12 kw 160-12m amp for sale.
I designed this amp (back in 2007) for a buddy, who is now SK. Current owner is in MT. It uses a custom 253 lb Dahl plate xfmr and 24 x 3900uf lytics. Vac relays used for the input + cut off bias. Paralleled Jennings RJ2B's used for the output. We tested the manually tuned, tuned input with a 800 watt CCS cxr for 10 mins, on each band. Input swr is dead flat across all bands. Triple wafer model 85 switch used for the 12 kw PI net. Multronics MI-14 1/2" tubing coil used for 160-80-60-40-30m. HB 1/2 tubing coil used for 20-17-15-12m. This is a 9 band amp. 1000 pf @ 15 kv jennings tune cap. 3000 pf @ 5 kv jennings load cap. Bias is adjustable, on the fly with a 20 position rotary switch. Dual line section bird, with 25 kw forward slug and 1 kw reverse slug. Pep board also installed. Kicks offline if reflected power too high. 10 kw out with 500w of drive. 12 kw with 600 watts of drive. 7-16 DIN output connector. I also have a spare, nib blower, on my shelf. 253 lb dal xfmr has pri taps at 198-208-218 vac....and also 230-240-250 vac. Sec taps at 2300, 2900, 3900, 4600, 5000, 5400 vac. ( single phase 60 hz). 3 x 300 amp contactors used on the 240 vac input. One per each leg..and the 3rd one used for the step start. Separate step start and variac used for the fil xfmr. There is only 5600 hrs on the hour meter. You need 200 amp service...and also a 100 amp breaker installed in the main 200 amp panel...and a min of 3 ga copper wire from main panel to amp.
If interested, contact the seller below.
A SUPERBLY HAND BUILT 3CX-6000A7 HF AMPLIFIER IN A 6 FT RACK ON WHEELS. DESIGNED BY A PROFESSIONAL ENGINEER. PETER DAHL HV SUPPLY WITH TAPS DELIVERS UP TO 8000 VDC AT 3 AMPS. ANY TRANSCEIVER WITH A 500 WATT INTERMEDIATE AMP CAN PRODUCE OVER 10KW OUTPUT. INPUT AND OUTPUT BAND SWITCHES WITH TUNED PI NETWORKS FOR ALL HAM BANDS 160-12 METERS AND TUNABLE TO OTHER HF FREQUENCIES 3.5-24 MHZ. HUGE ADJUSTABLE OUTPUT VACUUM CAPS AND VACUUM RELAYS. ADJUSTABLE BIAS FOR BOTH LINEAR AND CLASS C. EXTENSIVE METERING, PROTECTION CIRCUITS AND FUSING THROUGHOUT. OVER $10,000 IN PARTS AT 2010 PRICES AND UNTOLD HOURS WERE SPENT BUILDING AND PERFECTING THIS INCREDIBLE MACHINE. WE CALL IT THE MONSTER AMP. ASKING $10,000 OR BEST OFFER. WE HAVE DETAILED PHOTOS. ONSITE DEMONSTRATION OF THIS AMP¡¯S OPERATION AND CAPABILITES IS AVAILABLE IN MONTANA. TOO HEAVY TO SHIP. SERIOUS BUYERS CALL 406-240-5428 OR 406-830-6360 FOR MORE INFORMATION. NOTE: OPERATION HIGHER THAN 1500 WATTS IN US HAM BANDS VIOLATES FCC RULES.
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60/50 = 1.2?
SWR of 1.2:1? is good enough.?
Typ with DL resistors..... once u cook em a few times, they will drift a few ohms up in value.?
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My Bird 5Kw? reads 50r + - 2 ohms through 900mhz ,? but I wouldn't hesitate to feed my 30S-1 into a 60 ohm load.
Don W4DNR?
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On 2023-09-29 11:46 am, HaL Mandel wrote:
Gents,
?
Looking at resistive DL¡¯s for QRO
is an interesting pursuit, and the
recommendation about employing
a VNA makes it a good return on
investment when selecting the
¡°²ú¾±³Ù²õ.¡±
?
One of my DL¡¯s is a Palstar 5K.
?
It¡¯s not brand new and it¡¯s seen
some excitation, and has smoked,
even, with whatever Murphy dumped
when I wasn¡¯t looking.
?
Now here¡¯s the rub:
?
The DL returns a 60.1 Ohm DC resistance.
?
To my understanding a 60 Ohm (R) is
not 50 Ohms, (Zero) j. So I telephones
the factory and ask about buying some
in-spec tubulars for my Load, and I was
told that ¡°Fifty ohms or sixty ohms doesn¡¯t
matter. A null anywhere near the resonant
frequency of your tank circuit is good enough.¡±
¡°And besides, they don¡¯t make resistors
in that wattage at fifty, only sixty.¡±
?
I have a DL in the shed that¡¯s fifty at J zero,
but it¡¯s liquid cooled and I can¡¯t shlep it
from building to building anymore.
?
And I don¡¯t think a 245 foot chunka RG8
will pass the Wiltron test for Non-Baloney.
?
Comment?? Suggestions?
?
TNX
?
Hal Mandel
W4HBM
?
?
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If you use them (or it) for a dummy load, they (or it) will require a large heat sink.
? 73?? Bill K3HZP
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Gents,
?
Looking at resistive DL¡¯s for QRO
is an interesting pursuit, and the
recommendation about employing
a VNA makes it a good return on
investment when selecting the
¡°²ú¾±³Ù²õ.¡±
?
One of my DL¡¯s is a Palstar 5K.
?
It¡¯s not brand new and it¡¯s seen
some excitation, and has smoked,
even, with whatever Murphy dumped
when I wasn¡¯t looking.
?
Now here¡¯s the rub:
?
The DL returns a 60.1 Ohm DC resistance.
?
To my understanding a 60 Ohm (R) is
not 50 Ohms, (Zero) j. So I telephones
the factory and ask about buying some
in-spec tubulars for my Load, and I was
told that ¡°Fifty ohms or sixty ohms doesn¡¯t
matter. A null anywhere near the resonant
frequency of your tank circuit is good enough.¡±
¡°And besides, they don¡¯t make resistors
in that wattage at fifty, only sixty.¡±
?
I have a DL in the shed that¡¯s fifty at J zero,
but it¡¯s liquid cooled and I can¡¯t shlep it
from building to building anymore.
?
And I don¡¯t think a 245 foot chunka RG8
will pass the Wiltron test for Non-Baloney.
?
Comment?? Suggestions?
?
TNX
?
Hal Mandel
W4HBM
?
?
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It would take the op all of 30 secs to parallel the 2 x 100 ohm resistors and see if they are inductive.? ?Heck only 1 is required for this test.??
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Thanks for all the replies. I don't need a dummy load, I just have this stuff laying around. I'll probably just try for the heck of it. Again, thanks for the replies.
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Hi ¨C ? I would say giver it a try. Put it together and then use a network or antenna analyzer and check the DL for return loss. 73 ¨C Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 ?
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From: [email protected] < [email protected]> On Behalf Of N0EE via groups.io Sent: Thursday, September 28, 2023 10:14 PM To: [email protected]Subject: [ham-amplifiers] Dummy Load Resistor ? I'm wondering if a Planar resistor can be used for an RF dummy load. I have a couple 1KW 100 ohm Planar resistors and an 18# heat sink, I can't find my answer anywhere. Any information will be greatly appreciated.
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Scott,
I may be reading too much into this, but when people post to a group named "ham-amplifiers" and mention "a couple 1KW ... resistors" I can only assume that they plan to homebrew an HF dummy load.
They'd be much better off to buy a surplus dummy load in the 5 kW range that's good to at least 6 meters, preferably higher.? There may be some FM broadcast surplus kicking around ...? I know a guy who knows some guys.? Whatever.
73 Jim N6OTQ
You can always take two of the 50 ohm resistors in series,
paralleled with another two 50 ohm resistors in series.
Should give you 400 watts of dissipation.
I'm using 2 paralleled strings of 4-100 ohm resistors
to get 200 ohms capable of dropping the 8 watts
to slow a fan down cooling my stereo. (120VAC)
They are 1 watt resistors I had in my junque box.
On 2023-09-28 22:23, Jim Strohm wrote:
> ebay has some 50 ohm non-inductive resistors?but they're not good for
> much more than 100 watts and most are 50 ohms.? For higher power
> values, you'll need to search the surplus channels.? Just how big a
> dummy load do you need, anyway?
>
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Mite want to check the SWR of it or a scan with a VNA or some such to see how it looks.
A
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On 9/28/2023 9:43 PM, Scott, KB3JQQ via groups.io wrote: You can always take two of the 50 ohm resistors in series,
paralleled with another two 50 ohm resistors in series.
Should give you 400 watts of dissipation.
I'm using 2 paralleled strings of 4-100 ohm resistors
to get 200 ohms capable of dropping the 8 watts
to slow a fan down cooling my stereo. (120VAC)
They are 1 watt resistors I had in my junque box.
On 2023-09-28 22:23, Jim Strohm wrote:
ebay has some 50 ohm non-inductive resistors?but they're not good for much more than 100 watts and most are 50 ohms.? For higher power values, you'll need to search the surplus channels.? Just how big a dummy load do you need, anyway?
--
"Where the Old Soo crossed the New Soo"
Duplainville, Wisconsin
Web page: Http:/www.dupyrail.com
Youtube Channel:
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Reminds me, I built a dummy load with twenty half watt
1000 ohm resistors in parallel between two coax braids
dunked in a gallon of ND30 motor oil in a one gallon pain can.
I haven't killed it yet using up to one minute tests with 100+ watts.
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On 2023-09-28 22:43, Scott, KB3JQQ via groups.io wrote: You can always take two of the 50 ohm resistors in series,
paralleled with another two 50 ohm resistors in series.
Should give you 400 watts of dissipation.
|
You can always take two of the 50 ohm resistors in series,
paralleled with another two 50 ohm resistors in series.
Should give you 400 watts of dissipation.
I'm using 2 paralleled strings of 4-100 ohm resistors
to get 200 ohms capable of dropping the 8 watts
to slow a fan down cooling my stereo. (120VAC)
They are 1 watt resistors I had in my junque box.
toggle quoted message
Show quoted text
On 2023-09-28 22:23, Jim Strohm wrote: ebay has some 50 ohm non-inductive resistors?but they're not good for much more than 100 watts and most are 50 ohms.? For higher power values, you'll need to search the surplus channels.? Just how big a dummy load do you need, anyway?
|
John,
Does the datasheet for that "planar resistor" say it's non-inductive?? If not, then it probably won't work as a dummy load, except at audio.
ebay has some 50 ohm non-inductive resistors?but they're not good for much more than 100 watts and most are 50 ohms.? For higher power values, you'll need to search the surplus channels.? Just how big a dummy load do you need, anyway?
73 Jim N6OTQ
I'm wondering if a Planar resistor can be used for an RF dummy load. I have a couple 1KW 100 ohm Planar resistors and an 18# heat sink, I can't find my answer anywhere. Any information will be greatly appreciated.
|
I'm wondering if a Planar resistor can be used for an RF dummy load. I have a couple 1KW 100 ohm Planar resistors and an 18# heat sink, I can't find my answer anywhere. Any information will be greatly appreciated.
|
Re: Plate modulated GG triodes
Jim, that sound about right.? Years ago I ran a Ranger and a Thunderbolt amp.? This combo is very inefficient.? ?In AM mode they ran the pair of 4-400 with 350 MA if idle current. Then, they had your drive the amp up to 10 to 15 ma of grid current. You ended
up with nuclear hot tubes, 300watts and no peaks.? No matter how you loaded it, It would never show any peak power.
One day I decided to switch the T bolt in to Class C.? It has that mode for CW.? Then, I drove the ranger into it.? It took twice the drive but the ranger could do that easily with the padder removed.??
I ended up with a cool running amp, 1200 pep from a 300 watt carrier.? I checked it both ways on my Spec AN and found 1 db of difference. ALL of the heat was gone.??
I am unsure what would happen if you added the choke.? It might be worth a try.
We tried many different methods.? Including applying audio to the grid via a transformer.?
The way Gates handled this was to have a separate winding on the mod trans. This winding modulated the Driver tube.? This way the drive power is modulated.
What I want to try and will soon, is to modulate the drive on a plate modulated rig.?
In the case of my friends rig, There is 60 watts not modulated as drive for the 500 ish watt of carrier unless you come up with a way to modulate it, That 60 watts just sits there on the scope
C
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Just curious, the feed through power of a G-G Amp might be ~ 2 to 5% of the power output when the tube has a high Mu. For a low Mu tube, that could be upwards of 20%. The self modulated control grid adds a new to me concept that I never have seen before.
I presume the Plate Modulated GG triode is run class C?
If the feed through power is low, the limitation to downward modulation will be minimal. A high Mu tube needs a bit of a kick in the pants to get to plate current saturation, where the peak grid-cathode swing is way positive, and drawing significant grid current.
A low Mu tube might reach the same saturation plate current at zero bias where there is no grid current, but a much larger swing in voltage grid to cathode.
I run a Gonset GSB-201 with 4 Russian 811A's (high Mu) for AM. On AM I use 12v bias, which at 1500v B+, the tubes idle at the edge of cutoff. For SSB I use -4.5v with an idle current at about 60ma.
On AM, old texts from the 1930's call this class BC amplification. What is the result?
* very clean (AM)
* gain drops from 10 db to about 7 db (takes more drive)
* resting carrier efficiency changes from around 30% to about 38%
* I can achieve 800w PEP from a 150-175 watt carrier that has a drive that has asymmetrical modulation. With normal mode (-4.5v bias), the drive is reduced (more gain), efficiency drops, and max PEP output drops to around 600 watts PEP
* With Class BC, the output modulation percentage is about 5% higher than the modulation percentage of the driver stage.
So, If I biased my Amp class C (maybe 24v bias), added a grid choke (20H), and plate modulated the 811A plates, then what would happen?
Jim
Wd5JKO
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Re: Plate modulated GG triodes
Just curious, the feed through power of a G-G Amp might be ~ 2 to 5% of the power output when the tube has a high Mu. For a low Mu tube, that could be upwards of 20%. The self modulated control grid adds a new to me concept that I never have seen before. I presume the Plate Modulated GG triode is run class C?
If the feed through power is low, the limitation to downward modulation will be minimal. A high Mu tube needs a bit of a kick in the pants to get to plate current saturation, where the peak grid-cathode swing is way positive, and drawing significant grid current. A low Mu tube might reach the same saturation plate current at zero bias where there is no grid current, but a much larger swing in voltage grid to cathode.
I run a Gonset GSB-201 with 4 Russian 811A's (high Mu) for AM. On AM I use 12v bias, which at 1500v B+, the tubes idle at the edge of cutoff. For SSB I use -4.5v with an idle current at about 60ma.
On AM, old texts from the 1930's call this class BC amplification. What is the result?
* very clean (AM)
* gain drops from 10 db to about 7 db (takes more drive)
* resting carrier efficiency changes from around 30% to about 38%
* I can achieve 800w PEP from a 150-175 watt carrier that has a drive that has asymmetrical modulation. With normal mode (-4.5v bias), the drive is reduced (more gain), efficiency drops, and max PEP output drops to around 600 watts PEP
* With Class BC, the output modulation percentage is about 5% higher than the modulation percentage of the driver stage.
So, If I biased my Amp class C (maybe 24v bias), added a grid choke (20H), and plate modulated the 811A plates, then what would happen?
Jim
Wd5JKO
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Re: 3CX-10,000A7 for sale...... $2500.00
The tube hi-pot tests 30 kv (anode to grid)...and? 5 kv (grid to cathode).? This is normal for a 3x10.?
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Re: Operating RTTY FSK and Alpha 86
I went to local "Lowe's" hardware (may not be same in VE) and bought foam filter material ($4) and cut to fit.
Frost King 15-in W x 24-in L x 0.1875-in Washable Cut To Fit Air Filter
if the link doesn't work, go to Lowes site ( HomeDepot does similar, etc.)?? and search for foam filter. $4 and picked up same day.? Cut and installed on Acom 2000A - great option.
73 W5AJ Robert
On Fri, Sep 8, 2023 at 9:25?AM James Wolf < kr9u@...> wrote: Jim, ? Can you point us to a good filter material to use?? Maybe a link? ? Jim ¨C KR9U ? ? This is exactly why you install or retrofit a filter on the air intake.?
On a side note, a shop vac on the bottom of the tube will get most of the crud + dust out...from the bottom.? ? Then try compressed air from the top. Then stick it in the dishwasher....that works superb.? ? Go to 3M's? home page.? ?They make filters as small as 7" x 7".? ?They also have washable, and cutable filters, that can be cut to fit a specific size.
Don't get ur fingers on the ceramic.? Any skin oil / fingerprints etc, will result in reduced hi-pot test results.
Jim? VE7RF
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3CX-10,000A7 for sale...... $2500.00
Scott, KB1SEL (amprepairguy.com) has a recently rebuilt (by Econco) Svetlana 3CX-10,000A7 for sale.? ZERO hours on the rebuilt tube....and also a full warranty.
Contact Scott Mitchell at KB1SEL@... or phone him at (203) 892-4119
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This is why I bought that 0-15 kvdc? hi-pot tester from W8JI.? Ur dead in the water without it.?
Hi-pot from anode to grid ( with grid temp bonded to cathode)
Then hi-pot from grid to cathode ( with anode temp bonded to grid).?
If the grid is shorted to the cathode? ( tube on bench, with a dvm between grid and cathode)? you have a 50% chance of clearing it.? Temp apply ( quick blip) 12 vdc from a car battery between grid and cathode.?
It will either:
(A)? blow it open
(B)? weld it permanently closed.?
?
Lou, what is typ hi-pot test results on a GOOD? 572B? ( anode to grid...... and grid to cathode)? ???
Jim? ?VE7RF
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Bill K3HZP
HaL Mandel
Scott, KB3JQQ
Robert, W5AJ