Re: Topband: Anyone have a boat load of J-310s?
Thanks, Andy I understand your IP and trade-secret issues. That's an interesting approach. I'll have to give it some thought, although I don't expect to be building preamps anytime in the foreseeable future. Was just curious why so many J-310/309. Now I understand. Have a good afternoon! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Monday, August 26, 2013 6:29 AM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Charlie wrote on Aug. 26. Your preamp sounds very interesting! It must be fairly elaborate, if it uses 8 of the J309 FETS! I'd be interested in the circuit! Charlie, I don't disclose circuit diagrams for commercial reasons. However the design is a push-pull using 4 fets in parallel to increase the gm and reduce the channel resistance, hence lower the noise. 73 Andrew G8LUG _ Topband Reflector _ Topband Reflector
Topband: Anyone have a boat load of J-310s?
The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Oooops - forgot to mention quantity --- four would be nice (in case they go south again) Jim R. The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Okee Dokede - someone offered to send me four - he said he has thousands of those J-310sthanks to all that replied with info! Jim R. From: rodenkirch_...@msn.com To: topband@contesting.com Subject: Anyone have a boat load of J-310s? Date: Sun, 25 Aug 2013 07:16:31 -0600 The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
What's taking out the J-310s, Jim? I have some around here somewhere, but it's been years since I've seen them. Did you try Digi-Key? Do you need to modify your preamp a bit to better protect the J-310s? 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James Rodenkirch Sent: Sunday, August 25, 2013 9:40 AM To: topband@contesting.com Subject: Re: Topband: Anyone have a boat load of J-310s? Okee Dokede - someone offered to send me four - he said he has thousands of those J-310sthanks to all that replied with info! Jim R. From: rodenkirch_...@msn.com To: topband@contesting.com Subject: Anyone have a boat load of J-310s? Date: Sun, 25 Aug 2013 07:16:31 -0600 The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Jim, If you really have trouble getting some J-310s, let me know. I'd really have to hunt -probably out in my garage. The J-310s that I have, if I could find them, are, I expect, at least 20 years old and pre-date the shenanigans that Paul is warning you about. The ones that I had, are, as I recall, either ON Semi or NSC. I probably should find mine, I guess. I bought the JFET version of the old AMECO preamp, from my friend, Bill, K4CIA, so I might need some spares someday. The vacuum tube version of the AMECO preamp didn't have those vulnerabilities, and worked great on all the low bands up through 30m, for the same purpose that you are using yours for. Paul's giving you some good advice. That's why I asked if you had tried Digi-Key. GL! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Sunday, August 25, 2013 2:44 PM To: James Rodenkirch; topband@contesting.com Subject: Re: Topband: Anyone have a boat load of J-310s? Jim, The major semiconductor manufacturers (e.g., Fairchild) who once mass-produced JFETS in TO-92 style cases have now obsoleted most of them. This occurred approximately 2-3 years ago. When shockwaves of the news hit, many folks (and the on-line bottom feeders), started hoarding the remaining supply. Even the SMD versions are now in danger of going obsolete. Presently, only InterFET Corporation and Linear Systems appear to be manufacturing both through-hole and SMD versions of high-performance JFETs although their per-piece prices are very high. Before the wave hit, I purchased hundreds of various JFETs in TO-92 style cases -- J310s being one type. You're welcome a to a few. True, in many applications it may not make a big difference between say a J310 and MPF-102, but it unnerves me when I don't know exactly what I'm using in a circuit. Be careful when sourcing any semiconductor. As you noticed, JFETs are widely available on the Asian market but when making a purchase through small on-line retailers - and the big auction site, it's not possible to trace the supply chain of the component to its origin. For example, some Toshiba low-noise bipolar transistors are in fact re-labeled 2N3904 devices. Unless the purchaser has access to a curve tracer and a means to perform critical noise and frequency response testing, one is left to trust the seller for a clean chain of custody between the time of manufacture and point of sale. When China is the only source of many TO-92 JFETs, the red flags are up (no pun intended). Because of this, I have only purchased semiconductors direct from the OEM or through well-established distributors including Newark, Mouser, Digi-Key, Arrow, AvNet, and Allied. For an interesting perspective concerning the severity of the counterfeit semiconductor market, see the following report issued by the Semiconductor Industry Association (SIA): http://tinyurl.com/l9hqpw6 Let me know if you're address is currently good on QRZ. Paul, W9AC - Original Message - From: James Rodenkirch rodenkirch_...@msn.com To: topband@contesting.com Sent: Sunday, August 25, 2013 9:16 AM Subject: Topband: Anyone have a boat load of J-310s? The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased production about 2 years back. I did a last time buy from Mouser for several thousand J310 and the much more linear J309. 73 Andrew Ikin G8LUG _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
I've found what I'll need, Charlie, courtesy of Andy Ikin! Thanks to all for the assistance on this project! 72, Jim Rodenkirch K9JWV From: charlie-cunning...@nc.rr.com To: w...@arrl.net; rodenkirch_...@msn.com; topband@contesting.com Date: Sun, 25 Aug 2013 15:55:21 -0400 Subject: Re: Topband: Anyone have a boat load of J-310s? Jim, If you really have trouble getting some J-310s, let me know. I'd really have to hunt -probably out in my garage. The J-310s that I have, if I could find them, are, I expect, at least 20 years old and pre-date the shenanigans that Paul is warning you about. The ones that I had, are, as I recall, either ON Semi or NSC. I probably should find mine, I guess. I bought the JFET version of the old AMECO preamp, from my friend, Bill, K4CIA, so I might need some spares someday. The vacuum tube version of the AMECO preamp didn't have those vulnerabilities, and worked great on all the low bands up through 30m, for the same purpose that you are using yours for. Paul's giving you some good advice. That's why I asked if you had tried Digi-Key. GL! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Sunday, August 25, 2013 2:44 PM To: James Rodenkirch; topband@contesting.com Subject: Re: Topband: Anyone have a boat load of J-310s? Jim, The major semiconductor manufacturers (e.g., Fairchild) who once mass-produced JFETS in TO-92 style cases have now obsoleted most of them. This occurred approximately 2-3 years ago. When shockwaves of the news hit, many folks (and the on-line bottom feeders), started hoarding the remaining supply. Even the SMD versions are now in danger of going obsolete. Presently, only InterFET Corporation and Linear Systems appear to be manufacturing both through-hole and SMD versions of high-performance JFETs although their per-piece prices are very high. Before the wave hit, I purchased hundreds of various JFETs in TO-92 style cases -- J310s being one type. You're welcome a to a few. True, in many applications it may not make a big difference between say a J310 and MPF-102, but it unnerves me when I don't know exactly what I'm using in a circuit. Be careful when sourcing any semiconductor. As you noticed, JFETs are widely available on the Asian market but when making a purchase through small on-line retailers - and the big auction site, it's not possible to trace the supply chain of the component to its origin. For example, some Toshiba low-noise bipolar transistors are in fact re-labeled 2N3904 devices. Unless the purchaser has access to a curve tracer and a means to perform critical noise and frequency response testing, one is left to trust the seller for a clean chain of custody between the time of manufacture and point of sale. When China is the only source of many TO-92 JFETs, the red flags are up (no pun intended). Because of this, I have only purchased semiconductors direct from the OEM or through well-established distributors including Newark, Mouser, Digi-Key, Arrow, AvNet, and Allied. For an interesting perspective concerning the severity of the counterfeit semiconductor market, see the following report issued by the Semiconductor Industry Association (SIA): http://tinyurl.com/l9hqpw6 Let me know if you're address is currently good on QRZ. Paul, W9AC - Original Message - From: James Rodenkirch rodenkirch_...@msn.com To: topband@contesting.com Sent: Sunday, August 25, 2013 9:16 AM Subject: Topband: Anyone have a boat load of J-310s? The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Actually, Jim - for 160 and 80m, where you could tolerate some capacitance, you could even try back-to-back 1 amp rectifiers, like IN4004-1N4007. You surely wouldn't blow those out! :-) I'd probably start with the 1N4148, though. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James Rodenkirch Sent: Sunday, August 25, 2013 4:43 PM To: Charlie Cunningham; 'Paul Christensen'; topband@contesting.com Subject: Re: Topband: Anyone have a boat load of J-310s? I've found what I'll need, Charlie, courtesy of Andy Ikin! Thanks to all for the assistance on this project! 72, Jim Rodenkirch K9JWV From: charlie-cunning...@nc.rr.com To: w...@arrl.net; rodenkirch_...@msn.com; topband@contesting.com Date: Sun, 25 Aug 2013 15:55:21 -0400 Subject: Re: Topband: Anyone have a boat load of J-310s? Jim, If you really have trouble getting some J-310s, let me know. I'd really have to hunt -probably out in my garage. The J-310s that I have, if I could find them, are, I expect, at least 20 years old and pre-date the shenanigans that Paul is warning you about. The ones that I had, are, as I recall, either ON Semi or NSC. I probably should find mine, I guess. I bought the JFET version of the old AMECO preamp, from my friend, Bill, K4CIA, so I might need some spares someday. The vacuum tube version of the AMECO preamp didn't have those vulnerabilities, and worked great on all the low bands up through 30m, for the same purpose that you are using yours for. Paul's giving you some good advice. That's why I asked if you had tried Digi-Key. GL! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Sunday, August 25, 2013 2:44 PM To: James Rodenkirch; topband@contesting.com Subject: Re: Topband: Anyone have a boat load of J-310s? Jim, The major semiconductor manufacturers (e.g., Fairchild) who once mass-produced JFETS in TO-92 style cases have now obsoleted most of them. This occurred approximately 2-3 years ago. When shockwaves of the news hit, many folks (and the on-line bottom feeders), started hoarding the remaining supply. Even the SMD versions are now in danger of going obsolete. Presently, only InterFET Corporation and Linear Systems appear to be manufacturing both through-hole and SMD versions of high-performance JFETs although their per-piece prices are very high. Before the wave hit, I purchased hundreds of various JFETs in TO-92 style cases -- J310s being one type. You're welcome a to a few. True, in many applications it may not make a big difference between say a J310 and MPF-102, but it unnerves me when I don't know exactly what I'm using in a circuit. Be careful when sourcing any semiconductor. As you noticed, JFETs are widely available on the Asian market but when making a purchase through small on-line retailers - and the big auction site, it's not possible to trace the supply chain of the component to its origin. For example, some Toshiba low-noise bipolar transistors are in fact re-labeled 2N3904 devices. Unless the purchaser has access to a curve tracer and a means to perform critical noise and frequency response testing, one is left to trust the seller for a clean chain of custody between the time of manufacture and point of sale. When China is the only source of many TO-92 JFETs, the red flags are up (no pun intended). Because of this, I have only purchased semiconductors direct from the OEM or through well-established distributors including Newark, Mouser, Digi-Key, Arrow, AvNet, and Allied. For an interesting perspective concerning the severity of the counterfeit semiconductor market, see the following report issued by the Semiconductor Industry Association (SIA): http://tinyurl.com/l9hqpw6 Let me know if you're address is currently good on QRZ. Paul, W9AC - Original Message - From: James Rodenkirch rodenkirch_...@msn.com To: topband@contesting.com Sent: Sunday, August 25, 2013 9:16 AM Subject: Topband: Anyone have a boat load of J-310s? The J-310s in my little preamp are kaput - I looked at Mouser but the shipping costs are way too high for a couple of little Jfets - any body have lots of extra J-310 (or equivalent) they could spare? What ever your costs would be, including mailing them off, would be far cheaper than what it would cost me to buy them outright! Thank you, in advance, for any help -- reply off line works good for me72, Jim Rodenkirch _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem with tuned loop that was using J310s. The IMD was caused by Radio Free Europe on 13m. 73 Andrew - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com; 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 9:14 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as well, and aren't so sensitive to transients etc. :-) (Showing my age, I guess!) -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 3:58 PM To: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased production about 2 years back. I did a last time buy from Mouser for several thousand J310 and the much more linear J309. 73 Andrew Ikin G8LUG _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Yes, we could swing the grids of those tubes quite a ways before encountering enough non-linearity to produce a significant amount of intermod, Andy! The old original AMECO tunable vacuum -tube preamp, that I borrowed from Bill, K4CIA, worked really well with my KAZ terminated RX loop for the low bands. It was connected to the receive antenna port on my FT-1000MP, so I wasn't blowing FETs! My electronic design career began before the end of the vacuum-tube era, and I used the 6DJ8 commercially in some VHF monitor receivers, as a cascode RF stage in the front-end. 73, Charlie, K4OTV -Original Message- From: Andy Ikin [mailto:andrew.i...@btopenworld.com] Sent: Sunday, August 25, 2013 5:16 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem with tuned loop that was using J310s. The IMD was caused by Radio Free Europe on 13m. 73 Andrew - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com; 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 9:14 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as well, and aren't so sensitive to transients etc. :-) (Showing my age, I guess!) -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 3:58 PM To: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased production about 2 years back. I did a last time buy from Mouser for several thousand J310 and the much more linear J309. 73 Andrew Ikin G8LUG _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Charlie, When I was poor man 40 years ago, I always wanted Tektronix 545B Scope, which I couldn't afford. So I built a Chinese Copy with discarded parts from the Calibration department of the computer company I worked for. The scope use many 6DJ8s. I did get it working after about a year; not bad for some one with no formal electronics training Tektronix were very helpful in supplying some critical parts. Looking back I must have been mad, but it was one hell of away to learn how these things work. Bye the way I manufacture a special Head Amplifier for the KAZ and other Flags. This has 1100 Ohm input matching/isolation transformer, about 20dB gain and a less than 1dB NF and uses 8 x J309s plus a string of 1N4148 limiting diodes. Wellbrook FLG100LN. There are about 70 units in service mainly in the US with MW Dxers. 73 Andrew G8LUG - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com Cc: 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 10:29 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Yes, we could swing the grids of those tubes quite a ways before encountering enough non-linearity to produce a significant amount of intermod, Andy! The old original AMECO tunable vacuum -tube preamp, that I borrowed from Bill, K4CIA, worked really well with my KAZ terminated RX loop for the low bands. It was connected to the receive antenna port on my FT-1000MP, so I wasn't blowing FETs! My electronic design career began before the end of the vacuum-tube era, and I used the 6DJ8 commercially in some VHF monitor receivers, as a cascode RF stage in the front-end. 73, Charlie, K4OTV -Original Message- From: Andy Ikin [mailto:andrew.i...@btopenworld.com] Sent: Sunday, August 25, 2013 5:16 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem with tuned loop that was using J310s. The IMD was caused by Radio Free Europe on 13m. 73 Andrew - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com; 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 9:14 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as well, and aren't so sensitive to transients etc. :-) (Showing my age, I guess!) -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 3:58 PM To: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased production about 2 years back. I did a last time buy from Mouser for several thousand J310 and the much more linear J309. 73 Andrew Ikin G8LUG _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Gee, that's really interesting, Andy! I also built a much simpler oscilloscope when I was a teenager and new ham! Yours was a really elaborate and impressive 'scope project! Congrats! Glad to hear from someone who has experience with the KAZ and flag antennas. My KAZ was for 160 and terminated in 1000 ohms - mostly because that's what I had on hand. It was a very good RX antenna for 80, 40 and 30m as well. Your preamp sounds very interesting! It must be fairly elaborate, if it uses 8 of the J309 FETS! I'd be interested in the circuit! Best regards, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 6:32 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Charlie, When I was poor man 40 years ago, I always wanted Tektronix 545B Scope, which I couldn't afford. So I built a Chinese Copy with discarded parts from the Calibration department of the computer company I worked for. The scope use many 6DJ8s. I did get it working after about a year; not bad for some one with no formal electronics training Tektronix were very helpful in supplying some critical parts. Looking back I must have been mad, but it was one hell of away to learn how these things work. Bye the way I manufacture a special Head Amplifier for the KAZ and other Flags. This has 1100 Ohm input matching/isolation transformer, about 20dB gain and a less than 1dB NF and uses 8 x J309s plus a string of 1N4148 limiting diodes. Wellbrook FLG100LN. There are about 70 units in service mainly in the US with MW Dxers. 73 Andrew G8LUG - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com Cc: 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 10:29 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Yes, we could swing the grids of those tubes quite a ways before encountering enough non-linearity to produce a significant amount of intermod, Andy! The old original AMECO tunable vacuum -tube preamp, that I borrowed from Bill, K4CIA, worked really well with my KAZ terminated RX loop for the low bands. It was connected to the receive antenna port on my FT-1000MP, so I wasn't blowing FETs! My electronic design career began before the end of the vacuum-tube era, and I used the 6DJ8 commercially in some VHF monitor receivers, as a cascode RF stage in the front-end. 73, Charlie, K4OTV -Original Message- From: Andy Ikin [mailto:andrew.i...@btopenworld.com] Sent: Sunday, August 25, 2013 5:16 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem with tuned loop that was using J310s. The IMD was caused by Radio Free Europe on 13m. 73 Andrew - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Andy Ikin' andrew.i...@btopenworld.com; 'Topband Reflector' topband@contesting.com Sent: Sunday, August 25, 2013 9:14 PM Subject: Re: Topband: Anyone have a boat load of J-310s? Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as well, and aren't so sensitive to transients etc. :-) (Showing my age, I guess!) -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 3:58 PM To: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased production about 2 years back. I did a last time buy from Mouser for several thousand J310 and the much more linear J309. 73 Andrew Ikin G8LUG _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
On 08/25/2013 06:31 PM, Andy Ikin wrote: Charlie, When I was poor man 40 years ago, I always wanted Tektronix 545B Scope, which I couldn't afford. So I built a Chinese Copy with discarded parts from the Calibration department of the computer company I worked for. The scope use many 6DJ8s. I did get it working after about a year; not bad for some one with no formal electronics training Tektronix were very helpful in supplying some critical parts. Looking back I must have been mad, but it was one hell of away to learn how these things work. Bye the way I manufacture a special Head Amplifier for the KAZ and other Flags. This has 1100 Ohm input matching/isolation transformer, about 20dB gain and a less than 1dB NF and uses 8 x J309s plus a string of 1N4148 limiting diodes. Wellbrook FLG100LN. There are about 70 units in service mainly in the US with MW Dxers. 73 Andrew G8LUG Hi Andrew, When we build our own gear we do learn a lot. The first gear I built was a V-O-M in a cigar box. I was around about 13 and somebody gave me meter movement. Cigar boxes were free and so were junk televisions and radios. The ARRL handbook was over at the library. I didn't have a mode switch or a range switch but plugged resistors into an octal socket to make up each mode/range. I used it for almost two years before I got a *real* V-O-M. The real one was a little more accurate and a lot more convenient to use. But to this day I am familiar with how voltmeters work! That was about 50 years ago... I'm 66 now. 73, Bill KU8H _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
On 8/25/2013 6:29 PM, Charlie Cunningham wrote: Gee, that's really interesting, Andy! I also built a much simpler oscilloscope when I was a teenager and new ham! Yours was a really elaborate and impressive 'scope project! Congrats! Glad to hear from someone who has experience with the KAZ and flag antennas. My KAZ was for 160 and terminated in 1000 ohms - mostly because that's what I had on hand. It was a very good RX antenna for 80, 40 and 30m as well. Your preamp sounds very interesting! It must be fairly elaborate, if it uses 8 of the J309 FETS! I'd be interested in the circuit! Best regards, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Sunday, August 25, 2013 6:32 PM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Charlie, When I was poor man 40 years ago, I always wanted Tektronix 545B Scope, which I couldn't afford. So I built a Chinese Copy with discarded parts from the Calibration department of the computer company I worked for. The scope use many 6DJ8s. I did get it working after about a year; not bad for some one with no formal electronics training Tektronix were very helpful in supplying some critical parts. Looking back I must have been mad, but it was one hell of away to learn how these things work. Bye the way I manufacture a special Head Amplifier for the KAZ and other Flags. This has 1100 Ohm input matching/isolation transformer, about 20dB gain and a less than 1dB NF and uses 8 x J309s plus a string of 1N4148 limiting diodes. Wellbrook FLG100LN. There are about 70 units in service mainly in the US with MW Dxers. 73 Andrew G8LUG Andrew, i used a antenna similar to the KAZ when I first was on 160, except I fed it in the middle of the horizontal bottom leg(6 inches above ground) just like a K9AY, using a 9:1 xfrmr. It worked like a dream. I used two mounted at right angles just like a K9AY and rigged it to work in 4 directions like a K9AY, 1000 ohm termination worked great. http://www.suddenlink.net/pages/w5uc/160.html#The%20K9AY%20Type%20Array 73, Mike, W5UC _ Topband Reflector
