The AM Forum

Check out this stuff I just found. One of the RF amps says "Jaws II" on it. They have 3CX3000A's for tubes. Also an audio processor and a dummy load of some kind.
http://www.bunkerofdoom.com/jawsii/

Been a while since anyone dropped off 'junk' like that here. Good find, er....haul?

one has to wonder what happened to Jaws 1.

Use Jaws for 75 as a lin yar and rape teh Henry for a HB rig.

I bet there are sum tall ships drooling over that Harris. I like my stock D-104's my own bad self.

That Jaws II is a pretty FB looking amp, although the tank coil looks a tad on the wambly side for a 3CX3000.

That Henry is a 13.56 MHz ISM amp, probably for sputtering, etc.

Boy if I could find a link for the The Tool Man Tim oooh ooh ooh...get a load of that Harris..Das Goot Schtuff.... :)

Ya got the makens of a FBOM station there OM....what's yer plans...there's alot of Help on this forum to walk you through a build up.  :)

JN, you jogged a memory cell loose when you said sputtering.  :o I used to run a vac sputtering unit when I worked for the heart pacemaker place. we deposited platinum thru holes onto each individual ceramic feedthru, hundreds at a time. This was in 1998.


I got out of there when Hittman got purchased. My boss was retiring and so was the owner, Hittman. I was the tail end of a 4 man engineering team and everyone thought they were going to move everything to NY. Lotsa rumors and so on. I actually drove from West Virginia to Columbia MD. every day for a year, but hit the road after that. Couldn't take the commute any longer.

the blue glow inside the vac chamber was cool as hell. tank was about 7 ft in diameter with a 5 inch viewing window in front. You tuned it by raising or lowering the platform to max out the current. I don't remember the power but it took 440 3 phase input IIRC.

I have no idea why I went into all that.  ::)

A new friend broiught me there treasures.

I'm not sure what to do with the Harris, never had anything like that before. It's obvious a FB piece, but got no tubes inside. It might clash with the RCA BA-6A compressor.
I really don't know what to do with all the audio stuff I have except connect it in a logical order till the rack is filled up.

I am confused on the Harris why I would want to select the "expand" function when transmitting. but it must be there for a reason.

There is also going to be stuff left over if I have to make room for the Harris. I'm going to have to evict, from the rack, the Marti compressor and CBS Volumax limiter along with the small 30W hi-fi amp I was going to use as the mod driver, and the CCTV surveillance monitor has to go.

Maybe I could run this lash-up based on what's here:

1.) Altec mike amp

2.) Kahn Symmetra-Peak SP 58-1A (for a bigger voice in AM-FM and TV broadcasting [TM]) -yet I see the Harris has + and - peak protection -but that is differnt, the Khan moves the peaks, the harris protectes against theit amplitude?

3.) Harris MSP100 processor (would it go here?)

4.) RCA BA-6A compressor limiter to set general the level (?).

5.) switchable in/out passive audio bandwidth filter and/or EQ to shape the response according to transmitter's modulation characteristic.

6.) Presto or Altec power amp to drive the modulator

7.) The modulator

Is this too much stuff? I've seen pictures of stations with -alot- of audio stuff.

Jaws 2 will do all the "processing" you need.

hey don't you give jaws a look over and then plug it in and drop teh maul? i got a funny feeling that that thing is gonna work.  :D

Yeah I think you'e right Derb, I don't need any of that audio processing crap with JawsII. JawsII+plastic radio.. hahahaha! - But I was told it takes 200W to drive it all the way up, so it might be a job for the Viking I. And I think it has 4000V B+, I better be careful with it or I won't be posting any more. I bet it will run real cool on AM. No more burning up 8122's in the NCL2000. Soon as the weather cools off, I can load it up on the 40FT randome wire.

Jaws needs some dental work first. It needs a RF choke for the plate, a 25 ohm "fuse resistor" in the plate circuit, there are a few loose items, and also I was warned to carefully reform the electrolytics in the HV power supply. I have not opened that yet. Maybe this fall will be a good season of ham radio for me..

[][][]

I was also shown these things below. I am going to try and trade for them if my friend will consider it. This is a "Norton" audio amp. I'm told they made some big amps, and this one used four 845's. It was suggested I could uses zero bias 838's, since the 845's are all taken up by the phools' SE class A amps now. It has a 500 ohm output. I have not yet found any "Norton" info on the www. This kind of thing makes me very interested. I just want to smell it; the smell of old radios. (yeah I know that is really the smell of mildew and PCB oil in wood, but whatever) I guess it qualifies as a Buzzard audio amp.

Ralph sez: Hey Norton!

Can you 'splain bout the coil? It's thin, but made of flat spiral, I thought it was about 3/16" wide. Is there not enough turns? There is a coil below, with more turns, not sure yet really how it is all conected.

I thought perhaps it was edgewound, in which case it's certainly up to the task at hand ;D

prolly got another coil that switches in for more L on 160. Are You Sure? that thing does 4KV on the plate? I'd blow no more than about 50 watts carrier into it after you give it a going over.

Re the plate choke: the one I got from Frontier Engineering for maul #1 is primo very top quality for 35 bucks on ebay. he has a store on there. You tell him what you need and he winds a custom job just for you upon price quote and approval. On a amp that big there's no way I'd try to stick some hamfest plate choke in there. You are now in the big strapper class with that amp. That means you will have to
spend a bit. take some measurements of the length you can fit in there. tell him you got the tube, voltage, current, etc. and he will fix you up. He can wind it on Delrin, ceramic, or teflon.

I got no connection with the guy but I dont think you're going to get a custom made plate choke better for less. you can even pick the color of the magnet wire, blue, green, yellow, etc. I got 2. I just told him I had 4 572B's @ 1800vdc 1000 ma max current 80-10 meters and he did the rest.

I am working like hell in the shack. Gotta get back to it. maybe some pix later.

www.freng.com/ (http://www.freng.com/)

Pat,

took another look at Jaws 2. Saw something - maybe nothing, but one or 2 of the mounting screws on the jennings vac cap looks a little askew to me, possibly like it took a hit. Get together with GFZ on here and see what he thinks of it, and rotate the knob on that mother
very tenderly until you figure out if it's just loose or someone wrenched on the cap knob with the name of Hambone.

Also, I dont know of a factory made tuner that would handle that thing into a 40 ft random wire. Not even a KW Matchbox. That thing with 4 KV on it assuming everything else is good on it is capable of more than 7~8000 watts peak on slopbukit and would run 21~2300 carrier on am all day long. ifn the iron is big enough, and it looks like it is.

That thing is too much fer a random wire. I think things would randomly start blowing up in yer shack real fast.

and it's got a electro stack at 4 KV? I believe I would be using some decent oil jobs and find a big ass swinging choke an change it over to choke input so you dont need so much capacity. Couple of good oils ....say;  total 20 mf @ 10 kv. Expensive but I wouldnt trust a electro stack @ 4KV.

You gotta pay the price to get out nice.  8)

You can use Chinese 845s... they work quite well.

Of course 211s are also an option.

Perhaps even 813s strapped for triode.

838s and 805s are possible but check the plate Z differential if any.

         Nice finds!

                Geez, I have no friends by comparison...  :(



          _-_-bear

Derb,

I had a good look at the mounting screws, they seem to be fine. It turns real nice but the knob is right up against the panel. The screws at the back end connector look askew, but the connector there is off the backend post of the cap. So it's askew. Nothing looked bent or broken. I was told the amo is now wired for 160M only, although I am not sure why the bandswitch is there, except it has taps on the coil, maybe for segments of the band? I have to investigate further in a couple weeks. Sure enough I will just tickle it at first once I have replaced the missing items. I have not even looked inside to see if it has a T/R switch. It is pretty well made for a HB amp. I have sen factory made ones that did not look as nice.

as for the tube, oh my.. How will I be sure to obey the 1500W rule? It's easy to reduce drive. I best come up with a simple peak measurement device once it gets resotred and comes off the dummy load (assuming there's anything left of that).

I believe I understand why it is good to use an overkill amp for regulation power levels. I recall an old article about a big linear amp commercially sold to hams, called the Elenco "commander". It used a 4-1000 in GG with 6KV on the plate. input 4KW PEP SSB, 1.5KW AM, 3-30MHz coverage, made in 1958-1959. The findings were that an amp capable of X output would have much less distortion at X/n output level.

Bear,

I didn't know 845's are still being made.
But I don't have that Norton amp yet. I maybe have to trade for it or buy it, so we will see. There might be some 838's available which are the zero bias similar type. Probably not popular with the audiophools since they need some grid current.

In the meantime, does anyone know how good these things are: collins modulation monitor and 26U-2 audio limiter?  They are not mine, I just have pics. I'm used to using a scope for mod monitoring.

a amp that size probably has a vacuum T/R switch as well. the bandswitch is for different bands. you dont need taps on a correctly designed tank to cover all of 160. More likely it was hacked in some manner and you will have to un hack it.

what are you going to do about your real problem? There's no tuner on earth that can handle that beast into a 40 ft random wire. Unless you improve your antenna situation you cant use it. you can test it into that huge dummy load though. Got a ready source of 220? That thing don't run on 110.

You're going to have to give the whole thing a good going over. Maybe more work than you wanna do, I dunno.

Are you sure that these mysterious things that showed up were not destined for the VORTEX??? Somehow these things get confused and show up on someone's front door.
Make a big wave on AM!!!!!

Fred

Ya, dee Chineze make 'em.
Buy 'em by the pallet or the container full...  ;D
Think there are several US distributors, including Electro-Harmonix.
Let me know if you need any Chineze toobes, or Ruskie tubes of the audio persuasion.
Anyone else too... just need to buy more than one or two usually... I am technically an OEM buyer from EH.

The 838 is a bit of sleeper, but most audiophiles who roll their own use the 845s in A2 anyhow... 211s also A2.

Part of the problem with the 838 is finding a bit of iron that will handle the snot/monkey swing from a pair... that being for 8ohm type iron, not mod iron.

<secret message>Btw, I'll be packing that thing this weekend for you...  </secret message>  ;)

                        _-_-bear

Strangely it is wired for 120V and has a big-ass plug on it. It's a 30A or 50A RV type plug.  It is supposed to be rewirable for 240V, I am sure I will do that. It will be a fun project. You are right about the antenna. I have to put up a real antenna. But I will work on the amp now and try for the antenna in the coool weather of the fall, it will be fun and I kind of have to, if ya know what I mean.

I looked inside the accompanying dummy load. It's been hot. Someone or something has cooked up the 4300 watt dummy load.


Bear,

as for the 838's and 845's, looks good. I will know if I am getting the Norton amp this saturday. I found out what it is for. It is a chimes amplifier. Must have come from a church and played the bells. It is in a maybe 7FT black rack with a turntable, driver stage with 6B4's, and the rest has been shown. The front panel is beautiful and very dignified, just as something from church should be. Anyway I get to see it on saturday. I will judge the size of the OPT iron and if it looks like it will make 200W into 500 ohms then I'll try for it. That and an H pad should make rock solid well regulated driver to a pair of 3-500Zs.

pat,

does it still measure 50 ohms at the terminals? - and is it an oil filled load? if you take the covers off the PS at some point, snap some pix - I'd love to see the Iron in that thing.

I'm bored as hell - as have to stay down here at my dad's until SATURDAY. Urk. Urg.

Cant do radio work when you're never home.  :-\

I would like to do that soon -open the dummy. I have not measured it, all I had time to do was hide it in the storage building with Jaws and Henry. It's air cooled by convection and has several racks each with several large resistors in it, maybe 1" diameter and 8-10" long. It's air cooled and has a grating I could peek through, and it looked like wire was exposed on some.

In looking at the ratings - 4.3KW AV - 13500V peak. I have no idea what it is originally for. Might not be 50 ohms regardless of the PL-259 connector, which would probably melt at 4300W.

I need to show some pictures of the parts I have been collecting for the "tuna" but it's a ways off, since the coily things will have to be driven by motors as they are pretty hard to turn. They make the one in the jaws look sissy. I have the motors but none of this has any limit switches, so I have to deal with that too. I think it will have to be built on a set of rack panels. and put in a cabinet. The vriable inductors on one motor shaft and the variable caps on another. I can use a big knife switch to place the caps on the TX side of the coild or the feedline side of the coils. the Balanced in/out, and a 5KW (1:1) balun will have to be bought and put at the front where the radio hooks up. So far I have two 0-15uH roller coils from a 10KW BC station, some non-matching fixed coils (need pairs), and a bunch of air variable caps, some 1000pF/3500V and some about 200pF and 5000-7500V. I hope to be able to have a heavy duty coax switch where I assume the position and pick from the tansmitters, and then just one cable going to the tuner about 30FT away by the wall, and have the ladder line go out from there.

I got this idea from "A Balanced Balanced Antenna Tuner By Richard L. Measures, AG6K" and "Home Brew Balanced Antenna Tuner by Philip KB4I", both of which appear here, where I have scurriously assembled some papers on antenna tuners into one document, without asking anyone's permission at all:
http://www.bunkerofdoom.com/lit/bal_xmit/HFbaltransys.pdf
(no one has complained yet)

I wish you didn't have so many boring days stuck where you can't do radio!

This is the schematic for the tuner, any comments welcome. On the left shows the evolution of this from an unbalanced pi network. It seems to be supported by the writings cited.

ifn you are going to use gear drives make sure you have the ability to slow down the rotation enough to make very fine adjustments, or you will forever be overshooting the exact match point and going back and forth.

you could make a swr autosense circuit and drive teh motors with that.

I'd prefer manual tuning, but the transmitters are at the end of the building and the best place for the feedthrough is on the side in the middle.

I'm not sure I'm smart enough to make an SWR autosense that would cover 1.8 to 30MHz. Also consider the size of the boatanchors that have been washing up on the shore lately is pretty scary.

The guy in the article put a multi-turn pot on his tuner, pretty smart.

Lucky the motors on hand are multi-gear reduction so they will stop quick, and will turn slowly with lower voltages. They are 24 volts. The biggest problem with using them is a 0.315" (8mm) shaft on the motors and a 0.375" shaft on the caps and coils. Since I am not very good at machinery, I won't be able to exactly align it all, and will try to use some long shafts and those flexible couplings to make up any small amount of misalignment.

Do you think I have enough capacitance? Looking at some charts, I should have twice as much, but the big air variables are not easy to get.

Update on the shack.

Thanks to my apprentice, we got started at 11AM and cleared out over 120 SQ FT of space in the shack and also brought in a rack and stuffed it full of low voltage power supplies for in case of having to use or work on transistorized radios. It was a job because these things are not to be taken lightly. To fill up the rack, we laid the rack on the floor face up, and dropped the supplies in. So, from top to bottom:
12V supply additional filtering - basically a chassis same as the 12V supply, with L&C, less PWR XFMR
12V supply additional filtering - basically a chassis same as the 12V supply, with L&C, less PWR XFMR
12V supply  - does 12.55V @ 37A as measured - It's from some Motorola set.
0-35V 15A regulated supply - a monster full of those big round geraniums.
24VDC 25A Sola resonant regulator supply
24VDC 25A Sola resonant regulator supply (put in parallel with same above for 50A)
48VDC 4A Sola resonant regulator supply
The holes were not for the usual 10-32 screwes so I rant a tap through them to make ready. The drawers were already in, so I left them. I can put power cables etc in there. The main disadvantage is the rack is now front heavy so I will want to bolt a couple if 2x4's under it that stick out in front and help revent any unfortunate tipping.

To erect the rack, we used a hoist with a block and tackle tied throughthe top frame of the steel rack. Ye Younge Apprentice could not do well with the hoist, so I provided the required ballast to pull the rope down. This is a very easy way to fill up a rack, alot easier than supporting several 50-80LB equipments by hand and trying to stab the screws.

Jaws II Update

Back to the JAWS II amp - we went and got it from storage and it was 11 PM, so for some reason, probably because he is 20, he had to go over to his YL's house. She is very nice, and when she calls and he says we are working with electrical equipment, she does not complain.

I removed the covers from the power supply, as the previous owner had bragged on it alot, telling me about a Dahl transformer, etc. I didn't find PWD iron, but it was still pretty large.

The power supply has seen a few mice but not too bad and the rectifier diodes seem to have been hot and show deterioration and cracks around the terminals. The solder was so hot it has loose joints. This could have been the reason the amp was put out of service. I believe I will replace them before doing anything else.

The architecture is a full wave voltage doubler with a 14 capacitor bank of 800uF/450V capacitors (57uF at 6300V). The transformer has these specifications:

pri: 220V 50/60Hz, 1070WV to GND
sec: 1760V/1.53A (2694VA), 6420WV to GND, (10 Ohm measured DCR)
Langeview MFG corp. L-1527 Grade 1 Class A

It would be interesting to know what the transformer was from.

The transformer appears to have an impedance of 18 Ohms. Based on that, Duncan Amps PSUD II indicates that this power supply might provide these conditions:

4237VDC @ 2.057A (RL=2K)
4389VDC @ 1.463A (RL=3K)
4484VDC @ 1.121A (RL=4K)
4548VDC @ 0.909A (RL=5K)
4594VDC @ 0.769A (RL=6K)
4657VDC @ 0.582A (RL=8K) (2710VA - possibly near a realistic CCS value)
4699VDC @ 0.470A (RL=10K)
4762VDC @ 0.317A (RL=15K)
4798VDC @ 0.239A (RL=20K)

However, much of this simulated information rests on the transformer's assumed impedance and its behavior when overloaded. The program does not take into account overloading's effect on the core.

Real performance can be arrived at accurately only by testing later and like everything else, probably won't be as good.

AM performance also faces limitations from the 3CX3000.
The datasheet indicates these values for carrier conditions in AM Grid-driven amplifier service. The Carrier operating conditions do exceed the power supply transformer VA capacity by 10% assuming no losses elsewhere. I don't know what will happen with modulation. I have not checked the size of the 220V circuit breaker on the front panel.

Plate voltage = 4000V
Zero Signal Plate Current = 0.25A
DC Plate Current = 0.74A
DC Grid Current = 0.13A
Peak RF Grid Voltage = 85V
Peak Driving Power = 11.5W
Plate Dissipation= 1830W
Single Tone Plate Output Power = 1130W (Carrier, so PEP would be 4520W)
Resonant Load Impedance = 1750 Ohms
Peak RF Plate Voltage = 2000V

For practical purposes, I'm sure the power supply and amplifier will idle along easily in any mode at the full power permitted in the Amateur Radio serivce. That's all I really wanted, a linear amp that would take AM service at the legal limit and not cry about it.

reforming the caps in the power supply:
http://amfone.net/Amforum/index.php?topic=19257.0

Today I took the amp to task. There are a couple of issues besides some missing parts.

But first I want to comment on the cathode compartment. It is amazing. The first thing that caught my eye was a 50 amp B&W filament choke. It's huge, almost 3" diameter and 8-9" long. The tank circuits for the cathode drive (I was hoping it would be a swamped grid driven unit) are all wound on 1/2" diameter ceramic or fiberglass forms with slugs in them. The smallest coil wire I saw looked like #14. Many were teflon insulated, as was all the wire going from the big ceramic bandswitch to the coils. It looks like a pi network. All bands except 160M have a tank. the 160M band goes straight through. I think it might be because the coil form could not hold enough wire turns. 1 out of the 6 is not wound. The fimament connections and socket are very well made of heavy plate. Between the plate for the outer filament ring and the plate for the inner filament stud are four 1000pF doorknobs. As if this were not enough, the 2" of thick straps between the filament choke and the socket is terminated at the choke with a huge dipped mica cap. I know I should have the appropriate pr0n, later I will take some.

The issues I found are the tuning and loading caps. Someone mentioned before they looked crooked. The top one seems OK, but the bottom one is about 1 degree off. It might be because the holes for the dial turns counters were off, I cannot say. The top one turns easily enough but the bottom one is harder to turn. Maybe because of the angle or misalignment.

The turret-style metal part on the snout of the tuning cap is fairly loose. The one on the loading cap is tight. Both can be turned. These are the items the shafts emerge from.

1. are these supposed to be loose?

2. how do you adjust them?

3. what is the deal on them? - besides protecting the bearings or whatever. Are they to be oiled or anything?  There is a small hole in the side of each one.

the attachment show the kind of caps in the unit. It is more like the tuning cap in appearance.

any advice on this would be welcome.