Colin,
I guess it depends on where the noise is coming from. If it's in the
receiver itself, you might be able to use a preamp to get the signal above
the noise floor, but if it's in the atmosphere, it's just another signal and
the preamp won't help. I have a feeling that most preamps are included just
to make customers feel better by boosting S-meter readings. I've seen cases
where they help, but like any other tool, you have to know when to use them.
Steve
----- Original Message -----
From: "colin McDonald" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 26, 2011 13:41
Subject: Re: Really Big Transmitters
>I know on HF and LW frequencies, space is obviously an issue and that's why
> this antenna is desireable.
> However, would this antenna be better than say a discone, or even a
> quarter
> wave vertical on frequencies above 100MHZ?
> One has to wonder.
> I mean, if this thing can pull signals out on the VHF band that would be
> unreadable with a quarter wave or 5/8's wave, then definitely worth the
> investment I think.
> For a scanner or wide band receiver anyway.
> I find most preamps merely increase the noise level of the noise floor,
> and
> don't do anything to actually increase the quality of the signal. Sort of
> like having an extra volume control that introduces other unwanted
> variables
> into the signal path.
> Yes, it'll make the S meter go up, but that is a factor of the entire
> noise
> floor being raised up including the faint signal.
> Perhaps I've never used a really good preamp, but if I hear a signal, then
> turn on the preamp, I don't hear the signal any better than before, just
> louder audio.
> even in radios like the ts2000, the preamp seems to just increase the
> noise
> floor and boost up the signals audio and not the actual signal itself.
> Perhaps they make preamps now that focus on digging the signal out and
> amplifying what you want to hear instead of everything around it.
> 73
> Colin, V A6BKX
> ----- Original Message -----
> From: "Martin McCormick" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, January 26, 2011 9:35 AM
> Subject: Re: Really Big Transmitters
>
>
>> Maybe we should change the subject line to Really Little
>> Antennas. I don't know anything about that particular antenna,
>> but amplified or active antennas have been around for a while
>> and keep getting better mainly due to FET amplifiers with lower
>> and lower noise figures.
>>
>> The only down side to an antenna like this is that when
>> you use it indoors, it is going to pick up all the crud from all
>> the gear you are running so you will have an even better way of
>> listening to your switching power supply, that little switching
>> circuit that makes compact fluorescent lamps go and lots of
>> other hash generators.
>>
>> Also, if you live near a very powerful AM or FM radio
>> station, you might discover that the powerful transmitter
>> overloads the preamp in the antenna which could cause you grief
>> by creating lots of mixing products far away from the frequency
>> you are trying to hear.
>>
>> If you have a relatively quiet location, this antenna is
>> probably fine.
>>
>> It sounds kind of interesting so let us know if you get
>> one and listen through it.
>> Russ Kiehne writes:
>>> The reason I ask, do you know anything about the following antenna?
>>> The AOR LA390
>
|
