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Am1000 Rangemaster Test

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Today, I put my rangemaster on 1700; i was fighting with Oakland Int'l airport, but I managed to get a solid 1.2 miles clear as crystal sound.

What's so remarkable about this? No grounding at all. This was on a 6' pole on top of my house (so about 25' up) - zero grounding.  and a coupler with a 16" extender on my 102" antenna to give me my 3 meters.

I got the idea from a fella on facebook.

so that tested and working even under the evil that is oakland's 10watt thing on the other side of the bay from me, i presume that grounded this may work better, but totally legally.. its doing 1.2 miles in dirty channels.. 

 

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Coverage Area Article

Talking house, changed antenna?

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Did talking house change antenna design?

Saw talk of old one with coil and coax.  Current looks to be chassis coil and whip.

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Knight Kit

Insane Ideas

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The Extended Band, the AM "X" Band, is different for every location.

In this particular location 1600 kHz is occupied by a local licensed station which has smartly discontinued their iBAH digital racket, leaving 1610 clean and sweet.

All the channels from 1620 to 1700 have no local traffic, except for 1700, the 2nd harmonic of a local station located near here which puts iBAH noise on 1680 through 1710, but only in the daytime.

So I'm thinking, we setup AMT5000s on EVERY "X" CHANNEL! Hey now!

Let's see, that would be 1620, 30, 40, 50, 60, 70, 80, 90, 1700... NINE TRANSMITTERS TOTALLY DOMINATING THE X BAND!

Why not?

Over to you.

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measuring FM deviation / occupied band width

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no mod monitors available to me so I did a little experiment with what I had

on hand to check my FM occupied bandwidth.

this is what I did.

Tools:Atenn AT5005 spec analyzerCarver TX11b with aftermarket IF TapRG 58 with BNC connectors

hookup:Spec An set to 88.9 (my operating frequency) set for 0.200 scan width andvideo filter enabled connected via RG58 to the IF out of the TX11b which wasalso set to 88.9

is this the proper setup and settings to read my occupied bandwidth for FM?

it looked to me that I was slightly under 200khz total occupied bandwidth ifI did everything right.

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FM Slaughter

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The FM dial here in the St. Louis area keeps getting more plugged up by more translaters, boosters, several LPFMs will be starting, and outlying high power stations keep moving closer in.

I had a sweet spot at 107.1 but a 250 watter popped on at 107.3, right up against 100 kW 107.7 and their iBah buzz-saws.

Well, I notice that on FM you can't hear the iBah the same as AM, but I can see it on the spectrum analyzer, and it looks like two christmas tree fires on either side of a main carrier.

So I moved to 101.9, another great spot, until a local translater at 101.5 moved to 101.9 and did me out.

I'm very close to all the FM towers.

One frequency I tried for awhile but rejected actually just got a booster, 103.7. It hasn't shown up yet on radio-locater, but I can hear it on the dial.

I was here when FM amounted to three stations, none of them were 24-hours.

I did the first all night FM program in the city as "The Night Hawk."

Some time afterword George Nory used the name "Nighthawk" on a show he did on local AM, but I no longer maintained a claim to the name so no big deal, except that I bet he got the name by hearing me use it in earlier times. Again, no big deal; small potatoes; nothing ventured nothing gained; if you throw dirt you will lose ground; what goes up must come down; a penny saved is a penny earned; everyone gets 15-minutes of fame, but lucky me got 20-minutes.

I think FM is suffocating and will soon stop working.

Join the ALPB.

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Pre-emphasis why different curves for U.S. and Europe


Stereo Tool 222 Workaround

From Orban about Asymmetrical Modulation

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Orban:'While the physics of carrier pinch-off limit any AM modulation system to an absolute negative modulation limit of 100%, it is possible to modulate positive peaks as high as desired. In the United States, the FCC permits positive peaks of up to 125% modulation. Many countries have similar restrictions. However, many transmitters cannot achieve such modulation without substantial distortion, if they can achieve it at all. The transmitter's power supply can sometimes be strengthened to correct this. Sometimes, RF drive capability to the final power amplifier must be increased. Voice, by its nature, is substantially asymmetrical. Therefore, asymmetrical modulation was popular at one time in an attempt to increase the loudness of voice. Traditionally, this was achieved by preserving the natural asymmetry of the voice signal. An asymmetry detector reversed the polarity of the signal to maintain greater positive modulation. The peaks were then clipped to a level of -100%, +125%. OPTIMOD-AM takes a different approach: OPTIMOD-AM's input conditioning filter contains a time dispersion circuit (phase scrambler) that makes asymmetrical input material, like voice, substantially symmetrical. OPTIMOD-AM permits symmetrical or asymmetrical operation of both the safety clipper and multiband distortion-canceling clipper. Asymmetrical clipping slightly increases loudness and brightness, and can produce dense positive peaks up to 125%. However, such asymmetrical processing by its very nature produces both odd and even-order harmonic and IM distortion. While even-order harmonic distortion may sound pleasingly bright, IM distortion of any order sounds nasty. There is really nothing lost by not modulating asymmetrically: Listening tests easily demonstrate that modulating symmetrically, if time dispersion has been applied to the audio, produces a considerably louder and cleaner sound than does asymmetrical modulation that retains the natural asymmetry of its program material. Some of the newer transmitters of the pulse-width modulation type have circuitry for holding the carrier shift constant with modulation. Since artificial asymmetry can introduce short-term DC components (corresponding to dynamic upward carrier shift), such carrier shift cancellation circuitry can become confused, resulting in further distortion."

 

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Current Carrier Article

Frequency switch Settings For SS-Tran AMT-3000

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So my first AMT-3000 is at my house.

But my second AMT-3000 is with

somebody else quite some distance

from me.  I believe both instruction

manuals are in that far away place,

also.  Communications with my friend

"öut there" is difficult, because of his gigantic

work schedule. 

So...  Can one of you guys give me the

frequency switch settings for putting the

AMT-3000 on 620 kHz?

No hurry. 

Bruce, Mon. Stn., CT

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Thoughts and Ideas

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Things change over time. It might be redundant to say so, since change, by definition, requires time in which to occur, therefore mentioning that "change happens over time" is like saying "given enough time things won't stay the same." You could just say "things don't stay the same."

Having made that point I have examples of things that have changed, and, true to form, they changed over time.

For months on end I had a recurrent zapping and buzzing sound on the x-band (the upper AM frequencies) coming from a defective street lamp that kept trying to turn on but was evidently short on viagra. But it kept trying and the zapping interfered with my weak AM signal. After searching for and finding the lamp I planned to pull over and write down the pole number so I could call the electric company, but they fixed it, bless their hearts, families, pets, and work ethic.

But another disturbance lurked in the background, that 2nd harmonic of AM 850 appearing at 1700 kHz as a buzz-blaster, made all-the-worse by the iBAH chainsawing at 1690 and 1710. This went on for a long time. It even started leaking into my signal at 1680 kHz forcing me to move to 1640.

But again, things don't stay the same, although they happen until they stop, which is a factor of passing time. This week 1700 is clean, and the noise is cured. At first I doubted this so I checked and found 850 is in operation, they still have iBAH, but their 2nd harmonic is finally supressed. What I think is that their engineer fixed it. I also think he had to wait for a part, custom made, which took awhile to come in. I could just call over there and ask about it, but I'd rather use my imagination to explain it away.

In my third paragraph I used the expression "months on end", and I have no idea what that actually means, but it's an expression we've all heard. What is "on end"?

Finally, since people tend to look for new posts but very quickly get bored reading them, I want to know how close two transmitting antennas can be spaced so as not to interfere with each other. For example, if a transmitter/antenna at 1640 kHz is one-foot away from another transmitter/antenna at 1680 kHz each one will be back-modulated by the other and neither signal will sound right. But how far apart do they need to be? 5-feet? 10-feet? 20-feet? 30-feet? 32-feet? What?

Some things never change, yet time goes by.

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Knight Kit Fan Page

dirt cheap Medium Wave PLL Synthesizer


We are a hot topic over at HB.net

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I just got word from my inside man over at HB.net that we are the topic of discussion behind HB.nets iron curtain forum Aka: one to one forum.

 

wonder we we are of such interest to them and why the need to attempt to keep it so secret from anyone not in their little inner circle.

 

very interesting indeed.

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Amazing Radio Brandy Snake Oil Antenna!

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Here's the problem, gang.  I know some of you have read this ad before and knew enough to simply poopoo it off right away. 

The trouble is we're getting questions from people that *believe* what is advertised.

The item of which I speak is the amasing "Ultimate FM" antenna foisted upon the uneducated by Radio Brandy.  

http://www.radiobrandy.com/FMAntenna.html

This antenna is SO amazing that it DEFIES THE LAWS OF PHYSICS!  Anyone with even the most minimal knowledge of radio signals immediately knows that this advertisement is complete and utter bold face lying. First of all most of their testimonials are clearly from people who can't possibly be legal. Unless of course they're actually running a 7 watt transmitter that is running so poorly, and with the system so ineffeciently designed that they are still managing only the legal 250uv/m @ 3 meters. 

What needs to be simply and clearly stated, for all those who inquire about the amazing comverage they expect to get using this "Ultimate FM Antenna" is that if they are Part 15 legal, meaning no more than 250uv/m @ 3 meters their signal is not going to be listened to at a mile away.  Or a half mile away.  It may indeed be possible to be a mile away with an incredibly sensitive field strength meter, with a good, external, directional antenna, and be able to find the signal and take a reading and come up with something ridiculous like 0.0000000675 uv/m that has been mentioned in other posts, but really that number is so far down into atmospheric noise that it doesn't even matter. That's so far down below anything receiveable by even the best radio built that it just doesn't matter. The fact that a super weak signal may be identified doesn't mean it's "coerage area" or that it can be heard by a radio.

The ad for this antenna is clearly violating every possible rule for advertising. It's like saying "Your 1986 Buick that gets 16 miles per gallon will get 1600 miles per gallon when you put on these Ultimate Mileage Tires".  It's just not posible, folks.  It's not a matter of if engineers agree, it's a matter of being able to change the laws of physics. And as Scotty once said "Aww Jim, I cannot change the laws of physics". 

So many who get interested about Part 15 do a little web searching and come across the Radio Brandy web site and get sucked in by this and it bugs me.

Bottom line, ladies and gentlemen, is if you are at 250uv/m at 3 meters no change in antenna is going to get you more coverage.  If you put up some sort of gain antenna and are 250uv/m at 3 meters in the sweet spot, the rate that signal strength drops off at greater distances remains the same. If you invent a magical antenna that gives you 250uv/m at 3 meters, and also at 4 meters, it would NOT BE LEGAL. 

The Ultimate FM Antenna advertisement on that web page is chock full of out and out lies, wives tales and fantasy. Apparently they spent an amazing 17 years desiging a copper dipole. I built my first amazing copper dipole when I was 11 years old.  That was in 1969. I would have gladly shared my notes with them and saved the all that time figuring it out. 

Tim in Bovey

AKA "Mythbuster"

 

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How much compression do commercial FM stations use?

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I've always wondered around what ratio of audio compression do commercial Fm stations use? You know 2:1 4:1 6:1 like that

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Enhancing The Ramsey for CC

FM Pre-emphasis

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I'm currently experimenting with an older FM transmitter that I ran across, and it has, I believe, 50us pre-emphasis.  I note that when I listen to this transmitter with a receiver that uses 75us de-emphasis, I get enhanced bass and reduced higher frequencies.  From my somewhat limited knowledge on the subject, that appears to be as it should, but I just wanted to verify those facts with people more in the know than I.

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