The AM Forum

Hi everyone,

I'm new to radio and trying to understand the difference between all the different types of transmitters (when/why certain types are used and where) and the pros and cons between products. Does anyone have any advice on how to learn more about this? Is there a primer that exists on this topic?

Thanks from a newbie!

Choices are infinite, from home brew to turn key appliance. What bands do you plan to operate on, what modes, what power levels, what kind of operating, ragchew, DX, hi fi, etc?

And how much money are you willing to spend or invest depending on how you look at it..  I'd like to have a 32v2 another KW1..i'm on a fixed income so pickens are slim...and it's device dependent...a 100 watt Transmitter maybe up to 500 dollars....500 watt transmitter you can build Class E and save some money other wise a coupla grand depending on the device....stand back Read and take your time...

73
Jack.

Thanks to you both for the quick reply and now I'm realizing I should have been more clear. I'm doing research for a financial firm so that should help to explain why I know so little! Given I don't have any specific product needs but am just trying to understand things more broadly, does anyone have any advice on ways to get an overview of the transmitter industry? For example, why do some stations choose high-power vs. low-power, who makes the best HD radio transmitter, what are pros and cons of Harris vs. Nautel vs. Broadcast Electronics vs. R&S etc.? Thanks again. Also, if anyone is willing to chat on the phone about it, please let me know!

Ah. This is an AM amateur radio forum. I will take a wild guess and say there are Broadcast Consulting Engineers who will save you a lot of trouble trying to put together an overview on your own. They may even help you for free if there's some future business potential for them.

Yea,This is an Amateur Radio Forum, ...if you need an overview you come to the right place..There's Plenty of Overviews here........LOL. ;D

73
Jack.

Send me a PM. I have a little extra time right now in-between jobs.

Phil

The reality is that the choice of transmitters depends usually on only a few things:

- what the Chief or Consulting Engineer(s) prefer
- the power that the station is licensed for
- the budget

Not much more...

Things like reliability, circuit design and build quality are really secondary...

In other words a good used box is just as useful and good as a new fancy box in a vast majority of installs...

And, it's a small market that is shrinking over time... not much "financial" future in that biz as things now stand...

Yeah, there is/was a pop up due to the DTV switchover, but that's shortlived...

          _-_-bear

Many older tube type broadcast transmitters fall into amateur radio hands when they are retired from broadcast service.  The main motivating factor for replacing tube type transmitters with modern solid state ones is much higher power efficiency, resulting in substantial savings on the electric bill.

...but with nowhere the fidelity, FCC allowed or otherwise.
-alas.

No where the fidelity?  I'm assuming this is a follow-on to Don's comments immediately preceeding the quoted topic  :D

Having worked on numerous broadcast transmitters when I was in broadcasting (many years ago!), the newer transmitters (PWM, solid state, etc.) DEFINITELY and ABSOLUTELY will give a more faithful reproduction of the modulating signal than the older transformer-coupled BC xmtrs.

And, the solid state transmitters are better than their tube counterparts - even in the PWM world. 

This is only because you can actually get a high power solid state transmitter to give a "perfect" reproduction of the modulating waveform.  I have never seen this with any _high power_ tube transmitter, anywhere unless it was very inefficient (AM linear, etc.).  Only with a DC coupled, class A series modulator or as a linear amplifier have I been able to achieve this result with tubes.

It is possible to get very close, and some here have done so - quite impressively, I must say  8)

There are a number of professional listings in the broadcast industry publication RadioWorld, where you may find someone who can bring you up to speed as to the financial factors of transmitter purchase and investment.

From my experience, station owners rarely choose their power level. They take what level they can get based more importantly on an available frequency allocation. The concept of power level is further shaped by whether their signal needs to protect other stations, through the use of directional antennas. Thus, a 10,000 watt AM station may sound impressive to prospective advertisers, unless the signal is directed mostly to ships at sea.

Transmitter selection is influenced by the capital expenditure budget and the budget available for ongoing expenses. A station short on credit may not be able to afford a new, solid-state transmitter, but can continue to maintain an older tube-type transmitter and cover the higher utility bills. Listeners won't know the difference.

When a new transmitter is considered, station administrators often take a look at the vendor's support for maintenance and repair. This reflects changes in the broadcast industry where local stations no longer have a full-time, staff engineer. Consequently, the prospective sale can be influenced by whether the deal includes a service contract with the vendor, which then takes responsibility for finding someone to keep the transmitter going. Or, if the station's contract engineer is involved in the purchase, that person can suggest a transmitter whose manufacturer provides the best component-level support for rapid repairs and maintenance.

Here's a link to that trade mag. Pick around their site. I couldn't find the engineering and technical consultant listings right away. In the hardcopy version they're in the classifieds.

http://radioworld.com/search.aspx?q=consultants