Some possibly demented thoughts......
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In (nearly) all cases, if the frequency of operation, and impedances at both sides of the matching network are known, the needed component values in the network can be calculated
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In a tube amp, the input impedance, and the output impedance are fairly constant despite changes in frequency, so the only thing that needs to be taken into account when designing the network...is the frequency....and those "make sense" as far as less capacitance or inductance is needed as the frequency goes up.
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With an antenna tuner, the impedance at one end is usually 50 ohms with no reactance while the other end of the antenna tuning tuner is presented with a wildly varying impedance, so the component values in the tuner need to take into account the both the impedances as well as the frequency.?
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Eric
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Re: Electrical Improvements
Well that would work! Bob W4JFA
Yes, I remember this exact situation when I was growing up in the 50s. The solution my father had was to not touch the stove and refrigerator at the same time.?
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Re: the WORST ham built amplifier?
Two ?plate RF chokes in series ?were used in the homebrew 4-1000A amplifier that I designed and built in the early 80's and is still in reliable service at my 4X4NJ station. At the time, I didn't have convenient access to any references that detailed the construction of a suitable single plate choke. And I felt that even given the lacking information, it would have been unlikely that I would be able to find the proper coil form for the choke. ?The need for a second choke arose because of the undesirable frequency of the series resonance of the first choke. Instead of cut-and-try attempts to get a single choke to work properly, it was much simpler just to add a second choke in series with the first choke.? Since the total impedance is the sum of the impedances of both chokes, and the second choke series resonant frequency was far away from the resonant frequency of the first choke, the problem was solved.? An additional advantage was the overall increased impedance of the two choke combination on most frequencies. The obvious potential disadvantage was the increased space for two chokes, but this was not a problem (in this project) with plenty of space for a second choke. 73, Riki Kline K7NJ/4X4NJ -- Riki, K7NJ
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Re: Electrical Improvements
Yes, I remember this exact situation when I was growing up in the 50s. The solution my father had was to not touch the stove and refrigerator at the same time.?
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Re: Electrical Improvements
Jim, A possibility I was thinking was if there's an open neutral?then the ground now becomes a current carrier. If the ground potential is different between the fridge?and the stove, current flows, a shock when touching both. What do you think? Bob W4JFA
The 4 x burners on top of the electric stove all run on 120 vac....and still do.? ?One big and one small? burner each run on 120 vac....and are on 1 side of the buss.? ? ?The 2nd big and? 2nd small burner run on the other side of the buss.?
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Re: the WORST ham built amplifier?
That amp uses a PI-L output for the 11m tank.? ? The vertical plate choke has the B+ fed to the top of it....and existing the bottom.?
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56 pounds sterling = $72.00? US dollars.? ?You could get it for way less than that.? ?The pair of tubes, sockets, blower, 2 x caps is probably worth $50.00? ? ?Good for some parts if the tubes are any good.?
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Re: Electrical Improvements
The 4 x burners on top of the electric stove all run on 120 vac....and still do.? ?One big and one small? burner each run on 120 vac....and are on 1 side of the buss.? ? ?The 2nd big and? 2nd small burner run on the other side of the buss.?
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Re: Electrical Improvements
There was a hood light and a hood fan.
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The oven didn’t have a light.
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The ‘fridge had a light.
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At the time I was very immersed in Mars Observer
and was just glad the LL family treated me like
family and had whomever manage the yanking
and cranking while I spent my 16 hour days
in Secaucus…
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Hal
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Re: the WORST ham built amplifier?
From the looks of it, it appears the amp is only for 11 meters. With the small inductors and the caps missing plates, I bet it was designed with CB in mind. I also do not think that it has ever been fired up. Those chokes would have so many self-resonances they would be black. The markings on the front panel is an attempt to make it look legit. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ?
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From: [email protected] < [email protected]> On Behalf Of Brandon DX via groups.io Sent: Wednesday, October 30, 2024 11:15 PM To: [email protected]Subject: [ham-amplifiers] the WORST ham built amplifier? ? I understand a chap in the UK has made the seller aware of the utter poor quality of this linear I wanted to know who built it with two plate chokes in series?? At least they knew to place them at right angles.... but why so much L?? ? hurry and see it before someone buys it ?? as my Scottish friend would say "Perish the thought!"
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the WORST ham built amplifier?
I understand a chap in the UK has made the seller aware of the utter poor quality of this linear
I wanted to know who built it with two plate chokes in series??
At least they knew to place them at right angles.... but why so much L?? ?
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hurry and see it before someone buys it ?? as my Scottish friend would say "Perish the thought!"
Reid? W6MTF
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Re: Econco 3cx3000 Rebuild cost
Hi Jim
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Thanks, I? will chase it up the costs with Econco. I just have to ship from outside the USA so can be a bit complicated when Econco has agents that they prefer to send you to which doubles the costs.
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RFPARTS wont ship anything overseas? for what reason I dont really understand. I bought thousands from them now they dont want to know their overseas customers.
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I might just try and do by taking a holiday there and then getting it done.
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Loardes from Econoco did indicated that it was possible to convert the 3cx3000F1's to the A7 version since these are genuine Eimac it might be a good investment that will see me into the grave!
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Henry
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Re: Electrical Improvements
Usually 120 is used for the clock and oven-light if there is one. ? Mod-U-Lator, Mike(y)/W3SLK ? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Bob
Sent: Wednesday, October 30, 2024 8:35 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Electrical Improvements ? I wonder if one of the appliances had an open neutral? I know the range was probably 240 v but maybe it still used 120 v for some functions? ? The revised electical laws regarding grounding of appliances and not using their chassis’ as a.c. returns hit home one day when I was cooking . ? I was stirring something on the electric stove with a stainless stirring spoon and reached for the ‘fridge door so I could retrieve an ingredient, and there was some sort of fault and I got knocked on my ass. ? The fault voltage, later measured was 65 volts from the chassis of the electric stove to the chassis of the refrigerator. ? I showed this all to my LL’s son and he took a chance on touching the pair of appliances at the same time, too. ? Sears was there the very next day with a new ‘fridge and a new stove. ? Bless someone’s heart…. ? Hal Mandel
W4HBM ?
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Re: Electrical Improvements
I wonder if one of the appliances had an open neutral? I know the range was probably 240 v but maybe it still used 120 v for some functions?
Any opinions?
Bob W4JFA?
The revised electical laws regarding grounding of appliances and
not using their chassis’ as a.c. returns hit home one day when I
was cooking .
?
I was stirring something on the electric stove with a stainless
stirring spoon and reached for the ‘fridge door so I could retrieve
an ingredient, and there was some sort of fault and I got knocked
on my ass.
?
The fault voltage, later measured was 65 volts from the
chassis of the electric stove to the chassis of the refrigerator.
?
I showed this all to my LL’s son and he took a chance on touching
the pair of appliances at the same time, too.
?
Sears was there the very next day with a new ‘fridge and a new
stove.
?
Bless someone’s heart….
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Hal Mandel
W4HBM
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Re: Electrical Improvements
Eric,
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Both the stove and the ‘fridge were relics of the ‘Fifties!
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Hal
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Re: Electrical Improvements
Bonding the stove frame to neutral, or to the grounding wire, serves to cause a circuit breaker to open if a fault within the stove tries to energize the frame?
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New (after the mid 1990s) stoves are set up, by default, for wiring to a new circuit that includes the two hot wires, a neutral and a grounding wire.
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If, however, the stove is connected to an older circuit without that grounding wire, a bonding jumper must be connected between the stove frame and the neutral.? Without that jumper, a fault within the stove can energize the frame without opening the circuit breaker....and the only way the fault is found is when someone gets shocked.?
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The stove works perfectly without that bonding jumper, so it is often overlooked/ignored...despite all the ever larger, ever brighter, ever more strident warning stickers.?
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Eric
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Isolating the neutral and grounding systems within the amplifier shouldn't be too hard, and I haven't installed the 120/240VAC circuit in the garage, so I have no excuse.? :-)
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Eric
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The revised electical laws regarding grounding of appliances and
not using their chassis’ as a.c. returns hit home one day when I
was cooking .
?
I was stirring something on the electric stove with a stainless
stirring spoon and reached for the ‘fridge door so I could retrieve
an ingredient, and there was some sort of fault and I got knocked
on my ass.
?
The fault voltage, later measured was 65 volts from the
chassis of the electric stove to the chassis of the refrigerator.
?
I showed this all to my LL’s son and he took a chance on touching
the pair of appliances at the same time, too.
?
Sears was there the very next day with a new ‘fridge and a new
stove.
?
Bless someone’s heart….
?
Hal Mandel
W4HBM
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By fixing I guess you would need to bring a ground to each receptacle and switch? Not so easy to do.
The electrical standards here have evolved over the years, but older installations do not need to be upgraded to comply with the newer standards unless there is a significant amount of work done to the old system. ? How the word significant is defined is subject to a lot of controversy. :-)
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I could use the "it was compliant when it was constructed" argument and use the neutral as the grounding means with no GFCI/RCD system on that circuit? But, especially since it is so easy to bring it into compliance with modern standards....why not do so.... :-)
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The electrical standards here have evolved over the years, but older installations do not need to be upgraded to comply with the newer standards unless there is a significant amount of work done to the old system. ? How the word significant is defined is subject to a lot of controversy. :-)
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I could use the "it was compliant when it was constructed" argument and use the neutral as the grounding means with no GFCI/RCD system on that circuit? But, especially since it is so easy to bring it into compliance with modern standards....why not do so.... :-)
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Re: Econco 3cx3000 Rebuild cost
Scott has had a few Eimac 3x3's rebuilt by Econco...as have other's over the years.
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Phone / e-mail econco....and ask em what it will cost...... with u providing the dud.? I THINK it's aprx $800.00?
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A new 3x3? from Penta is $997.00? ? ($1200.00? ?from DXE).? ?
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IMO, if you can get the Eimac rebuilt for? $1400.00? or less..... I would go that route.?
Econco told me a while back that they could rebuild chinese tubes....and also Russian Svetlana tubes.? ?However, I would not spend $800.00? to rebuild a $997.00 chinese tube.?
I do have 2 x new Svetlana 3x3 tubes...and they are well constructed....and use a spiral mech fil.?
Jim? ?VE7RF
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Bob
HaL Mandel
Brandon DX
