New Part-15 AM TX

[rfry]

we do have a large apt building here in this city (im est. 230ft at roof) im estimating it would post a readable signal apx 7 to 10 miles ( on clear channel) with a good ground.

The better coverage of such a system would come from the fact that the radiator length includes the metal frame of the building, if that is considered to be "ground," and not because the 3-meter whip is 230 feet above the earth. Problems there with meeting 15.219.

But to put an upper bound on what coverage to expect, I ran some numbers for 50 mW of power radiated by a 240 foot vertical monopole using a broadcast-type radial ground system (2 ohm loss). The inverse distance field at 1 km would be about 2.2 mV/m. At 11.3 km (~7 miles), it would be about 0.2 mV/m, which would be very noisy signal. Note these calculations do not account for loss due to ground conductivity, or "urban loss" due to wires, buildings etc -- which can be significant.

Given that the real r-f ground for the building system would be much greater than 2 ohms, and that the Part 15 tx may have problems delivering even 50 mW to the antenna system, the useful range of such an installation probably will not be as great as expected.
//

 

[Don2]

Quote.. Rich..

"I ran some numbers for 50 mW of power radiated.."
"Part 15 tx may have problems delivering even 50 mW to the antenna system.."

If I understand the Rangemaster system correctly, adjustments can be made on the output of the unit to assure near 100 mW output via the I/V chart provided with the unit even if there is a poor ground scenario.

Would the numbers change much if there was at least 80/90 mW getting to the antenna?
~Don

 

[rfry]

Would the numbers change much if there was at least 80/90 mW getting to the antenna?

Not much. If the radiated power is doubled, the field (but not the distance to a given field strength) increases by about 41%.
//

 

[Krimles]

Hi, just wanted to introduce the Procaster Part 15 AM transmitter officially and clear up some inaccurate postings in this thread.
The Procaster 42 channel PLL Part 15 AM transmitter has been created by the same folks that created the TalkingSign transmitter almost 8 years ago - so we have been around for quite a while now and will continue to offer engineering, support and easy-to-use solutions in the radio broadcast field. Our products are Canadian designed and manufactured - and we stand behind them and pride ourselves in offering quality equipment and excellent service and attention to our customers. The TalkingSign website has now been folded into ChezRadio.

Our 'flagship' Procaster is the culmination of 2 years of development and as far as we can see, it embodies all the 'goodies' the Part 15 people seemed to want: the range of the Rangemaster with the sound quality of the SSTRAN, all in a fully approved (FCC and Industry Canada) package and at a reasonable price.

It is not a Rangmaster copy! Grey NEMA-type boxes are, well, grey and rectangular and they tend to all look alike. But that's where the similarities end.

The Procaster has a direct-coupled audio chain which gives essentially a flat response from 20Hz - 20kHz - it's a true Hi-Fi device. The coupling transformers as used in the Rangemaster are typically 300Hz - 3.4kHz +/- 3dB at rated power and are usually used for speech bandwidth products. In real terms, you don't get the bass response. We also added an audio processor which really makes this transmitter shine. The extra 'punch' delivered by this processor increases the range by adding more power into the sidebands and really makes your radio station big and bold. This audio processor can be disabled if you use an external processor.

Range: we use a custom wound low-loss air coil. Rangmaster uses a toroidal core which is more lossy than just plain air. So we see ours as more efficient. Couple that to a substantial antenna (included) and our range is as good as it gets. As well as using an efficient MOSFET output, we have also added an auto power manager so you don't have to fiddle around with such things when you're hanging onto a ladder Xft in the air trying to tune it.

Making the Procaster easy to setup and use is one of our goals and we have used this simplicity of operation in our TalkingSign unit and have had many compliments to that effect. Anybody can set up the Procaster quickly and easily!

In the coming months, we are going to be adding unique products to accessorize the Procaster - will keep you posted on developments as they happen. If there are any questions you would like answered, please let us know. Cheers.

 

[XRQKFM]

I just added the new Procaster to the Radio Brandy part15 AM website http://www.radiobrandy.com/RBpart15am.html The Procaster blends the best of the Sstran and the Rangemaster for under $700. I have also added a new AM antenna for those who purchased a Ramsey AM transmitter, and no the Ramsey will never perform up to the Procaster or Rangemaster.


Steve
www.radiobrandy.com

 

[dbdigital]

Hi, just wanted to introduce the Procaster Part 15 AM transmitter officially and clear up some inaccurate postings in this thread.
The Procaster 42 channel PLL Part 15 AM transmitter has been created by the same folks that created the TalkingSign transmitter almost 8 years ago - so we have been around for quite a while now and will continue to offer engineering, support and easy-to-use solutions in the radio broadcast field. Our products are Canadian designed and manufactured - and we stand behind them and pride ourselves in offering quality equipment and excellent service and attention to our customers. The TalkingSign website has now been folded into ChezRadio.

Our 'flagship' Procaster is the culmination of 2 years of development and as far as we can see, it embodies all the 'goodies' the Part 15 people seemed to want: the range of the Rangemaster with the sound quality of the SSTRAN, all in a fully approved (FCC and Industry Canada) package and at a reasonable price.

It is not a Rangmaster copy! Grey NEMA-type boxes are, well, grey and rectangular and they tend to all look alike. But that's where the similarities end.

The Procaster has a direct-coupled audio chain which gives essentially a flat response from 20Hz - 20kHz - it's a true Hi-Fi device. The coupling transformers as used in the Rangemaster are typically 300Hz - 3.4kHz +/- 3dB at rated power and are usually used for speech bandwidth products. In real terms, you don't get the bass response. We also added an audio processor which really makes this transmitter shine. The extra 'punch' delivered by this processor increases the range by adding more power into the sidebands and really makes your radio station big and bold. This audio processor can be disabled if you use an external processor.

Range: we use a custom wound low-loss air coil. Rangmaster uses a toroidal core which is more lossy than just plain air. So we see ours as more efficient. Couple that to a substantial antenna (included) and our range is as good as it gets. As well as using an efficient MOSFET output, we have also added an auto power manager so you don't have to fiddle around with such things when you're hanging onto a ladder Xft in the air trying to tune it.

Making the Procaster easy to setup and use is one of our goals and we have used this simplicity of operation in our TalkingSign unit and have had many compliments to that effect. Anybody can set up the Procaster quickly and easily!

In the coming months, we are going to be adding unique products to accessorize the Procaster - will keep you posted on developments as they happen. If there are any questions you would like answered, please let us know. Cheers.

What?! No AM stereo, no provision for linking multiple transmitters?! Oh, well.

It still looks like a great TX and at a very good price point.

db