Tuner or Preselector?

[riverrat373]

What's the difference between a SWL tuner and a preselector?

 

[ka3jjz]

We have sections covering both in this article...

Improving HF Reception - The RadioReference Wiki

Mike

 

[Boombox]

Short answer: one is active, the other is passive.

And other differences, too, but that's the biggest difference that comes to mind.

 

[ka3jjz]

There's a lot more to it than that - read the article and you'll understand better...Mike

 

[pjxii]

There's a lot more to it than that - read the article and you'll understand better...Mike

That's a very good article that will explain a lot, well worth reading.

 

[WA8ZTZ]

The term "tuner" has come to mean just about any device with knobs placed between the antenna and the receiver. The linked article does help to clear up the confusion.

Perhaps the best name for a tuning device placed right at the antenna feed point should be an antenna coupler.

 

[ka3jjz]

I think that's what SGC calls theirs...Mike

 

[riverrat373]

I guess what I'm looking for is a transmatch. I use an Icom R-75 receiver for shortwave listening with a Par end fed shortwave antenna and a 100' long random wire antenna. I am wondering if a MFJ-959 "antenna tuner" would help reception, especially with the random wire?

 

[ka3jjz]

Leave it off the PAR; the 100 foot MIGHT benefit from the transmatch at times,and at times it might not. Every RF environment is different and generalizations are all that you can do

Actually you shouldn't even need a transmatch, really. Those are potentially useful when you are using a less than efficient antenna, or on one that isn't working well on a particular band. But keep in mind that propagation isn't really doing well lately. You're better off experimenting with other antennas, not spending money on a transmatch. If something is not working on a particular band with one antenna, then switch to the other.

Mike

 

[majoco]

IMHO as soon as you use a bit of coax from your antenna down to your receiver where you have installed your "tuner", you have nullified any tuning effect. As mention by Mike and the article, the tuner tunes the antenna - if your antenna finishes at a matching transformer up on your roof or wherever then there's no point in trying to 'tune' it at the bottom of the coax. You may make some form of preselector but that's about all.

Bring the end of a long wire down into your room and directly to the tuner - no coax - then you can 'tune' the whole antenna.

 

[ka3jjz]

If the transmatch is at the station position, it will attempt to tune the antenna and, if the antenna uses this, the feedline as well. A classic example of this is an inverted L, where the feedline is part of the antenna.

Transmatches can help with antennas that don't work well on a particular band, just for a listening application (hams have a number of other things they can be used for). Personally speaking, you're better off fooling around with a different antenna, if you had the space for it.

Mike

 

[riverrat373]

If the transmatch is at the station position, it will attempt to tune the antenna and, if the antenna uses this, the feedline as well. A classic example of this is an inverted L, where the feedline is part of the antenna.

Transmatches can help with antennas that don't work well on a particular band, just for a listening application (hams have a number of other things they can be used for). Personally speaking, you're better off fooling around with a different antenna, if you had the space for it.

Mike

My space for an antenna is limited by my 85"x85" lot which has lots of trees on it. I had to bend the random wire at an angle to get it to fit. Both antennas are fed with baluns and rg8x coax.

 

[ka3jjz]

Since everything is fed with baluns, I suspect a transmatch isn't going to help much. If you want better reception, put up better antennas and sacrifice your first born to the propagation gods and pray it gets better (HEH HEH). It's greatly dependent on old Sol, and it isn't going to get better anytime soon

Mike