Antenna Tuner Question

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radioetc

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From reading I have done, it appears that and in general, antenna tuners increase signal strength as much as noise in a receive only context. So they are generally not useful for receive.

If that's true, what if somebody has an old vintage receiver where the sensitivity is low on certain bands? Such that suppose one is listening to a station with a great signal to noise ration but the signal is weak. And consquently, one has to crank the volume up or all the way up to hear that signal.

Would an antenna tuner help boost the signal so as to better drive the audio amplifier? Or would an RF pre-amp be better?
 

prcguy

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An antenna tuner will generally not change or improve the signal to noise ratio but if there is an extreme mismatch between the antenna system and the radio it can get more signal and accompanying noise into the receiver. If you can borrow one to test that would be better than buying one only to find it didn't improve anything. You might have one of those extreme cases where the radio is actually starved for signal due to its age and condition where a little more level off the antenna might help. For everyone else a tuner usually does nothing useful.
 

ArloG

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I'm compelled to add a couple of pennies here.
Preselector. Covered here on RR.
Going back years when surplus electronics vendors were all over the place I got a flyer and there were TRF..Tuned Radio Frequency radios for a few dollars. They covered the AM broadcast band and some shortwave.
I was a kid back then. Hooking up the radio to a few feet of wire brought in local stations.
Remembering back there was a knob for Antenna, RF, IF....where other superhet radios had ganged sections.
Every station you received had you tweaking the knobs for the best reception. Get the knobs too far off and you'd get no signal or it would distort. And the radio reminded you of the old movies where they tuned a broadcast and there was a squeal (like coming up on CW in SSB mode).

Jump up a few years. Lived in the fringes. Learning electronics and doing side repair jobs. There were 2 FM stations that needed a good antenna to receive. Forget stereo mode usually (MPX hiss). One was at 95.7 and the other at 101.1 MHz. Nothing else across the band.
I found out that sticking to FM alignment procedures in the book but veering a bit by bringing the antenna and RF trimmers up to peak in between those 2 stations worked very well. In essence removing linearity of those 2 ganged-capacitor circuits. Signal strength was improved by a few meter notches and stereo hiss was reduced by a lot.

What I'm not so sure of is if a passive or active preselector works better than or is close to the same thing as an antenna tuner for TX.
But for RX only.
 

a29zuk

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The tuner tunes your antenna(makes it resonant) to the frequency you are listening to. The preselector rejects signals above and below the signal you are listening to.

Jim
 

ka3jjz

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A bit oversimplified, but yes. There are 2 kinds of preselectors - active (which has an amp that is tuned) and passive (no amp). The actives are great for older receivers where their sensitivity tends to die off as you get higher in frequency; the passives are pure gold for those folks living in areas with lots of MW, FM and/or TV stations nearby, and are using SDRs. Think of a passive preselector as a tunable filter - it will allow only those frequencies to which it's tuned to pass through, but rejects anything else.

Mike
 

a29zuk

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A bit oversimplified, but yes. There are 2 kinds of preselectors - active (which has an amp that is tuned) and passive (no amp). The actives are great for older receivers where their sensitivity tends to die off as you get higher in frequency; the passives are pure gold for those folks living in areas with lots of MW, FM and/or TV stations nearby, and are using SDRs. Think of a passive preselector as a tunable filter - it will allow only those frequencies to which it's tuned to pass through, but rejects anything else.

Mike
You're right Mike. I responded that way because he/she is a newer member. As you mentioned earlier reading the wiki will help him/her to understand.

Jim
 

a29zuk

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It was directed to Arlo's post as he seemed a little confused between the tuner and preselector.
 

valdyjr

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Hello. Any antenna tuner that operates on the HF frequency can be used for SWL?
 

ka3jjz

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In a word, yes. But don't bother with these 1 kw models - for strictly listening, that's overkill....Mike
 

ka3jjz

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Undoubtedly because that's how a transmatch - a more correct name than 'antenna tuner' - is typically used...Mike
 

valdyjr

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Undoubtedly because that's how a transmatch - a more correct name than 'antenna tuner' - is typically used...Mike
Thank you so much Mike. I bought this transmatch (MFJ 948; it still hasn't arrived) and I was worried that it wouldn't be suitable for my TECSUN-S2000 due to the expression "transmitter", and my radio is just a receiver.
 

WA8ZTZ

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The 948 instruction manual will explain how to use the tuner for receive only but basically proceed as follows.
Hook a PL-259 to BNC coax jumper from TRANSMITTER on the back of the tuner to the SW ANT jack on the right hand side of the S2000
(make sure the switch next to the SW ANT is in the EXT external position). Connect your antenna lead-in to the COAX 1 or COAX 2
jack on the tuner (or on the WIRE binding post if you are using a wire lead-in). Select proper position on the tuner ANTENNA SELECTOR (TUNED) based on where you connected your antenna lead-in. Select the desired frequency on the S2000 and rotate the INDUCTOR switch on the tuner for maximum noise/signal or maximum S-meter reading in the receiver. Then alternately tune the ANTENNA and TRANSMITTER controls for maximum noise/signal or S-meter reading. The ANTENNA and TRANSMITTER controls interact somewhat so it may take some back and forth tuning for best results. You will have to re-tune if you make a big change in frequency or change bands. There will be no indication on the meter on the tuner as that is only used for transmit.
Otherwise, observe all usual antenna lightning protection precautions and have fun with your new tuner.
 

ka3jjz

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And don't expect radical changes. Maybe a s unit but maybe not much beyond that. There may be times when the tuner can't make the antenna work any better, too. It's perfectly normal...Mike
 

valdyjr

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The 948 instruction manual will explain how to use the tuner for receive only but basically proceed as follows.
Hook a PL-259 to BNC coax jumper from TRANSMITTER on the back of the tuner to the SW ANT jack on the right hand side of the S2000
(make sure the switch next to the SW ANT is in the EXT external position). Connect your antenna lead-in to the COAX 1 or COAX 2
jack on the tuner (or on the WIRE binding post if you are using a wire lead-in). Select proper position on the tuner ANTENNA SELECTOR (TUNED) based on where you connected your antenna lead-in. Select the desired frequency on the S2000 and rotate the INDUCTOR switch on the tuner for maximum noise/signal or maximum S-meter reading in the receiver. Then alternately tune the ANTENNA and TRANSMITTER controls for maximum noise/signal or S-meter reading. The ANTENNA and TRANSMITTER controls interact somewhat so it may take some back and forth tuning for best results. You will have to re-tune if you make a big change in frequency or change bands. There will be no indication on the meter on the tuner as that is only used for transmit.
Otherwise, observe all usual antenna lightning protection precautions and have fun with your new tuner.
Dear friend. I have no words to thank you! Just one thing I didn't like: I won't see the little needles move...
 

valdyjr

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And don't expect radical changes. Maybe a s unit but maybe not much beyond that. There may be times when the tuner can't make the antenna work any better, too. It's perfectly normal...Mike
Dear Mike. I'm prepared for that. But, as they say here in Brazil: "any pleasure amuses me". Thank you.
 

Ubbe

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And don't expect radical changes. Maybe a s unit but maybe not much beyond that.
One S unit are 6dB, so 400% stronger signal. That's good enough for me. I have a tuner never unboxed since 10 years. Maybe I should try it if it will give me that kind of improvement.

/Ubbe
 

valdyjr

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One S unit are 6dB, so 400% stronger signal. That's good enough for me. I have a tuner never unboxed since 10 years. Maybe I should try it if it will give me that kind of improvement.

/Ubbe
If you decide to unboxed, report the results here.
 
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