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Receiver System Performance

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Receiver System Performance

Sometimes people judge the performance of a transmit system by the quality of the audio produced by their receive system when tuned to that transmit system.  But such observations also are  heavily dependent on the receive system in use, as well as its geographic location.

For example, I have two cars: a 2008 KIA Optima and a 2016 Toyota Corolla. Checking today while parked in my driveway in my city of 40,000, the Toyota radio produces very listenable (but not noise-free) daytime groundwave reception of WBBM and the other Chicago Class As. The lengths of those propagation paths to my location all exceed 225 miles. My Toyota radio also listenably receives a 530 kHz TIS station transmitting from a state park more than 30 miles away from me.

The KIA radio does not detect any of those signals from my receive location.

Another Observation About Radio Receivers

In addition to the stark differences between radio receivers I have always wondered why it is that, when the radio manufacturers ocassionally produce an excellent radio receiver the models come and go. They become available for awhile, then are discontinued.

It would be better for we consumers if the best radios remained available for longer periods of time.

In fact, I've noticed in a relationship with Universal Radio, one of the major suppliers for the U.S., the sales staff tend not to be familiar with many of the models they distribute for the very reason that radios don't stay in their catalog for long through no fault of their own.

Carl Blare

My current OEM car radio

My current OEM car radio (2013 Ford Flex) has a HORRIBLE (and I do mean horrible) AM section.  I can barely pick up the strongest local stations on it.  The FM is OK, but not great.  And this is a relatively expensive vehicle.

The radio in my previous car, an econo Nissan Cube, was fantastic.  One of the more sensitive (other than aftermarket) radios I've used, and the AM section was sensitive and noise free.

You can't really talk about signal quality and range unless you specify the receiver you use.

Receiver quality

Receiver quality is as much of a factor in how far your signal will go as the transmitter power, even for commercial stations.

When someone asks me if talking about my hobby station how far you can go I always say there's no set distance, it depends on your radio.

The radio in my Chevy Cobalt is the same radio they had in the Buicks and it's very good on AM and FM.

 

 

Mark

Antennas

Also antenna placment is critical along with the type. 4 inch Rubber Ducks can't be too efficient on FM let alone AM. My Honda Pilot has an in-glass antenna on the driver rear window. My Ford F-150 has a 31 inch vertical on the passenger side front. As things being equal radio-wise, guess what vehicle does best?

Druid Hills Radio AM-1710- Dade City, FL. Unlicensed operation authorized by the Part 15 Department of the FCC and our Resident Hobby Agent.  

One of the big problems with

One of the big problems with car radios these days (particularly with AM) is noise, what with all the electronics in vehicles.  The Flex is particularly succeptible to this.  When the car is turned off, and the radio plays (on AM), it's much better, but still not great.  When the car is running, there is a tremendous amount of hashing, whistling, etc. that completely obliterates all but the strongest signals.

With me

With me the electric power steering motor causes a whistle or whine on AM but only on certain frequencies when the wheel is turned.

 

Mark

Radios Are Killing the Hobby

I think people develop loyalties for inferior radios because it's what they've got.

Not any more for me.

Having invested quite a bit in radios over the past few years I am now thinking about junking all of them. Each one has something wrong with it because of flawed design or manufacture.

Most recently I am hating the Grundig SATELLIT 750, which mainly is dressed up with enough buttons and display features to resemble a fancy radio, but it's packed with defects.

The audio is buggy. With the bass/treble controls set for "flat" response it sounds like the sound is coming through a large sewer pipe... very tubby and tooby. Not suitable as a reference monitor for audio production.

The voulume control sometimes INCREASES in volume when turned fully CCW, and jiggling it makes the sound pop on and off. Could be a broken solder inside.

Trying to open it up for inspection 2 out of 4 screws came free, but the remaining 2 are so thight that the heads would become stripped by an attempt to loosen them.

The "S" meter is a desirable feature for MW and SW but on FM only tops out at 4/5 of scale, being incorrectly calibrated.

Here at KDX we have a whole room full of imperfect radios and nothing in the future to keep the station alive.

I'm that close to calling the hobby done.

Carl Blare

Sounds like the volume

Sounds like the volume control could use a shot of contact cleaner if you can access the inside of the pot.

You are not going to really quit the hobby are you?

The Grundig field radio has a newer version that now also has a woofer, tweeter and port for bass and looks good. It's the 550.

https://radiojayallen.com/etongrundig-field-550-ngwfb/

Saw it here at Radioworld here in Toronto.

 

Mark

 

To the Bitter End

Mark asks:  "You are not going to really quit the hobby are you?"

Oh no, I'm hooked because I need to have decent radio programs to listen to and the local stations around here couldn't be worse they are so terrible.

Plus the hobby gives me a platform to complain about the defects of radio recievers.

What I was thinking is that the inferior radios could spoil the hobby for others, people who might not be so obsessed.

Carl Blare

Agressive Action

Executive Solution for Control Point Radio Monitoring

On board audio systems of portable or table radios are not acceptable for critical monitoring in the Control Area of a radio station.

Yet, radios with an audio line output might be completely useable by attaching an audio amplifier and laboratory standard speaker system.

Beyond that, many interesting AM FM tuners can be found.

There comes a day when a serious radio station has got to get picky.

Carl Blare

Professional Radio Tuners

Beyond portable and table models is the field of rack mountable tuners.

This selection from B&H Photo Video starts out with a number of industrial-grade tuners, then scrolls through a few boom box types and kids toy room radios.

Serious AM FM Tuners from B&H

I have my eye on the Rolls HR78X AM FM Tuner.

Meanwhile, at universal-radio.com I don't see the Eton/Grundig Field 550 mentioned by Mark, maybe it's too new and will show up soon.

My last few radios came from Universal Radio and it's astounding how quickly the models come and go. One gets the impression the radio manufacturures are deliberately trying to produce disposable products that need to be replaced at regular intervals.

Carl Blare

Carl...
Is It the Same Radio?

Thanks Mark. I saw that radio, but it doesn't display the words "Field 500", so I didn't know if it was the same one.

Also now we see on the left column alongside the radio the word "Discontinued"!

Carl Blare

It's the 550

...but it's called Eton/Grundig Field on the unit.

Discontinued and the BT(blue tooth) model replaces it. Same radio(newest version)

Here it is at Radioworld here in Toronto.....https://www.radioworld.ca/eton-grundig-field-bt

And Grundig site...http://www.etoncorp.com/en/productdisplay/field-bt

And Amazon...https://www.amazon.com/dp/B01K2LQAZ0/ref=sr_ob_1?ie=UTF8&qid=1506377781&...

 

 

Mark

Mark Keeps Things Organized

In the world I occupy things are always becoming disorganized so I am impressed when someone comes along who can make sense out of the world and explain it.

Wow.

The Eton/Grundig Field Radio looks like a real winner!

We owe gratitude for not letting us dismiss it due to our misunderstanding.

Meanwhile, I have demoted the Grundig SATELLIT 750 because of poor audio. and restored the C.Crane Radio Plus which at least has become familiar after several years of use as a station minitor.

This isn't over.

Carl Blare

SATELLIT 750 Audio Analysis

Sharing Engineering Research

It is my opinion that the designers of the Grundig SATELLIT 750 applied a loudness contour to the audio sound.

In a moment I will give a Wikipedia link explaining "Loudness Compensation" for those unfamiliar with the concept.

For many years some glitzy audiophile equipment included "Loudness" switches for the reasons explained in the link.

Cheaply designed audio sections of consumer radios include a fixed loudness curve to please the ear of unprofessionals who have no skill for analyzing sound, which is why many are apt to think the SATELLIT 750 sounds fine.

The audio is also distorted in the SATELLIT, not by much, but just enough to add a ragged edge somewhere in the crossover range between upper midrange and tweety highs. This may be a by-product of a power supply imperfection, nothing more than a wall wart whose buzz can be heard on the loudspeaker when the volume is turned down... seemingly an AC hum inter-modulated by a switching frequency.

Loudness Explained

Carl Blare

I Almost Thought So

Over on Radio Jay Allen's Radio Review Website I noticed he'd reviewed the Grundig SATELLIT 750 so I did a read.

O.K., THAT explains why I thought my AM1550 transmitter was over modulating!

After trying several of the radios Radio Jay noted that when the receivers displayed a frequency, like 1550 kHz, they were actually detuned several notches and could only be center tuned by off-setting the frequency reading on the LCD!

Besides trying to compensate by reducing my transmitter modulation, I also acused Stereo Tool the software audio processor of going goofy. Everything I listened to had splishy sibelance.

RadioJayAllen Gives it to the SATELLIT 750

Carl Blare

Shaping the Sound for the Radios

On an accompanying thread I've been building a column titled "Shaping the Sound to the Transmitter", about the audio frequency limitations of various kinds of transmission.

Talking about AM radios, music stations are apt to focus their attention on wide-bandwidth to pass the maximum possible fidelity to the listeners, but the typical AM receiver isn't designed to reproduce so much bandwidth making the channel over-splash nothing more than interference to adjacent channels where DXers might be trying to hear far away signals.

One approach worth considering is an all out promotional campaign encouraging listeners to upgrade to better receivers.

If only it were that easy. As already revealed in this thread finding decent radios is like looking for haystacks.

Life is smoother for stations like KDX because we broadcast talk which comes across on little radios.

I'm taking the knee because pledging allegiance to a flag does nothing to improve radio.

Carl Blare

Introducing Our New Rolls

KDX Radio Gets Slick

Ebay had the right price for a ROLLS HR78X Tuner so we went ahead.

Last night we installed the tuner at our Control Point, where eventually it will have its own audio amplifier and a precision monitor loudspeaker.

As an interim measure we are using the Aux capability of the C.Crane Radio Plus, the outgoing station monitor, which functions as a temporary amp/speaker.

The ROLLS includes a smallish AM loop antenna which can be set in any position for best reception and a neat FM dipole suitable for wall hanging.

Today we are monitoring the KDX transmitters on the new tuner and it's perfect, because we have a good engineer, of course.

There's a certain amount of AM band noise being generated by the computing system, so we'll extend the loop antenna a few more feet to our indoor bamboo tripod tower.

The loudspeaker will require a suspended mount arrangement which I have yet to design and bulid, and having one more project is the way it goes.

Carl Blare

And Guys...

It will look swell in your room!

Druid Hills Radio AM-1710- Dade City, FL. Unlicensed operation authorized by the Part 15 Department of the FCC and our Resident Hobby Agent.  

Good Line

Advertising Script

DHR says  "It will look swell in your room!

That line shows you understand good salesmanship.

When the customer demonstrates their interest in a product by mentioning it, you get them to visualize the product in their room. That doubles the customer's inclination to buy.

Carl Blare

Back in my stereo equipment

Back in my stereo equipment sales daze when a customer wanted to buy a new cartridge and stylus my question would be: "What kind of turntable do you have?" That way I knew what way to steer them. It never failed. Well maybe a couple of times it did.

Druid Hills Radio AM-1710- Dade City, FL. Unlicensed operation authorized by the Part 15 Department of the FCC and our Resident Hobby Agent.  

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