Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11
thanks Pete and Bernie i'll do that. i have a HT20 that uses that tube. Rob K5UJ On Fri, Feb 12, 2010 at 5:38 PM, Bernie Doran wrote: > Fair radio in Lima, Ohio had a huge stock of them, I believe thousands at a > very reasonable price, give them a call or email. Bernie W8RPW > - Original Message - > From: "Rob Atkinson" > To: "Discussion of AM Radio in the Amateur Service" > > Sent: Friday, February 12, 2010 1:55 PM > Subject: Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11 > > > Jim, where do you get a 4D32 these days? > > thanx > > rob > K5UJ > >> >> Jack, >> >> First off, I have an HT-20 on the air and it does well on AM, so the >> problem is not generic to the transmitter design. I have not used a light >> bulb for a dummy antenna, at least not recently, but my average-reading >> watt meter does not bobble during modulation. I would expect a light bulb >> to get brighter during modulation, not dimmer, which is something you also >> know. >> >> From the list of things that Larry suggested, above, I would not think >> that #1 would not be a cause of this particular problem. Human voice audio >> is not symmetric, so you can achieve more full modulation by selecting the >> better phasing connection, but neither phasing connection should cause >> "downward modulation." #5 is also not likely to be the problem if the rig >> has the original modulation transformer. The other suggestions are all >> likely causes. Another one might be a very flat (low gain, low emission) >> 4D32 final amplifier tube. >> >> Let me know how much final grid drive you are running and what the loaded >> plate current is for the final amp. The manual recommends 260 ma plate >> current for CW and 320 ma for phone, but I don't run any more than 200 ma >> for either phone or CW. 4D32's are too expensive! It also recommends 10 ma >> for grid current. The ARRL Handbook ratings for a 4D32 are a maximum of >> 240 ma for CW and 220 ma for phone, with 12 ma of grid current for the CW >> condition and 10 ma for phone. I can compare your operating parameters to >> the ones I'm running currently on my rig. Mine is tuned up on 14286 right >> now in anticipation of the Classic Exchange AM event on Sunday. >> >> Good luck, >> >> Jim Hanlon, W8KGI >> __ >> > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to amradio-requ...@mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to amradio-requ...@mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11
Fair radio in Lima, Ohio had a huge stock of them, I believe thousands at a very reasonable price, give them a call or email. Bernie W8RPW - Original Message - From: "Rob Atkinson" To: "Discussion of AM Radio in the Amateur Service" Sent: Friday, February 12, 2010 1:55 PM Subject: Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11 Jim, where do you get a 4D32 these days? thanx rob K5UJ > > Jack, > > First off, I have an HT-20 on the air and it does well on AM, so the > problem is not generic to the transmitter design. I have not used a light > bulb for a dummy antenna, at least not recently, but my average-reading > watt meter does not bobble during modulation. I would expect a light bulb > to get brighter during modulation, not dimmer, which is something you also > know. > > From the list of things that Larry suggested, above, I would not think > that #1 would not be a cause of this particular problem. Human voice audio > is not symmetric, so you can achieve more full modulation by selecting the > better phasing connection, but neither phasing connection should cause > "downward modulation." #5 is also not likely to be the problem if the rig > has the original modulation transformer. The other suggestions are all > likely causes. Another one might be a very flat (low gain, low emission) > 4D32 final amplifier tube. > > Let me know how much final grid drive you are running and what the loaded > plate current is for the final amp. The manual recommends 260 ma plate > current for CW and 320 ma for phone, but I don't run any more than 200 ma > for either phone or CW. 4D32's are too expensive! It also recommends 10 ma > for grid current. The ARRL Handbook ratings for a 4D32 are a maximum of > 240 ma for CW and 220 ma for phone, with 12 ma of grid current for the CW > condition and 10 ma for phone. I can compare your operating parameters to > the ones I'm running currently on my rig. Mine is tuned up on 14286 right > now in anticipation of the Classic Exchange AM event on Sunday. > > Good luck, > > Jim Hanlon, W8KGI > __ > __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11
Rob, Fair Radio in Ohio... -73- Peter K2LRC www.k2lrc.com In God We Trust ! -Original Message- From: amradio-boun...@mailman.qth.net [mailto:amradio-boun...@mailman.qth.net] On Behalf Of Rob Atkinson Sent: Friday, February 12, 2010 1:55 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11 Jim, where do you get a 4D32 these days? thanx rob K5UJ > > Jack, > > First off, I have an HT-20 on the air and it does well on AM, so the problem is not generic to the transmitter design. I have not used a light bulb for a dummy antenna, at least not recently, but my average-reading watt meter does not bobble during modulation. I would expect a light bulb to get brighter during modulation, not dimmer, which is something you also know. > > From the list of things that Larry suggested, above, I would not think that #1 would not be a cause of this particular problem. Human voice audio is not symmetric, so you can achieve more full modulation by selecting the better phasing connection, but neither phasing connection should cause "downward modulation." #5 is also not likely to be the problem if the rig has the original modulation transformer. The other suggestions are all likely causes. Another one might be a very flat (low gain, low emission) 4D32 final amplifier tube. > > Let me know how much final grid drive you are running and what the loaded plate current is for the final amp. The manual recommends 260 ma plate current for CW and 320 ma for phone, but I don't run any more than 200 ma for either phone or CW. 4D32's are too expensive! It also recommends 10 ma for grid current. The ARRL Handbook ratings for a 4D32 are a maximum of 240 ma for CW and 220 ma for phone, with 12 ma of grid current for the CW condition and 10 ma for phone. I can compare your operating parameters to the ones I'm running currently on my rig. Mine is tuned up on 14286 right now in anticipation of the Classic Exchange AM event on Sunday. > > Good luck, > > Jim Hanlon, W8KGI > __ > __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11
Jim, where do you get a 4D32 these days? thanx rob K5UJ > > Jack, > > First off, I have an HT-20 on the air and it does well on AM, so the problem > is not generic to the transmitter design. I have not used a light bulb for a > dummy antenna, at least not recently, but my average-reading watt meter does > not bobble during modulation. I would expect a light bulb to get brighter > during modulation, not dimmer, which is something you also know. > > From the list of things that Larry suggested, above, I would not think that > #1 would not be a cause of this particular problem. Human voice audio is not > symmetric, so you can achieve more full modulation by selecting the better > phasing connection, but neither phasing connection should cause "downward > modulation." #5 is also not likely to be the problem if the rig has the > original modulation transformer. The other suggestions are all likely > causes. Another one might be a very flat (low gain, low emission) 4D32 final > amplifier tube. > > Let me know how much final grid drive you are running and what the loaded > plate current is for the final amp. The manual recommends 260 ma plate > current for CW and 320 ma for phone, but I don't run any more than 200 ma for > either phone or CW. 4D32's are too expensive! It also recommends 10 ma for > grid current. The ARRL Handbook ratings for a 4D32 are a maximum of 240 ma > for CW and 220 ma for phone, with 12 ma of grid current for the CW condition > and 10 ma for phone. I can compare your operating parameters to the ones I'm > running currently on my rig. Mine is tuned up on 14286 right now in > anticipation of the Classic Exchange AM event on Sunday. > > Good luck, > > Jim Hanlon, W8KGI > __ > __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] AMRadio Digest, Vol 73, Issue 11
Jack Schrader wrote: > I hope you remember me, Jack with the ht20. > > Got the ht20 hooked up and have god output in cw but not am. I hooked up a > 100w 210v test light to the antenna output on the ht20 but when I speak into > the mic on am the light gets dimmer not brighter. Any idea about that? > > TnxJack > > Possibilities: 1) audio out-of-phase 2) insufficient drive to grid of final 3) final not properly loaded 4) insufficient capacitance in filter of HV supply to final/modulators 5) improper impedance match in mod tranny If after checking the obvious and it still occurs, just put it on the air. I have one rig that does this but still sounds quite acceptable. You can look deeper into it later, but have some fun with it in the mean time... Does the modulation envelope look OK on the scope? 73, -Larry/NE1S Jack, First off, I have an HT-20 on the air and it does well on AM, so the problem is not generic to the transmitter design. I have not used a light bulb for a dummy antenna, at least not recently, but my average-reading watt meter does not bobble during modulation. I would expect a light bulb to get brighter during modulation, not dimmer, which is something you also know. From the list of things that Larry suggested, above, I would not think that #1 would not be a cause of this particular problem. Human voice audio is not symmetric, so you can achieve more full modulation by selecting the better phasing connection, but neither phasing connection should cause "downward modulation." #5 is also not likely to be the problem if the rig has the original modulation transformer. The other suggestions are all likely causes. Another one might be a very flat (low gain, low emission) 4D32 final amplifier tube. Let me know how much final grid drive you are running and what the loaded plate current is for the final amp. The manual recommends 260 ma plate current for CW and 320 ma for phone, but I don't run any more than 200 ma for either phone or CW. 4D32's are too expensive! It also recommends 10 ma for grid current. The ARRL Handbook ratings for a 4D32 are a maximum of 240 ma for CW and 220 ma for phone, with 12 ma of grid current for the CW condition and 10 ma for phone. I can compare your operating parameters to the ones I'm running currently on my rig. Mine is tuned up on 14286 right now in anticipation of the Classic Exchange AM event on Sunday. Good luck, Jim Hanlon, W8KGI __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
