Harris Gates 1KW AM Transmitter

[wx3k]

I have been glancing through a bunch of old pictures and I am puzzled by this transmitter I worked on years ago. It was a Harris Gates 1kw AM transmitter BUT it did not have 833's as a final. I seem to remember a single tube on this beast. I remember replacing a open choke on the final tube that was causing it to draw excessive plate current. I have another picture around but cant find it but the one I have shows the filament/plate control buttons. It is not a BC1H as the control buttons are a bit different nor is it a BC1T due to the cabinet styling. Can you identify the model ?

[Mike/W8BAC]

That appears to be a Gates Vanguard II. The single tube is a 4CX3000. Produced between 1966 and 1968. The tube is basically a class A amp. A built in, very early solid state exciter was the rig's downfall. They drifted a bit with heat. Overall 30 percent efficiency didn't help either.

[wx3k]

Ah ! Yes, A 4CX3000. So how does one find these old transmitters(any) that stations are taking out of service ? Did most of the early AM transmitters have single phase 220 power requirements ?

That appears to be a Gates Vanguard II. The single tube is a 4CX3000. Produced between 1966 and 1968. The tube is basically a class A amp. A built in, very early solid state exciter was the rig's downfall. They drifted a bit with heat. Overall 30 percent efficiency didn't help either.

[Mike/W8BAC]

Hi Stephanie,

Did most of the early AM transmitters have single phase 220 power requirements ?

All of the retired 1 KW tube type BC rigs I have seen run on 220 single phase. As far as finding one it helps to know what your looking for first I suppose. Things like what tube or tubes you prefer like 833's vs 4-400's. Another issue is some BC rigs had a tunable output which is easily modified for the ham bands vs fixed capacitance and inductance. Next decision you might have to make is do you have room for an 1150 pound, 7' tall rig.

I prefer the Collins equipment like the 20V-2 and 20V-3. They use 4-400's which are still plentiful and the transmitters use an easily modifiable and tunable design.

The Gates Vanguard 1's and 2's aren't that common. One advantage to them was they had a smaller footprint than most everything on the market at that time but in any case a good place to watch is right here on this board and eBay. Let all of us
know what your looking for and I'll bet you'll find one .

Here is a Vanguard 1

Mike

[wx3k]

Hi Mike,

Well, I have a 4-400 project which I have the building blocks for but requires additional tank circuit parts which I need to find. Sometimes I wonder if it would be a better approach to modify an old broadcast rig like the Collins, RCA or Gates transmitters. The Vanguard wasnt exactly a nice looking transmitter in terms of being able to view the nice glass tubes in operation. I like the old tube broadcast rigs just like most of the AM enthusiasts. What is it about that tube glow that attracts us ?

Room ? I have have room and it would be nice to have some extra heat in my basement right now. Its cold down there and the Ranger is not warming up the basement. ;-)

How much do these old rigs, say the 20V-3, price out for these days ?

Hi Stephanie,

Did most of the early AM transmitters have single phase 220 power requirements ?

All of the retired 1 KW tube type BC rigs I have seen run on 220 single phase. As far as finding one it helps to know what your looking for first I suppose. Things like what tube or tubes you prefer like 833's vs 4-400's. Another issue is some BC rigs had a tunable output which is easily modified for the ham bands vs fixed capacitance and inductance. Next decision you might have to make is do you have room for an 1150 pound, 7' tall rig.

I prefer the Collins equipment like the 20V-2 and 20V-3. They use 4-400's which are still plentiful and the transmitters use an easily modifiable and tunable design.

The Gates Vanguard 1's and 2's aren't that common. One advantage to them was they had a smaller footprint than most everything on the market at that time but in any case a good place to watch is right here on this board and eBay. Let all of us
know what your looking for and I'll bet you'll find one .

Here is a Vanguard 1

Mike

[Mike/W8BAC]

What is it about that tube glow that attracts us ?

Why do we sit and stare into a roaring fire? I don't know, maybe a primal instinct. I agree a big window and big tubes are fun to look at. I posted a picture below of a recent high end restoration of a 20V-2 sporting a quad set of 4-1000's belonging to Jeff/W0XV. Bling! Talk about a warm glow!

Prices are all over the place from free, come and get it to maybe $2500. I have seen 4 freebie's in as many years. They might be a rescue from a transmitter vault or a ham that has lost interest. Generally the higher priced rigs are ones that have been converted and spruced up a bit. Start scouting out the small broadcasters in your area. Find the chief engineers and ask for a tour. You might not find a thing but have a fun day looking at a working transmitter plant or you might find treasure. A few broadcast engineer email reflectors exist and you can join and watch for surplus gear that way.

I'll let you know if I hear anything regarding a 20V-2 or 3. Other opinions exist but in my opinion those are the very best.

Mike

[wx3k]

  That Collins looks very nice

I think it is a primal instinct to seek warmth. I dont have a fire place either and if I were to get one, I think the cost would be more. Lets see, paying an electric bill for a 20V-2 or paying for a cord of wood that I have to clean up after ? Hmmm....giggle.....Im being silly ;-)

Mike, Please keep me in the loop on the 20V-2 or 3 transmitters.....Personally, I dont mind restoring and putting some elbow grease into something that needs attention to make it work if the cost is a matter of rescue with a day of huffing and puffing to move a transmitter in a hurry. Although it is a nice thought to get something squeaky clean and working, the fun for me is troubleshooting something and getting it working. $$$ is a little hard to come by these days. I wish I could fork out $2500 at a clip without flinching but that is nearly impossible. 

What is it about that tube glow that attracts us ?

Why do we sit and stare into a roaring fire? I don't know, maybe a primal instinct. I agree a big window and big tubes are fun to look at. I posted a picture below of a recent high end restoration of a 20V-2 sporting a quad set of 4-1000's belonging to Jeff/W0XV. Bling! Talk about a warm glow!

Prices are all over the place from free, come and get it to maybe $2500. I have seen 4 freebie's in as many years. They might be a rescue from a transmitter vault or a ham that has lost interest. Generally the higher priced rigs are ones that have been converted and spruced up a bit. Start scouting out the small broadcasters in your area. Find the chief engineers and ask for a tour. You might not find a thing but have a fun day looking at a working transmitter plant or you might find treasure. A few broadcast engineer email reflectors exist and you can join and watch for surplus gear that way.

I'll let you know if I hear anything regarding a 20V-2 or 3. Other opinions exist but in my opinion those are the very best.

Mike

[w3jn]

Just as a note, I moved this from the Transmitters section of the HANDBOOK forum.

The TECHNICAL FORUM is for discussion of transmitters, receivers, antennas, etc.

The HANDBOOK section is for finished projects, "how to's", etc., and isn't the best place to ask questions.

[wx3k]

ok...got it

Just as a note, I moved this from the Transmitters section of the HANDBOOK forum.

The TECHNICAL FORUM is for discussion of transmitters, receivers, antennas, etc.

The HANDBOOK section is for finished projects, "how to's", etc., and isn't the best place to ask questions.

[flintstone mop]

The slim type meters and the manual controls for power on and plate on looks more like a BC1-H. There isn't enough more to see to be sure. But I think that there was a version of the Vanguard that had the appearance of a 1-H not the Juke-Box version of the Vanguard.
The Vanguard was supposed to be the finest sounding A.M. transmitter on the market, but the ineffecient electronic design, THEN the Juke-Box cabinet was a turn-off to broadcasters. It didn't look like a broadcast rig.
I know a chief in Youngstown, Ohio who has one in storage but I'll have to work on him to be able to get it as a "warm storage" Use it, deal

Fred

[Mike/W8BAC]

Yeah Fred, The Vanguard 1 was the Juke Box. The Vanguard 2 has the more traditional upright UGLY look. Inside they used identical components. The Juke Box was a real departure from traditional design. It must have impacted sales. Not many survive. You ought to see if you can pick that one up. They make a nice amp.

OK Stephanie, I'll let you know if I find something. Gotta get that basement warmed up. 

[W4RFM]

An A M that I worked for young in my career bought a Vanguard 1.  I will call him Monday to see what ever happened to it.  I will publish info if it is available, I have no interest in it myself.
Bob

[W3SLK]

The one engineer I know has a Vangard I and II. I was working on him a while ago about snagging one of them. I haven't seen Harry in a long time. Wasn't the Vangard low level AM?

[Mike/W8BAC]

Not sure what you mean by Low Level AM Mikey. It used a 100 watt solid state AM exciter and a 10 DB class A amp. Add a tunable tank circuit and a 100 watt exciter and you have a Henry 8K on steroids.

A word of caution, The iron is really noisy and the fan is loud as well. They had to keep the temperature down so that internal exciter didn't drift. The plate transformer buzz will drive you out of the shack.

I have a manual and some other paperwork if you pick one up. I can make a copy.

[W3SLK]

That is it Mike. It was nothing more than something like a Ranger driving a Henry 8K like you said. Class A has got to make lots of heat. It would help out on a day like today with regards to the current temps. But I hate like hell being in the transmitter room during the summer.

[flintstone mop]

Yea it makes me a little crazy to know that engineers from the big corporate stations have warehouses full of 1KW tube rigs and won't let them go fer free. We know that many chiefs are Hams too. They hold onto these things like they're worth gold.

True the Vanguard was nothing but a Henry on steroids, but the odd design and that is was the very finest hi-fi audio for A.M. No modulation transformer to fight with and no complicated PWM,  makes it a challenge to try to find and/or own one and brag a little that "transmitter here is a Gates Vanguard".
Fred

[kf5ccn]

Speaking of transmitters I have one for sale.
______________________________________

5,000 AM BROADCAST TRANSMITTER FOR SALE

Harris MW-5 5KW AM TRANSMITTER ON 1300 AM FOR SALE TO BE PICKED UP IN AUSTIN, TEXAS. IT IS A HARRIS MW-5. I WILL SELL IT FOR $9,500.00. IT HAS A WHOLE LOT MORE PARTS IN IT THAN A THOUSAND DOLLARS OF COURSE. IT COULD BE PARTED OUT OR EASILY MADE READY TO USE. IT IS A MODEL MW-5 AND WAS MADE IN THE LATE 80s.

I WILL ALSO CONSIDER TAKING GOOD 1 KW GATES, RCA, MCMARTIN, ETC. TRANSMITTERS OR HAM RADIO GEAR IN ON TRADE FOR THIS TRANSMITTER.

BRIAN
KF5CCN

KF5CCN@ARRL.NET

_____________________________________________________________________
Harris MW5 Specifications

Power Input:
208/230 Vac, 60 Hz closed Delta or 380 Vac, 50 Hz Wye.

Power Consumption:
9.4 kVA at 5000 watts carrier and no modulation.
13.0 kVA at 5000 watts carrier and 100% modulation.

Audio Input:
10 dBm 2 dB, 600/150 ohms balanced.

Audio Frequency Response

+1 dB from 20 to 10,000 Hz at 95%

modulation.

Audio Frequency Distortion

Less than 2% at 20 to 10,000 Hz, 95% modulation.

Power Output

Rated 5000 watts. Power reduction to  1000 watts

Spurious Output

Meets or exceeds FCC and CCIR re quirements.

RF Frequency Range

535 kHz to 1605 kHz.

RF Output Impedance

50/300 ohms, as specified.

RF Harmonics

-80 dB. Meets or exceeds FCC or CCIR specifications.

Carrier Shift

Less than 2% at 100% modulation.

Noise (Unweighted)

60 dB or better below 100% modula tion at 5000 watts output.

Positive Peak Capability

125% positive peak program modulation capability at 5600 watts.

Power Factor

95%

Tubes

Modulator - 4CX3000A

Power Amplifier - 3CX2500F3

MECHANICAL

Height

78 inches (198.12 cm)

Width

72 inches (182.88 cm)

Depth

32 inches (81.28 cm)

Weight:

Unpacked

1250 pounds (566.99 kg)

Export Packed

1850 pounds (839.15 kg),

Domestic Packed

1600 pounds (727.75 kg),

Cubic Area

120 cubic feet meters), packed (3.398 cubic feet)

ENVIRONMENTAL

Temperature

-20° to +500C (-4° to +1220F)

Humidity

0 to 95%

Altitude

0 to 7500 feet (2286 meters)

AIR VOLUME

1000 CFM

TEMPERATURE RISE (Air)

9°C

DISSIPATION

5.1 KW, 17,496 BTUH

CABINET THERMAL RADIATION

250W (estimated)

[K5UJ]

<<Yea it makes me a little crazy to know that engineers from the big corporate stations have warehouses full of 1KW tube rigs and won't let them go fer free.>>

I don't know about "warehouses full"--I don't think they have that much  but it's out of an engineer's hands.   In the corporate world assets are all in an inventory with a (usually an inflated) value assigned each item.   There's paper work, bean counting, excess property control and inventory employees at headquarters....some guy in the field can't just pull the corporation's property and sell it to some ham.  If he did that without securing an okay in writing with all the property transfer paper work he might loose his job.  So the gear sits somewhere because someone thinks they might need it some day.  It's usually better to deal with little stations -- less bureaucracy.

Rob

[WA1GFZ]

4CX3000A is a very nice tube. Same size as a 4-1000A and a lot more juice

[The Slab Bacon]

4CX3000A is a very nice tube. Same size as a 4-1000A and a lot more juice

But it doesnt have that nice, warm glow to snuggle up to  

[k4kyv]

That appears to be a Gates Vanguard II. The single tube is a 4CX3000. Produced between 1966 and 1968. The tube is basically a class A amp. A built in, very early solid state exciter was the rig's downfall. They drifted a bit with heat. Overall 30 percent efficiency didn't help either.

Actually, a tube type plate modulated transmitter won't have much better overall efficiency, i.e. rf out/a.c. mains input.  With high level modulation, you have the additional plate and filament power consumed by the modulator and driver tubes, plus the plate dissipation loss in the modulators and audio power loss in the modulation transformer (xfmrs are not 100% efficient).  That was one of Continental Electronic's selling points for their transmitters.  They never did manufacture a plate modulated rig.  Mostly grid modulated or Doherty circuit.

The significant advantage of plate modulation is that a smaller final tube can be used, and plate modulated rigs are much less critical to tune up and properly load into the antenna.

Some  corporate type a-holes will send discarded stuff to a locked dumpster before they will let an employee take it home, because they think the latter would be "giving away company property".  Someone once told me about that happening at a place where he worked.  They decided to clear out hundreds of unused 1930's vintage tubes that had been gathering dust for decades but the boss told him that if he took any of the tubes for personal use, he could be fired for "theft".  Instead, they were crushed on the concrete floor with a tractor, and the remains scooped up and hauled to a landfill.

Some people just ought to be shot.

[John K5PRO]

I dunno if i ever posted mention of it here, but some time ago I scanned the Gates Vanguard II catalog pages, & posted here:

http://louise.hallikainen.org/BroadcastHistory/index.php/GatesRadioCompany

Soon, within a few days, the rare Gates BC-1E manual will be placed there. I scanned it last night, found it in a silent keys books in Albuquerque two summers ago. Now that was a nice looker for a Gates.

[Opcom]

Speaking of transmitters I have one for sale.
______________________________________

5,000 AM BROADCAST TRANSMITTER FOR SALE

Harris MW-5 5KW AM TRANSMITTER ON 1300 AM FOR SALE TO BE PICKED UP IN AUSTIN, TEXAS. IT IS A HARRIS MW-5. I WILL SELL IT FOR $9,500.00. IT HAS A WHOLE LOT MORE PARTS IN IT THAN A THOUSAND DOLLARS OF COURSE. IT COULD BE PARTED OUT OR EASILY MADE READY TO USE. IT IS A MODEL MW-5 AND WAS MADE IN THE LATE 80s.

I like the power reduction feature. Is it push pull plate mod or is the mod in series as in PWM? I don't know that unit.

If it is $9,500.00, and has a whole lot more parts in it than a thousand dollars, what is the advantage?  Do you mean it is $950.00? If so, I'm interested and a drive from Dallas might be in order. Right now I want to understand the price statement please.

Thanks,

[Opcom]

They decided to clear out hundreds of unused 1930's vintage tubes that had been gathering dust for decades but the boss told him that if he took any of the tubes for personal use, he could be fired for "theft".  Instead, they were crushed on the concrete floor with a tractor, and the remains scooped up and hauled to a landfill.

Some people just ought to be shot.

Shot? Is that before they are hanged, or just after the hanging has been started and right before the commencement of the drawing and quartering?

The company policies of destroying worthwhile and irreplacable items is not new. They know nothing about what they are doing, except what the bean counters and lawyers tell them. The place I work at now at least had several sales and employee auctions. It was quite nice of them.

[kf5ccn]

The price is $9,500 (Nine Thousand Five Hundred Dollars USD) neg.
It is series modulated PWM.
I will also consider trading for an old Collins, RCA, Gates, or other brand 250-1000 Watt AM broadcast transmitter that is in good condition to convert to 40-160m HF HAM bands, or HF linear amps and other HAM equipment. The transmitter was retired from service last month and was working perfectly when retired. The unit can be fired up into a dummy load if buyer pays for generator rental, which I have quotes for. A visit would have to be scheduled in advance.
Thanks.
Brian
KF5CCN
kf5ccn@arrl.net