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67pf capacitor


Brent WB4X
 


Looks like I need a 40 meter capacitor 67pf 7.5kv.  Where is the best place to get one?

Charles  WB4X


tony stokes
 

DXE has them for sure.

On Sunday, July 12, 2020, 08:18:27 PM EDT, Brent WB4X <bsutphin@...> wrote:



Looks like I need a 40 meter capacitor 67pf 7.5kv.  Where is the best place to get one?

Charles  WB4X


Artie KD0GY
 

The less expensive Chinese one I bought on eBay has worked like a champ at 100w, but I can't say how it would hold up at higher power, not having an amp here. I made a temporary one out of coax, using my MFJ analyzer, and couldn't tell much difference at 100w.

Artie KD0GY


On Sun, Jul 12, 2020 at 7:38 PM tony stokes via groups.io <kn1mexico=yahoo.com@groups.io> wrote:
DXE has them for sure.

On Sunday, July 12, 2020, 08:18:27 PM EDT, Brent WB4X <bsutphin@...> wrote:



Looks like I need a 40 meter capacitor 67pf 7.5kv.  Where is the best place to get one?

Charles  WB4X


Dennis W0JX
 

I also made a 67pf capacitor out of RG8U coax. There is high voltage on that cap and I melted it at about 500 watts. 100 ought to be OK.

73 Dennis W0JX

On Sunday, July 12, 2020, 09:22:04 PM EDT, Artie KD0GY <artielangston@...> wrote:


The less expensive Chinese one I bought on eBay has worked like a champ at 100w, but I can't say how it would hold up at higher power, not having an amp here. I made a temporary one out of coax, using my MFJ analyzer, and couldn't tell much difference at 100w.

Artie KD0GY



Brent WB4X
 

I thought about also making one out of coax but will be running legal limit power, so maybe that’s not such a good idea.

 

Brent WB4X

 

Sent from Mail for Windows 10

 

From: Dennis W0JX via groups.io
Sent: Sunday, July 12, 2020 9:32 PM
To: butternut@groups.io; Butternut@groups.io
Subject: Re: [butternut] 67pf capacitor

 

I also made a 67pf capacitor out of RG8U coax. There is high voltage on that cap and I melted it at about 500 watts. 100 ought to be OK.

 

73 Dennis W0JX

 

On Sunday, July 12, 2020, 09:22:04 PM EDT, Artie KD0GY <artielangston@...> wrote:

 

 

The less expensive Chinese one I bought on eBay has worked like a champ at 100w, but I can't say how it would hold up at higher power, not having an amp here. I made a temporary one out of coax, using my MFJ analyzer, and couldn't tell much difference at 100w.

 

Artie KD0GY

 

 

 


--
Charles  WB4X


Brent WB4X
 


-- I found one on ebay. It is a Jennings 67pf 7.5kv door knob.  This cap was made in the USA and looks very robust.  The one that DXE sells looks to be Russian made.  Both are very close in price. So my question is which do you think would be the best to buy?

Charles  WB4X


Bill KP4SX
 

I got Russian ones from a vendor in Bulgaria.  Exact same ones as pictured at DXE.  I think the cost was $13 for 8 - shipped!


Brent WB4X
 

I wish I could find a deal like that!  Is that guy still on Ebay?

 

 

Sent from Mail for Windows 10

 

From: Bill KP4SX
Sent: Monday, July 13, 2020 10:47 AM
To: Butternut@groups.io
Subject: Re: [butternut] 67pf capacitor

 

I got Russian ones from a vendor in Bulgaria.  Exact same ones as pictured at DXE.  I think the cost was $13 for 8 - shipped!

 


--
Charles  WB4X


Rag LB-Three-RE Stein-Roar LB3RE
 

Hello

I bougth in ebay 67-68pF 15kV-20kv

30m cap burns on 500 watt

If you need urgent a coax stub of 66 cm is equal to 67pF 

Best Regards,
Stein-Roar Brobakken
post@...
LB3RE K3RAG 
Skype: lb3re.rag

13. jul. 2020 kl. 16:47 skrev Bill KP4SX <radioexray@...>:

I got Russian ones from a vendor in Bulgaria.  Exact same ones as pictured at DXE.  I think the cost was $13 for 8 - shipped!


Ron K2NS
 

Try this place        http://www.highenergycorp.com/

I don't know if they will sell one, as they are a manufacturer, but it's worth a try.

RON....K2NS
--
THERE ARE NO STRANGERS IN AMATEUR RADIO----ONLY FRIENDS THAT WE HAVE NOT YET MET !!!


Bill KP4SX
 

Dunno if that particular one is around but there should be others.  Search 68pf, not 67.


tony stokes
 

75pf will work OK also.

On Tuesday, July 14, 2020, 09:25:28 AM EDT, Bill KP4SX <radioexray@...> wrote:


Dunno if that particular one is around but there should be others.  Search 68pf, not 67.


Dennis W0JX
 

An interesting question is how much latitude is there in the values of the capacitors on a Butternut vertical? What are the minimum and maximum values one can use and the antenna will still work acceptably?

73 Dennis W0JX

On Wednesday, July 15, 2020, 07:19:20 AM EDT, tony stokes via groups.io <kn1mexico@...> wrote:


75pf will work OK also.

On Tuesday, July 14, 2020, 09:25:28 AM EDT, Bill KP4SX <radioexray@...> wrote:


Dunno if that particular one is around but there should be others.  Search 68pf, not 67.


 

Dennis,
The value was chosen to optimize the tuned circuit with desired Q and minimum loss.  It is a normal procedure discussed in text like the ARRL handbook..  Yes you can vary the cap but the change needed in the inductor may not optimize the other parameters and therefore may not give you the desired bandwidth.
Al
WB9UVJ