I just read a discussion elsewhere about the supposed 'best' AM transmitter.
Use of the term best is very misleading. What is best to one person and application may not be so good to another. It is a highly qualitative judgement, and I'd rather deal with specifics. In the case I referenced, the author was actually referring to the fact that in a comparison test between AM transmitters conducted multiple years ago, the Hamilton Rangemaster had the highest field strength. But even that statement needs an asterisk, as the comparison was flawed in many aspects - I'm not going to rehash those flaws here but they can be found in historical posts.
Now, Artisan Radio hasn't always used FM. Back in the early to mid 2010s, we broadcast on AM 1570, and used/experimented with a number of transmitters, including the aforementioned Rangemaster, the Procaster, the Talking House and the Talking Sign (precursor to the ProCaster).
I wouldn't have the necessary hubris to label any one of these as the 'best'. What I would say is that all of them have strengths and weaknesses and all can be used for various specific Part 15 broadcasting applications. The best for your application is really up to you.
I thought I'd ruminate on these transmitters, giving newcomers at least a starting point in their investigations if they are looking at broadcasting, and dispel some of the misinformation that is out there.
I'll be looking at field strength, but also such factors as cost, sound quality, reliability and ease of use.
First, let's talk about the elephant in the room, field strength. I actually consider that to be the least important when considering an AM transmitter. There are so many other things that affect range more - where you've installed the transmitter/antenna, ground conductivity, the quality of your transmitter ground, buildings and other obstructions, electrical noise, even the weather. All of these transmitters will give you range of a mile or more under ideal conditions. All will suck and you'll be lucky to get 1/4 mile range if, say, you have poor ground conductivity in your area, or lots of concrete buildings.
But with that being said, and if those extra few feet matter to you, the Rangemaster will be able to give you them, as you can manually tune it to deliver exactly 100 milliwatts to the final amplifier. All the others have non adjustable power, usually a bit less than the allowed maximum to allow for manufacturing variability. The Rangemaster would be followed by the ProCaster, then the Talking Sign and finally the Talking House.
But those extra few feet have a cost in ease of use. The Rangemaster takes a while to set up and tune if you're going to do it right (i.e., manually), requiring taking internal measurements with a multimeter. It does have accessories to supposedly let you know when you're tuned, but I never found they worked all that well. If that turns you off, and you want plug and play, all the other transmitters fit the bill. As I said, there are no power adjustments on any of them, and even the antenna tuning is automatic on the Talking House. With the ProCaster and the Talking Sign, it's just a matter of turning a knob and peaking a meter to tune the antenna.
Sound is something that is important to most broadcasters, although the quality of your source material plays a large role. Music would require better sound; voice, not as much, and for historical recordings such as OTR, it matters the least. Both the Rangemaster and the ProCaster have high quality sound. The Talking House has mediocre sound at best, and the Talking Sign is somewhere in between. I should note that there is a version of the Talking House that has better audio, but it's more expensive. The older models can be modded, but that's outside the scope of this discussion.
All except the ProCaster require external audio processing if that is desired; the ProCaster has built in limiting and compression, making it more of an all in one solution.
Moving on to installation, the Rangemaster and ProCaster were designed to be installed outdoors with whip antennas (the ProCaster supplies this as well). Both are fed power and audio through interfaces located indoors. The Talking Sign and Talking House come with wire antennas, and are meant for indoor installation. Outdoor installation normally is recommended for the best range, as it gets the antenna away from your house wiring and any interfering outside walls. It is possible, however, to run the wire antennas from these transmitters outside and up over the roof, and that is exactly what I did with my Talking Sign install. With that configuration, range was in the ballpark of an outdoor ground-mounted Rangemaster or ProCaster.
Now let's talk about reliability. The only transmitter I ever had issues with was the Talking House. I've owned many, and I'd say that approximately half had issues, and/or didn't get much range at all (i.e., only a few feet). Most of the problems revolved around the internal automatic antenna tuner (it would get stuck, or just tune incorrectly).
I've left the final consideration to last, deliberately. Cost. The Rangemaster is expensive. Well over US$1000 and that's for the base model, no accessories, which can run the price up even further. That's a lot and I find it difficult to justify the price/performance when the end result is at best broadcasting a mile (and a lot less static free).
The ProCaster is expensive as well, but US$400 cheaper than the Rangemaster, and that, at least for dedicated enthusiasts, starts making a bit more sense. You get more for less money (when you consider the internal audio processing). I guess you have to decide if the minute difference in range that slightly stronger field strength gives you from the Rangemaster is worth it.
Overall, I found the Talking Sign to be the best value, and it's too bad it's discontinued. It is worth noting that many of the parts and some of the design went into the ProCaster, so you're basically getting an earlier version of that transmitter. It gives you reasonable sound, at a low price, at least if you can find one. I purchased mine new for about C$250 each (that was a heavy discount because I bought a number of them), and you should be able to pick them up for around US$100 today. I probably used the Talking Sign for the longest period of time, consistently getting a mile+ range to a decent car radio.
I find it difficult to recommend the Talking House because of the reliability issues I've had. You can pick up older models new on e-bay for under US$100 and there's a reason for that. But if you can find a deal and it works, it would be OK for starting out, experimenting or playing programming such as Old Time Radio shows.
If I ever did move back to a place where I could use AM, such as a house with yard space, I would probably go with a ProCaster, used if I could find one. While I was paying out the money, I'd probably also wish that I hadn't gotten rid of the Talking Signs when I had no expectation of ever going back to AM.
Here's another one that scored well at the top of the tests that were done by the transmitter "challenge" that seems to go unnoticed.
http://www.waynemillerassociates.com/GI/GI100features.htm
I'm currently using the Procaster and have been quite happy with the results so far. After having it on air for 1 year. It has pretty decent audio quality and range up to 2 miles in most directions. I only had to retune it once in that time. That was because I had to remount it. It's mounted about 15 feet above the ground. I also have the Rangemaster I'm hoping to get on the air soon and will report back the results.
The "transmitter challenge" invalidated itself at the outset yet is still milked as if it was a historic milestone. It is a laughing stock and would best be left to the forgotten past.
Through experience and the recommendations of trusted part 15 associates, I settled on the Procaster and am continuously impressed by its professional performance. I would not hesitate to place a Rangemaster into service and am looking forward to having a Wayne Miller Transmitter.
On more ambitious days I daydream about home-building an AM tube transmitter with many fancy features like windows to look in at the tube-glow and rows of meters with many adjustable knobs.
Yes Carl, I'm really impressed with the Procaster myself. I'm hoping to have the Rangemaster in service soon. The Wayne Miller transmitter probably wouldn't work well for my station due to it very limited 3khz audio bandwidth. I limited the audio bandwidth on my station using my audio processor to 3.5khz and wouldn't work. If I ever have a need for a total voice no music at all station it would work fine for that.
I certainly didn't mean to diss other AM transmitters in my dissertation. The ones I discussed were the ones I have extensive experience with. I have also owned the AMT3000, but didn't use it all that much - I found that it was essentially a poorer cousin of the Talking Sign, although it too filled the needs of either experimentation (you had to build it) and/or an inexpensive, decent transmitter.
The whole point of the topic was to show that there is really no 'best' transmitter. What is best for you is a function of your budget and your needs (such as the type of programming you use, location, etc.). They can all work well, depending on what you're doing.
I didn't see your post that way. I found it informative.
Artisan, along with Roy I also did not think you 'dissed' any of the part 15 transmitters. I took it the way you meant it, as a kind of review of the differences between all of them, with thought toward their best application.
And since you mentioned the AMT3000 from SSTran, I will offer what I found in having two of them...
Built in its simple kit form it is almost a toy, but the well detailed upgrade to loading coil and outdoor antenna placement puts it in a league with the better transmitters. In fact, with the improvement it competed with the AMT5000, something the manufacturer did not make a point of mentioning.
From the outside view, without ever having one, I figured out that the Talking House had its share of imperfections which I chose not to wrestle with. However the companion ATU offered from the same company is worth wondering about.
@carl-blare I owned the older version of the Talking House ATU. It had a plastic case, wasn't particularly waterproof, and I believe the only reason it added range is because the connecting cable radiated, effectively adding to antenna length. The Talking House/ATU pair was certified in the U.S., but the Talking Sign and its equivalent ATU was not able to be certified in Canada because of that issue.
Just a word about the Rangemaster. There appear to have been various upgrades and changes made to the Rangemaster over the years. I purchased a brand new Rangemaster from Keith in 2017. At the time, he was offering a cheaper version of his transmitter, dubbed the AM1000E, that didn't have the circuitry for synchronizing carriers in multiple transmitters. I didn't have plans for a multiple transmitter installation, so I bought that one. As much as I wanted a Rangemaster, the price was making it hard for me to get on board. The significantly cheaper price of what I believe was the short-lived AM1000E was the decider.
My AM1000E has two features that make tune-up quite straightforward. Keith offered an option to permanently install a meter inside the transmitter enclosure, which I took. To tune up the transmitter, with the piston cap at mid-travel, I find the coil tap that gives the highest meter reading, then adjust the cap for the highest reading. Next, to set the input power to 100mW, there is a bicolor LED mounted on the board. I adjust a trimpot until the LED turns from red to green, which indicates that the input power is 100mW. Done! This tune-up process is significantly easier than it would have been with earlier versions of the Rangemaster, which I don't believe had these two very useful features.
My input to this transmitter thread. With the exception of the Wayne Miller Grain Industries transmitter that has audio only to 3K?, and maybe the older Talking Houses that weren't improved, the audio quality is determined by your receiver. The Schlockwood user manual written by Jim Wood specifically talks about this and mentions the "miserable crop of lousy receivers". What leaves the transmitter can be full range audio response 20Hz to 20kLz but if your receiver squeezes that into a compressed band width typical of "run of the mill" receivers which can be to 2.5-3kLz in a shrill little 2" speaker that's very hard to listen to and crappy tiny audio chip it won't sound very good, even the Rangemaster and Procaster. Older radios from before the 1990s commonly had the AM bandwidth to the standard 10kLz(plus or minus 5 kLz) band width that gave at least to 5kLz frequency response and didn't sound all midrange and "muffled". But there are "good" receivers available today.
That being said, I am using the Talking Sign right now, which is the predecessor to the Procaster, certified in 2000 and made for a few years until it was replaced with the Procaster. It was made for real estate "talking signs" but unlike the Talking House before mods it has decent audio as can be heard on a capable receiver.
Listening on a decent receiver that has bandwidth adjustment and a half decent audio section it can sound close to FM. The audio range for music is there. If you really want to compare sound quality of different transmitters you have to listen on the same radio and a good quality one. Some are...Sangean MMR-99(excellent), CCrane EP pro, Eton Field, older GE super 3,2, Sangean PR-D4, just a few, that have AM bandwidth adjust and good sound. Or older sonys/Panasonics from the 80s and before like the Panasonic RF-2800 for example. Also an eighties Carver tuner was made for AM quality. With the MMR 99(sangean) the audio with my Talking Sign sounds "close" to just like FM, which proves the Talking Sign is putting out decent frequency response, low end also. But if you have a transmitter like the Wayne Miller one with frequency response of 3Klz no matter what receiver you have it can only hear what it is fed. Also the audio source that is feeding the transmitter has a lot to do with it. The Procaster and Rangemaster may have better, "cleaner" sound quality than the Talking Sign but if the receiver is not that good or you audio source material isn't the best my point in this post is what leaves the transmitter even the best ones is only as good as the audio source, and the end receiver being listened on.
I had a Procaster a few years ago and I was using it indoors and indoors you can't use the stock antenna as the floor to ceiling isn't high enough and it's not practical to use a rigid rod inside so I had a 104" length of wire attached to the antenna lug instead as I don't have facilities for an outdoor install and I was told that changing the antenna was a violation of certification. Any opinions on that?
Anyone using or used a Procaster, indoors with a wire instead?
I still would like to use a Procaster as it's the only other one certified in Canada but I am hesitant because of the wire antenna instead of the stock 3 section metal one it comes with.
I've actually been considering contacting Wayne Miller about his Transmitter and suggesting he try marketing it with a different encloser, one more like what the Rangemaster or Procaster use.
I never heard of anyone who uses that transmitter, and I'm pretty sure it's because of the way it looks.. a piece of PVC pipe with caps on each end. It looks like it was built in a shed and I think that's what turns people off.
As for Chez discontinued Talking Sign AM.... is the Procaster just a reprise of the Talking Sign? Or did they actually have another design certified?
And if the Talkiing Sign is, as suggested previously, a "better" transmitter than the Procaster, why dont they reprise it? They wouldnt have to get it certified again
@richpowers The Procaster was a new design to take over from the Talking Sign but maybe shared some components but a new design has to have new certification. The Talking Sign and the Procaster were certified on two separate occasions. The Procaster was an upgrade to be used outdoors and with audio upgrade.
It is "better" in the fact that it was certified with 100 mW no modulation taken from output not input according to Gerry so potentially better range wise. Gerry told me the lab back in 2000 here near Toronto did it that way saying you could have up to 100mW out. But the Talking Sign isn't bad audio wise. Again, it also depends on your audio source and what you are listening on.
@mark I guess that changes the question to why did they discontinue the Talking Sign at all? They went through th he expense of certification to manufacture another unit, and discontinued the previous unit - Why? Is there more to the story? Did it have something to do with the previous mistakenly having a 100mw output instead input to final stage? - Is the Talking Sign certification still valid?
Oh, incidentally, Did you know Greg Herrick of Radio Realty (New Pulot Communications) trademarked "Talking Sign" back in 1981?, it expired or something and that's when Chez picked it up the name for their own transmitter evidently.