Re: [Flexradio] 100W PA Bias Adjustment ECO
Eric and Gerald: Could you please confirm that my black box has the proper bias adjustment? Thanks, Ryk N6DQ --- [EMAIL PROTECTED] wrote: Eric and Gerald: I haven't done this ECO mod yet, but expect that I need it from audio reports I've received. When measuring total current (DC) drain before actually doing anything, I found it to be 1.98 amps. Since this is significantly higher than the 1.5 amps mentioned in the ECO, I thought I better check with you on whether or not this is a problem. What do you suggest? (You may not recall, but I was the guy who had an oscillating 100PA until I went in and resoldered several things. After that, it seems to work fine - minus some distortion on SSB. PSK is very clean.) Any idea what qiescent current draw should be? Gary AI4IN -- Original message -- From: Eric [EMAIL PROTECTED] FYI: The ECO document has been updated to clarify several things in the documentation. The newer document is available on the private download site. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gerald Youngblood Sent: Tuesday, August 30, 2005 2:21 PM To: MailFlexRadio Subject: [Flexradio] 100W PA Bias Adjustment ECO Dear FlexRadio customers, The SDR-100WPA, 100 Watt amplifier module is included in all SDR-ASM/TRA 100 Watt model radios and is offered as an upgrade option for existing SDR-ASM/TR 1 Watt models. The amplifier uses a push-pull pair of IRF510 FETs in the driver stage followed by a push-pull pair of 2SC2879 bipolar transistors in the final stage. 100W radios and amplifier modules shipped before July 15, 2005, had the FET bias set to either 30mA or 50mA per transistor. Recent experiments have shown that IMD distortion at the lower bias levels may result in a low level of distortion on SSB transmissions which may or may not be audible on the air. Before and after recordings demonstrate that this distortion is no longer audible when the FET bias is set to 100mA per transistor. IMD products as displayed on a spectrum analyzer are reduced as well. We have posted a completely optional bias adjustment procedure (ECO-027) on the private customer download site that can be used to modify these settings. Radios shipped on or after July 15, 2005 include the 100mA bias settings. 73, Gerald K5SDR FlexRadio Systems ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Re: [Flexradio] 100W PA Bias Adjustment ECO
Your unit shipped 7/21, so you should be good to go. Eric -Original Message- From: Ryk Houseman [mailto:[EMAIL PROTECTED] Sent: Thursday, September 01, 2005 3:57 PM To: [EMAIL PROTECTED]; Eric; 'Gerald Youngblood'; 'MailFlexRadio' Subject: Re: [Flexradio] 100W PA Bias Adjustment ECO Eric and Gerald: Could you please confirm that my black box has the proper bias adjustment? Thanks, Ryk N6DQ --- [EMAIL PROTECTED] wrote: Eric and Gerald: I haven't done this ECO mod yet, but expect that I need it from audio reports I've received. When measuring total current (DC) drain before actually doing anything, I found it to be 1.98 amps. Since this is significantly higher than the 1.5 amps mentioned in the ECO, I thought I better check with you on whether or not this is a problem. What do you suggest? (You may not recall, but I was the guy who had an oscillating 100PA until I went in and resoldered several things. After that, it seems to work fine - minus some distortion on SSB. PSK is very clean.) Any idea what qiescent current draw should be? Gary AI4IN -- Original message -- From: Eric [EMAIL PROTECTED] FYI: The ECO document has been updated to clarify several things in the documentation. The newer document is available on the private download site. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gerald Youngblood Sent: Tuesday, August 30, 2005 2:21 PM To: MailFlexRadio Subject: [Flexradio] 100W PA Bias Adjustment ECO Dear FlexRadio customers, The SDR-100WPA, 100 Watt amplifier module is included in all SDR-ASM/TRA 100 Watt model radios and is offered as an upgrade option for existing SDR-ASM/TR 1 Watt models. The amplifier uses a push-pull pair of IRF510 FETs in the driver stage followed by a push-pull pair of 2SC2879 bipolar transistors in the final stage. 100W radios and amplifier modules shipped before July 15, 2005, had the FET bias set to either 30mA or 50mA per transistor. Recent experiments have shown that IMD distortion at the lower bias levels may result in a low level of distortion on SSB transmissions which may or may not be audible on the air. Before and after recordings demonstrate that this distortion is no longer audible when the FET bias is set to 100mA per transistor. IMD products as displayed on a spectrum analyzer are reduced as well. We have posted a completely optional bias adjustment procedure (ECO-027) on the private customer download site that can be used to modify these settings. Radios shipped on or after July 15, 2005 include the 100mA bias settings. 73, Gerald K5SDR FlexRadio Systems ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Re: [Flexradio] 100W PA Bias Adjustment ECO
Eric and Gerald: I haven't done this ECO mod yet, but expect that I need it from audio reports I've received. When measuring total current (DC) drain before actually doing anything, I found it to be 1.98 amps. Since this is significantly higher than the 1.5 amps mentioned in the ECO, I thought I better check with you on whether or not this is a problem. What do you suggest? (You may not recall, but I was the guy who had an oscillating 100PA until I went in and resoldered several things. After that, it seems to work fine - minus some distortion on SSB. PSK is very clean.) Any idea what qiescent current draw should be? Gary AI4IN -- Original message -- From: Eric [EMAIL PROTECTED] FYI: The ECO document has been updated to clarify several things in the documentation. The newer document is available on the private download site. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gerald Youngblood Sent: Tuesday, August 30, 2005 2:21 PM To: MailFlexRadio Subject: [Flexradio] 100W PA Bias Adjustment ECO Dear FlexRadio customers, The SDR-100WPA, 100 Watt amplifier module is included in all SDR-ASM/TRA 100 Watt model radios and is offered as an upgrade option for existing SDR-ASM/TR 1 Watt models. The amplifier uses a push-pull pair of IRF510 FETs in the driver stage followed by a push-pull pair of 2SC2879 bipolar transistors in the final stage. 100W radios and amplifier modules shipped before July 15, 2005, had the FET bias set to either 30mA or 50mA per transistor. Recent experiments have shown that IMD distortion at the lower bias levels may result in a low level of distortion on SSB transmissions which may or may not be audible on the air. Before and after recordings demonstrate that this distortion is no longer audible when the FET bias is set to 100mA per transistor. IMD products as displayed on a spectrum analyzer are reduced as well. We have posted a completely optional bias adjustment procedure (ECO-027) on the private customer download site that can be used to modify these settings. Radios shipped on or after July 15, 2005 include the 100mA bias settings. 73, Gerald K5SDR FlexRadio Systems ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
