Recommended Antenna Tuners for receivers only (no xmit)

KevinC_63559

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Looking to get into SDR (probably with a SDRplay unit) and will have at least 2 antenna's for the unit - one for < 30MHz (probably a MLS 30+) and something undetermined for > 30 MHz (Recommendation appreciated). The SDRplay unit comes with 2 antenna inputs so I won't be using an antenna switch.

Seeing recommendations that I should have an antenna tuner. Feels like I'd need two? No clue what would be appropriate for a receiver only setup - no transmitting (so no power wattage concerns).

Recommendations? Budget of, oh, idk, $200 or less, especially if I need two, which would be mechanically implied.

Thanks in advance.
 

ka3jjz

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Correct. Technically a true antenna tuner goes at the antenna feedpoint, and uses a bit of power to tune it. That's not an option here.

Now adding some filtering before the amp is a very good idea, especially in an urban areas with a plethoria of FM and TV stations about. If that is your situation, you might consider getting one of the W6LVP loops. Larry has been known to add filtering when needed. The MLA30+ amp is about as wide as a barn door, and if you are in an urban area, you may find you need extra filtering anyway.

No transmatch (which is what you would use with a receiver, or a ham transceiver) needed....Mike
 

KevinC_63559

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Where did you see these recommendations for a receiver? I’ve never seen or used a tuner for receive.

Oh, stumbled across it several time when talking about wideband receivers. But here is one link: Antenna tuner - Wikipedia
Just scroll down to the receiver section.

I'm am 20 miles from any city with over 500 people, and the closest one has 20,000... so the local air should be pretty "clean" (if that is a term).
 

mmckenna

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Feels like I'd need two? No clue what would be appropriate for a receiver only setup - no transmitting (so no power wattage concerns).

Recommendations? Budget of, oh, idk, $200 or less, especially if I need two, which would be mechanically implied.

Thanks in advance.

Antenna tuners hide issues, they don't really fix anything.
For 30MHz and up, you'd do better with an antenna that is resonate on the frequencies you want. Easy way to do that is to get a discone. Save the money you'd spend on a tuner and use better coaxial cable and get the antenna up as high as you safely can.

As for below 30MHz, I had a basic MFJ versatuner from a long time ago that I'd use with an HF receiver and it did seem to help a bit. It's harder to get a resonate antenna that covers the entire HF band in a reasonable amount of space.
 

RFI-EMI-GUY

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What SDR receivers lack is an RF preselector. A preselector limits the bandwidth of the signal arriving from the antenna to a focused width, say 3 to 5 MHz wide. This is accomplished by a tunable coil and capacitor arrangement. The purpose is to minimize receiver spurious responses (aliasing for SDR) and minimize out of band energy that overwhelms the active components of the receiver such as RF AMPS and A/D converter of an SDR. conventional analog receivers like discussed in your other thread have this built in. You can find external preselectors sold by MFJ, Kenwood and Yaesu. Though the last two would be found on used market. your SDR experience will be far better with a preselector.
 

KevinC_63559

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What SDR receivers lack is an RF preselector. A preselector limits the bandwidth of the signal arriving from the antenna to a focused width, say 3 to 5 MHz wide. This is accomplished by a tunable coil and capacitor arrangement. The purpose is to minimize receiver spurious responses (aliasing for SDR) and minimize out of band energy that overwhelms the active components of the receiver such as RF AMPS and A/D converter of an SDR. conventional analog receivers like discussed in your other thread have this built in. You can find external preselectors sold by MFJ, Kenwood and Yaesu. Though the last two would be found on used market. your SDR experience will be far better with a preselector.
Thanks.
 

merlin

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MFJ has a decent preselector, that is what I would go with had I not already built one.
Look up MFJ-1040x
 

ka3jjz

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Here is a YouTube video showing Paul in Alaska listening to a Brazilian station using a SDR receiver, a EmTech transmatch and an active loop. Seems to work quite well for him...



Mike
 

KevinC_63559

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MFJ has a decent preselector, that is what I would go with had I not already built one.
Look up MFJ-1040x
Thanks for the reference!

(Side note - horrible name, most of the Google hits are for the MFJ 1040 US federal tax forms <lol>)
 

belvdr

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Thanks for the reference!

(Side note - horrible name, most of the Google hits are for the MFJ 1040 US federal tax forms <lol>)
Restricting to MFJ's domain helps:
Code:
site:mfjenterprises.com 1040
 

Scan125

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I have MFJ-956 and the more expensive MFJ-959C.

They both appear to work very well but I have no quantative / measured data to offer.

Both can actually help tune out annoying signals that can penetrate where you are tuning too. It is difficult to say that they really enhance without technical testing and analysis. However they do reject very much like a pre-selector will do and seem to thus pull in fainter signals much better.

A nice feature of the 959C is that it has sitchable two inputs and two outputs as well as a low gain amplifier (when powered) but can be used with no power just as well.

Both unit have Bypass settings so you can audibly (or if you have the kit electronically) hear or analyse the effect / improvement they are offering you.

If you have just the singple reveiver and antenna then the cheaper and simple 956 may be your better choice of the two.
 
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