{"id":3703,"date":"2011-09-16T10:03:32","date_gmt":"2011-09-16T14:03:32","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=3928"},"modified":"2023-04-29T13:40:33","modified_gmt":"2023-04-29T17:40:33","slug":"the-crown-fm2000a-transmitter","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2011\/09\/the-crown-fm2000a-transmitter\/","title":{"rendered":"The Crown FM2000A transmitter"},"content":{"rendered":"\n

I had the opportunity to work on one of these recently, thought I’d post a few observations.  The transmitter itself comes in three parts, the FM100 which serves as the exciter and driver, the PA2000, which holds the RF amplifiers and combiner and the PS2000 with supplies the DC voltages to run the PA.<\/p>\n\n\n\n

\"Crown<\/a>
Crown FM2000A transmitter running at half power<\/figcaption><\/figure>\n\n\n\n

That configuration has some advantages and disadvantages. First, it takes up much more rack space than the comparably powered Nautel VS2.5. \u00a0Second, because the unit does not come with slide-out rack rails, each part needs to be removed from the rack for servicing, which makes things a little difficult when working alone as the PS2000 weighs quite a bit. \u00a0As far as the rest of the design, the PA2000 is very modular, all of the PA modules, controller card, fuse board, and RF combiner easily come out of the chassis for service.<\/p>\n\n\n\n

\"Crown<\/a>
Crown FM2000A top cover removed<\/figcaption><\/figure>\n\n\n\n

This unit had been in service at WBEC in Pittsfield, MA for an undetermined amount of time. As such, there was quite a bit of dirt and bugs inside the PA chassis. I used an air blower to clean everything out. Checked the fans for bad bearings, checked all RF connections for signs of overheating, etc. \u00a0I also cleaned out the power supply and rinsed all of the air filters.<\/p>\n\n\n\n

\"Crown<\/a>
Crown FM2000A front cover off<\/figcaption><\/figure>\n\n\n\n

My other minor complaint is the power adjust pot is under the front cover. \u00a0When making adjustments and such, the LED display indicates operating constants based on a little LED light next to the display. \u00a0The legend is on the cover, which has been removed to adjust the power. \u00a0Minor thing, but slightly annoying, nonetheless.<\/p>\n\n\n\n

There are four RF modules in the PA2000, each one generating 500 watts. \u00a0This particular transmitter has a bad device in PA3. \u00a0When the transmitter is running the DC fault LED flashes and the PA3 reading shows no current. \u00a0The device is a BLF278, which is a fairly common, inexpensive RF MOSFET. \u00a0According to the factory tech, they can be replaced in the field provided one can solder. \u00a0After replacement, there is no special tune-up or anything needed as the module is wide-band.<\/p>\n\n\n\n

\"Crown<\/a>
Crown PA2000 500 watt RF module<\/figcaption><\/figure>\n\n\n\n

The four modules are combined and then sent to the RF output filter which has the low pass harmonic filter and directional coupler.<\/p>\n\n\n\n

\"Crown<\/a>
Crown PS2000 output filter<\/figcaption><\/figure>\n\n\n\n

It is a pretty simple transmitter, no bells or whistles or fancy things like IP connectivity. \u00a0Overall, it seems to be well-made, robust, modular, and efficient. \u00a0The remote control interface is via DB-25 connector on the back of the PA2000.<\/p>\n\n\n\n

I did not get a chance to hear it on the air, I was just cleaning and testing the RF sections. \u00a0The exciter is an FM100 transmitter, which I had to change frequencies on. \u00a0I found that to be self-explanatory.<\/p>\n\n\n\n

It would be fun to compare this to some of the other broadband FM amplifiers like PTEK and Armstrong.<\/p>\n","protected":false},"excerpt":{"rendered":"

I had the opportunity to work on one of these recently, thought I’d post a few observations.  The transmitter itself comes in three parts, the FM100 which serves as the exciter and driver, the PA2000, which holds the RF amplifiers and combiner and the PS2000 with supplies the DC voltages to run the PA. That … Continue reading The Crown FM2000A transmitter<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[15],"class_list":["post-3703","post","type-post","status-publish","format-standard","hentry","category-tech-stuff","tag-fm-transmitters"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3703","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=3703"}],"version-history":[{"count":9,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3703\/revisions"}],"predecessor-version":[{"id":11717,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3703\/revisions\/11717"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}