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SpitFire AM Transmitter

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SpitFire AM Transmitter

Hi guys!

Doug here. I just got my new SpitFire AM Transmitter in the mail from the UK. It's on the air on 1500. I have the wire antenna taped to a piece of wood trim. It's leaning against the wall. With NO earth ground, and the internal ATU turned OFF, my whole four-plex, plus my neighbors around me receive a loud, clear signal! And NO HUM!! That's a first!

I tested it using my laptop. I need to find a spare mixer to feed it from my Orban 424A Comp/Limiter. So far, I love this little thing!

Doug

1500 am KLW

So you finally got it working!

Sounds like it doing good with no ground.

 

Mark

Great to hear it's going, I

Great to hear it's going, I thought it was probably a decent transmitter, being that the Spitfire has been on the market for some years now.

What did you do to get it going? It might help other Spitfire users. I saw that you changed the frequency to 1500 and bypassed the internal matching circuit, and now it's working and reaching 4 buildings from indoors.

Depending if the Spitfire has a audio level control on the input, you might need a resistive pad to drop the Orban's output level from pro to consumer. I don't know what the Spitfire can take, but it's something to watch out for until you know.

Orban To SpitFire

Yeah, The SpitFire has NO input level. The Orban has no working output level. So I drive a cassette deck and use the headphone out to pad down the level. It works good! Loud, clean signal! I'm impressed. 

What I did was, changed the frequency to 1500 and switched OFF the internal ATU. I have an old coax in the wall. I wonder if the shield is grounded...

Doug

Grounded power supply

I wonder if the Spitfire grounds through the power supply, does the manual say anything about that? Glad to hear you are having fun with AM. Same here, SStran AMT3000 running 24/7 on 1620 AM with talk and Heavy Metal Whether the neigh bores like it or not.


Barry at BBR 1620 AM

 Barry of Blue Bucket Radio 1620 AM  - http://bluebucketradio.com - WQYY 664

Not Grounded

Nope, Barry. The power supply is a two prong. I have NO idea how this thing plays with NO hum! My TH 5.0 was a hum box! My SSTRAN had a slight hum as well. This thing...dead air is a slight hiss. Amazing...

Doug

Pretty Average Sound

It's easy to drive this thing to distortion. I have no way to measure modulation, since my tuner was removed temporarily. The Spitfire has no GAIN or MODULATION contols. It's pretty much straight in, and drive it till it distorts and then back it off. The Big Boys don't do it that way...

I need to find a decent AM Mod Monitor, cheap. A Belar would be epic! Right now, I have a Denon tuner driving a Sanyo Cassette deck that's locked into Record mode. I find a local AM station and set levels to 100%. I then match mine to that. It works. 

But this, I have to set by ear. I got lucky, I guess...

Doug

 

 

You know if there was a way to get some actual range with that Spitfire I’d switch to that for my AM Transmitter. I have a TH5 and its a piece of pure T junk as far as I’m concerned. The audio sounds like a Fisher price toy transmitter. I’ve even heard a Plannet DJ from the Sears catalog back in the 70’s sound better than that horrible thing.

 

The fact that the spitfire doesn’t hum is a major plus for it. I wonder how much one costs? Maybe I should try that one out with a wire connected to a 6 Ft piece of copper pipe. If it has a built in ATU I could tune up to it just fine. All i’d need is a few inches of wire to connect to the pipe. Maybe simply a roach clip or just have a screw on the bottom of the pipe and screw the bare wire into the copper pipe.

 

With no hum and good audio at least I’d have HQ audio. Worst comes to worst I’d do the same and have a old cassette deck with the VU meters on it and match the meters so that my station is close to the volume of the bigger stations. Even the old turn till it distorts and back off ¼ turn does work in a pinch. Its what many low power stations did in the day when people actually could hear and appreciated good audio but didn’t have the mega bucks.

 

I suppose Auydacity and its meters too could work for setting modulation and comparing it to the bigger stations. Get a close match and your all set.

Progressive Rock (Album Rock, Deep Tracks), Classic Rock

http://thelegacy.shorturl.com

More Power for Hobby Broadcasters

http://the-initiative.boards.net/

You can deduce your

You can deduce your modulation level by listening several channels away for clipping of the carrier, with your signal at a loud, but not overpowering level on a radio.

If you're on 1500, then listen on 1530 and higher, or 1470 for splatter, it varies with how much overmod you are.

 

Pro Equipment

Wow, thanks guys! I do need pro equipment to do it right. I ain't paying a thousand dollars, though...

Hey, this blows away the TH, sound-wise. Now, If I made a serious loaded coil whip, and used the internal ATU, I bet this thing would make it downtown! The TH did that no problem, but sounded like a telephone.

But I ain't done with the SSTRAN. I gotta fix my problem first. But I have enthusiastic neighbors. So I run the Spitfire. And I like that it's made in the UK. They are known for excellence in broadcast equipment. My Veronica 30-Watt FM Stereo transmitter is a fine example. Although not on the air, it sets the bar. Rock solid and clean!

This Spitfire is in that league. Although bare minimum, it holds its own! Literally plug & play, assuming you don't change the 1440 kHz frequency. Up here, 1500 is clear. And I am amazed at no hum! There is no Earth ground up here. I got a two-way plug on the power supply! Baffling.

Doug

"It's pretty much straight in

"It's pretty much straight in, and drive it till it distorts and then back it off. The Big Boys don't do it that way..."

You would be very, very surprised. LOL!

You're Right Mighty!

Radio transmissions do odd and funny things when over-modulation occurs. Imagine a 50,000 watt blowtorch like WRKO winging it! Ha!

I see the AMM3 Belar just went for $775 on the auction site. Too much. My retirement pension can't cover anything like that. Oh well. That's why we wing it! Ha!

Doug

The full power I'm at doesn't

The full power I'm at doesn't have a mod monitor either, modulation levels are set by cranking up the audio till the transmitter shuts off, then back it down from there till it stays on. There are a few stations here that have either no mod monitor or a broken one. The biggest stations definately have the correct gear however but don't be surprised if your local mom and pop just "wings" it lol!

Full Power Bare Minimums

",,,modulation levels are set by cranking up the audio till the transmitter shuts off, then back it down from there till it stays on."

Awww MAN! Mark Osbourne would go balllistic! He is a station owner who has always done it right. By the book. I learned a lot when he built KISS 94. Imagine setting modulation levels by cranking up the audio till the transmitter shuts off, then back it down from there till it stays on! Haa haha! That would only happen ONCE! LOL!

Doug

SStran Ground

The reason I asked about the Spitfire grounding through the power supply, was that the SStran offers the option to ground through the walwart power supply using a jumper.

If the jumper is not used, the sstran will ground through the antenna ground connection.

EDITED TO INCLUDE SCREENSHOT:

Barry

 Barry of Blue Bucket Radio 1620 AM  - http://bluebucketradio.com - WQYY 664

Earth Ground

Interesting, Barry. The SpitFire has a two prong plug. Nothing is attached to the terminal marked Earth Ground. Yet the audio is clean and hum-free. All over the building, across the street, next door. It must be grounded through one prong somehow.

I still have testing to do. I want to try setting the ATU to the wire. I may need the ground then. A coil & whip are next. For now, this thing WORKS. I am impressed.

Doug

 

 

Now tell me does the Spitfire have a external antenna/ATU jack like the TH? If it has a built in ATU I can imagine you can tune up to just about anything maybe up to 8 foot? I wonder if I can use a short piece of wire connected to a 6 Ft copper pipe and get good range?

 

I assume this transmitter is fully assembled? Let me know about the range when connected to a good outside and inside antenna. If I want to transmit on 1630 Khz what do I do? This thing sounds like something I should try and get with my Radio station donations. How much is it?

Progressive Rock (Album Rock, Deep Tracks), Classic Rock

http://thelegacy.shorturl.com

More Power for Hobby Broadcasters

http://the-initiative.boards.net/

How much is it?

$107 delivered on eBay. Fully built, plug & play. I taped the 10 foot wire to a piece of wooden siding trim, and it's leaning against the wall. It's terminated with an RCA plug. That alone covers this fourplex building, the houses across the street, and next door on both sides. No further though.

A tuned whip, mounted out the window (2nd floor) should hit downtown, two blocks away, like the TH did. I still am building my SSTRAN 3000. I have a feeling this performs in a similar way. 

"Now tell me does the Spitfire have a external antenna/ATU jack like the TH?"

No, Legend, just an RCA jack. Same as the SSTRAN. 

"If it has a built in ATU I can imagine you can tune up to just about anything maybe up to 8 foot? I wonder if I can use a short piece of wire connected to a 6 Ft copper pipe and get good range?"

10 foot copper pipe. Or a 9+ foot with connecting wire. The ground wire, I might run a cable out the window to a ground rod. Eff the stupid ground lead rule. I'll just take the whole thing down if I get a visit. No biggie. I just wanna see what works best.

This thing will cover a good size apartment building as it is! So will the SSTRAN! These are a better deal than the Talking House "i.AM Radio" improved audio version at $295. Smaller, too.

No question the SSTRAN is superior, but the SpitFire comes BUILT at the same price! I like the challenge of a kit. But I needed to get back on the air ASAP! And the clarity now, compared to the old TH 5.0, is night and day!

Now, there is a Tube Transmitter at $264 on eBay right now. If you read the description, you see why I am interested:

"...a 3 tube AM Broadcast transmitter as pictured. Use it with your antique or vintage AM radio to listen to your favorite music. The unit can be operated with various sources and produces a clean full range audio sound when connected to a audio line level (even at extremely low levels) or speaker level source.  I have built many of these over the years for individuals to use with their antique radios both here in this country and for export to other countries and overseas. The Broadcaster makes it possible for owners to listen to their favorite music or programs wirelessly and is especially usefull for radios that do not have a separate audio input to use.  It has two controls: Off/On Volume - to turn the unit on and adjust the level to match the sound source that it is connected to and Tuning - to select a frequency for the radio to receive the signal. It includes an audio cable with two male RCA phono type connectors for mono or stereo sources and can be adapted where necessary and a 9.8 foot antenna wire.  The unit has a polarized power cord and power transformer for safety, built from more than 65 new and NOS parts and incorporating four stages - three tube based in operation using a shunt feed Hartley oscillator, modulator, carrier control and output amplifier. I settled on the original design back in the 90's with considerable refinements to provide much cleaner and more effective output power with wideband audio response (not limited to 5Khz) for a crisp alive sound but still have the warmth of sound in tube based operation.  The Broadcaster is extremely frequency stable. Once you have set the frequency that you want it will not drift from when first turned on each time and will not drift after having been on for hours or days. There is no interaction between the antenna and the surroundings including people.  You can pick up the antenna and hold it in your hand and the Broadcaster will not change frequency. It can be safely operated 24 hours a day 7 days a week. It does produces a noticeable amount of heat but allowing for normal use with proper ventilation.  I began hand building them in the 90's one at the time and all of them essentially the same in looks and operation, performance and durability, the quality of my craftsmanship and a proven design. Examples of audio sources the Broadcaster can be connected to are: iPads, iPods, nano's, PC audio: Lap, Notebook, Desk Top, Cell phone audio and Tuners, CD players, Cassette players, Stereo and Component receivers (including vintage equipment).  The Broadcaster is legal to use without a license relating to FCC rules Part 15 in that the transmitter may generate no more than 100 milliwatts (1/10 of 1 watt). Under these FCC rules the transmitter has a limited range on average 40 feet. The signal received by the radio is tuned in just like tuning in a regular radio station.  Using just two controls - one to adjust the volume to the source it is connected to and the other control to select a location (frequency) for the radio to tune in the signal, the unit is very easy to operate and includes easy to follow setup instructions. I have been collecting and restoring electronics for over 50 years. My background in broadcast engineering was life long until retirement." http://www.ebay.com/itm/AM-BROADCASTER-TRANSMITTER-HEAR-YOUR-MUSIC-ON-AN... 40 feet? For that price? LOL! That's a NOPE! Doug

SStran is a two prong

Many years ago, before building codes were changed for electrical service in homes, outlets would only accept two prongs and in some cases the ground was strapped to the neutral and sometimes there was no ground. I'll take grounded 3 prong outlets for $300 Alex.

The SStran power supply is routing the ground to the neutral prong which can be bypassed of course. I have noted in the past on this forum that part of my coverage is extended by the RF coupling with the power lines despite being on the opposite end of the house away from the breaker box.

On a good day my signal covers 1/4 mile via the power lines running along the road I live on and the main road up to where two or three transformers stop my signal cold.

But considering I live on a mountain, this is pretty amazing.

Sounds like you're on the right track though and more importanly, enjoying that Spitfire.

Have Fun,

Barry of BBR 1620 AM
In the smokey Appalachian Region of Kentucky

 Barry of Blue Bucket Radio 1620 AM  - http://bluebucketradio.com - WQYY 664

Right Dugger, those tube rigs

Right Dugger, those tube rigs seem to be more about nostalgia, if you're an old radio collector, you'll want something with tubes. It would be fine around the house but isn't crystal locked, so there would be some drift and the carrier most likely will have FM on it too, as well as AM.

Old radios wouldn't care as much with continuous tuning and wide IF bandwidths. I see those "patterned after" transmitters as more like collecter art than something serious.

The range

These things look very interesting!

(I'm new to this page, and I am 12 years old)

 

If I get this, what is the range with the supplied antenna outside? I don't want to waste £60 for it to reach short distances. Any measurement. (Preferable meters or miles/km)

SpitFire Range

As is, wire antenna, and internal ATU turned OFF...maybe 100 feet. Less at night. Now with a coil loaded and tuned whip antenna, ground-mounted with radials...maybe a mile. Maybe more.

Doug

Part 15 Range

Seriously, we cannot expect any serious Community Radio with Part 15, unless we:

1. Invest money. One CANNOT be broke. Find another hobby.

2. Develop and maintain an ideal condition for your SSTRAN, SpitFire, ProCaster or Hamilton RangeMaster. Mounting, tuned, correct antenna and ground, etc.

3. Forget FM. It ain't happening (legally).

If you are galvanized to get 1-3 miles from a transmitter...forget Part 15. If you are not willing to experiment, tweak and try stuff, forget Part 15. Most importantly, if you're not willing to obey FCC Rules, definately forget Part 15! It's all or none. Break one rule, ya may as well have gone Pirate!

The SpitFire, SSTRAN and other micro AM transmitters will NOT make you a broadcaster. ONLY with a LICENSE can you do that. Then you BUY a 1Kw AM somewhere and really do it!

Myself, after 40+ years in the business, I like the hobby aspect of it.

Doug

Range

First of all welcome to the new member Europedx!

@ Radiodugger....I think this new forum member is in Europe and in his country the rules could be different than the FCC in the USA.

In Canada we can almost get on FM the same range as you can with AM in the USA.

With AM the only way to get the range like up to a mile is with the expensive elaborate set up and needing to have your own property to do it.

The new member is 12 years old and maybe doesn't have the money or expertise to do what you are suggesting.

 

Mark

 

 

 

“If your broke forget part 15”

 

That is the type of attitude that another website had and he ran a few good people off the hobby. You CAN get donations and a sponsor if you are in the right place and know what you're doing. Even get others to be “repeater” stations for your broadcast so you can reach a wider audience. Already a restaurant in Deltaville likes my station but has issues with my station fading when people walk near it. I can go AM with the antenna near the business or on top of it and they will hear it better. I could get a Procaster and have the antenna above the business and then I’d cover Deltaville. I saw a youtube video of one that got 2 miles and that would cover my little town. Or I can modify a Archer Space Patrol base station as I have a friend who will help me with it. On Ebay you can get them for $7 and beat the Talking House transmitter all to hell. Plus that base station would transmit through a series of coat hangers twisted together up to 10 feet (I did it on CB). So I anm looking into this as a way to do it. The Yapper CB (Bike toy CB) can also be modified for AM and still sound better than the Talking House. And you know what they modulate FM onto an AM carrier so guess what you may be able to modify them for AM Stereo. So $7 for the TX and buy a few parts and then set it up for Stereo. And to boot you spend far less than $100.

 

Also I’m broke because of my disability and because of people who took advantage of me. I started Rich like some of you where as I could buy a 7K stereo without blinking an eye and most of the time pay CASH MONEY. I could have had a Rangemaster or Procaster and mixers and everything it takes to make a kicking A Radio station and get out.

 

One thing about this hobby is that I don’t see people trying to help the average apartment dweller who may have had some hard luck and now can’t put up a huge antenna. My landlord has allowed me to bend some rules as long as the antenna is not an eye sour. So worst case I can get 100 coat hangers and put them inside a plastic pipe and run my modified Archer Space Patrol base station and maybe get out 2 miles with that. We’ll see cuz I may have my friend help me do it just like he did.

Progressive Rock (Album Rock, Deep Tracks), Classic Rock

http://thelegacy.shorturl.com

More Power for Hobby Broadcasters

http://the-initiative.boards.net/

Here ya go 2 1/2 miles on AM

Progressive Rock (Album Rock, Deep Tracks), Classic Rock

http://thelegacy.shorturl.com

More Power for Hobby Broadcasters

http://the-initiative.boards.net/

Hi Europedx and welcome! 12

Hi Europedx and welcome! 12 is around when I started to get into radio broadcasting too, using a build it yourself kit transmitter from an electronics store. It had a board and all of the parts to plug into the holes and wire underneath, it wasn't too hard. I could broadcast all through my house and down the block a little way, not bad!

Since I started that way, I think everyone should build their first transmitter from parts.  :) Really, it is a good way to start out and you'll learn more.

Besides that, it can be very cheap to hack out a circuit yourself. Look for MRAM 1500's transmitter here on the site that uses just 3 main parts. That costs something like 5 dollars/pounds.

Good luck, and what kind of show are you planning to do?

By the way, here's MRAM 1500's transmitter:

http://part15.us/forum/part15-forums/transmitter-talk/nifty-am-transmitt...

Here's the project on a science page:

http://makerf.com/posts/fun_with_crystal_oscillators_part_1

I always get atleast 5 1/2

I always get atleast 5 1/2 miles of coverage during the day from my AM. About 1 mile at night, decent coverage is certainly doable on AM.

I kinda have to agree with Dugger Legacy, it takes a very good chunk of change to build a significant AM footprint. It can be done cheaply but I've found coverage is nearly directly related to cost.

The key for this kind of

The key for this kind of range:

- outdoor antenna, with low(er) loss pipe & coil (although technically his ground lead is over the legal limit - the transmitter appears to be mounted at about 6 feet above ground)

- rural, so minimizes noise

- radials in addition to ground rods (lots of radials, 4 ground rods)

- flat terrain, few man-made obstructions

- most likely a sensitive car receiver (although we don't have any info on it, at least in the first video - I didn't watch the 2nd).

You're not going to get the same range in urban or even semi-urban environments.  Or with indoor antennas.

Somehow balance is achieved,

Somehow balance is achieved, city range is smaller, with more buildings and noise, but the population is concentrated closer to your antenna, where rural has the distance, but fewer residents in homes or driving along. It seems to be the same with Carrier Current broadcasting as with antenna, city to rural.

I think part fifteen radio is great for a small neighborhood that has its own identity, especially if it's a rural place, like a one horse town with a strong identity that the station can lock into.

It's different for a station close to a major city, lots of high power stations that get all the attention, but that's where a neighborhood station can work, because people can feel assimilated in cities, and might like a small station that talks about what's happening around their block, though it takes foot work and staying in touch with the beat of the street.

Virtually all of the

Virtually all of the successful serious (or semi-serious) business-oriented Part 15 ventures that I've seen have been in small towns/rural areas, where there is a strong sense of community.  The population (or lack thereof) is inversely proportional to the enthusiasm with which such a station is received.

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