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uBITX & 160 meters
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Rocco Conte
¿ªÔÆÌåÓýI was playing with the uBitx I just completed and noticed that it will TX on 160 meters. Is the reason it is not used on 160 the filtering? I seem to remember a post or something showing a filter to use on 160. Can someone give me the scoop on this? ? Thanks, Rocco ¨C WU2M ? Sent from for Windows 10 ? |
¿ªÔÆÌåÓýSee this post:It works you just need a low pass filter. I found it draws more current so make sure you have a good heatsink or fan to keep the finals cool. On May 3, 2018, at 6:20 PM, Rocco Conte <rconte41@...> wrote:
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Interesting, have a couple of questions: how much power output do u see on 10m and how much current? I had an amplifier for 160m that has its own low pass filters for 160m, should I use lowpass filters also between the Ubitx and the amplifier? 73 Franco Il 04/mag/2018 00:27, "bill richardson" <ng1p.bill@...> ha scritto:
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Typo I meant how much power output do u see on 160m and how much current? Il 04/mag/2018 15:37, "iz oos" <and2oosiz2@...> ha scritto:
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Rocco Conte
I saw about 12 watts but did not look at the current draw. It was an accident I ended up on 160. When I noticed it would hear, I switched to the dummy load to check for tx and sure enough it worked! On Thu, May 3, 2018 at 6:20 PM, Rocco Conte <rconte41@...> wrote:
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Good to know, luckily I made one low pass filter for 160m so I could try it but I have not any power supply with the current meter beyond 2A. My 13.6vdc 25A has no meter at all. Il 04/mag/2018 18:16, "Rocco Conte" <rconte41@...> ha scritto:
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You can reduce power out by twiddling RV1 on the uBitx.
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Turning it clockwise reduces power (it's backwards from most pots in this world.? as are the RV2 and RV3 IRF510 bias pots) Alternately, reduce mike gain somehow. Jerry On Fri, May 4, 2018 at 09:39 am, iz oos wrote:
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Not unexpected, looks vaguely like a square wave, which is what you get from a sum of odd harmonics.
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The relays are selecting the 80m low pass filter, with a corner about halfway between 4mhz and 7mhz, so 6.0mhz. Third harmonic of 1.8mhz is 5.4mhz, which is going to get passed quite well by your 80m filter. The push-pull amp probably nulls out most of the second harmonic.? So we get the fundamental and the 3'rd harmonic. Hook that up to an antenna and you will be getting heard quite well on both 1.8 and 5.4 mhz. Jerry On Fri, May 4, 2018 at 10:21 am, John wrote: This how CW at 160m looks like. |
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Of course, that linear amp should be vaguely linear, and not flat-topping your 1.8mhz into a square wave.
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Could be that it will clean up considerably if you turn down the gain at RV1. But even if you get it looking like a sine wave on the scope, will still need the 160m filter. On Fri, May 4, 2018 at 10:36 am, Jerry Gaffke wrote:
Not unexpected, looks vaguely like a square wave, which is what you get from a sum of odd harmonics. |