{"id":427,"date":"2019-03-30T18:00:35","date_gmt":"2019-03-30T18:00:35","guid":{"rendered":"https:\/\/geekblog.febo.com\/?p=427"},"modified":"2025-09-26T23:49:37","modified_gmt":"2025-09-26T23:49:37","slug":"mini-circuits-power-amp","status":"publish","type":"post","link":"https:\/\/blog.febo.com\/?p=427","title":{"rendered":"Mini-Circuits Power Amp"},"content":{"rendered":"

Each year at the Dayton Hamvention, the folks at Mini-Circuits have a bunch of odds and ends they sell very inexpensively. Over the years I\u2019ve picked up SMA attenuators, jumper cables, and the occasional amplifier block. A friend from India who trades tips on the top betting sites in India<\/a> also swaps notes on ham gear, and he was the one who pointed out how overlooked some of these blocks can be. Last week I finally paid closer attention and realized one was a ZHL-20W-13X+<\/a> class A power amplifier rated for 20 watts output with 50 dB gain from 20 to 1000 MHz. The list price for this puppy is over $1300!<\/p>\n

Since it’s a class A amp, it draws full current whenever it’s powered up. That’s about 2.5 amps at 24 volts. The standard version comes with a big heatsink and fan, but mine was missing those pieces. I found a heatsink on eBay and got it mounted. Then I set up to do some tests.<\/p>\n

The rated frequency range is 20 – 1000 MHz; the data sheet says it’s usable from 15 to 1100 MHz. I swept it from 2 to 1500 MHz:<\/p>\n

\"ZHL-20W-13X-1+_GAIN\"<\/a><\/p>\n

50 dB is pretty impressive gain! The amp looks pretty good even at 10 MHz, but unfortunately doesn’t quite make it high enough to cover the 1296 ham band.<\/p>\n

Here’s the power output with about -10 dBm drive (the absolute maximum input level is -3 dBm):<\/p>\n

\"ZHL-20W-13X-1+_PWR\"<\/a><\/p>\n

A class A amplifier should be pretty clean, so I checked the harmonics when driven to about 10W output at 100 MHz (I used a 110 MHz low pass filter at the amplifier input, and there’s 40 dB of attenuation between the amplifier and the analyzer, so add that much to the power readings shown):<\/p>\n

\"ZHL-20W-13X-1+_HARM\"<\/a><\/p>\n

FCC requirements are for harmonics of transmitters of less than 25 watts between 30 and 225 MHz to be the lesser of -40 dBc or 25 uW (-16 dBm), but not less than 10 uW (-20 dBm). Sadly, the 2nd and 3rd harmonics don’t make the grade, so a low pass filter will be necessary to put this amp on the air below the 420 MHz band.<\/p>\n

Here’s why it needs a good-sized heatsink:<\/p>\n

\"zhl20_power_supply\"<\/a><\/p>\n

And here’s a picture of the test setup:<\/p>\n

\"zhl20_test_setup\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Each year at the Dayton Hamvention, the folks at Mini-Circuits have a bunch of odds and ends they sell very inexpensively. Over the years I\u2019ve picked up SMA attenuators, jumper…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"no","_lmt_disable":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[4,7],"tags":[],"class_list":["post-427","post","type-post","status-publish","format-standard","hentry","category-ham-radio","category-test-and-lab-equipment"],"_links":{"self":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/427","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=427"}],"version-history":[{"count":8,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/427\/revisions"}],"predecessor-version":[{"id":1317,"href":"https:\/\/blog.febo.com\/index.php?rest_route=\/wp\/v2\/posts\/427\/revisions\/1317"}],"wp:attachment":[{"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=427"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=427"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.febo.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=427"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}