{"id":639,"date":"2020-04-15T15:47:07","date_gmt":"2020-04-15T13:47:07","guid":{"rendered":"http:\/\/lz2jr.com\/blog\/?p=639"},"modified":"2020-04-19T06:49:59","modified_gmt":"2020-04-19T04:49:59","slug":"vbf-variable-bandwith-filter-and-agc-response-options","status":"publish","type":"post","link":"https:\/\/lz2jr.com\/blog\/index.php\/vbf-variable-bandwith-filter-and-agc-response-options\/","title":{"rendered":"VBF (variable bandwith filter) and AGC response options"},"content":{"rendered":"

Switching ON and OFF of the VBF always interacts with RGO ONE receiver Automatic gain control system (AGC). Since VBF reduces noises in RX path – from the ether and from previous IF amplifier, AGC system will act slightly different. Let’s discuss these cases:<\/p>\n

1. VBF is not in use (or not installed) AGC treshold is aligned with R26 on IF\/AF board in order to obtain S1 or no indication on S-meter. (This procedure has been already done by manufacturer)<\/p>\n

2. VBF is installed and is selected (B01 – B10) via pressing FLT button. IF signal + noise is decreased and then AGC response and action will be decreased. Reading on S-meter will fall down. AGC treshold must be realigned with R26 potentiometer in order to have proper AGC response and S-meter reading. But if you decide to switch VBF off and use standard filter again – S-meter reading will not be valid and R26 must be realigned again.<\/p>\n

How to deal this issue.
\nSuggestions:<\/strong><\/p>\n

1. If you like to achieve best AGC response and you are mostly CW operator and you are using mainly narrow filters – then engage VBF and align R26 to null S-meter reading with no antenna connected to RGO ONE 50 ohm input. First rotate R26 counterclockwise and when S-meter starts to raise – slightly\u00a0 and carefully return back till S1 on S-meter flickers or no segments appear lit on LCD. In order to achieve true S-meter readings – always use VBF – for CW and sideband modes – just increase or reduce bandwith with encoder 1 on the front panel.<\/p>\n

2. If you are not using narrow filter much – align AGC treshold with R26 when VBF is off or do not align it if S-meter reading is null (with no antenna connected). Though S-meter reading might not be accurate on some filter bandwiths when VBF is on. Received signal strength won’t degrade or been lost with this adjustment. Just S-meter reading will show some S units.<\/p>\n

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

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

Switching ON and OFF of the VBF always interacts with RGO ONE receiver Automatic gain control system (AGC). Since VBF reduces noises in RX path – from the ether and from previous IF amplifier, AGC system will act slightly different.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"ngg_post_thumbnail":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-639","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/posts\/639","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=639"}],"version-history":[{"count":6,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/posts\/639\/revisions"}],"predecessor-version":[{"id":650,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/posts\/639\/revisions\/650"}],"wp:attachment":[{"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=639"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=639"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lz2jr.com\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}