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Re: AL80-A
Harold Mandel
¿ªÔÆÌåÓýAll you need to do is study the management philosophy and practices of WalMart. ? WalMart dictates the selling price to their suppliers, and when they say to WalMart that they cannot supply a product at what WalMart wants to pay, WalMart directs them to an overseas supplier of labor or parts, or parts and labor. If the supplier wishes to stay in business they follow orders. ? There are no television manufacturers left in America. ? There were never, not one, ever, facsimile machine manufacturers in America. ? American business has chosen to divert
monies to volumetric production schemes to lower consumer prices in research and development. The Japanese still devote a large portion of their manufacturing revenue into R&D. That is why they have surpassed the United States. ? Our cellular telephone providers would rather sink money into radio systems increasing bandwidth and coverage volume than they would on hardening the system with backup generators, towers that are not at the 85% windload factor and battery plants that serve anything more than noise filters, as it would take a 100% increase in capacity to afford any sort of uninterruptible backup. ? Find out who goes to medical schools these days. ? Is it our sons and daughters who have studied hard and achieved academic excellence in their baccalaureate endeavors? ? Or is it mostly off-shore students whose parents can afford to fund a chair? ? Mike, you are entirely correct. RF amplifiers are too expensive to build here. Look at the latest edition that was touted on the reflector. Kilobucks.? Even the offshore amplifier companies are outrageous, like Emtron. The Ameritron might be our last chance. Alpha sure won¡¯t be the last bastion because their targeted market is so narrow. It¡¯s going to be Joe Ham that keeps Ameritron in the running, and Ameritron will need to contend with the competition FROM China for the last remaining component resources as the supply dwindles. ? Hal Mandel W4HBM ? From:
ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Mike(W5UC) & Kathy(K5MWH) ? At 08:42
AM 12/29/2006, you wrote:
"age
& treachery will overcome youth & skill" |
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Re: AL80-A
Mike(W5UC) & Kathy(K5MWH)
At 08:42 AM 12/29/2006, you wrote:
After WW- Isn't that amazing?? And now American automobile mfrs wonder why the mind set in this country (including me) is to buy Japanese cars. Now GM is struggling to regain it's reputation, and the labor unions are still wanting to price themselves out of a job and GM out of the market. I wonder what percentage of ham amplifier products are made in the US?? If they are being made off-shore, how much labor would it cost to build a quality product. Did you ever wonder what happened to Hallicrafters & Hammarlund? If someone knows what caused the demise of these two I would like to hear the story.? I still miss my HQ-129X. (No I didn't sell it.? It went under in 6 feet of salt water in Hurricane Carla in 1961) 73, Mike, W5UC
"age & treachery will overcome youth & skill" |
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Re: AL80-A
On Dec 28, 2006, at 10:31 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:** In 50-yrs of Hamming, I have had one case of electrolytics that were damaged by a bad rectifier.would look for a shorted diode or diodes in the power supply. ** .. and it also keeps the service department busy. ** Currently we are paying about 15-cents each for a reel of 1400, 1N5408s. (rated: 3A-avg, 200a-recurrent peak, 1000piv, typically test at c. 1400piv) Thus, protecting a typical electrolytic filter bank would cost c. $1.20 plus the cost of labor. ** Or maybe kerblam, slam up against the ceiling. cuz some bonehead conveniently forgot to install** In "The Nearly Perfect Amplifier" (January, 1994 *QST*), I listed the cost of each improvement. The total worked to about a 10% cost increase -- mostly due to the cost of the high-speed vacuum relay. This was apparently what caused the most tight jaws among amplifier manufactures. To me, this is crazy. If a manufacturer did his homework, he would realize that most people will gladly pay more for a quality product that will give good service. As I see it, a QST ad for an amplifier that listed the specific reasons it was better would sell amplifiers. Example: During WW-II, Japanese engineers and manufacturers were taken with the remarkably high quality of American airplanes that crash-landed. Some of the more intact American airplanes even went on tour around Japan. During the war, one of the Americans who was responsible for this quality was Dr. W. Edwards Deming. After WW- II, Dr. Deming was invited to Japan to give lectures on how to go about making high quality things that people will want to buy. cheers, Jim R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: TL-922 parts:
On Dec 28, 2006, at 1:01 PM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:** What is this obvious problem?are They also have an internal bandswitch** Why? The 922 does it with no problems once the 120MHz parasite problem is taken care of. Throw in distance between** Good point. RF-actuated T/R bias undoubtedly isn't good engineering practice. ** Bandswitches should not arc from RF-actuated bias switching. ...** #22don't### I think the straps I used in my L4B's are 1/2" wide cu... and IOW... ur saying with one** Correct, Jim. And above series-resonance, capacitors exhibit inductive reactance (positive j-ohms). ** Below resonance, caps exhibit capacitive reactance, or negative j-ohms. At 100MHz or 1MHz, a 1" long strap has inductive reactance, or positive j-ohms. ** chortleRICH SEZ... It doesn't change much because 1/2" (12.7mm) strap does What test gear was Terman using** guffaw I can't even measure any uh on my B+K 875a/b** Does that mean it has zero L ? According to Fred Terman, it has L. I did not get off my lazy posterior and calculate L but my guess is c. 1.5nH -- which would resonate with 100pF c. 450MHz. ** A dip-meter is indirectly capable of measuring inductances that are too small to measure resolutely with typical LCR-meters. To perform such measurements with a dip-meter, one needs a 50 - 100pF or so C with c. 25mm leads for a reference. (time out: attach a paper tag the cap, and solder small Cu clips on the reference-C leads) Next one needs to determine the L and C of the reference-capacitor . Clip it to a C meter, measure C, and record the value on the tag. To determine the L of the ref-C, clip the clips together to short it, and measure resonance with Tom's infernal, eternal enemy, the dip- meter. Calculate L using the std. resonance formula. Record the value of L on the tag. To measure an unknown L, clip the ref.-C to the item, and measure the new, lower, dip frequency. Calculate total L, subtract the L of the ref-C, and the result is the L of the unknown whatever. For added accuracy, measure the dip-meter's freq. of oscillation with a counter. ** I will wager one, whole, any topping, Costco pizza that a 100pF doorknob cap has less L than 10" of 2" wide Cu strap. ... IF somebody was** Nobody in their right mind uses these suckers to bypass an 8170 screen. You don't see anybody** True, and folks who know don't use doorknobs either. ** I hope Jim likes surprises as much as I like pizza. Strap has a bigger circumference to it... since it has two** Is circumference directly proportional to L? ** What g-g amplifier has a 1.00 to 1 input SWR?who knows.Why the drive requirements drop 20-25 watts on every band.... ** Do you have access to a dip-meter?grounding. Because the cap's negative reactance cancels some of... Why u insist on semi floating the grids on a GG amp isRICH SEZ... The grids are not floating at 100MHz with cap- If that was the case... the 3-** Correct. There is virtually no difference because the root of the VHF oscillation problem is not in the grid circuitry, it's between the anode and the Tune-C. What is** With C grid-grounding, a SB-220 measures something better than 38db down. What transceiver did you use to make this measurement? Cap grnding doesn't provide any NFB at all.** Agreed. Orr didn't have his oars in the water on this one. ** According to Eimac's 8877 development team, the 8877 exhibited an occasional "oscillation condition" (possibly UHF) during the testing phase, and it seems likely to me that they were using an Eimac 8877 grid-grounding collet. [ref. W. B. Foote] ** Good engineering practice --- provided some schlub doesn't replace a blown fuse with a 20A-slowblow . ... R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: TL-922 parts:
FRANCIS CARCIA
Home Depot sells copper flashing by the foot. I think it is about 1 foot wide.
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pentalab wrote:
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Re: TL-922 parts:
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
are whytwo of the most parasitic prone amps in existence.... which is boththe east coast guys call em the "fire cracker". So even though RICH SEZ... The VHF suppressors in the SB-220, AL-82, and the TL-have their grids tied directly to chassis... Ameritron has still 922 have a Q of 4.5 to 5.5 at 100MHz,and all have a reputation for squirreliness. If direct-grounding the grids is the sure cure for VHF instability, why isn't the one with direct-grounded grids stable? ### Simple... cuz Ameritron obviously has a layout problem some where in those 2 x amps. They also have an internal bandswitch resonance problem.[hence switching in caps between bandswitch contacts] Things like placement of plate choke,lead length's, whether plate block caps are separate.. or mounted to rfc can all make an amp squirelly. Having to pad a tune cap via the bandswitch for 160m is asking for more trbl. Throw in distance between cabinet side and top tid to tank components will make a big difference. Then their t/r relays are not sequenced right either... u can easily have drive applied to the cathode of an al80/82 b4 the ant is connected.... which is an invite to a disaster. ### Anybody who buys an Ameritron AL80/82 is virtually guaranteed to have flames spitting out of the bandswitch. The AL-82BX is the most piss poor designed amp available these days. We won't even discuss anything made by Dentron... those belong straight into the trash heap... no useable parts inside any of em. don't afeed us this crap about a 200 pf disc ceramic having less L than ### That would depend on the lead lengths of the 26 ga wires1/2" wide solid CU strap.... it doesn't.Rich sez... A 200pF cap with short, shorted leads dips at c. 130MHz. hanging out each end of the cap. IOW... ur saying with one particular config... one cap is series resonant at 130 mhz. At 100MHz, it has a small amount of negative reactance. ### Now ur saying the above single 200 pf cap... with leads long enough to series resonate at 130 mhz... will exhibit capacitive reactance at a lower freq. At 100MHz, a 1/2" wide Cu strap 1" long has c. 65-ohms of positive reactance. At 100MHz, which has more inductive reactance, the cap or the strap? ### The cap. RICH SEZ... It doesn't change much because 1/2" (12.7mm) strap does Not have half the inductance per unit length that 1/4" (6.35mm) strap has. According to Terman, inductance is a logarithmic function of width. Thus, if Terman is right, there is not a lot of difference in inductance between 10" (254mm) of #14 Cu wire and 10" of 2"-wide Cu strap. ### I guess Terman is wrong then. What test gear was Terman using back in the 30's ?? I can't even measure any uh on my B+K 875a/b LCR.. with a 3' length of 3/4" wide CU strap.... but I can easily measure .65 uh on a 2' length of 18 ga wire. ### 2" wide copper strap...12" long will read zero uh. To experimentally see the difference, one can alternately connect 10" of #14, and 10" of 2" strap across a 50 to 100 pF doorknob cap and measure each resonant frequency with a dipmeter. From these measurements, one can calculate the inductance of the #14 and the inductance of the 2" strap. I have the needed materials to perform this experiment. Would anyone like to venture a guess as to how much less L the 2" strap exhibits than the #14 wire? #### I dont have have any 2" wide strap in the shop. I usually buy it and get it chopped into 1" wide strips... and 3/4" wide. It comes in 3' x 7' sheets. I get it chopped into 3' lenght's. Why even mess with a grid dip meter ?? Just measure the damn thing with a LCR meter. ### You will have more internal inductance inside the 100 pf doorknob cap.. than the 2" wide strap alone ! There is also a big difference between 100 pf 5 kv TX ceramic doorknob caps.. with machine screws on each end.... and 200 pf disc ceramics.. with 24- 26 ga long wire leads.... apples and oranges. IF somebody was gonna rf grnd the grids... the correct component would be a 200- 1000 pf TX ceramic doorknob cap. ... just like u would use for a screen bypass cap on a metal tetrode. You don't see anybody using disc ceramic caps for screen bypass caps on a metal tetrode. ### measuring inductance of 12" long piece of 14 ga wire is easy.... just stuff it directly into the LCR meter.. and measure it. The formulae in the ARRL hand book for calculating inductance of straight pieces of wire is very accurate. I'll measure 12" of 14 ga wire tonight.. and report my results. I'm guessing it will be about .20 uh. The 2" wide CU strap of course will be zero uh. Strap has a bigger circumference to it... since it has two sides.. way more surface area on a piece of 2" wide strap... than the circumference of 14 ga wire. I think 14 ga wire is only abt .083" diam... and circumference would only be .26" vs 4" for the 2" wide strap ! RICH SEZ... Unless there is zero reflected power and the power meterWhy has recently been calibrated, power meter measurements are untrustworthy. ### BS.. In all cases reflected power IS zero... both before and after grids are directly grnded. Even if any reflected power is indicated... u just subtract the rvs power reading from the forward power reading.. to read net real forward power... which is what both bird/cd says ....and is correct. grounding. Because the cap's negative reactance cancels some of... Why u insist on semi floating the grids on a GG amp isRICH SEZ... The grids are not floating at 100MHz with cap- the grid's inductance, the grids have a less +j-ohms path to ground at 100MHz than is afforded by Cu straps. Thus, cap-grounding slightly increases the grid's resonant frequency and allows for grid fusing. ### I don't buy that for a second. If that was the case... the 3- 500z' would be more stable using caps... and they are not. What is accounting for the the extra 20-25 watts of drive requirement when using cap grnding ?? The IMD gets WORSE with cap grnding as well. Cap grnding doesn't provide any NFB at all. ### and u won't see anybody semi floating the grids of a metal triode either... that's just an invite to parasitic hell. ### You can STILL use grid fusing with wide CU straps...... just install a rear mount 3agc fuse holder... and wire between chassis and lower end of grid shunt if a multi meter us used.... or between chassis and neg terminal of a dedicated grid meter. Use a super fast 3agc fuse... and when it blows open it shuts off BOTH tubes asap. Input swr rises to infinity.. and xcvr shuts down. With NO path for dc grid current.. amp can't be driven... and you will see zero watts on output wattmeter. A rear mount 3agc grid fuse can be replaced in 3 seconds... after you determine what took out the fuse in the 1st place ! later... Jim VE7RF
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Re: AL80-A
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
would look for a shorted diode or diodes in the power supply. are not protected from AC by reverse diodes, the electrolytics are DOA. ### agreed. Which is why I always install at least one reverse connected 6A10 [1 kv-6A CCS-400A surge] diode across each HV electrolytic. Now Ameritron isn't the only ones who leave out the RVS connected diode across each lytic...they all do. I don't see any RVS connected diodes across caps in alpha's, qro, Command technology, heath, dentron, amp supply, or anybody else. They are all on the..... "get cheap program". ### I'm tellin u fellows.... if these manufacturer's of ham gear can eliminate just one diode, screw, washer, or anything else, they will do it in a heart beat.... to enhance profits. ### Rauch keeps bragging about how Ameritron pays very little for parts in bulk. Have u any idea what a diode cost... when ur buying 100,000 to 500,000+ of em at one shot ? ### So here's yet another potential case of 8x expensive lytics down the toilet.. cuz some bonehead conveniently forgot to install 16 cents worth of diodes at the factory. Can u imagine smoking 20-30 x 2000-5200 uf lytics in a real HV supply ? ### At least they should offer two versions of any amp.... the 2nd one costing $5.00 more.... that's designed and built right. Later... Jim VE7RF ...R. L. Measures, AG6K, 805.386.3734 |
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Re: TL-922 parts:
On Dec 27, 2006, at 5:27 PM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:6 grid pins The VHF suppressors in the SB-220, AL-82, and the TL-922 have a Q of 4.5 to 5.5 at 100MHz,and all have a reputation for squirreliness. If direct-grounding the grids is the sure cure for VHF instability, why isn't the one with direct-grounded grids stable?with wide strap. Then the stock suppressor's will worktrbl.just fine. A 200pF cap with short, shorted leads dips at c. 130MHz. At 100MHz, it has a small amount of negative reactance. At 100MHz, a 1/2" wide Cu strap 1" long has c. 65-ohms of positive reactance. At 100MHz, which has more inductive reactance, the cap or the strap? It doesn't change much because 1/2" (12.7mm) strap does Not have half the inductance per unit length that 1/4" (6.35mm) strap has. According to Terman, inductance is a logarithmic function of width. Thus, if Terman is right, there is not a lot of difference in inductance between 10" (254mm) of #14 Cu wire and 10" of 2"-wide Cu strap. To experimentally see the difference, one can alternately connect 10" of #14, and 10" of 2" strap across a 50 to 100 pF doorknob cap and measure each resonant frequency with a dipmeter. From these measurements, one can calculate the inductance of the #14 and the inductance of the 2" strap. I have the needed materials to perform this experiment. Would anyone like to venture a guess as to how much less L the 2" strap exhibits than the #14 wire? WhyUnless there is zero reflected power and the power meter has recently been calibrated, power meter measurements are untrustworthy. ... Why u insist on semi floating the grids on a GG amp isThe grids are not floating at 100MHz with cap-grounding. Because the cap's negative reactance cancels some of the grid's inductance, the grids have a less +j-ohms path to ground at 100MHz than is afforded by Cu straps. Thus, cap-grounding slightly increases the grid's resonant frequency and allows for grid fusing. ... R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: AL80-A
On Dec 27, 2006, at 5:32 PM, Mike(W5UC) & Kathy(K5MWH) wrote:
I'm not familiar with this amp, but a good guess is that I would look for a shorted diode or diodes in the power supply.If a HV rectifier diode shorts, and the electrolytics are not protected from AC by reverse diodes, the electrolytics are DOA. ...R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: AL80-A
Mike(W5UC) & Kathy(K5MWH)
I'm not familiar with this amp, but a good guess is that I would look for
a shorted diode or diodes in the power supply.
73, Mike, W5UC At 07:27 PM 12/27/2006, you wrote: The problem at this time is that the amp takes out the 10 amp fuses
"age & treachery will overcome youth & skill" |
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Re: TL-922 parts:
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
pf xcaps from the same grid pins..... and then directly ground the 6 RICH SEZ... According to my dipmeter, directly-grounding a 3-500Zsgrid pins with wide strap. Then the stock suppressor's will work grid pins makes little difference in the grid's resonant frequency. The AL-82 is as unstable as are the TL-922 and SB-220, yet the#### The AL-82...and it's little bastard brother.. the AL-80BX are two of the most parasitic prone amps in existence.... which is why the east coast guys call em the "fire cracker". So even though both have their grids tied directly to chassis... Ameritron has still managed to screw em both up. ### I think the straps I used in my L4B's are 1/2" wide cu... and as short as practical. I can name u 12 guys I know who directly grounded the grid's on TL-922's.... and all reported the same results... and 100+ more who directly grounded the grids on SB- 220/221's. ..same deal.... same results. Rock stable.... and 20- 25 watts less drive required.... using stock suppressors. And don't feed us this crap about a 200 pf disc ceramic having less L than a 1/2" wide solid CU strap.... it doesn't. ### Why the grid resonance doesn't change much... who knows. Why the drive requirements drop 20-25 watts on every band.... who knows. All I know from repeated tests... and having done it umpteen times is [a] drive drops 22 watts [b] stabilty is enhanced [c] IMD is improved.... then improved again.. since xcvr output can be reduced by 20-25 watts. ### I'm 100% convinced that parasitic stability starts with how well the grids are bonded to the chassis. I'd bond the grids to chassis... then if amp is still squirelly... proceed with a fix.... whether that involves using a small globar.. or nichrome.. is a moot point. It's worth it just for the decreased drive. ### The TL-922 owner's who had nichrome suppressor's in em... reported they could replace em with stock kenwood suppressors... and the amp was stable. .... provided the grids were directly grounded. Why u insist on semi floating the grids on a GG amp is beyond me. Jim VE7RF R. L. Measures, AG6K, 805.386.3734 |
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Re: AL80-A
Vernon J. Kunes, Jr.
The problem at this time is that the amp takes out the 10 amp fuses
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when I turn it on. High voltage problem? --- In ham_amplifiers@..., R L Measures <r@...> wrote:
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Re: AL80-A
On Dec 27, 2006, at 12:31 PM, Tony King - W4ZT wrote:
The AL-80A manual can be downloaded fromSorry, Jim. My mistake. The 922 uses Tune-C padders on 160m and 80m.160m ? agreed## I can see now where these amps could easily give plenty of trbl. R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: TL-922 parts:
On Dec 27, 2006, at 12:24 PM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:According to my dipmeter, directly-grounding a 3-500Zs grid pinsc. makes little difference in the grid's resonant frequency. The AL-82 is as unstable as are the TL-922 and SB-220, yet the AL-82 has directly-grounded grids. Jim -- How long is the grid grounding strap for a 3-500Z ? R. L. Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: source for GU-95B / 4CX5000 data sheet ?
Peter Voelpel
Except being a tetrode with same anode dissipation there is nothing
equivalent 73 Peter ________________________________ From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of R L Measures As I understand it, the GU-95B is equivalent to the 5cx5000A / 8170. |
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Re: AL80-A
Tony King - W4ZT
The AL-80A manual can be downloaded from <> or a paper copy can be obtained directly from Ameritron.
pentalab wrote: --- In ham_amplifiers@..., R L Measures <r@...> wrote:The schematic shows padding C1 on 160 meters only but padding C2 on 160, 80 and 40 meters.Hi, Vernon##### Rich.... do they actually pad the C1 tune cap on 160 + 80m on a AL-80 B ??? I can understand maybe padding the C1 cap on 160m... but not 80m. ### I think they pull the same stunt on the TL-922 on at least 160m ?73, Tony W4ZT |
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Re: TL-922 parts:
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
bandswitches for the TL-922. The stock TL-922 uses VHF parasitic suppressorswith a Q of c. 5.5 @ 100MHz. Since the the TL-922's originalsuppressors with a pair of fresh 3-500Zs can produce intermittent oscillationsc. 120MHz which can arc, melt & even evaporate the 10m and 15m Leither switching to lower-Q VHF suppressors to lower VHF-gain, or byusing worn-out 3-500Zs to do the same.### Owner's can avoid the parasitic problem altogether by simply removing the 2 x rf chokes from the gid pins... plus the 6 x 200 pf caps from the same grid pins..... and then directly ground the 6 x grid pins with wide strap. Then the stock suppressor's will work just fine. ## By semi-floating the grids you are just asking for parasitic trbl. Later... Jim VE7RF
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Re: AL80-A
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
##### Rich.... do they actually pad the C1 tune cap on 160 + 80m on a AL-80 B ??? I can understand maybe padding the C1 cap on 160m... but not 80m. ### I think they pull the same stunt on the TL-922 on at least 160m ? ## I can see now where these amps could easily give plenty of trbl. There is one heluva lot of RF on a tune cap as is. ### padding a load cap is no big deal... padding a tune cap is a big deal. Later... Jim VE7RF |
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