Hello all,

It is nearing Christmas time and I am preparing my wish list for the
family. Before I put one on my list I would like some of your opinions on
pre-selectors. I am mainly looking at the MFJ line. If any of you have any
of these products I would be interested in hearing how you ell about them.
With this in mind I also need to let you know that I wish to enhance my
listening abilities, *NOT* make it an overly complex task. Some of these
look as though I could spend hours fiddling and not be able to take the time
to listen.

As usual your help is always appreciated.

Regards

Tim

Tim ODonnell wrote:

Hello all,

It is nearing Christmas time and I am preparing my wish list for the
family. Before I put one on my list I would like some of your opinions on
pre-selectors. I am mainly looking at the MFJ line. If any of you have any
of these products I would be interested in hearing how you ell about them.
With this in mind I also need to let you know that I wish to enhance my
listening abilities, *NOT* make it an overly complex task. Some of these
look as though I could spend hours fiddling and not be able to take the time
to listen.

As usual your help is always appreciated.

Regards

Tim

Why do you think you need a preselector?


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This may be a bit naive of me but I just want to get the best reception that
I can. I have read some of the advertisements and a few reviews of
pre-selectors and everyone said that the helped reduce noise, and aided in
better reception. Now if these are a gimmick to grab your bucks then please
enlighten me. I really thought that they were common-place in peoples
shacks? Your question makes me think otherwise.

I also use a Sony AN-LP1 antena with my portable when traveling. This is an
active loop with a pre-selector. It is better than the whip with my DX398
and sometimes by tuning the pre-selector off band I can reduce gain and
noise and get a bit better reception or audibility.

So now my question is this. Is my thinking off? I just want the best
reception that I can get. I just thought that a pre-selector might help.
Like Dan said below I really don't expect to use it all the time. Just when
it may help.

Regards

Tim

"starman" wrote in message
...

Why do you think you need a preselector?

Tim ODonnell wrote:
So now my question is this. Is my thinking off? I just want the best
reception that I can get. I just thought that a pre-selector might help.
Like Dan said below I really don't expect to use it all the time. Just when
it may help.

You can hear down to the internal noise of the receiver. If the antenna brings the
propagating noise up over that level, no further improvement in the antenna will help,
except making it directional to favor signal or disfavor noise, if noise is directional.

Modern receivers are very sensitive, but tend to succumb to overload and cross modulation
that results (hearing anything loud in lots of places instead of the one it's at).

A preselector kills off loud things that aren't where you want to listen, giving you
the ability to get a little bigger antenna to work for you, up until it exceeds the
internal noise, and then a bigger antenna doesn't help again.

So you get the possibly small improvement between hearing propagating noise and
the intermodulation limit somewhat expanded, is all. The usual experience though
is that the preselector ``reduces the signal,'' because you tend to compare it with
the big antenna without preselector and not the built-in whip.

They put a preselector on some active antennas because of the intermodulation; other
active antennas (McKay Dymek DA100E) have lots of headroom and don't need the
preselector, and so you don't have to tune it. It may still overload your receiver
though, for instance almost any portable; and then you have to add a preselector
because of the receiver. It doesn't overload an R8B.
--
Ron Hardin


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

Ron Hardin wrote in message ...
Tim ODonnell wrote:
So now my question is this. Is my thinking off? I just want the best
reception that I can get. I just thought that a pre-selector might help.
Like Dan said below I really don't expect to use it all the time. Just when
it may help.

You can hear down to the internal noise of the receiver. If the
antenna brings the propagating noise up over that level, no further
improvement in the antenna will help, except making it directional
to favor signal or disfavor noise, if noise is directional.


RH,

So What Is Your Choices: (Why? -v- Why Not?)

[ ] Continue to use a simple Random Wire Antenna
and ADD a "Pre-Selector" to make it 'better'.

[ ] First improve your old antenna and try rebuilding/replacing
it into a "Low Noise" Antenna a la John Doty.

~ RHF



Modern receivers are very sensitive, but tend to succumb to overload and cross modulation
that results (hearing anything loud in lots of places instead of the one it's at).

A preselector kills off loud things that aren't where you want to listen, giving you
the ability to get a little bigger antenna to work for you, up until it exceeds the
internal noise, and then a bigger antenna doesn't help again.

So you get the possibly small improvement between hearing propagating noise and
the intermodulation limit somewhat expanded, is all. The usual experience though
is that the preselector ``reduces the signal,'' because you tend to compare it with
the big antenna without preselector and not the built-in whip.

They put a preselector on some active antennas because of the intermodulation; other
active antennas (McKay Dymek DA100E) have lots of headroom and don't need the
preselector, and so you don't have to tune it. It may still overload your receiver
though, for instance almost any portable; and then you have to add a preselector
because of the receiver. It doesn't overload an R8B.

RHF wrote:
So What Is Your Choices: (Why? -v- Why Not?)

[ ] Continue to use a simple Random Wire Antenna
and ADD a "Pre-Selector" to make it 'better'.

[ ] First improve your old antenna and try rebuilding/replacing
it into a "Low Noise" Antenna a la John Doty.

I'd always go to a low noise antenna; I do it myself on MW chiefly by
using pairs of outdoor active antennas combined in an ANC-4; it's low
noise because it's outdoors on buried coax, and I can steer a null on
an interference source. It works on locally-generated interference (ie.
not skywave) on any frequency, but skywave only on the low end of the
MW band. But on MW weak signals aren't much of a problem compared to
competing stations.

A broadband active loop plus a co-located active whip does the same thing
without taking any real estate, combined in and ANC-4. Its nulls are a
steerable V shape from one double-null endfire to the other, ``endfire''
being in the plane of the loop (its stand-alone maximum). With two whips
instead of a whip and a loop, endfire is in the direction of separation
of the whips (give it a quarter wave if you can) and you get the same V shape.

Lots of people use passive antennas instead of active in the same arrangement.

I don't go in much for a low-noise _single_ antenna because I'm never trying to
dig out a really weak signal, just one that's weaker than competition.

If your receiver overloads (mine doesn't) you'll have to use a preselector in any
case.
--
Ron Hardin


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

Why do you think you need a preselector?


Good question..

IF you use an antenna amp, the Preselector can go in between the
pre selector & the radio.
If you have continuous overload problems, Then maybe you need one.
I do have one, ( MFJ 1046 ) have had it hooked up for years
but rarely use it except on pass-thru mode..

Dan

In article , "Al - KA5JGV"
writes:


Personally I wouldn't bother with a preselector. The slight improvement is
not worth the cost, the additional knob tweaking required, or the lost space
taken up by it. If you are having problems with overloads, save the
preselector money and invest it into a better receiver.

Al KA5JGV

- I've rarely used mine ( Except with the cheap one IF sets)
- But they look Cool As Hell

If they had a blinking light to show how the'd saved your set from overload
they'd sell a million

ToD,

Pre-Selectors: Do They Work ?
- Sometimes Yes )
- - Sometimes NO ;-{

MFJ makes many Antenna Tuners and Pre-Selectors.

1. Some are for SWL "Receive Only" Use.
* MFJ-956
* MFJ-959C
* MFJ-1020C (Active Antenna & External Antenna Pre-Selector)

2. Many others are for HAMs who are using them with Transmitters.
- - - If devise has a SWR-Meter, Inductor or Delay Function then it is
a HAM type unit.
* MFJ-901B
* MFJ-904
* MFJ-1040B (Active Antenna & External Antenna Pre-Selector)
* MFJ-1048
* MFJ-949
* MFJ-901B

3. If you have 'noise' problems in your area/location; then consider a
"Passive" Pre-Selector (NO built-in Amplifier).
* MFJ-1045C
* MFJ-1026 (Noise Cancelling Antenna)

4. If you do NOT have 'noise' problems in your area/location the
consider an "Active" Pre-Selector (with a built-in Amplifier).
* MFJ-959C

TBL: When it comes to Pre-Selectors:
- Can't Hertz ;-{
- - Just Mitz Help )
It is better to focus on your Antenna
and Spend your Time & Money there first.


iane ~ RHF
..
..
= = = "Tim ODonnell"
= = = wrote in message .. .
Hello all,

It is nearing Christmas time and I am preparing my wish list for the
family. Before I put one on my list I would like some of your opinions on
pre-selectors. I am mainly looking at the MFJ line. If any of you have any
of these products I would be interested in hearing how you ell about them.
With this in mind I also need to let you know that I wish to enhance my
listening abilities, *NOT* make it an overly complex task. Some of these
look as though I could spend hours fiddling and not be able to take the time
to listen.

As usual your help is always appreciated.

Regards

Tim


..