| List members: Bob (W4BD), George (N4GRN), Henry (W4HK), Mel (W4HJF), Rick (KC4HYM), John (N4JML), Gordon (N4LR), Darryl (N4OME) and Tony (W4ZT) Latest message on top. Share the wealth, find a stash, save the cash! Date: Sun, 21 Nov 2004 01:15:36 -0500 From: w4zt Subject: 2 tube socket lives okay guys... here it is! http://gs35b.com/socket/x2/ 73, Tony Date: Mon, 25 Oct 2004 08:42:15 -0400 From: Tony King W4ZT Subject: Baking out tubes Hi folks, While most of us have not been very active working on our amps lately there have been a few interesting discussions about topics we need to think about. One of these I have been following on the Amps reflector has been the discussion of "baking out tubes" or restoring old tubes to like new condition after many years of storage. Besides the previous discussions we have had about "burn in" there is a school of thought that indicates that there is a need to apply a slowly increasing high voltage source between the anode and nearest element (grid) to the point that there is internal (or external) sparking. I have posted a few links on my GS-35B discussion list that will give you the long and short of it I think. http://gs35b.com/discussion.html What this does is make me wonder if building a hi-pot tester isn't a good idea and making sure that it will go to nearly 20 Kv and perhaps be able to do this kind of restoration work. Comments? 73, Tony W4ZT Date: Fri, 09 Jul 2004 19:43:28 -0400 From: W4ZT Subject: GS35B Amps - new link added Hi Guys, I've just received an email from Dominique, F1FRV, including links to logic, cathode control and metering boards that he's got there. I had a problem loading his page because it appears to require Internet Explorer and would not work with Mozilla or FireFox. Here are the links: Main page - http://f6kbf.free.fr (click on La technique) (The following links WILL open with Mozilla) Part 1, Logic Card - http://f6kbf.free.fr/main5i.html Part 2, Cathode control and meters - http://f6kbf.free.fr/main5j.html HV metering and OV trip - http://f6kbf.free.fr/main5h.html 73, Tony Date: Tue, 22 Jun 2004 10:50:09 -0400 From: w4zt Subject: HV power supply testing After Field Day it'll be time to think about other things... maybe amps again. I have in my mind to build a dummy load to test HV power supplies at the 3kv-4kv 1 amp level. It'll be no easy chore to dissipate 3,000 watts at 3,000 volts without creating much smoke! I do have a plan and I'll share that with y'all later. I think I can put this thing together for under $50! 73, Tony Date: Sat, 19 Jun 2004 16:03:33 -0400 From: w4zt Subject: Fwd: [Amps] Eimac Tube Conditioning Interesting reading... Tony From: "craig vk3he" Date: Sun, 30 May 2004 17:59:46 -0400 From: w4zt Subject: single tube by wb8wju Date: Sun, 30 May 2004 17:56:26 -0400 From: w4zt Subject: twin gs35b amp by wb8wju Tom has all the parts in the box and working. Linked from his site here's the url to that project: http://home.comcast.net/~wb8wju/prt.html Tony Date: Sat, 03 Apr 2004 20:01:39 -0500 From: w4z Subject: New Member - N4GRN Date: Thu, 1 Apr 2004 11:48:52 +0100 To: w4zt From: G3SEK Subject: Re: FW: RE: g3sek triode board Hello Tony Tom passed your message to me for reply. (Apologies for the delay that followed, which was all mine.) >I'm convinced that Ian's board is the one to use but I have a >question or two. I don't know if you can answer or if I need >to try to get ahold of him. I haven't seen an email for him. >If you were going to have multiple RF decks, would it be advisable >to use only one triode board, say mounted in the power supply, >instead of using multiple boards, one for each RF deck? Looks >like trying to use only one would introduce some unique problems >related to metering, bias and status indications. >I've looked but it doesn't appear he has the instruction book on >his web site. It might help but haven't seen one yet. >73, >Tony W4ZT The basic information is in the "interconnections 2" schematic which is a link from the Triode Board technical information page: www.ifwtech.co.uk/g3sek/boards/triode/triode-3.htm However, it *is* tricky to decide exactly what to do with multiple amplifiers. I tend to think of it in terms of what you want to see from the operating position... and then you make the engineering meet those needs. * The amplifier selection switch and the meters need to be right in front of you, where you can see them all the time... but that only requires a relatively small control box. * The amplifiers need to be somewhere within arm's reach, but they don't need to be front-and-center. * The HV supply needs to be out of the way, on the floor or in the bottom of a rack. So that's three different locations. What I'd suggest is: * A single Triode Board in the control box, with the Ig and Ia meters and the selection switch. * In each amplifier, a separate heater transformer, blower and cathode connection - "cathode" being where the DC connection to the cathode comes out of the RF deck. The cathode connection in each amp should have a 10-22k resistor to ground, so that the tube is effectively cut-off when not in use (and a 90V spark gap or Varistor would be a useful backup). You can then switch between amps from the control box by selecting the appropriate B-minus returns. The Triode Board takes control of the in-use amp, and the other tubes sit safely in the cut-off condition. There may be some small interaction between amps, for example the grid current meter will not show exactly zero because of the small currents through the bias resistors in the unused amps. All this assumes that all the amps will be OK with the same bias voltage, meter ranges, and trip levels for Ig and Ia... if not, don't worry - there are some work-arounds. What you do with the B+ is your choice. You could either leave it connected to all the amps, or to switch it between amps. There are no strong reasons either way - except that it would be totally insane to open-up *any* of the amps when *any* part of this system is powered up. Even if you're not going to leave B+ on the unused amps, be absolutely paranoid about multiple ground bonding, with backups to your backup connections! <snip> Date: Wed, 31 Mar 2004 23:40:13 -0500 From: w4zt Subject: bleeder and meter multiplier board test Well folks, John (N4JML), his son Michael, and I did a HOT test on the bleeder and meter multiplier board today and it works fine. You can definitely feel the heat coming from it with 3600 volts applied but nothing is getting too hot individually. Had to parallel the two 1k resistors with ONE - 51 ohm resistor to bring the range of the 10k pot in for a 50 ua meter movement. All adjusted and works like a champ. Next step.... put the juice on the 4-400s and see what happens! tk Date: Wed, 10 Mar 2004 18:15:18 -0500 From: w4zt Subject: Welcome to Mel, W4HJF Welcome to Mel, W4HJF, joining us in the amp group. He'll be doing a desktop MLA2500 pretty much like WB8WJU has done. Mel, take a look at http://gs35b.com and feel free to contribute links, ideas, items for discussion, parts discoveries or anything else you feel this group will find useful. Hope you find this fun and enjoyable! 73, Tony Date: Mon, 01 Mar 2004 23:14:01 -0500 From: w4zt Subject: transformer wiring Here's the basic wiring as a result of the tests we ran the other night. The actual voltages will have to be verified once I put full input voltage on it but this schematic will show you what we'll do and it plugs right into the circuit diagram of the g3sek triode control board. It is linked from the parts listing for the transformer: http://gs35b.com/ps.html Tony Date: Mon, 01 Mar 2004 05:03:21 -0500 From: w4zt Subject: HV control, blower, relays etc Looking at the G3SEK triode control board and trying to sort out what we'll need external to it to make things play. Here is the connection diagram showing the input AC control for the HV and Blower. This covers the delay relay for inrush protection on the HV transformer, blower delay to keep it running even after shut down to insure cooling of the tube, and also shows us that we need another small transformer to provide control voltages for the relays. The options are 12 volt or 24 volt relays and since the vacuum relays for antenna switching are going to require the 24ish volts anyhow, I'd prefer to just use 24 volt relays throughout. One thing this does not do is show the connection for a sail switch but that can easily be done: http://www.ifwtech.co.uk/g3sek/boards/triode/triode-intercn1.htm This is the interconnections diagram that shows how it fits into the circuit providing the tube bias, metering and front panel LED indications: http://www.ifwtech.co.uk/g3sek/boards/triode/triode-intercn2.htm There's a little better view of the metering etc on this diagram: http://www.ifwtech.co.uk/g3sek/boards/triode/triode-sheet1.htm So, I'm adding the small 30 volt, 1 amp transformer to the parts list and the relays too. I also moved the vacuum variable info off to its own page. Tony From: n4lr Subject: Re: Improving Relay Operate Time - Kilovac Date: Sun, 29 Feb 2004 13:20:06 -0500 I dont know but I have seen a message or two on this... I see if I can find them again.. Maybe this is a good question for the amp reflector.. ----- Original Message ----- From: w4zt To: n4lr Sent: Sunday, February 29, 2004 1:02 PM Subject: Re: Improving Relay Operate Time - Kilovac yes that is. Now, I have to ask you this... at what cw speed is this going to become a factor? What is the dit time at 20 wpm? 35 wpm? Can you go faster? Then we have to consider a 48 volt supply in the amp and switching it with the key lead. How are we going to switch it? If it has to be switched with ANOTHER relay, how fast is IT going to switch? I'm just trying to figure out if we really need an HC-1 to be faster. tk At 12:16 PM 2/29/2004, you wrote: INTERESTING http://relays.tycoelectronics.com/kilovac/appnotes/operatetime.stm Date: Sun, 29 Feb 2004 07:47:41 -0500 From: w4zt Subject: chimney alternative Here's an interesting alternative: http://www.nd2x.net/VK8RH.html See the 5th picture down and click on it. Text next to the picture says: "View of the air flow "chimney" of the GS-35b. This tube requires at least 90 cubic feet per minute (~150 cubic meters per hour) of air flow to keep tube temperatures within spec's. The "chimney" is a 100mm PVC conduit junction. It is bolted to the chassis by 4 "L" brackets. On the bottom of the conduit is a gasket of cork material to get a good air seal. The air entry port of the system accepts a 50mm PVC conduit fed by a blower". tk Date: Sun, 29 Feb 2004 07:36:15 -0500 From: w4zt Subject: GS-35B tube cost compared More from our discussions yesterday... GS-35B from Tom: $119.95 plus shipping: http://www.tomstubes.com/tubes.htm GS-35B from *RUSSIA*: Single tube: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4675&item=3055540882 Buy it now: $73.00 Shipping and handling: $28.00 Shipping insurance: $7.00 --------------------------------- Total delivered: $108.00 Two tubes: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3080178607&category=4675 Two tubes: $135.00 (or $144 buy it now) Shipping and handling: $48.00 Shipping insurance: $7.00 --------------------------------- Total delivered: $180.00 ($90 per tube) It's interesting, this tube can be purchased WITHOUT the cooling fins, a good way to have a spare. $59.99 + Shipping and handling: (first item) US $17.00, Cost per additional item: $12.00 + Shipping insurance: $4.00 for a total of $80.99 for the first spare then $75.99 for each additional one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4675&item=3051997567 or... A lot of TEN tubes: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=31456&item=2584634462 Buy it now: $595.00 Shipping and handling: $195.00 Shipping insurance: $45.00 ------------------------------- Total for ten tubes: $835.00 ($83.50 per tube) tk Date: Sun, 29 Feb 2004 06:58:21 -0500 From: w4zt Subject: GS-35B socket Going back to our conversations yesterday... The socket/chimney combination for this monster is available directly from WB8WJU, who appears to be the maker of the things, for $20 less than other places; $70 delivered including schematics: http://home.comcast.net/~wb8wju/gs35.html Now, combine that with the less expensive tubes if you will, and see how it looks. tk Date: Sat, 28 Feb 2004 21:37:50 -0500 From: w4zt Subject: Iron Take a look at this: http://wb0nni.dakotamade.com/xfmrpwr.html Based on that, I'd say 50 lbs yields 1.3 KW CCS and off the scale for ICAS, probably upwards of 3 or more. Tony Date: Wed, 25 Feb 2004 06:52:27 -0500 From: w4zt Subject: Power Supply Filter Caps Gordon and I were looking at a cap on Ebay but found that a nice one is at http://www.rfparts.com/caps4.html#oil It's 32 uf at 4500 VDC oil filled which should just about fill the bill and actually gives you as much capacitance as a stack of 10, 320 uf, 450 volt electrolytics without all the parallel balancing resistors. 73, Tony Date: Wed, 25 Feb 2004 06:31:10 -0500 From: Tony King w4z Subject: Questions for discussion I've added a link on the amp page, http://gs35b.com, to questions we might want to discuss. It's a short list but certainly should get longer. Just some things that I came across and thought I would share. Please feel free to send me others you think that would be good to add to that list. I've tried to provide a link to some answers so it's not just unanswered questions. 73, Tony Date: Wed, 25 Feb 2004 06:25:16 -0500 From: w4zt Subject: Roller Inductors on Ebay Just found an item on Ebay that was JUST posted within hours ago for a 7 day listing, 6 days 17 hours remain. It's a complete old Heathkit antenna tuner with roller inductor and large air variable caps. For the price, it might appeal to someone. Buy it now price is $125 with a reserve which is probably near that same price: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3080735294&category=48711 There are three others that are very interesting as well. The first is a large open roller inductor that has been repaired. One of the ceramic end pieces has been replaced with plexiglass but otherwise the unit looks very nice. There are 3+ days remaining, no "buy it now", and the current price is $30 with one bid: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3079943436&category=1502 The second is a smaller roller inductor with turns counting dial. It has the single roller contact with 35 turns on a ceramic form about 2 inches in diameter: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3079614857&category=4671 The third is a group of 3 components to build a tuner. There is a very nice roller inductor with tapered turns on one end (this is a nice one), a large split stator tuning cap and a broadcast style loading cap. It's now in the $20 range but should move up some over the remaining 4+ days: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3079656490&category=48711 Share the wealth, find a stash, save the cash! 73, Tony Date: Sat, 21 Feb 2004 01:30:49 -0500 From: w4zt Subject: Parts list - vacuum variable chart added http://gs35b.com/parts.html I just added a chart which is the result of a query on the Jennings site. It shows the capacitors in their current product line that have a maximum capacitance between 250 and 500 pf. I then highlighted the ones that fit into our window of need so you can see what they are. These don't carry the old "UCS" numbers that we're used to seeing and I haven't found a cross ref on that yet but I did find another site which has some listed so I put that link below the chart. Tony From: kc4hym Subject: RE: amp links page redesign Date: Fri, 20 Feb 2004 20:44:29 -0500 Good stuff for amp beginners like me http://wb0nni.dakotamade.com/basic.html Rick ----- Original Message ----- From: w4zt Sent: 2/20/04 9:14:41 AM Subject: amp links page redesign I redesigned the links to include thumbnails of the pages they refer to: http://gs35b.com Also the mail archive appears to be okay. I strip out headers and addresses: http://gs35b.com/mail.html From: n4lr Subject: 144_new_amp Date: Thu, 19 Feb 2004 23:54:24 -0500 nice construction pictures.. P.S. Tony... He's using the wd7s graph display... http://www.qsl.net/wb5apd/144_new_amp.html (link added, tk) Date: Thu, 19 Feb 2004 23:50:04 -0500 From: w4zt Subject: roller inductor and loading cap the coil and the loading cap look good http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3079656490&category=48711
From: n4lr
Subject: {Collins} Re Millen Products
Date: Thu, 19 Feb 2004 23:51:48 -0500
i see a lot of messages on the internet about Millen HV
connectors not being the best choice..
http://mailman.listserve.com/archives/collins/2001-11/msg00235.html
Date: Thu, 19 Feb 2004 16:03:25 -0500 From: w4zt Subject: Re: new link ?? - ADDED That's a nice page! I've added the link: http://gs35b.com At 03:48 PM 2/19/2004, n4lr wrote: http://www.geocities.com/maxmartin3/drake/l4b_8877.html This is another 8877 link but at the moment the power supply info is what interests me.. Look at the how do I get started section.. Gordon N4LR. From: n4lr Subject: very rough cost estimate Date: Thu, 19 Feb 2004 16:59:17 -0500 Transformer 1 ea 350 350 25 5000 cap 1 ea 100 100 330ufd 450 vdc 10 ea 2.75 0 k2aw 14kv rec 4 ea 15 60 51k 15w bleeder 10 0.54 5.4 50k 7w bleeder 10 1.5 17.5 subtotal 532.9 control board 135 gs35b/socket 189 tub/control 324 plate tune cap 1 65 65 cathode tune cap 1 85 85 blower 1 50 50 plate choke 1 24.95 25 cathode choke 1 17.95 18 242.9 1099.9 From: n4lr Subject: new link ?? Date: Thu, 19 Feb 2004 15:48:25 -0500 http://www.geocities.com/maxmartin3/drake/l4b_8877.html This is another 8877 link but at the moment the power supply info is what interests me.. Look at the how do I get started section.. Gordon N4LR. Date: Thu, 19 Feb 2004 15:47:26 -0500 From: w4zt Subject: Re: plate transformer and modules CCS = Continuous Commercial Service - Key down, 24/7 ICAS = Intermittent Commercial & Amateur Service - Not running RTTY? it's ok Sure CCS would be better. It means there's more iron in the core and it dissipates the heat. The windings are probably the same size wire for the current you're going to draw. And pulling in your other questions: "Which ones do we need. It looks like I've seen the 14kv used most of the time.. They go down to 6kv which are $5 vs $15 x 4 ???" The diodes (block or string) in a bridge configuration are going to see the full peak AC voltage from the transformer secondary across each leg of the bridge. In your example below, the peak AC voltage is 3535 and it is wise to double that for your diode PIV (peak inverse voltage) rating. Since the K2AW blocks are built from 1 kv diodes the 6kv model falls short of the 7070 volts that would be double your example. Would it work? Probably. Would I use the larger one? Yes. "Looks like a new Peter Dahl transformer will be about $350.. I am still not clear on volts / amps... "IF" our target was 3500 v then Secondary 2500v x 1.414 = 3535 ???? at 1 amp ??? Sorry but I'm somewhat clueless.." Right on! That would be close enough for me or anyone else. This 1.414 stuff really does work and has for the over 40 years I've messed with it. I agree that $350 is a lot of cash for a transformer. That's why shopping around is a good thing. BUT, it is ALWAYS an option if you can't or don't find what you want or if you find something and want to change it later. I'd like to see the transformers that the guy around here makes too. For me, it isn't important that it carry the Dahl name but that it doesn't leak smoke. Tony At 03:27 PM 2/19/2004, n4lr wrote: If you look at the Peter Dahl site . They have a series starting with the letters ARRL. http://www.pwdahl.com/dahlcatalog/hamtrans011404.html ARRL-00X .... They are all $350 and 46 pounds. They have varying voltage choices at 1.5 amps ICAS... I see some transformers rated at CCS not ICAS. From looking at the prices I think the CCS is higher duty cycle.. for example: this one looks good but I dont plan to spend $350 on a transformer.. At least I hope not. ARRL-003 1900-2100-2600-2800 VAC AT 1.5 ICAS Gordon Date: Thu, 19 Feb 2004 15:30:11 -0500 From: w4zt Subject: Re: Plate Transformer hmmmm... at that price does it wash the dishes too? At 03:16 PM 2/19/2004, n4lr wrote: Here is one that will work !!! 5200/4800/3900/2300V @ 3A CS PLATE XFMR WITH +10,0,-10,208,240V PRI CORE) A-0550/ C-CORE STYLE #) 10 HIPERSIL C-CORE PR) +10,0,-10,208,240 VAC 60 HZ 1 PH S1) 0-2300-3900-4800-5200 VAC @ 3.0A CCS DM) HT = 15.688 WT = 15.950 DT = 10.750 MD = 6.750 MW = 10.000 PRICE) $1,475.00 Plus S&H FOB El Paso, TX WEIGHT) 253 LBS Date: Thu, 19 Feb 2004 15:02:10 -0500 From: w4zt Subject: Re: K2AW Hi-Voltage Modules That is an interesting testimonial FOR the K2AW blocks. He matches all the diodes before potting them so they are as balanced as they can be. As was said in it and the message that followed it, if you are going to take the time to build up your string of diodes properly with balancing resistors and capacitors (do we have the facilities to pick balanced diodes? no), then you are probably going to put more time and money into your diode stack. That said, it is likely that I have a bag of diodes and caps and resistors all sitting waiting for me to build my own. They are what I have because I collected them when there was not a better option. Bob may already have the same thing. BUT, if I find I have to reconsider it, the K2AW modules will be at the top of the list. The power supply is a simple device yet so important that if we skimp, it can go up in a shower of sparks that'll make you think I was welding in your shack. Three to five thousand volts at over an amp is VERY unforgiving. Tony At 10:33 AM 2/19/2004, n4lr wrote: Here is a message I found on the internet for the group. I am investigating a cheaper alternative to the k2aw which at $15 times 4 plus shipping for the power supply. This didn't cut and paste too well. It's easier to read at the below link.. http://dayton.akorn.net/pipermail/amps/1997-May/001404.html Gordon N4LR Before shooting of our mouths about a very nice person and his very nice products, why not take a moment or two to get the facts? Deja-vous, eh Rich? 1. K2AW Modules are made by hand by K2AW, with TLC! 2. Each module has a string of General Instrument 1N5408 diodes, personally matched by Frank before potting in "environmentally correct" epoxy. The 6kv module has 6 1N5408's, the 14kv module has 14 1N5408's etc. 3. Although the diodes are rated at 3 amps, Frank derates the module to 1 amp to make them "idiot proof" as they are used all over the world by many services. 4. There are over 20,000 modules in use in over 50 countries. 5. As I stated earlier, I have abused his products for 15 years with ZERO FAILURES. IMO, the use of strings of diodes and strings of electrolytic caps with strings of equalizing resistors feeding strings of vacuum tubes is something only for the amateur, C.B., and "freebander" markets where cost is the number one factor. This all works fine and saves a few bucks initially, but long-term reliability suffers, especially in power supplies delivering 5000 volts plus at several amps. One only has to look at RF equipment designed for industrial/military use vs the equipment for the amateur market to confirm this point. When one is pontificating about the use of components in a power supply, why paint with such a broad brush? Is this power supply going to be used for a tube with handles, or one of the popular "table-top toy" circuits popular today? There are thousands reading this reflector. I call them the "silent majority." They never post an article. Before one begins an assassination of a product or an individual, one should get the facts to avoid ramification. Those who do not bother to do this leave me with the impression that they may have a personal axe to grind, for whatever reason. There was absolutely no excuse for spreading the rumor on a technical forum that K2AW sells microwave oven diodes. Some day it might be your turn "in the barrel"...have fun! (((73))) Phil, K5PC Date: Wed, 18 Feb 2004 10:23:37 -0500 From: w4zt Subject: power supply filter caps And Gordon asked me: "how much is enough" in terms of capacitance on the power supply. For a full wave rectifier, either bridge or center tapped, you'll probably want 25 uf or more. That isn't the case with a voltage doubler but we're not talking about one of those. Typically the old saying "more is better" applies. The cap I plan on using in my HV power supply made Gordon's eyes bug out when he saw it... it's 130 uf at 5,000 volts, oil filled. That brings us to the question of oil filled or electrolytic? Electrolytics are light weight, sometimes smaller, and MAYBE cheaper in the short term. The building of the capacitor bank using electrolytics makes you consider the series string of low voltage electrolytic capacitors, typically 450 volt units to obtain the high voltage necessary. If for instance you were targeting a max voltage of 4500 volts, that would be ten 450 volt units in series. That's all well and good but it also divides the capacitance by ten. One typical supply filter bank we looked at had ten 220 uf 450 v electrolytics in it so the capacitance was 22 uf for the supply. The electrolytics also require balancing resistors across the caps to maintain equal division of voltage across them. Now that may not be a bad thing because you'll need a bleeder of some sort on the oil filled supply but not like that required for the electrolytics. Pricing may be near the same these days. We were looking at a NEW OLD STOCK Henry capacitor on Ebay and they were wanting $99 by it now for 25 uf. If you were paying 8 to ten bucks a piece for electrolytics then the price would be nearly the same. The oil filled cap will last much longer, probably a life time. That's a better deal in my book. So, bottom line, it's your choice. My personal preference is the oil filled cap and that's what I'll use. If you were going to spend the big bucks and try to make it small then electrolytics and a Dahl transformer would probably burn a sizable hole in your pocket! Tony Date: Tue, 17 Feb 2004 18:19:50 -0500 From: w4zt Subject: Loading caps Here's a view of an acceptable loading cap: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2597015025&category=4662 This one is only 800 pf so slightly small: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077647108&category=4675 Tony Date: Tue, 17 Feb 2004 18:19:02 -0500 From: w4zt Subject: Plate tuning cap - was i'm bidding... There are others available as well. That one is GREAT looking Gordon!!! Here is another, not as desirable but still in the ball park: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3079052629&category=1502 This one is larger and one would have to work on the attachment hardware, which is no trivial chore: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3078909288&category=4675 Here's a Russian one (I wouldn't send MY money to Russia!): http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077534688&category=4675 Tony At 06:05 PM 2/17/2004, n4lr wrote: I am bidding on a plate tunig cap. I expect this to go to $100 or more.. Item number: 3079059781 Jennings UCS-300-15S Vacuum Capacitor 15KV Date: Tue, 17 Feb 2004 17:25:30 -0500 From: w4zt Subject: parts list update I just updated the parts list. My apologies for the stupid listing of a plate voltage meter of 1.5 KV, it's now listed as 5 KV. I also noted: The need for two vacuum relays, one to switch input, one to switch output (they are tied together in receive). The minimum capacitance limitation for the plate tuning (about 15 pf) and max voltage for same (>7500v). This is an on going process. Other changes will come and I'll let you know if I make a change on the web page. Tony Date: Tue, 17 Feb 2004 17:05:00 -0500 From: w4zt Subject: amp control board Well it seems that G3WOS is thoroughly taken with the control board by G3SEK. This is the control board that Tom (tomstubes.com) sells and recommends. Gordon, I think you did a pretty good comparison of the two, perhaps you could just list the features side by side (without a spread sheet?) and we could see how it stacks up. I'm particularly interested in the built in metering capabilities and variable bias. Nothing says we have to use the same one, but it'd be nice to know all the pros and cons of the two side by side. I'd really rather build one of the two as a kit than build the thing from scratch. Tony From: w4zt Date: Tue, 17 Feb 2004 16:34:38 -0500 Subject: RE: ebay well it takes two... you have to switch the output and the input so a second one is in order. Allen Bond is OUT of them right now and is carrying a waiting list. He expects more but doesn't know if there will be enough to fill or go over the list. If we want some from him, we should put ourselves on the list for some number. He will be at the Hamfest in Dalton ALSO... he has the turns counter dials. Two types, the Henry Radio type.. flat looking, for about $25 and a refurbed nice looking EF Johnson for $35. He will not be bringing the EFJ's to the hamfest unless we specifically request them. They are my preference I think. You only need one if you use the roller inductor. Another if you were to use a vacuum variable. tk At 03:21 PM 2/17/2004, Rick wrote: Jennings RJ1A vacuum relay, I already got his other one http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3078658506&category=1502 From: kc4hym Subject: RE: ebay Date: Tue, 17 Feb 2004 15:21:47 -0500 Jennings RJ1A vacuum relay, I already got his other one http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3078658506&category=1502 ----- Original Message ----- From: n4lr Sent: 2/17/04 3:10:39 PM Subject: RE: ebay hey i need a lot of stuff... -----Original Message----- From: w4zt Sent: Tuesday, February 17, 2004 2:53 PM Subject: Re: ebay you're watching too much! LOL!!!! refine the searches and don't use as many At 02:47 PM 2/17/2004, you wrote: >I keep exceeding the limit on the number of items to watch... never done >that before.. > From: n4lr Subject: RE: GS-35B amp links and parts page Date: Fri, 13 Feb 2004 09:59:22 -0500 so is the key to find the transformer first.. we already know the tube/socket... -----Original Message----- From: w4zt Sent: Friday, February 13, 2004 9:44 AM Subject: RE: GS-35B amp links and parts page This will depend on your choice of transformer. At 09:38 AM 2/13/2004, n4lr wrote: >k2aw hi-voltage modules... > >HV 14-1 14KV-1A 250A SURGE $15.00 > >2 EA ?????? From: n4lr Subject: Cable-Wire - EBM CENTRIFUGAL BLOWER G2E120 SERIES - 1062 Date: Sun, 15 Feb 2004 21:38:49 -0500 http://www.ctrsurplusonline.com/index.asp?PageAction=VIEWPROD &ProdID=73&strVarSel=&strCompare= From: n4lr Subject: K7EM - Henry Radio 5K Classic Amplifier Home Date: Sun, 15 Feb 2004 20:29:52 -0500 Well i was going to inquire to the group about the dayton blowers but decided to do a google search , here is the first thing i found... doesnt sound good.. havent read the upgrade yet but maybe interesting.. we should create a group to email to.. maybe a yahoo group with only us as members.. or maybe sam could create one where sfares is.. http://www.bctonline.com/users/skelly/henry_amplifier/henry_5k_amp.html Date: Sun, 15 Feb 2004 22:10:29 -0500 From: w4zt Subject: Re: test Yes, for the amp group only, if you received this, you can reply to it and it will go to all of us. Or if you want to send a new email just send to amp at w4zt dot com with your links, ideas, finds, etc. Set it up with simple email forwarding so we didn't have to keep remembering who to send it to! Share the wealth, find a stash, save the cash! Tony PS... Gordon, share that blower info with the group. At 09:45 PM 2/15/2004, you wrote: TEST..... Wow !!!.. We now have our own mail group.. Just email xxxxxxx to talk to the whole group.. Gordon Date: Mon, 16 Feb 2004 09:50:52 -0500 From: w4zt Subject: measuring variable capacitors Biggest problem with surplus variable caps is figuring out the range. It's worse at hamfests. I just discovered one of those Rainbow Kits I purchased eons ago that'll allow you to roughly measure caps down to 2pf with a DVM. I think I'll slap that together and see if I can't get it to work ok in the range of 10 pf to 1000 or 2000 pf and take it along. It's supposed to check higher values than that easily up to about 2 uf. My DVM will do caps but not that low without the add on. http://www.rainbowkits.com/kits/ia-1p.html I see they also have a little inductance tester, which I don't have, that would be nice for coils. quicker than a grid dip meter and cap and it's portable. Anybody have one? Tony From: n4lr Subject: RE: Roller inductors for plate tank coil Date: Mon, 16 Feb 2004 09:43:26 -0500 Hi John, I have been doing a lot of research but haven't bid on anything yet.. Still trying to get the big picture as far as cost is concerned.. This project is a stretch for my knowledge.. What to buy is a big learning curve for me.. I dont know a 1 uh roller inductor from a million uh roller inductor.. but after scanning the internet way past my bedtime last night , I now know.. 229-201 is 10 uh 229-202 is 18 uh 229,203 is 28 uh Johnson is the standard.. They are now called Cardwell. So if you search ebay look for both.. Talking to tony looks like we can work with the 202 but 203 would be better. matter of $$$ vs convenience. Gordon N4LR Date: Mon, 16 Feb 2004 09:34:55 -0500 From: w4zt Subject: Re: Roller inductors for plate tank coil I think you're right. Besides, Bob and I have discussed the need to parallel some capacitance across the plate tuning for 160 meters. Reason, unless you use a vacuum variable, the physical size will make the minimum capacitance so large that it can't tune ten meters. So, if you're going to switch in a doorknob cap for the plate, opening a shorting contact across the extra coil on the cool end of the tank wouldn't be such a hastle. I think that coil would work fine with the add on. Bob, chime in here if you check your mail. John, I agree on the bidding war. Bob and I have already got our roller inductor. I'll be happy to place the bid for something if y'all need that. We definitely shouldn't bid against each other ;) I expect we'll end up with extra pieces as we shop and "find something better" and that's unavoidable. Just have to move them later. Darryl, hope it's warm there. I have to get out and replace my alternator belt today that keeps slipping. It's only going to be 45 they say. Tony At 09:24 AM 2/16/2004, n4ome wrote: That roller inductor looks very similar to the one in the Johnson Viking Thunderbolt Amp that doesn't work 160m. Back a few years ago I modified that amp to work 160m and had to add a coil (about as large as the roller) in series with the roller operated with a relay to switch it in and out. If you go that route then you might could operate a relay in conjunction with the band switch. Darryl From: n4ome Subject: Re: Roller inductors for plate tank coil Date: Mon, 16 Feb 2004 14:24:02 +0000 That roller inductor looks very similar to the one in the Johnson Viking Thunderbolt Amp that doesn't work 160m. Back a few years ago I modified that amp to work 160m and had to add a coil (about as large as the roller) in series with the roller operated with a relay to switch it in and out. If you go that route then you might could operate a relay in conjunction with the band switch. Darryl Johnson Roller Inductor 229-202 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077609654&category=48711 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077646210&category=1502 Last one on Ebay went for $64.52 These are $150 at http://www.surplussales.com/Antennas/TransVarInductor.html This coil MIGHT reach 160 without additional inductance but I wouldn't count on it. We know you'd have to add a strap for ten meters so a little bit added for 160 is no big deal. Tony Date: Mon, 16 Feb 2004 00:09:16 -0500 From: Tony Subject: Roller inductors for plate tank coil Johnson Roller Inductor 229-202 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077609654&category=48711 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3077646210&category=1502 Last one on Ebay went for $64.52 These are $150 at http://www.surplussales.com/Antennas/TransVarInductor.html This coil MIGHT reach 160 without additional inductance but I wouldn't count on it. We know you'd have to add a strap for ten meters so a little bit added for 160 is no big deal. Tony From: wb8wju To: Tony Subject: Re: GS-35B amp, referred by Tom Hix Date: Thu, 12 Feb 2004 07:48:57 -0500 Date: Wed, 11 Feb 2004 23:00:55 -0500 To: wb8wju From: Tony Subject: Re: GS-35B amp, referred by Tom Hix Hi Tom, Thanks for the speedy reply. >At 07:36 PM 2/11/2004, wb8wju wrote: >Hello Tony, >Glad to help I have tried both ways with and without the parasitic choke >only a small difference.(DON'T need it.) That's good news! >If you want 160 meters you will need a total or 30uH on your roller for a >single 1/2 that for a pair. okay... one tube, 30uh will be fine. I'll have to measure mine and if it isn't enough, a small add on can be done. I think it will work. It's one of the old long rectangular wire types. Solid and in good condition. >How much DC Voltage are you going to have?Let Me know in your next email >and i will run a program PULL DOWN VOLTAGE. and send it along with my pick >for a schematic. I'm not wanting to blow the lid off this thing but I'm open to suggestion (that means I'm easy.) I figure 3000 to 3500 though up or down a little doesn't really bother me. The big variac will keep the poll pig in check ;) Thanks so much for your suggestions. I've read all these links and been on every page on your web site I think. You've spent a lot of time doing this sort of thing. I spent ages collecting parts for a 4-1000 and now it just doesn't have the appeal. Too much trouble getting ten meters and lots of other stuff. This seems so clean and I'll enjoy it more even though I wont be able to see that warm glow! (of course I could put the 4x1 over in the corner of the box and light the filament just to keep me warm) ;-) 73, Tony W4ZT To: w4bd,w4hk, n4jml, n4lr, n4ome Date: Wed, 11 Feb 2004 11:42:51 -0500 From: Tony Subject: GS-35B amp links and parts page OK guys, here are the links and the beginnings of a parts list. Did you know all of you were interested in this? Send only GOOD links and I'll post them to share... after all, we do need one good place to go for them when we get to talking about it. http://gs35b.com It is also linked from my web page at http://w4zt.com Remember, no layout or construction until all the RF deck parts are in hand. Share the wealth, find a stash, save the cash! tk |