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Re: Plate blocking caps YC156

 

Hi Jim

I will order some HT57's from RFparts. I wont take a gamble with the Chinese copies since they similar in price. I? order 5.

I cant find any other caps with RF current ratings for the higher frequencies. RF parts only has rf current data for the HEC caps. Murata and Toshiba dont make RF ceramic capacitors anymore.? Thompson used to make some good capacitors but they? have stopped as well.? So this just leave the HEC, Dralorics(China) and the Chinese manufacturers. I suppose the?? ultimate option would be a fixed vacuum capacitor. I like HEC's because they will make a compact assembly.


Re: Plate blocking caps YC156

 

What superb engineering by the RF? Gods R&S. Just look at that? excellent bandswitch and finger stock contacts. Their older test equipment aslo? has such displays of excellence in engineering. I can only imagine what their amplifiers look like inside. I wonder if Rohde&S made a autotine HF amplifer like the Collinas HF8022? I have seen? Marconi copy of the HF8022. The only difference was the cabinet color.

Henry


Re: Dielectric grease for roller inductors ?

 

?
OEP still makes variable caps and all the TX variety use that grease/goo/goop
?
?
?

----- Original Message -----
From: Jim VE7RF
Sent: Monday, December 30, 2019 7:55 PM
Subject: Re: [ham-amplifiers] Dielectric grease for roller inductors ?

Oren Elliott? no? longer makes? rollers...? just? ?air? variables +? verniers.??

I'm? gonna? buy? some...'conducto? lube' .? ? 75%? pure? silver...and 25%? castor oil.? ?Made for? sliding? contacts.
I? use? High? tech? 3M? air? filters? ?on? the? air? intake? to? both? hb amps.? ?Sealed on? top? side...except for? exhaust.? ? Zero? dust.? ?

My? ?4 x gold? contacts? ?pinch? and slide on? the? sides of the? 3/8" silver? plated? ribbon.? ?It? needs? lube.?

Center? bar? is 1"? square,? silver plated? ?square tubing,? ?with more? sliding contacts (8) on? all? 4? x sides.? ?And? still? more? sliding contacts (4)? ?at? each? end? of? the? sq tubing..where? they? brazed? on silver? plated? discs.?

Jim? VE7RF


Re: Dielectric grease for roller inductors ?

 

Oren Elliott? no? longer makes? rollers...? just? ?air? variables +? verniers.??

I'm? gonna? buy? some...'conducto? lube' .? ? 75%? pure? silver...and 25%? castor oil.? ?Made for? sliding? contacts.
I? use? High? tech? 3M? air? filters? ?on? the? air? intake? to? both? hb amps.? ?Sealed on? top? side...except for? exhaust.? ? Zero? dust.? ?

My? ?4 x gold? contacts? ?pinch? and slide on? the? sides of the? 3/8" silver? plated? ribbon.? ?It? needs? lube.?

Center? bar? is 1"? square,? silver plated? ?square tubing,? ?with more? sliding contacts (8) on? all? 4? x sides.? ?And? still? more? sliding contacts (4)? ?at? each? end? of? the? sq tubing..where? they? brazed? on silver? plated? discs.?

Jim? VE7RF


Re: Dielectric grease for roller inductors ?

 

Scroll? to? extreme? right.? ?'Grease'






PRODUCT DETAILS


Two (2) graphite-lithium grease packets for use on all Palstar roller inductors. The grease is free. The handling fee is $3.45 and shipping cost is $0.50 via USPS.


Re: Plate blocking caps YC156

 

¿ªÔÆÌåÓý

Youre easily aroused
?
?
?

----- Original Message -----
Sent: Sunday, December 29, 2019 8:15 PM
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

I've got wood!

On 30/12/2019 12:46 am, Peter Voelpel wrote:

Rohde & Schwarz uses no other type of capacitor then mica for their atus.

On the photo you see a 200pf mica by Jahre in their 20KW tuner.

73

Peter


From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF
Sent: Sonntag, 29. Dezember 2019 16:13
To: [email protected]
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

The? problem? with? broadcast? ?mica's (or? any? mica)? is? they? won't handle? ?any current? on? higher? freqs.? But? they are? NPO.? ?Drake used switchable mica's? in their? MN-2000? ant? tuner (along? with? 2 x air? variables).? ?Drake? used? 7 (SEVEN)? ?mica's? in? parallel....just? for 10m? band.....just to handle 1200w? pep into? some? swr.? ?

Drake? used? a single? 700 pf? (NPO) mica? to? pad? the 1600? pf? load? cap on? 80m band....? on their L4B? 80-10? amp.?

Those CDE and? similar? mica? caps? are? typ rated? at? ?1? mhz? for? max current.? > 6? mhz, they? have? fallen? off really? fast.? >20? mhz,? they? are? down? to? nothing.?

Mica's? work? superb? on? low? bands (<6 mhz)....? and ceramic? caps work? superb? >2-3 mhz.?

For? a plate? block? cap, ceramic? is? used,? since? we? require? a cap(s) that? will? handle loads? of? current on? 21-29.7? mhz. (+6M).? ? On lower? bands,? plate? block? cap? current? drops? way? off.....non? issue.

HEC? is? still made? in PA...amish? country.??

Download? the? main? catalog for? CERAMIC? ??

Draloric is? still? made in? germany.?

Centralab? was? bought? out? by? ITT-Jennings.? Centralab? (ITT-Jennings)? ? 857 /? 859? is? the? same? as a HEC? ?HT-57? /? HT-59?

Everything? else? is? a chinese copy.? ?Also? factor? in? the? heat? from? the? anode? will? travel? down? the strap..to? one? side? of? plate block? caps.?

Jim? ?VE7RF


Re: Plate blocking caps YC156

 

Well, 4 HT-57's will be OK for a 8877 running hard. I use 6 for a 3CX1000A7 on 2M at 1500W. No drift

Carl

----- Original Message -----
From: tardivat@...
To: [email protected]
Sent: Sunday, December 29, 2019 12:31 AM
Subject: Re: [ham-amplifiers] Plate blocking caps YC156


Thanks for all the suggestions.

The HT57's look like the easiest capacitors to get.

Are HT57's now being made in China by HyEnergy? I see a lot of what looks like clone HT57's for sale on that Auction site.

The last thing I want is a crap capacitor failing because I was too cheap to buy the real thing.

Peter have you tried those Chinese Capacitors. I know that Draloric capacitors are now manufactured in China and that looks like a Draloric capacitor?

I have couple of monster CDM Type 293 1200pf 15kv 15 Amps broadcast micas. Rated at 1mhz. I dont know what the current handling is at 30mhz? These are monsters 3.5 inc by 2.5 inches.

Alek, I looked at the web page and found a couple that might be suitable. The K15U-1 15kV 470pF 40kVAR capacitors. They just look bulk and messy to strap them together.

4 x HT57S's strapped together would make a compact assembly as Jim has suggested. Thanks for all the tips Jim.

Anyway thanks for the suggestions

Henry


Re: Dielectric grease for roller inductors ?

 

I'm guilty too.... tune my roller inductor with 10 watts or so RF.
Never "fine tune" with QRO... just null with the capacitors. The noise bridge would be a much better solution.
Don W4DNR



Quoting "Cliff Fox (KU4GW)" <cliffku4gw@...>:

I've been using a Palstar AT1500CV roller inductor antenna tuner to tune my
260 feet 450 ohm ladder line fed doublet antenna with since 2002 and
Palstar makes no recommendations at all in the user manual about using any
type of dieletric grease or any type of lubricant on the roller inductor.
It does tell how to clean it. I clean it every 3 or 4 months when I blow
the dust out of my Ameritron AL-80B amplifier. I use those little alcohol
pads like I use for my diabetes tests and insulin injections to clean it
with. They do say to make sure to not leave any fluid or anything on the
inside of the turns on the inductor so I just wipe the outside of the turns
and the small brass wheel that runs on the inductor turns until I get a
clean pad. Usually there's a little bit of black dirt on them when I clean
it. WA4GEG, Byron Campbell, who specializes in repair of Yaesu FT-1000MP
line of transceivers recommends not using a roller inductor tuner at all
because he says not getting a good connection can damage the T/R relay
which is what was wrong with my Mark-V. He recommends using a noise bridge
instead. I've been using my MFJ-259B antenna analyzer hooked up to a
MFJ-1700B coax switch box that accepts up to 6 transmitters and 6 antennas
as if it's a transmitter itself and then tuning the Palstar tuner settings
for the match and it works great! Once I get a match I always write the
settings down in a little book I made of 3" x 5" index cards stapled
together on one side. When I return to that same frequency again I can
usually tune up with those settings and get a match in under 5 seconds!

Happy New Years and very 73!
Cliff, KU4GW




On Sat, Dec 28, 2019 at 1:35 PM Jim VE7RF <jim.thom@...> wrote:

I have a RI-40 ribbon style (3/8" x .082") roller coil....with no
lube on it. Can I use permatex dielectric grease on it ?
My RI-50 roller coil came with what appears to be green coloured
grease on it.

Both rollers have the ribbon pinched with a pair of gold plated
contacts, 2 per side. Coil is fixed. Contacts spiral around the
inside.

SSON no longer sells either version. I bought the RI-50 new,
years ago. The RI-40 was obtained used.

Jim VE7RF



Re: Plate blocking caps YC156

 

Hi, All-

I have followed this discussion on plate blocking caps with great interest.
Just wondering if anyone in the group might have a copy of old Sprague
literature that might have the specs on some caps I have here-
p/n 399A259. They are marked "2500MMFD- 5KVAC". I've been told
they can handle around 30KVDC. I did check them quickly with my
hipot tester and they were fine at the max on that instrument, around
14KV. Mine seem to be surplus/seconds, possibly used. Big 1/4-20
male and female studs on them. Around 2in tall and over 2in dia.
Encapsulated in epoxy, it looks like. Some measured a bit low on
capacitance, as low as about 1800pF on a couple. The caps are not
marked as to capacitance tolerance. All were low, no big deal to me.
Best pair were around 2200pF on my AADE cap meter. Usage here
would be strictly HF, mostly the low bands. 10 meters is pretty
useless right now.

These are a real hoss of a capacitor, looks like, but I'd be interested
in knowing how they were spec'ed as to RF current vs. frequency.
Likely to find their way into some amplifiers running 4 to 6KV anode
voltage. I'm really not contemplating running multiples of these-
I think a single cap would suffice for anything I'm planning on doing
with them. Some might be fairly high plate impedance, running
higher supply voltages with relatively lower anode currents. Pi-L
output networks. Date codes on these caps are typically "63nn"
1960's manufacture.

All specs/comments/advice welcome- thanks, guys!

73, David K3KY


Re: Dielectric grease for roller inductors ?

Cliff Fox (KU4GW)
 

I've been using a Palstar AT1500CV roller inductor antenna tuner to tune my 260 feet 450 ohm ladder line fed doublet antenna with since 2002 and Palstar makes no recommendations at all in the user manual about using any type of dieletric grease or any type of lubricant on the roller inductor. It does tell how to clean it. I clean it every 3 or 4 months when I blow the dust out of my Ameritron AL-80B amplifier. I use those little alcohol pads like I use for my diabetes tests and insulin injections to clean it with. They do say to make sure to not leave any fluid or anything on the inside of the turns on the inductor so I just wipe the outside of the turns and the small brass wheel that runs on the inductor turns until I get a clean pad. Usually there's a little bit of black dirt on them when I clean it. WA4GEG, Byron Campbell, who specializes in repair of Yaesu FT-1000MP line of transceivers recommends not using a roller inductor tuner at all because he says not getting a good connection can damage the T/R relay which is what was wrong with my Mark-V. He recommends using a noise bridge instead. I've been using my MFJ-259B antenna analyzer hooked up to a MFJ-1700B coax switch box that accepts up to 6 transmitters and 6 antennas as if it's a transmitter itself and then tuning the Palstar tuner settings for the match and it works great! Once I get a match I always write the settings down in a little book I made of 3" x 5" index cards stapled together on one side. When I return to that same frequency again I can usually tune up with those settings and get a match in under 5 seconds!?

Happy New Years and very 73!??
Cliff, KU4GW




On Sat, Dec 28, 2019 at 1:35 PM Jim VE7RF <jim.thom@...> wrote:
I? have a RI-40 ribbon? style (3/8"? x .082")? roller? coil....with? no? lube on? it.? ? Can? I? use? permatex? dielectric? grease? on? it ?
My? RI-50 roller? coil? came? with? what? appears to be? green? coloured? ?grease on? it.?

Both? rollers? have the? ribbon? pinched? with a pair of? gold? plated? contacts,? 2? per? side.? ?Coil? is? fixed.? ?Contacts? spiral? around? the inside.

SSON? no? longer? sells? either? version.? ?I? bought the? RI-50? new,? years? ago.? The? RI-40 was obtained? used.? ? ?

Jim? VE7RF


Re: Plate blocking caps YC156

 

¿ªÔÆÌåÓý

Weight of that tuner is 900kg!

?

?

73

Peter

?


From: [email protected] [mailto:[email protected]] On Behalf Of Alek Petkovic
Sent: Montag, 30. Dezember 2019 02:16
To: [email protected]
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

?

I've got wood!

On 30/12/2019 12:46 am, Peter Voelpel wrote:

Rohde & Schwarz uses no other type of capacitor then mica for their atus.

On the photo you see a 200pf mica by Jahre in their 20KW tuner.

?

73

Peter

?

?


From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF
Sent: Sonntag, 29. Dezember 2019 16:13
To: [email protected]
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

?

The? problem? with? broadcast? ?mica's (or? any? mica)? is? they? won't handle? ?any current? on? higher? freqs.? But? they are? NPO.? ?Drake used switchable mica's? in their? MN-2000? ant? tuner (along? with? 2 x air? variables).? ?Drake? used? 7 (SEVEN)? ?mica's? in? parallel....just? for 10m? band.....just to handle 1200w? pep into? some? swr.? ?

Drake? used? a single? 700 pf? (NPO) mica? to? pad? the 1600? pf? load? cap on? 80m band....? on their L4B? 80-10? amp.?

Those CDE and? similar? mica? caps? are? typ rated? at? ?1? mhz? for? max current.? > 6? mhz, they? have? fallen? off really? fast.? >20? mhz,? they? are? down? to? nothing.?

Mica's? work? superb? on? low? bands (<6 mhz)....? and ceramic? caps work? superb? >2-3 mhz.?

For? a plate? block? cap, ceramic? is? used,? since? we? require? a cap(s) that? will? handle loads? of? current on? 21-29.7? mhz. (+6M).? ? On lower? bands,? plate? block? cap? current? drops? way? off.....non? issue.

HEC? is? still made? in PA...amish? country.??

Download? the? main? catalog for? CERAMIC? ??

Draloric is? still? made in? germany.?

Centralab? was? bought? out? by? ITT-Jennings.? Centralab? (ITT-Jennings)? ? 857 /? 859? is? the? same? as a HEC? ?HT-57? /? HT-59?

Everything? else? is? a chinese copy.? ?Also? factor? in? the? heat? from? the? anode? will? travel? down? the strap..to? one? side? of? plate block? caps.?

Jim? ?VE7RF



Re: Plate blocking caps YC156

 

¿ªÔÆÌåÓý

I've got wood!

On 30/12/2019 12:46 am, Peter Voelpel wrote:

Rohde & Schwarz uses no other type of capacitor then mica for their atus.

On the photo you see a 200pf mica by Jahre in their 20KW tuner.

?

73

Peter

?

?


From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF
Sent: Sonntag, 29. Dezember 2019 16:13
To: [email protected]
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

?

The? problem? with? broadcast? ?mica's (or? any? mica)? is? they? won't handle? ?any current? on? higher? freqs.? But? they are? NPO.? ?Drake used switchable mica's? in their? MN-2000? ant? tuner (along? with? 2 x air? variables).? ?Drake? used? 7 (SEVEN)? ?mica's? in? parallel....just? for 10m? band.....just to handle 1200w? pep into? some? swr.? ?

Drake? used? a single? 700 pf? (NPO) mica? to? pad? the 1600? pf? load? cap on? 80m band....? on their L4B? 80-10? amp.?

Those CDE and? similar? mica? caps? are? typ rated? at? ?1? mhz? for? max current.? > 6? mhz, they? have? fallen? off really? fast.? >20? mhz,? they? are? down? to? nothing.?

Mica's? work? superb? on? low? bands (<6 mhz)....? and ceramic? caps work? superb? >2-3 mhz.?

For? a plate? block? cap, ceramic? is? used,? since? we? require? a cap(s) that? will? handle loads? of? current on? 21-29.7? mhz. (+6M).? ? On lower? bands,? plate? block? cap? current? drops? way? off.....non? issue.

HEC? is? still made? in PA...amish? country.??

Download? the? main? catalog for? CERAMIC? ??

Draloric is? still? made in? germany.?

Centralab? was? bought? out? by? ITT-Jennings.? Centralab? (ITT-Jennings)? ? 857 /? 859? is? the? same? as a HEC? ?HT-57? /? HT-59?

Everything? else? is? a chinese copy.? ?Also? factor? in? the? heat? from? the? anode? will? travel? down? the strap..to? one? side? of? plate block? caps.?

Jim? ?VE7RF


Re: Dielectric grease for roller inductors ?

 

I seem to recall that the Harris "RF Grease" for roller inductors was just Molybedenum Disulphide which is also conductive.

Besides moly greases have other attractive properties that is well suited to greasing applications

Henry


Re: Plate blocking caps YC156

 

¿ªÔÆÌåÓý

Rohde & Schwarz uses no other type of capacitor then mica for their atus.

On the photo you see a 200pf mica by Jahre in their 20KW tuner.

?

73

Peter

?

?


From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF
Sent: Sonntag, 29. Dezember 2019 16:13
To: [email protected]
Subject: Re: [ham-amplifiers] Plate blocking caps YC156

?

The? problem? with? broadcast? ?mica's (or? any? mica)? is? they? won't handle? ?any current? on? higher? freqs.? But? they are? NPO.? ?Drake used switchable mica's? in their? MN-2000? ant? tuner (along? with? 2 x air? variables).? ?Drake? used? 7 (SEVEN)? ?mica's? in? parallel....just? for 10m? band.....just to handle 1200w? pep into? some? swr.? ?

Drake? used? a single? 700 pf? (NPO) mica? to? pad? the 1600? pf? load? cap on? 80m band....? on their L4B? 80-10? amp.?

Those CDE and? similar? mica? caps? are? typ rated? at? ?1? mhz? for? max current.? > 6? mhz, they? have? fallen? off really? fast.? >20? mhz,? they? are? down? to? nothing.?

Mica's? work? superb? on? low? bands (<6 mhz)....? and ceramic? caps work? superb? >2-3 mhz.?

For? a plate? block? cap, ceramic? is? used,? since? we? require? a cap(s) that? will? handle loads? of? current on? 21-29.7? mhz. (+6M).? ? On lower? bands,? plate? block? cap? current? drops? way? off.....non? issue.

HEC? is? still made? in PA...amish? country.??

Download? the? main? catalog for? CERAMIC? ??

Draloric is? still? made in? germany.?

Centralab? was? bought? out? by? ITT-Jennings.? Centralab? (ITT-Jennings)? ? 857 /? 859? is? the? same? as a HEC? ?HT-57? /? HT-59?

Everything? else? is? a chinese copy.? ?Also? factor? in? the? heat? from? the? anode? will? travel? down? the strap..to? one? side? of? plate block? caps.?

Jim? ?VE7RF


Re: Plate blocking caps YC156

 

The? problem? with? broadcast? ?mica's (or? any? mica)? is? they? won't handle? ?any current? on? higher? freqs.? But? they are? NPO.? ?Drake used switchable mica's? in their? MN-2000? ant? tuner (along? with? 2 x air? variables).? ?Drake? used? 7 (SEVEN)? ?mica's? in? parallel....just? for 10m? band.....just to handle 1200w? pep into? some? swr.? ?

Drake? used? a single? 700 pf? (NPO) mica? to? pad? the 1600? pf? load? cap on? 80m band....? on their L4B? 80-10? amp.?

Those CDE and? similar? mica? caps? are? typ rated? at? ?1? mhz? for? max current.? > 6? mhz, they? have? fallen? off really? fast.? >20? mhz,? they? are? down? to? nothing.?

Mica's? work? superb? on? low? bands (<6 mhz)....? and ceramic? caps work? superb? >2-3 mhz.?

For? a plate? block? cap, ceramic? is? used,? since? we? require? a cap(s) that? will? handle loads? of? current on? 21-29.7? mhz. (+6M).? ? On lower? bands,? plate? block? cap? current? drops? way? off.....non? issue.

HEC? is? still made? in PA...amish? country.??

Download? the? main? catalog for? CERAMIC? ??

Draloric is? still? made in? germany.?

Centralab? was? bought? out? by? ITT-Jennings.? Centralab? (ITT-Jennings)? ? 857 /? 859? is? the? same? as a HEC? ?HT-57? /? HT-59?

Everything? else? is? a chinese copy.? ?Also? factor? in? the? heat? from? the? anode? will? travel? down? the strap..to? one? side? of? plate block? caps.?

Jim? ?VE7RF



Re: Plate blocking caps YC156

 

Thanks for all the suggestions.

The HT57's look like the easiest capacitors to get.

Are HT57's now being made in China by HyEnergy? I see a lot of what looks like clone? HT57's for sale on that Auction site.

The last thing I want is a crap capacitor failing because I was? too cheap to buy the real thing.

Peter have you tried those Chinese? Capacitors. I know that Draloric capacitors are now manufactured in China and that looks like a Draloric capacitor?

I have couple of monster CDM Type 293?? 1200pf? 15kv 15 Amps broadcast micas. Rated at 1mhz. I dont know what the current handling is at 30mhz? These are monsters? 3.5 inc by 2.5 inches.

Alek,? I looked at the web page and found a couple that might be suitable. The K15U-1 15kV 470pF 40kVAR capacitors.? They just look bulk and messy to strap them together.

4 x HT57S's strapped together would make a compact assembly as Jim has suggested. Thanks for all the tips Jim.

Anyway thanks for the suggestions

Henry


Re: Plate blocking caps YC156

 

¿ªÔÆÌåÓý

How about a CM88 CDE?? The one I have in my hand now is literally bigger than my door knob to the room.? 10KV, 30A @ 1 Mhz.? :)

73/jeff/ac0c
alpha-charlie-zero-charlie



On 12/28/19 10:31 AM, Jim VE7RF wrote:

Nope,? you? got it? ass backwards.? Measure? the plate? block? cap? current if u don't? believe me.? W8JI, W8ZR, and John? Lyles? also? concur.?
At? 29? mhz,? the anode? to? chassis? capacitance? becomes? most? of the resonant? tank? capacitance.? ?How? do u? ?think? the main? tank? coil? gets? connected? to the tube? C.....? via? the? plate? block? cap of? course.

If the plate? block? cap is? installed at the 50? ohm? end? of the? PI /? PI-L? network,? then? u? end? up? B+? on? both? the? tune +? load? caps, tank? coil(s),? bandswitch,? roller? coil? (if? used).? It? would? work, but? u just? added a ton? of? stress to? all? those? aforementioned? tank components.?

Those? 4-5" (100-120mm)? diam? 'puck'? style? caps? won't? handle 142A? like? 4 x? 250? pf? HT-59's? will.? ? Even? the? ?140-150-200-205-250 mm? 'puck'? style? caps? won't work.? ?Trying to parallel 'puck'? style?caps? is an? exercise? in? futility.? 2 x 200mm? pucks eats? up? ?8" x 16.5" !?

As? Carl? noted,? the? Centralab? 859? /? HEC? HT-59? is only? 2.25" diam? x 3" long.? ?I mounted? 4 x HT-59's? on a 3" x 3"? x 1/4"? thick? piece? of? copper..? (used on a single 3CX-20,000A7, 27 mhz amp).
4 x HT-59's? are? good? for 25 kv, 142A? CCS,? and? 200? KVA....? and? 1000? pf? total? C.? ? Good? luck? trying? to? find a? puck style cap that? remotely comes? close? to? those? specs... they? don't? exist.?

The? 'kva'? rating is? typ a non? issue.? ?Knowing? the capacitance? of? each? block? cap, the? XC? of? each? block? cap? is? easily? calculated.? ?We already calculated? the? current through? each? block? cap.
Current? x? XC? =? AC? Vdrop? across? each? cap...which? is? typ? a?very low? value.? ?The? AC? V? drop? +? any? bias (B+)? can't? exceed the block? cap's? stamped? V? rating.? ??

The? AC? current? through? the? block? cap....? x? the AC? Vdrop? across? the? cap = va power.?

Using the? 2 x 3x15 tubes on? 27? mhz? for the? following? example.?
250? pf? = 23.59? ohms.?
100.93 A? /? 4? =? 25.23A? PER? each? of? the? 250? pf? caps ( 4 x caps used? in parallel.)?
?23.59 ohms? ?x 25.23 A =? ?595 Vac? across? each? ?of? the? 4 x caps.?
595 vac? x 25.23 A? = 15,012? VA? ?( 15 kva)? Per? cap.
Each? cap? rated? for 50? kva...so? within? spec.?

On low? bands,? like? 160 ,? ?XC? per? cap is a lot? higher, but cap? current? is? very? low....so? it's? still a non? issue? as? far? as KVA? ratings.?

Download? the? HEC catalog.? ?It? depicts kva/current / voltage vs freq? in? graph? form? ?I? will? post? the? HEC Catalog on? this site since,? since I? have it already? in PDF? form.? ??

Jim? VE7RF??

?


Re: Dielectric grease for roller inductors ?

 

?
Call Oren Elliott and ask what they use. They proviided me a blob in a pill
bottle decades ago but forget the name.

Also Palstar.

I wouldnt use anything but what the pros use.

Carl
?
?
?

----- Original Message -----
From: Jim VE7RF
Sent: Saturday, December 28, 2019 1:35 PM
Subject: [ham-amplifiers] Dielectric grease for roller inductors ?

I? have a RI-40 ribbon? style (3/8"? x .082")? roller? coil....with? no? lube on? it.? ? Can? I? use? permatex? dielectric? grease? on? it ?
My? RI-50 roller? coil? came? with? what? appears to be? green? coloured? ?grease on? it.?

Both? rollers? have the? ribbon? pinched? with a pair of? gold? plated? contacts,? 2? per? side.? ?Coil? is? fixed.? ?Contacts? spiral? around? the inside.

SSON? no? longer? sells? either? version.? ?I? bought the? RI-50? new,? years? ago.? The? RI-40 was obtained? used.? ? ?

Jim? VE7RF


Re: Dielectric grease for roller inductors ?

Clint, VE3CMQ
 

¿ªÔÆÌåÓý

I use lubriplate lithium grease on most of my shafts.? Someone recommended it to me years ago.? So far, nothing I have used it on has gummed up, and no electrical problems have presented themselves.

?

Clint, VE3CMQ

?

From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF
Sent: December 28, 2019 12:35 PM
To: [email protected]
Subject: [ham-amplifiers] Dielectric grease for roller inductors ?

?

I? have a RI-40 ribbon? style (3/8"? x .082")? roller? coil....with? no? lube on? it.? ? Can? I? use? permatex? dielectric? grease? on? it ?
My? RI-50 roller? coil? came? with? what? appears to be? green? coloured? ?grease on? it.?

Both? rollers? have the? ribbon? pinched? with a pair of? gold? plated? contacts,? 2? per? side.? ?Coil? is? fixed.? ?Contacts? spiral? around? the inside.

SSON? no? longer? sells? either? version.? ?I? bought the? RI-50? new,? years? ago.? The? RI-40 was obtained? used.? ? ?

Jim? VE7RF


Dielectric grease for roller inductors ?

 

I? have a RI-40 ribbon? style (3/8"? x .082")? roller? coil....with? no? lube on? it.? ? Can? I? use? permatex? dielectric? grease? on? it ?
My? RI-50 roller? coil? came? with? what? appears to be? green? coloured? ?grease on? it.?

Both? rollers? have the? ribbon? pinched? with a pair of? gold? plated? contacts,? 2? per? side.? ?Coil? is? fixed.? ?Contacts? spiral? around? the inside.

SSON? no? longer? sells? either? version.? ?I? bought the? RI-50? new,? years? ago.? The? RI-40 was obtained? used.? ? ?

Jim? VE7RF