[AMRadio] WTB/WTS and a question
Good Morning, 1. I would like to buy or swap for two solid state plug-in replacements for the 872A mercury vapor rectifiers for my KW-1. Enuf said. 2. I am restoring a broadcast/shortwave radio set for my brother. It is an RCA 8BT, battery operated 'farm set' from the 30's. In addition to using three 45V batteries in series for the 135V B+, it used four small 1.5V cells for biasing the 1st detector and the 1st and 2nd IF's, and a multi-tapped battery to get 3V bias for the 2nd detector and 7.5V bias for the audio driver. As my brother doesn't live on an electricity deprived farm, I am building a solid state AC supply to meet those needs. The tubes all have 2V filaments. The radio has two inputs for a filament supply, 2V or 2.5V (the 2.5V input merely inserts a series resistor). My question iswhy did anyone manufacture 2V filament tubes and what kind of battery put out 2V or 2.5V? I am building a solid state supply for the 2V requirement as well so the question is merely to satisfy my curiosity. By the way, this set uses a pair of push-pull 49's for the audio output stage. These are zero bias tubes in Class B with 3.5W capability. Very cool. Thanks for reading, Brian WA5UEK
[AMRadio] 15 Meters Open
It's 15:20Z, and I have just finished a qso with K2UTC on 15 ssb. We had peaks of 15 over pretty consistently throughout the qso. This may be a good day to try AM, so I'll keep an ear on 21.425. K2UTC and I talked many times on 10 meter AM during the early 70s. Mike Duke, K5XU American Council of Blind Radio Amateurs
[AMRadio] BC Image on 21.425
I'm hearing what appears to be a mixing of 2 shortwave BC stations right on 21.425. Both the audio and carriers are pretty ragged, and I can't tell from whence they may be originating. I'll check 21.420 as the splatter is less there than it is on 21.430. Mike Duke, K5XU American Council of Blind Radio Amateurs
Re: [AMRadio] WTB/WTS and a question
A single wet cell (lead/acid) battery produced 2.2V. Bob Macklin K5MYJ Seattle, Wa. - Original Message - From: Brian K Harris [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; amradio@mailman.qth.net Sent: Friday, December 30, 2005 8:21 AM Subject: [AMRadio] WTB/WTS and a question Good Morning, 1. I would like to buy or swap for two solid state plug-in replacements for the 872A mercury vapor rectifiers for my KW-1. Enuf said. 2. I am restoring a broadcast/shortwave radio set for my brother. It is an RCA 8BT, battery operated 'farm set' from the 30's. In addition to using three 45V batteries in series for the 135V B+, it used four small 1.5V cells for biasing the 1st detector and the 1st and 2nd IF's, and a multi-tapped battery to get 3V bias for the 2nd detector and 7.5V bias for the audio driver. As my brother doesn't live on an electricity deprived farm, I am building a solid state AC supply to meet those needs. The tubes all have 2V filaments. The radio has two inputs for a filament supply, 2V or 2.5V (the 2.5V input merely inserts a series resistor). My question iswhy did anyone manufacture 2V filament tubes and what kind of battery put out 2V or 2.5V? I am building a solid state supply for the 2V requirement as well so the question is merely to satisfy my curiosity. By the way, this set uses a pair of push-pull 49's for the audio output stage. These are zero bias tubes in Class B with 3.5W capability. Very cool. Thanks for reading, Brian WA5UEK __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] WTB/WTS and a question
Hi Brian; In my ignorance, I have never heard of 2 volt tubes. What are their numbers? Thanks and HNY. 73, Ed Richards K6UUZ Simi Valley, Ca 93065 Home of the Air Force 1 pavilion On Fri, 30 Dec 2005 10:21:15 -0600 Brian K Harris [EMAIL PROTECTED] writes: Good Morning, 1. I would like to buy or swap for two solid state plug-in replacements for the 872A mercury vapor rectifiers for my KW-1. Enuf said. 2. I am restoring a broadcast/shortwave radio set for my brother. It is an RCA 8BT, battery operated 'farm set' from the 30's. In addition to using three 45V batteries in series for the 135V B+, it used four small 1.5V cells for biasing the 1st detector and the 1st and 2nd IF's, and a multi-tapped battery to get 3V bias for the 2nd detector and 7.5V bias for the audio driver. As my brother doesn't live on an electricity deprived farm, I am building a solid state AC supply to meet those needs. The tubes all have 2V filaments. The radio has two inputs for a filament supply, 2V or 2.5V (the 2.5V input merely inserts a series resistor). My question iswhy did anyone manufacture 2V filament tubes and what kind of battery put out 2V or 2.5V? I am building a solid state supply for the 2V requirement as well so the question is merely to satisfy my curiosity. By the way, this set uses a pair of push-pull 49's for the audio output stage. These are zero bias tubes in Class B with 3.5W capability. Very cool. Thanks for reading, Brian WA5UEK __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] WTB/WTS and a question
The tubes all have 2V filaments. The radio has two inputs for a filament supply, 2V or 2.5V (the 2.5V input merely inserts a series resistor). My question iswhy did anyone manufacture 2V filament tubes and Two volt tube were used in the 19 twenties and thirties for FARM radios. They used a 2 volt wet cell. One third of a car battery for those tubes. Also The audio always push pull class B triodes for maximum B battery utilization. Folks carried the cell to the service station or perhaps had a windmill generator from a T model Ford connected for recharging. REA did not start until about 1933 or so and almost no Farmer in America had Electric power. The dry B batteries were 135 volt and lasted a long time but many units had a vibrator pack that ran off a 6 volt wet cell battery from a car or the Edison Electric Company. By the mid 1930's the 230's etc were amost obsolete. Hope this helps HNY, 73 Mike
Re: [AMRadio] 15 Meters Open
Yes, Mike. 15 is certainly open. Just had a 90 minute QSO with W7ID in Idaho...59 +20 over most of the timeslight QSB. More AM ops should get on. Larry KC8JX St. Joseph, MI --- Mike Duke, K5XU [EMAIL PROTECTED] wrote: It's 15:20Z, and I have just finished a qso with K2UTC on 15 ssb. We had peaks of 15 over pretty consistently throughout the qso. This may be a good day to try AM, so I'll keep an ear on 21.425. Mike Duke, K5XU American Council of Blind Radio Amateurs __ Yahoo! DSL Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com
Re: [AMRadio] WTB/WTS and a question
--- Brian K Harris [EMAIL PROTECTED] wrote: The tubes all have 2V filaments. The radio has two inputs for a filament supply, 2V or 2.5V (the 2.5V input merely inserts a series resistor). My question iswhy did anyone manufacture 2V filament tubes and what kind of battery put out 2V or 2.5V? I am building a solid state supply for the 2V requirement as well so the question is merely to satisfy my curiosity. A wet cell. You will have to have very good filtering on the filament supply to avoid hum as the filament is also the cathode. Dave, VE1ADH __ Find your next car at http://autos.yahoo.ca
[AMRadio] FS: Ladderline (Real open wire)
FOR SALE: Two rolls of 600 ohm ladder line. This is the real feedline that has coppper wire and plastic spacers, unlike the plastic twinlead stuff with windows that is 450 ohm and cracks etc. This feedline can take it. Each roll is approximately 100 feet long. I am not going to unroll them and measure, but it is 60 turns coiled up and each is about 8 diameter average - so I figure there must be at least 100 feet here on each roll. I will sell the two rolls for $40.00 plus $8.50 for shipping
[AMRadio] 80 Meters Hot
It's just after 10 PM central time, and 3880 is full of 80 meter heavy-weights. From Mississippi, I am hearing Ko6NM, Wa3VJB, W5OD, W7ID, and several others, all with reasonable signals, some with amazing signals for my 80 meter qth. There's also some activity on 3885, but it's not nearly as strong here as the guys on 3880. Happy listening! Mike Duke, K5XU American Council of Blind Radio Amateurs
