W#hat to use for HV connectors.

[VE1IDX]

I figured I would ask this here as I know a lot of you guys have home brew gear with separate power supplies.I am planning to build a separate amp and power supply. This of course means that I need to bring all the operating voltages including the 2000 volt plate supply into the RF deck. I want to be able to unplug the cable from the back of the RF deck but I am not sure what to use for the HV connector. I had thought about using a nice large Jones plug but I don't know what they are like for high voltage. I would think they should be fine as they look like they are a bakelite type material or is my thinking all wrong on that? I haven't even started building things yet so I have some time to figure this part out but at least I do have all the parts. It would be nice to have all the wires in a single cable run and not several individual cables.

Tnx.

[w3jn]

Do a search on "HV connectors" in this forum - it's been discussed a lot before.

[W7SOE]

I went through this.  The Millen type are too $$$.  I bought some "beehive" type feed through connectors off ebay.

Rich

[WA1GFZ]

HN with RG213

[KA2DZT]

I figured I would ask this here as I know a lot of you guys have home brew gear with separate power supplies.I am planning to build a separate amp and power supply. This of course means that I need to bring all the operating voltages including the 2000 volt plate supply into the RF deck. I want to be able to unplug the cable from the back of the RF deck but I am not sure what to use for the HV connector. I had thought about using a nice large Jones plug but I don't know what they are like for high voltage. I would think they should be fine as they look like they are a bakelite type material or is my thinking all wrong on that? I haven't even started building things yet so I have some time to figure this part out but at least I do have all the parts. It would be nice to have all the wires in a single cable run and not several individual cables.

Tnx.

The large Cinch plugs, I don't think, are rated for 2KV, but I've seen them used in HV power supplies without any problems.  I have a regulated 1.5KV supply that uses one to bring the HV (along with other circuit wiring) from the main chassis to the regulator chassis.  I think the unregulated HV from the main chassis is up near 2.5-3KV.  I would have to pull one of the chassis from the rack to double check this (not easy).  IIRC there is only the one large multipin Cinch plug connecting the two chassis in this supply, which is commercially made.

I have used the small pattern Cinch plugs at near 1KV a number of times without any problems.  IMO I would go with the large Cinch plug for your project, provided it's not modulated HV.

I just re-read your post, sounds like you are trying to bring modulated HV to the RF deck.  I don't think a Cinch-Jones plug is going to work with modulated HV, unless your modulation peaks are not going much over 2KV.  I'm not sure what you are trying to build.

Fred

[VE1IDX]

Thanks for the ideas so far. I was in a hurry last night and posted this question as I was on the way out the door on my way to work so I apologize for being vague. A while ago I completely remodeled the shack and in cleaning up beforehand I found a pair of brand new Eimac 4CX250B's that I had forgotten about. They were stashed in a box that also contained a pair of Eimac sockets and the ceramic chimneys as well. My thoughts turned to a winter project and thought that these tubes would make a nice amplifier for 6m. I thought about HF at first but I want to build an amp with a  pair of 3-500Z's eventually so I figured that 6m was a good idea. The plan was to build the power supply in a floor console and have the RF deck sitting on the desktop. I was hoping to bring all the operating voltages and power ON/OFF control from the power supply to the RF deck in one cable which could be detached from the RF deck. The power supply may get used for other projects in the coming few years as I get back into homebrewing some stuff.

  Good suggestion about the beehive feedthru's. I never thought about that but I do have some good ceramic feedthrus and it would not be a big deal to cable everything else and bolt the HV separately.

The suggestion of using an HN and RG-213 brought back a memory. A fellow I used to know, he is now an SK but that is not related to my story. He built an amp using 813's and ran the HV using coaxial cable. I saw the back of the amp one day and asked him why there were three coaxial jacks. He replied " In. Out. And 2Kv"    I just about lost it thinking about getting the cables mixed up.

[WA3VJB]

Go to a neon signmaker's shop and see what they're using.

There are online sources of those components too, but you might want to get your hands on the items first just make sure they'd be right in a vintage homebrew project.

[Don, W2DL]

The 4CX250's are good in linear(SSB) mode and CW, but they were not designed for AM use with high level modulation. I worked at Bell Labs in the middle - late 1950's on the AN/TRC24 50 - 600 Mhz field telephone transmit-receive system, and at the start we used a single 4X150 runmning at around 1200 volts in each of the four amps that covered this frequency range. Occasionally we had some problems with arc-overs from the external plate assembly to the next lower part of the tube, and in subsequent talks with Eimac engineers (including Bill Eitel and W6SAI) found they had had similar problems. They told us ther were just preparing to come out with a new and improved tube (the 4CX250) to deal with this problem, also with a better metal-glass (now ceramic) seal where used.  Also, they increased the plate max from 1500 v to 2000. But, they told us not to plan on using the "new" tube with high level modulation at the 2KV level, (we weren't) it really wasn't designed for that. So, if you are possibly planning AM high level modulation at 2KV beware!

[WD5JKO]

At my work we use Glassman and Spellman HV supplies (up to 300KV). These folks use RG-59 up to 5 KV DC, and RG-8 up to 60KV DC (not the foam stuff). Here is one link where they detail the coax and connectors:

http://www.glassmanhv.com/ByWattage/fc_series.shtml

For the RG-8 coax they use a modified PL-259 / SO-239 combination.

On the plug side the center conductor comes through the PL-259 about 1" per every 10KV. Then the end is not stripped. Instead they insert what looks like a metal tack into the end wedged in between the strands.

On the jack side they use a SO-239 with the guts removed. They have a insulating tube glued into the metal S0-239 that guides the RG-8 center conductor to a spring loaded end, kind of like what we have in the back of a 3AG fuse holder. This end is insulated for the voltage used, i.e. up to 60KV.

The technique Glassman uses lends itself to a DIY HV connection that is cheap and reliable.

If you want store bought stuff, the King folks have the SHV which mates well to RG-59 coax (up to 5KV DC):

Here is the King SHV connector set rated for 3500vac/5000vdc:

Plug:
http://www.alliedelec.com/search/productdetail.aspx?SKU=5171000#tab=Specs
Jack:
http://www.alliedelec.com/search/productdetail.aspx?SKU=5171090#tab=Specs

PS The ratings of coax are usually AC RMS; for DC they take much more, i.e. 60KV for RG-8.

Jim
WD5JKO

[W2PFY]

Go to a neon signmaker's shop and see what they're using.

Good suggestion Paul, Another good thing that you can find at a neon sign shop is high voltage wire. The wire I use on my Westinghouse MW-2 is just that. It's # 14 gauge at 15 KV. It's very nice wire. I got mine surplus for $15.00 for 300 feet. I used quite a bit of it and gave the rest away. So now I'm looking for again for a cheap source???

[WD5JKO]

For HV wire, just Google the words. One hit is surplus sales of Nebraska:

http://www.surplussales.com/Wire-Cable/HVWire-1.html

they are a little pricey though...

So what about polyethylene insulated coax like RG-58, 59, 8, 213, etc?
Well if we use the grounded shield (pulled back on the ends), the inner field strength is very uniform. This means the stuff can take a lot of DC. See this discussion:

http://home.earthlink.net/~jimlux/hv/hvwire.htm


So using shielded HV wire offers safety and shielding (of RF on the wire) advantages.


So lets say your running 5KV on 50KV insulated wire. Would you pick it up when the DC is present? 

While looking at the Glassman web site, they have a 0-3000V regulated supply at 0-1 ampere. With 220v ac input it has > 85% efficiency. looks ideal for an 8877 legal limit linear. See KL3R1000:

http://www.glassmanhv.com/ByWattage/kl_series.shtml

Notice the rear panel, it shows the opened up end of an SO-239 for the HV out, and the supplied cable uses a modified PL-259, and RG-58 coax!!

Jim
WD5JKO

[VE1IDX]

The 4CX250's are good in linear(SSB) mode and CW, but they were not designed for AM use with high level modulation. I worked at Bell Labs in the middle - late 1950's on the AN/TRC24 50 - 600 Mhz field telephone transmit-receive system, and at the start we used a single 4X150 runmning at around 1200 volts in each of the four amps that covered this frequency range. Occasionally we had some problems with arc-overs from the external plate assembly to the next lower part of the tube, and in subsequent talks with Eimac engineers (including Bill Eitel and W6SAI) found they had had similar problems. They told us ther were just preparing to come out with a new and improved tube (the 4CX250) to deal with this problem, also with a better metal-glass (now ceramic) seal where used.  Also, they increased the plate max from 1500 v to 2000. But, they told us not to plan on using the "new" tube with high level modulation at the 2KV level, (we weren't) it really wasn't designed for that. So, if you are possibly planning AM high level modulation at 2KV beware!

Very good info, thanks Don. I would not be using AM on 6m but I certainly would be on 80m. I'm just a little PW station right now with my DX-60B but an amp is in the future and it's good to know the limitations of the 4CX250B's just in case.

[VE1IDX]

At my work we use Glassman and Spellman HV supplies (up to 300KV). These folks use RG-59 up to 5 KV DC, and RG-8 up to 60KV DC (not the foam stuff). Here is one link where they detail the coax and connectors:

http://www.glassmanhv.com/ByWattage/fc_series.shtml

For the RG-8 coax they use a modified PL-259 / SO-239 combination.

On the plug side the center conductor comes through the PL-259 about 1" per every 10KV. Then the end is not stripped. Instead they insert what looks like a metal tack into the end wedged in between the strands.

On the jack side they use a SO-239 with the guts removed. They have a insulating tube glued into the metal S0-239 that guides the RG-8 center conductor to a spring loaded end, kind of like what we have in the back of a 3AG fuse holder. This end is insulated for the voltage used, i.e. up to 60KV.

The technique Glassman uses lends itself to a DIY HV connection that is cheap and reliable.

If you want store bought stuff, the King folks have the SHV which mates well to RG-59 coax (up to 5KV DC):

Here is the King SHV connector set rated for 3500vac/5000vdc:

Plug:
http://www.alliedelec.com/search/productdetail.aspx?SKU=5171000#tab=Specs
Jack:
http://www.alliedelec.com/search/productdetail.aspx?SKU=5171090#tab=Specs

PS The ratings of coax are usually AC RMS; for DC they take much more, i.e. 60KV for RG-8.

Jim
WD5JKO

Again, good info. I knew I came to the right place.    I would have never considered RG-8 for up to 60Kv, that's almost insane.  I do know the difference in voltage ratings of polyethylene cable versus foam cable but had no idea the poly stuff would be good for that high voltage. I was planing on using either RG-8 polyethylene cable or shielding some 10 Kv HV wire I have with some coax braid. In fact I was planning to shield all the wires connecting the PSU and RF deck. Those connectors you referenced look interesting. I may have to give them a closer look.

[WD5JKO]

  I would have never considered RG-8 for up to 60Kv, that's almost insane.

Just remember that it is for 100% polyethylene, and the ends stick out at least 1" / 10 KV from the shield. Just using the center conductor alone, and laid against a metal edge, and it will fail. Same goes for many types of unshielded HV wire; lay it against a sharp grounded edge, and failure will occur eventually.

Jim

[WA1GFZ]

Nice thing about shielded HV wire is if anything sharp falls on it to crush the insulation you get a short rather than a bare conductor.

[W7SOE]

Do it the old-fashioned way, these worked fine for years and years




http://www.surplussales.com/wire-cable/hvwire-2.html

$27 

[VE1IDX]

Do it the old-fashioned way, these worked fine for years and years




http://www.surplussales.com/wire-cable/hvwire-2.html

Well I'll be darned, I missed those on wayoverpricedsurplussales.com   the last time I was there. I haven't been on their site in a while. I see they have a new site layout since I was last there but man it is slooooooowww for me today. I may suck it up and go with the Millen HV connectors or possibly go the cheap and easy route with the ceramic feed thrus. If all goes well I may get a start on the power supply on Sunday. It will be way overkill for the job but as you all know that's what happens when you work with the surplus junk you have on hand. Several years ago,OK about 20 years ago, the radio station where I worked at the time bought a couple surplus equipment racks to use at a couple TX sites. The only "drawback" was that they had to take the equipment that was installed in the racks at the time. The gear was old Royal Canadian Airforce VHF equipment so I volunteered to do my company duty and "dispose" of the old "junk". I landed some pretty decent Hammond plate and filament transformers as well as some decent filter chokes and two heavy chassis upon which to mount some stuff. It's about time I put some of that stuff to good use.The plate transformers are good for 750mA continuous duty so in SSB service they are loafing. All the stuff is 60Hz too so no worries about that 400Hz problem.

[Jim, W5JO]

Do it the old-fashioned way, these worked fine for years and years




http://www.surplussales.com/wire-cable/hvwire-2.html

Well I'll be darned, I missed those on wayoverpricedsurplussales.com   the last time I was there.

Use those Millen connectors with spark plug wire you buy at an auto parts store.  Cheap and easy.

[KE6DF]

RF Parts has those Millen connectors also:

http://www.rfparts.com/hvconnector.html

Not quite as expensive.

[VE1IDX]

RF Parts has those Millen connectors also:

http://www.rfparts.com/hvconnector.html

Not quite as expensive.

Man I'm feeling stooopid today. Perhaps it's because I just came off a round of night shifts and my brain is still fried. I need to make an order up from RF parts soon anyway and will include those connectors. Thanks you very much gentlemen for all the good info and advice.

[W7SOE]

RF Parts has those Millen connectors also:

http://www.rfparts.com/hvconnector.html

Not quite as expensive.

I would need three.  I am I cheap not to want to spend $80 for these??

[W3SLK]

With regards to using SO-239 & PL-259 connectors with COAX, I would be hesitant about using this configuration. It would leave too much possibility of placing the 'wrong wire in the wrong jack at the wrong time.' Those Millen HV connectors are good upto ~2.5 KV but I wouldn't use them over that. Best to be safe than sorry. I would use SHV style for anything over 2.5KV.

With regards to 4CX250B's. I considered using them in a rig. As a matter of fact, the T-195 uses a single 4X150 modded by a pair. I ran into the same issues about using them in a high-level plate modulation scheme. This can be attained by 1) using a tertiary winding to modulate the screen grid, or 2) placing an audio choke on the screen lead.
I haven't tried either but there was a fair amount of testing performed in the mid-60's. I have the article, (in my stacks of literature), but I can't remember whether it was in CQ or QST.

[Opcom]

here's my list of choices

http://connectronics.thomasnet.com/category/high-voltage-connectors
http://www.surplussales.com/wire-cable/hvwire-2.html
http://www.caton.com/manufactured-products/
http://teledynereynolds.com/
http://www.tycoelectronics.com/catalog/menu/en/12153?BML=10576,17560,17685
http://www.rfparts.com/hvconnector.html
http://antennasystems.com/connectors/RHV-100%20Series.html
http://www.ges-electronic.com/connector/slide_prods.php
http://www.usterminals.com/high.htm
http://www.thomasnet.com/products/connectors-high-voltage-17590563-1.html

[K5UJ]

or think outside the box by putting everything in one box.   go to fests.  find a rack like one of these:

http://cgi.ebay.com/Heavy-Duty-Rolling-2-Bay-Equipment-Rack-Aviation-Type-/260674178182

put everything in it.   No using coax and millen or shv or uhf coax connectors for hv, just regular hv wire and beehive feed throughs and such type hardware like what's done with bc rigs.

rob

[VE1IDX]

or think outside the box by putting everything in one box.   go to fests.  find a rack like one of these:

http://cgi.ebay.com/Heavy-Duty-Rolling-2-Bay-Equipment-Rack-Aviation-Type-/260674178182

put everything in it.   No using coax and millen or shv or uhf coax connectors for hv, just regular hv wire and beehive feed throughs and such type hardware like what's done with bc rigs.

rob

I'm not sure I could get a pair of 4CX250B's to fit in that cabinet.   

I have a Hammond 19 inch rack cabinet that is 42 inches high and is perfect for another project down the road involving some 3-500Z's and the power supply xmfr,rectifiers,filters, and other stuff from an AM broadcast TX but I want to make the 6m amp a desktop model.One xmfr I have will fit into the desktop cabinet but is a little light and all the others I have are too big and way over rated so I figure I'll go the big heavy floor unit and have it able to power different items.