Vent

[Steve - WB3HUZ]

Unless you made some changes, the standard display DPI for Windows XP is 96 DPI. So a higher DPI will not look any better on your screen. I agree the DPI needs to be higher for the drawing though, but for printing purposes. Here, printers can print with DPIs in the 1000 plus range, if needed. For simple line drawings like these schematics, 200-300 DPI is sufficient.

I've used several different programs to make the schematics. I'll might try EasyDraw for these schematics.

[W1RKW]

Got a new transformer for the 813 screen supply.  It arrived damaged though repairable and useable from Fair Radio.  This is the first time I received a part from Fair Radio with poor packing.  Anyone else have that experience?

[Opcom]

once 20 years ago. a 100uF 4KV cap arrived with a bent insulator. They replaced it after I returned it.

[flintstone mop]

The Magnet-O-Sphere is pretty nice!!!!

I guess Steve has to re-draw because of that "other operating system" he uses, called a MAC..................hi :>)

fred

[Opcom]

Thank you.. Tried to keep it tidy and avoid platform specific entanglements.

yeah those macs.. The user has the right to choose which o/s they wish to be annoyed by.

since fair radio was mentioned, there's a whole bunch of fall 2007 tourist pictures from it here:
http://www.bunkerofdoom.com/travel/steelsoldiers2/20071002a/index.html

[Steve - WB3HUZ]

It's sad so many people equate operating system with annoyance. I find it rare amongst Mac users.

[WB2YGF]

It's sad so many people equate operating system with annoyance. I find it rare amongst Mac users.

Off topic, but I got my first Mac (G3) last spring to play with.  Nothing I could download would run on 10.1.  I found a copy of Office that would run.  Then I upgraded to 10.4 and Office would not run.  I had to load a newer (much larger) version of Office that ran slower.

My impression was that OSX is very fussy about versions.  I have DOS programs and Windows 3.1 programs that still run on Vista.

[Steve - WB3HUZ]

Never had that problem. Then again, I don't use any Office stuff. It's MS junk and very likely the source of your problems.

It's sad so many people equate operating system with annoyance. I find it rare amongst Mac users.

Off topic, but I got my first Mac (G3) last spring to play with.  Nothing I could download would run on 10.1.  I found a copy of Office that would run.  Then I upgraded to 10.4 and Office would not run.  I had to load a newer (much larger) version of Office that ran slower.

My impression was that OSX is very fussy about versions.  I have DOS programs and Windows 3.1 programs that still run on Vista.

[W1RKW]

Hey guys,
Finally had some time to tinker with the 813 rig today.  Stiffened up the bleed resistors on the screen supply, big improvement and made a small mod to the RF deck.   Envelope is far more stable under modulation now but still I think it can go a little further. Plus, I'm seeing positive peaking!  Frequency response has improved for whatever reason.  It's not the best just yet but the clipping or squashing of the waveform has been significantly reduced.  Back to the grindstone.

[W1RKW]

OK,
Need to know how to tune this thing.  Should it be tuned up for max output, about 700w carrier and back off the drive to about 400x If I do that I seem to have the best results. Is this proper? Or should I tune it up at the intended output level, 375w carrier to be legal?  I don't seem to get the best result by tuning it up for the intended power level.  The transmitter doesn't like it from the arcing sounds I'm getting.

[Steve - WB3HUZ]

I'm assuming it's a Class C amp. Hit it with the proper grid drive and load up to the desired output or plate current. That's it.

[WA1GFZ]

Bob,
Sounds like your tank Q is too high for reduced power level. When you reduce power the plate z goes up if the plate voltage is about the same. The tank inductor is fixed so as you decrease power the Q goes up. Sounds like you want a bit more L at reduced power.  I'm not sure if you have a variac on the plate supply but you could tune up for 700 watts and reduce the plate voltage to get you down to the power you want to run.
I see the Sunoco opened up again.

[W3RSW]

Hey guys,
Finally had some time to tinker with the 813 rig today.  Stiffened up the bleed resistors on the screen supply, big improvement and made a small mod to the RF deck.   Envelope is far more stable under modulation now but still I think it can go a little further. Plus, I'm seeing positive peaking!  Frequency response has improved for whatever reason.  It's not the best just yet but the clipping or squashing of the waveform has been significantly reduced.  Back to the grindstone.

Glad the screen loading worked.

& Bob, don't forget to try opposite polarity from the modulator too.  Just switch the mod. plate cap wires if you don't have a phasing switch anywhere else.  I see mushy peaks go to emongus ranges on the scope with this simple fix. 

[W1RKW]

Frank, Rick, Steve,
Got a variac for the plate supply.  I can lower the plate voltage. May revisit the tank coil design.  OK on the swapping modulator plate leads.  Will mess around with the settings some more to understand how it all works and works best.  Getting closer.

Thanks.

BW

[WA1GFZ]

Bob,
Nice 3 way gas thing going on in Colchester. Just drove through. I only saw 2 other stations between here and the coast with gas that cheap. I'll stop buy sometime when I don't have the family in toe. I'll be going that way more often in about 4 weeks. You might also check your efficiency at high and low power to find the best plate voltage for the tank circuit. This will give you a clue to where you need to go but it sounds like you need a bit more L at lower power/higher Q

[W1RKW]

Hi Frank,
Actually the less expensive gas is in Portland.  It's about a nickel less but seeing the old Sunoco station towing the line with the other 2 stations is surprising.  It's been that way since they reopened.  I think the new owner only sells gas.  There's no auto service. I go to the Phillips joint.  I like the people that run it.

I've experimented with various settings and I'm finding that if I tune the rig up to what essentially Tom/JJ has stated (Is and Ig) in his Maul schematic I can get decent results on the scope and no intermittent arcs with good audio response.  I spent most of the day today securing things and doing some final touches and minor mods to each chassis.  Overall, it's getting close to it's maiden voyage on the air.

I need to work on the audio chain and some more permanent wiring including how this thing will be powered. Got to work around the grounding issue.  Right now the whole thing is a total JS and it makes me nervous.  With my memory being as short as it is these days, trying to remember what I did previously can be a potentially bad situation especially when dealing with HV.

Yes, stop by the next time you come through town.  Just give me a heads-up so I can be here. 

[Steve - WB3HUZ]

Updated the 813 page with your skizmatics. TNX.

http://www.amwindow.org/tech/htm/813/813.htm

With all the editing and saving, they are getting a little fuzzy. I'm picky. I like nice clean schematic, if I can help it. And I have so much free time! I will put up the current versions until I get the new ones done. Many thanks John.

Glad to help.

The original image was only 96 dpi.  It's amazing its not even more fuzzy.  I had to create new text, which when printed, stands out as less fuzzy.  With the components, I was able to create object blocks by copying the existing fuzzy parts so they blended in better,  Unfortunately, I had to double the size of the pic to add the text, because the original scaled down text is about 2 or 3 points and the program could not make text that small, then I reduced the image back to the original size.  I was actually expecting more distortion than I ended up with.  It would be nicer redrawn, but of course, it's more important to convey the correct information than be pretty.

What do you use to draw schematics Steve?

[W3RSW]

Thanks Steverino,
'you are a gentleman and a scholar.'
uh, urk....
Frank made me say it.

[K1JJ]

Updated the 813 page with your skizmatics. TNX.

http://www.amwindow.org/tech/htm/813/813.htm

Tnx, Steve!

Makes me wanna build a few more -  a quick-on-the-air  RF deck for each band, using a common modulator and powers supplies. 

But the question everyone is thinking but afraid to ask:  "Does it work on 11M?"   (caw mawn)

T

[W3RSW]

a quick-on-the-air  RF deck for each band, using a common modulator and powers supplies. 

Already done,
1963 handbook, pp 202-205
One Band Kilowatt Amplifiers

complete with switchable circuitry for either linear or class C operation.
and all the coil winding, capacitor data for 80 through 10 meters.

The 19" rack panel had the meters in the top panel, amp decks in the middle, and screen, bias, switching stuff in bottom panel.

"In the class C position of S2, +400 volts is applied to the screens and -150 connected to the grids. In class AB1 the screen is increased to 700 and the grid bias is dropped to a value detemined by the setting of R2.  This later setting should be one that gives best linearity without exceeding a no signal plate input of 150 watts for the two 813's; it depends on the plate voltage available."
 -Cool single band rigs. 

The 813's were horizontal assembled on a 13 x 17 bottom plate with two 5 x 13 x 3 inch chassis used as the side enclosures with grid L/C's on one side, plate L/C's on the other.

[K1JJ]

Hi Rick,

Yes, I remember those single band 813 amps very well from my first days as a Novice.  The 1964 Handbook was my first one, so I drooled over that one. But it seemed so complex and far away from my first days as a "radio moron" (as the Huz calls it) I just looked and looked.

It really is a feasible idea and if I were to start over, I wud definately do it. There's not much to the RF deck of a pair of 813's. The infrastructure of modulation and powers supplies take up all the effort - but has to be built just once.  Band to band would be a breeze.


BTW, I DID  try to build that 811A linear in the same 1964 hamdbook.  I started with my red chemistry set metal "suitcase" as a chassis. I didn't know anything about drills, so used a hammer and nail to try to punch a hole for the tube socket. (Might as well get started until I get the parts.) The chassis collapsed and that was that. Glad I didn't have the money to buy the parts -  I would have surely electrocuted myself.... :-)

T

[W3RSW]

boy that brings back memories.
My first chassis was a cardboard box where I rebuilt the power supply portion of the ocean  hopper. Missing the 12at6 and 50c5 caused excessive filament voltage.  good thing the dropping resistor was still in the string.  Yeah, later on I used a cake pan to build a 50c5 oscillator, using guess what the ocean hopper coil, tickler used for feedback and the very same 35w4 rectifier and hot connection to the line.

I did get quite a few shots of 115 in those days.

I'll never forget the day when all of a sudden schematics made sense.  Very similar to when I learned to read in the first grade.   Getting up in front of class to sound out the words, all of a sudden I realized I could read.  Spooky. 

I wonder what ever happened to my red box; it was Gilbert's erector set #5 or 7, I think. Anyway it had a picture of a motor driven ferris wheel on the cover but I never built anything that elaborate.  I think it was good for a small crane.  I can still see those wheel halves, brass axle stops and millions of screws and square nuts in my mind's eye.

[K1JJ]

Sounds like you actually made some good progress with the cardboard box circuit... :-)

My first RX was a single tube regen. It used a 67 1/2 V battery for the plate power. I never got it to work at all.  I didn't have the nerve to stick my tongue on the battery to test it. When I finally did, after a month of testing, it turned out to be dead after all!


Yep, I had the same Erector set with the Ferris wheel on the front.  My best project was to build a little model race car using the 1.5 volt motor. A friend in class saw it and built one too. The teacher let us race them one day in front of the class. His beat mine.

So I went home and discovered that I could put THREE 1.5 volt batteries in series and make that motor go like a bitch!  I came in the next day and asked for a rematch. My model took off so fast it flipped upside down. I restarted it and still beat him.... HA!

I see those Erector sets on eBay from time to time.

T

[WA1GFZ]

Tom,
My first linear was also that 811A 200 watter. Then I added a second tube.
A pair of TV plate transformers in series secondary. (I just found the bleeder resistor from that rig a few nights ago.) 400 watts from my bedroom with a 250 foot end fed. L network in the closet with wire coming through a small hole to the vent above my closet. I got some real RF burns off that set up.
I drove the family crazy so soon moved to the basement and put up a rhombic after investing $176 at Hatry for a KW match box. Ward and Corkey were proud of me for getting the KW Matchbox. 4-1000A came about a year later.
Once and a while I ran SSB on 20 Meters and got some real lip burns.

[K1JJ]

Pretty fun stuff, Frank.

Yes, that 200 watt 811A linear probably enticed a whole generation of baby boomer Novices.

We probably unknowingly crossed paths many times in Hatrys back in the 60's.

In the early days I built both the swr bridge and the tube keyer from the 1964 handbook. I even tried building that 2M transistorized transceiver - remember that one? Nothing ever worked right. All failures. I had really poor luck getting ANYTHING homebrew to work back then.   I was really a radio moron.... :-)  So I stuck to trading in over and over used rigs at Hatrys for the first 2 years or so.  I went thru quite a few boat anchors looking for the Holy Grail. No one could afford Collins gear - we all knew that was the best at the time.

Corky used to gloat about owning the S line. He would sometimes axe the customers, "when ya gonna get rid of all that shit and get some Collins?"  One day he celebrated and said, "Today I made my last payment to Hatry - the Collins is ALL MINE!"  He passed away about two years later.  Corky gave me my Novice test - great ham and full of ham spirit.

I spent most of my time, paper route money and energy on antenna masts, and antenna supplies. You can go thru a lot of $ when experimenting. At least those worked pretty well for me.

T