Discussion in 'Tuners' started by Old_Tech, Nov 26, 2009.
Jazz on 90.9 WDCB Chicago on the Luxman R1120a.
Every Sunday night I listen the "The Big Bands with Glen Woodcock" on CJRT Toronto FM 91.1, directly across Lake Ontario from me. Glen's has hosted the show since September 1975! Even though he has been doing the show 42 years, he has never sounded better to me through my recently acquired TU-9900. It will be going to Mike W soon, but it sounds great right now!
Very nice DC! Who did the service and how does it perform after the service?
I will assume the MR-74 doesn't go out back into the garden with you on cigar & cocktail nights.....
Mike W, of course, did the work. He’s magic.
And correct, the Mac doesn’t go outside for cocktails and cigars, though occasionally the cocktails and cigars come inside for Mac listening.
Exactly as it should be! I will be sending my TU-9900 to Mike within the next week or so. It's going to kill me to lose it for 6 months, but well worth it in the long run. Fortunately, I have theTM-1 FM module installed in my MX-132 which will have to do until Mike is finished.
I was actually listening to some FM last night....
90.1 NPR OKC - NAD 4130, now my garage tuner and sounds great there
what is that that ? Winamp ?
The program itself is called SDRUno. It's a "software-defined radio" program. SDR is basically the idea that you replace much of your physical radio hardware with software that performs those functions.
In this case, I have a device called an SDRPlay; it's basically a small black box with a USB port on one end and an antenna port on the other. To break it down to simple terms...inside is a digital tuner and a *very* fast analog-to-digital converter that basically digitizes the RF output of the tuner, in this case my device supports up to 10msps (10 million samples a second) at a resolution of 12-bits per sample. In lay terms, this thing is capable of digitizing around 10 megahertz of RF spectrum.
This digitized RF spectrum, which is in an I/Q format; is then sent in to the SDRUno software. There you can tune the segment of RF you want and the software will do all the demodulation.
It's basically a digital tuner on steroids since you're not getting an analog signal until it comes out of your sound card. All the functions outside of capturing the RF from the antenna are done entirely in digital and mostly in software. If you're wondering how software can demodulate either an AM or FM signal...just remember that all modulation schemes can be expressed as math in some form...so it can be done in software. The advantages of this is upgradability. If some new modulation scheme comes out; I'll be able to support it with a software upgrade.
It also eliminates a lot of variables in the quality of your tuner output. While the sound quality of a physical tuner can depend on a million variables; software is just working on a mathmatical level. The audio it produces from demodulation can be considered "mathmatically perfect". The only real variable in quality is the digitization of the RF spectrum.
Further in to that; you can do some interesting things you can't do with a traditional tuner. I can adjust the width of my IF spectrum to just about anything I want...symmetrical or asymmetrical. In some cases when I DX broadcast FM, I can actually reduce the IF to "ignore" a local adjacent station. This produces very distorted audio due to having half the deviation cycle; but it's enough you might be able to catch a station ID. This program happens to feature "FM Stereo Noise Reduction", which applies some noise reduction to the MPX portion of the signal. Of course, it can also apply RF noise reduction to the entire spectrum as needed. In fact, this is really handy when you're trying to listen to AM...and of course...flexible IF in the software means I can listen to a *full* 20khz AM channel vs the 10khz you usually get out of a real radio.
So in the screenshot I posted, the big spectrum in the bottom right is the current incoming RF spectrum from the SDRPlay...I don't run it 10mhz wide because I don't have a PC that can keep up with it...so this is just a 1mhz slice of the FM band. You can see three stations in this screenshot, two have HDRadio carriers and the one I'm tuned to doesn't. The spectrum above it is the IF spectrum. Kinda useless on FM...but when you're dealing with AM it's very handy for helping set your IF width as well as notch filters. Yes, I can actually set notch filters to block out interference within the IF. The hardware itself is extremely frequency agile...supporting 100khz up to 1.2ghz continuously.
Of course, this isn't a high-end unit; it only cost around $120 so it's performance is far below an SDR that might cost a few thousand dollars. But the real jewel of this thing is just how flexible it is as a tuner...completely redefines what one think is possible. Here's an example:
This is a small slice of the AM Band. You can see on the big spectrum the local "powerhouse" on 1460khz at a full 20khz. You can also see another "local" station on 1420 that's putting out a full 20khz but looks narrower due to the signal level. I'm actually tuned to 1430 WNAV. On a normal radio, the sidebands from 1420 would swamp it; but as you can see, I'm mostly tuned to the upper sideband and a portion of the lower that's not getting swamped. Does it sound great? It's a noise bandwidth-limited AM signal, but it's clear enough I was easily able to identify it. I'm also doing "synchronous AM" detection, entirely in software. You can also see a very faint carrier at 1440 and one at 1450...and at 1410. Impossible to identify...but really neat to see something. I can tell from experience by looking at the "dashed" line at 1450 that it's actually TWO am carriers that are "zero beating" each other.
This is a pretty complex and expensive device if your goal is to just listen to local broadcasts. However, it works really well for those applications in addition to letting you tune in to the rest of the RF spectrum. Another interesting feature that appeals to the DXer in me is the ability to record entire swaths of RF spectrum to listen to later. So instead of recording a single station, I can record the *entire* AM band at once and then "tune" it as if it was coming in live. Record an entire hour of the AM broadcast band and all you have to do is then retune and listen for station ID's; you won't miss anything.
Wow, that is slick!!
Actually: Gregory Porter- live ( 2hrs30min) in Wiesbaden/Germany, Rheingau Musikfestival FM 101,3 Station ID: hr2. Would have been there by myself, but no chance, tickets sold out since 4 months.
But this Nakamichi Receiver ( and my Spendor Speakers ) bring the guys into my appartment.
Earlier this morning listened to 107.3 WAAF out of Brighton/Boston Mass on my Akai AT-2600 tuner.
Yup. As someone who primarily listens to music through the PC...it's a neat way of maintaining traditional radio listening. Though if I was serious I'd need to put up a real FM antenna. A dipole/doublet designed for the 40m ham band running through a tuner that's only designed to work up to 6m doesn't make for a very good antenna at 88 - 108 mhz.
I also forgot to mention...it's more involved, but you can listen to the SCA subcarriers on FM stations with this. You have to send a full-bandwidth demodulated FM baseband in to a second SDR program to further tune the subcarriers....but it does work.
That's one of the best looking tuners IMO. I'm sure it sounds great, too.
Nice Nak. I'll bet it makes those Spendors sing. I have had a Nak TA-2a and SR-3a and they both sounded great and had good tuners.
The wine here is much cheaper than there at the concert
Listening to an Americana Music show on public radio, tonight with Roger McGuinn, on the SonyHD in the main rig.
Rotel tuner. Listened to Coast to Coast AM every night for 8 years on it now.
WSMW through a HH Scott 342-C driving a pair of Advent Legacy IIs just using a t-bar antenna. Was listening for hours until it just got noticeably quieter. Lost the right channel. Moving the volume or tapping on top brings it in and out so have to hunt the intermittent connection. Just set DC and bias on the Yamaha CR-800 have to shift to it and the KLH Model 17s in the work room.
Back in business with the Yamaha. Was in the workroom on the computer anyway.
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