in Seattle, most of Europe is over the magnetic pole which makes
for miserable reception - others may have better experience. I have
had scant reception of Africa, outside of Radio South Africa (I was a
club member in the 60s). I had a very different experience with
Africa that I will describe in response to your next question below:

BTW: anyone have any strong opinions on a good $ 250 max table top
(preferred)or portable sw receiver for a very non-technical person ?
Would want it to have memories. SSB not necessary.

I took a digital tuned SW radio (available from Radio Shack for $35)
to South Africa and casually tuned the bands there. With its whip
extended it was pretty boring, but it certainly had more signals than
I could hear from in Seattle. I came prepared for underwhelming
reception, however. Before expanding on this reception statement, I
would point out that "table top" radios are filled mostly with air so
that they can be big enough to call "table top." My $35 radio was the
size of a large paper back book. I have a $200 radio shack radio that
I suspect offers no better performance, but is too large for
intercontinental travel.

When we went to Africa, I brought along 30 feet of wire wrap wire with
an alligator clip on one end, and a quarter taped to the other. I
tossed the quarter over the rafters in our "hut" (built to 4 star
guest expectations) or into the canopy of the trees (the height was
never more than a dozen feet or so) and tuned in:

Shortwave in Zulu Natal
freq Time Station
MHz GMT
3.26 2214 BBC
African Interviews
4.97 2220 Radio Christian Voice
5.10 2225 BBC
African Interviews
5.92 2226
African Music
Arabic talk radio
6.07 0610 Radio Christian Voice
6.15 0615 BBC
in Russian
6.20 0615
in English
6.17 2200 Zambia N C
News in English
6.225 2205 DW
News in English
5.83 2207
Arabic music pgm
5.85 2209 CBC
English
5.87 2210
Arabic
5.89 2215 Vatican Radio
News in English
5.92 2220
Round Table in African
7.125 2226 DW
News in English
7.195 2228 DW
News in English
7.28 2113
Pgm in Chinese
9.50 2118 DW
Pgm in Arabic
9.53 2119
Pgm in Russian
9.60 2121
Pgm in French
9.74 2136 Family Radio
Pgm in Arabic
9.79 2146
African moder music pgm
12.035 0555 BBC
News in English
12.785 0600 RFI
News in English
12.865 0605 RFI
News in English
13.69 0607 RFI
News in English
13.775 0609 Vatican Radio
News in English
14.18 0611
"Sherlock Holmes"
14.29 0615

14.345 0617
Music pgm. in Arabic
14.395 0620
Pgm. in French
14.445 0624 CRI (China)
News in English
14.51 BBC
News
14.56 0629 CRI (China)
News in English
10.000 0630 WWV
Time signal
15.000 0630 WWV
Time signal
15.10 0632
Arabic music pgm.
15.11 0632 Kuwait?
English pgm.

********

Shortwave in Simonstown
freq Time Station
MHz GMT
4.935 2214 VOA
African music pgm
4.935 0529 VOA
African news pgm
5.98 0537
African music pgm
9.64 0547
News pgm. In French
9.69 0549
News pgm. In French
11.65 1536 DW
African music pgm.
12.71 1600 VOA
African music pgm.
13.66 1623 Family Radio
Arabic pgm.

I could have listened to so MUCH more, but I took the time to linger
and try to pick up a call or interval signal.

There was more radio-activity on SW there, than on AM here; but I had
to be there (a lot of this stuff was low power as you might imagine).

The bottom line is, cheap does pretty good if you know the limitations
(the whip) and how to overcome them (a penny worth of wire). And,
yes, it has memories (probably the simplest thing that could be done
for cheap and digital).

More could be said.

73's
Richard Clark, KB7QHC

On Aug 8, 8:56*am, Bob wrote:
Hello,

Not an antenna expert, so thought I'd ask here.
I've gotten some great info. from you folks in the past, which I really
appreciate.

Will be buying a portable sw receiver for a gift.

Many of them seem to come with a built in telescopic antenna.
I guess the intent is to use fully extended, and vertically, although
horiz. use also seems to be doable from the pictures, but would sure be
awkward in a horiz. position I would think.

How "good" can one receive 30 MHz (and the normal fm broadcast bands)
using one of these antenna vertically ?

Aren't most sw signals horiz. polarized, or, by the time they actually
make it here, the polarization has become pretty much randomized ?

Will try with a "lon'wire" of course, but thought I'd ask re how good
the built in antennas, vert. oriented, are as a general question.

BTW: *anyone have any strong opinions on a good $ 250 max table top
(preferred)or portable sw receiver for a very non-technical person ?
Would want it to have memories. *SSB not necessary.

The front end of many of these portable SW radios is typically "hot"
and has no problem hearing band noise with just the built-in antenna.
That doesn't mean that it's the world's most perfect antenna, it won't
hear nearly as good as something 100 feet up in the air, but it's fine
for the flamethrower SW stations.

But if you attach a longwire... you may find that you have intermod
issues with local AM/FM broadcasters. The front end in most of these
portable SW radios has very little preselection so they're susceptible
especially once you raise the local broadcasters to the level of
hundreds of millivolts. A tuner of some kind will help here.

Tim N3QE