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Is there such a things as an antenna that will get me everything from HF to VHF with reasonable strength?
I have a BNC telescope antenna ..
M. Hamed wrote:
Is there such a things as an antenna that will get me everything from HF to VHF with reasonable strength?
** Yep.
No.
I have a BNC telescope antenna ..
** Connected to what exactly ??
.... Phil
Phil Allison
M. Hamed wrote:
Is there such a things as an antenna that will get me everything from HF to VHF with reasonable strength?
** Yep.
No.
Is there such a things as an antenna that will get me everything from HF
to VHF with reasonable strength?
I have a BNC telescope antenna that seems to get FM broadcast and higher
but very little once you start going below 100 MHz.
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Are there limitations on that gizmo?
On Sun, 28 Sep 2014 10:55:57 -0700, M. Hamed <mhdpublic@gmail.com> wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get signals
from the FM broadcast band well to 950MHz or even higher with one Antenna.
Now if I want to receive HF, do I have any other options besides these huge
monster antennas?
Again, it ALL depends on your noise floor and the signal strength. A 1 inch
wire is an adequate antenna *if* the signal is 'decent'.
A litle ferrite rod works very nicely down around 1MHz [AM Radio]
On Sun, 28 Sep 2014, RobertMacy wrote:
On Sun, 28 Sep 2014 10:55:57 -0700, M. Hamed <mhdpublic@gmail.com
wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Again, it ALL depends on your noise floor and the signal strength. A 1
inch wire is an adequate antenna *if* the signal is 'decent'.
A litle ferrite rod works very nicely down around 1MHz [AM Radio]
Of course, there's quite a bit of wire in there.
Car radios did the same thing in the old days, attach the antenna to the
very high impedance point of a tuned circuit. That's why they needed
that special cable between the antenna and the radio, and that trimmer
that lessened the loading of the cable on the tuned circuit (or was it
to compensate for the extra capacitance in that tuned circuit caused by
the cable and antenna?).
It got rid of the direcionality of the loop, and the whip antenna acted
like a "probe" to get the signal into the radio.
In effect, an early "active antenna", though by the time those came into
being about the seventies, they used high impedance devices to transform
the high impedance very low voltage signal from the whip into something
the rest of the radio could handle. Eliminates the tuning, which makes
it broad, though probably extra front end tuning could help some radios.
A lot or maybe most of the shortwave portables on the market have that
stage of high impedance buffer so things work better with the built in
antenna.
When I first read about them, in 1973 or 74, it was called a "voltagOn Sun, 28 Sep 2014 20:31:30 -0400, Michael Black wrote:
On Sun, 28 Sep 2014, RobertMacy wrote:
On Sun, 28 Sep 2014 10:55:57 -0700, M. Hamed <mhdpublic@gmail.com
wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Again, it ALL depends on your noise floor and the signal strength. A 1
inch wire is an adequate antenna *if* the signal is 'decent'.
A litle ferrite rod works very nicely down around 1MHz [AM Radio]
Of course, there's quite a bit of wire in there.
Car radios did the same thing in the old days, attach the antenna to the
very high impedance point of a tuned circuit. That's why they needed
that special cable between the antenna and the radio, and that trimmer
that lessened the loading of the cable on the tuned circuit (or was it
to compensate for the extra capacitance in that tuned circuit caused by
the cable and antenna?).
It got rid of the direcionality of the loop, and the whip antenna acted
like a "probe" to get the signal into the radio.
In effect, an early "active antenna", though by the time those came into
being about the seventies, they used high impedance devices to transform
the high impedance very low voltage signal from the whip into something
the rest of the radio could handle. Eliminates the tuning, which makes
it broad, though probably extra front end tuning could help some radios.
A lot or maybe most of the shortwave portables on the market have that
stage of high impedance buffer so things work better with the built in
antenna.
I built one of those probes in the mid eighties, from precious little
knowledge (no Internet yet, then).
It was little more than a yard-long whip antenna with a whisp of resistor
to ground, going into the gate of an MPF-102 set up as a source follower.
That was in the box with the antenna -- from that point on it was just
RJ-58 to the radio several yards away.
It worked great on the roof of the university electronics building,
although from my house all it picked up was the nearest electric fence.
Good FETs such as the BF862 are astonishingly quiet, so if you don'tOn Sun, 28 Sep 2014 20:31:30 -0400, Michael Black wrote:
On Sun, 28 Sep 2014, RobertMacy wrote:
On Sun, 28 Sep 2014 10:55:57 -0700, M. Hamed <mhdpublic@gmail.com
wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Again, it ALL depends on your noise floor and the signal strength. A 1
inch wire is an adequate antenna *if* the signal is 'decent'.
A litle ferrite rod works very nicely down around 1MHz [AM Radio]
Of course, there's quite a bit of wire in there.
Car radios did the same thing in the old days, attach the antenna to the
very high impedance point of a tuned circuit. That's why they needed
that special cable between the antenna and the radio, and that trimmer
that lessened the loading of the cable on the tuned circuit (or was it
to compensate for the extra capacitance in that tuned circuit caused by
the cable and antenna?).
It got rid of the direcionality of the loop, and the whip antenna acted
like a "probe" to get the signal into the radio.
In effect, an early "active antenna", though by the time those came into
being about the seventies, they used high impedance devices to transform
the high impedance very low voltage signal from the whip into something
the rest of the radio could handle. Eliminates the tuning, which makes
it broad, though probably extra front end tuning could help some radios.
A lot or maybe most of the shortwave portables on the market have that
stage of high impedance buffer so things work better with the built in
antenna.
I built one of those probes in the mid eighties, from precious little
knowledge (no Internet yet, then).
It was little more than a yard-long whip antenna with a whisp of resistor
to ground, going into the gate of an MPF-102 set up as a source follower.
That was in the box with the antenna -- from that point on it was just
RJ-58 to the radio several yards away.
It worked great on the roof of the university electronics building,
although from my house all it picked up was the nearest electric fence.
On 9/29/2014 1:03 PM, Tim Wescott wrote:
On Sun, 28 Sep 2014 20:31:30 -0400, Michael Black wrote:
On Sun, 28 Sep 2014, RobertMacy wrote:
On Sun, 28 Sep 2014 10:55:57 -0700, M. Hamed <mhdpublic@gmail.com
wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher
with one Antenna.
Now if I want to receive HF, do I have any other options besides
these huge monster antennas?
Again, it ALL depends on your noise floor and the signal strength. A
1 inch wire is an adequate antenna *if* the signal is 'decent'.
A litle ferrite rod works very nicely down around 1MHz [AM Radio]
Of course, there's quite a bit of wire in there.
Car radios did the same thing in the old days, attach the antenna to
the very high impedance point of a tuned circuit. That's why they
needed that special cable between the antenna and the radio, and that
trimmer that lessened the loading of the cable on the tuned circuit
(or was it to compensate for the extra capacitance in that tuned
circuit caused by the cable and antenna?).
It got rid of the direcionality of the loop, and the whip antenna
acted like a "probe" to get the signal into the radio.
In effect, an early "active antenna", though by the time those came
into being about the seventies, they used high impedance devices to
transform the high impedance very low voltage signal from the whip
into something the rest of the radio could handle. Eliminates the
tuning, which makes it broad, though probably extra front end tuning
could help some radios.
A lot or maybe most of the shortwave portables on the market have that
stage of high impedance buffer so things work better with the built in
antenna.
I built one of those probes in the mid eighties, from precious little
knowledge (no Internet yet, then).
It was little more than a yard-long whip antenna with a whisp of
resistor to ground, going into the gate of an MPF-102 set up as a
source follower.
That was in the box with the antenna -- from that point on it was just
RJ-58 to the radio several yards away.
It worked great on the roof of the university electronics building,
although from my house all it picked up was the nearest electric fence.
Good FETs such as the BF862 are astonishingly quiet, so if you don't
overdrive them, they ought to do a very good job even from a crappy
high-Z mess of an antenna.
On Sun, 28 Sep 2014, M. Hamed wrote:
Ok so the short answer is no. I have an RTL-SDR stick and I can get
signals from the FM broadcast band well to 950MHz or even higher with
one Antenna.
Now if I want to receive HF, do I have any other options besides these
huge monster antennas?
Are there limitations on that gizmo?
I don't know, but some people are playing with things intended for UK TV,
a little USB gizmo. And since they are intended for tv, they suffer at
lower frequencies because they weren't designed for low frequencies. So
one issue perhaps is that performance rolls off below a certain frequency.
At VHF and UHF, as someone pointed out, short antennas are full length
antennas. Of course, just because an antenna at a given frequency
receives signals doesn't mean it's very good. If you want gain from the
antenna, you have to have a bigger antenna.
At low frequencies, you may not have much gain, even if the antenna is
large. It depends where in the HF spectrum, 10MHz a dipole is reasonably
short, at 3MHz it would be quite a big larger. And in both cases, you
only get a bit of gain, you'd have to double them to double antenna gain,
and so on.
People have given suggestions. Forty years ago, I don't remember have
much trouble receiving shortwave with an SP-600 and a random length of
wire connected to the antenna. That was a long time ago, I'm not sure if
it was the receiver or maybe just that there were so many signals, it
didn't take much to still receive quite a few. I notice now, I have to
take my shortwave receivers (with whip antennas) to the window in order to
get much signal strength on signals, the house has become too well
shielded, and likely also, there are all kinds of devices plugged in that
generate noise, so the incoming signals have to be stronger than forty
years go to be noticed.
I built one of those probes in the mid eighties, from precious little
knowledge (no Internet yet, then).
It was little more than a yard-long whip antenna with a whisp of resistor
to ground, going into the gate of an MPF-102 set up as a source follower.
That was in the box with the antenna -- from that point on it was just
RJ-58 to the radio several yards away.
It worked great on the roof of the university electronics building,
although from my house all it picked up was the nearest electric fence.