[Today’s run:\u00a0\u00a0 run\/walk 4 miles in the afternoon]<\/p>\n
I think it was in 2001.\u00a0 I had gotten interested again in ham radio shortly before 2000 and by 2001 I was back on HF with a 40 meter QRP radio.<\/p>\n
I was on some email mailing lists about QRP\u00a0 (low power) radio topics.\u00a0 Someone put together a group project.\u00a0 People who wanted to participate could buy the Small Wonder Labs\u00a0 SW-20 QRP transceiver and be lead through the construction step by step.<\/p>\n
I decided to give that a try.\u00a0 I really learned quite a bit.\u00a0 The SW-20 is based on the NE-602 mixer\/amplifier chip.\u00a0 It is CW only, its varactor tuning covers about 50 kHz of the 20 meter band, and has a nice\u00a0 IF crystal filter in it.\u00a0\u00a0 The power output is around 2 watts.\u00a0 It has NE-602 chips in the front end and as the product detector.<\/p>\n
I got mine built ok.\u00a0 The enclosure I bought was a bit tight.\u00a0 I ended up grinding down the sides of the board just a bit to allow it to fit.\u00a0 Small Wonder sold an add-on kit called a Freq-Mite which tells you your working frequency in the headphones using morse code.\u00a0 I bought that too.<\/p>\n
Anyway, I was using my other 20 meter qrp rig the other day\u00a0 (the Willamette, another group project) and decided to give the old SW-20 a comparison run.\u00a0 It wasn’t working well at all.\u00a0 I discovered that the antenna jack had become disconnected on the ground side.\u00a0 After I fixed that I touched up the alignment and used it to talk to a guy in Ohio.<\/p>\n
As for comparison, the SW-20 is a\u00a0 single-signal superhet and that crystal filter makes quite a difference in listening performance.\u00a0 I think the direct conversion Willamette is a bit more sensitive and a purer signal.\u00a0 An interesting feature of the SW-20 is that the side-tone is generated by\u00a0 leakage from the transmitter.\u00a0 I thought that was a neat idea.\u00a0 The Willamette has RIT\u00a0 (which can be added to the SW-20). I personally enjoy the direct-conversion-with-RIT operating experience more then the superhets.\u00a0 A classic example of what I’m talking about is the TenTec Century 21.<\/p>\n
There is a modification I could do to expand the frequency coverage.\u00a0 I am thinking about that and about maybe putting it in a different enclosure.<\/p>\n
I have my old SX-11 and GPSDO projects still in play, so maybe the SW-20 improvements\u00a0 will happen later down the line.<\/p>\n
(I would really like to get another 40 meter qrp rig and something that will operate on 30 meters.)<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
[Today’s run:\u00a0\u00a0 run\/walk 4 miles in the afternoon] I think it was in 2001.\u00a0 I had gotten interested again in ham radio shortly before 2000 and by 2001 I was back on HF with a 40 meter QRP radio. I was on some email mailing lists about QRP\u00a0 (low power) radio topics.\u00a0 Someone put together […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-1545","post","type-post","status-publish","format-standard","hentry","category-ham-radio"],"_links":{"self":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/1545","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1545"}],"version-history":[{"count":2,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/1545\/revisions"}],"predecessor-version":[{"id":1547,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/1545\/revisions\/1547"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1545"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1545"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1545"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}