Sunday, April 28, 2013

[HamBrewers] Nice collection of Amateur Digital Modes, history and future?

 

http://www.astrosurf.com/luxorion/qsl-ham-history15.htm


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[HamBrewers] Great document on RFI and baluns

 

Thanks K8RI for sharing this article by K9YC.

http://www.audiosystemsgroup.com/RFI-Ham.pdf

73,
Yan.
---
Yannick DEVOS - XV4Y
http://xv4y.radioclub.asia/
http://varc.radioclub.asia/

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Thursday, April 25, 2013

Re: [HamBrewers] Re: 811 Filament choke value

 

Hari

         My first amp was with two tubes and 20 - 25 watts is enough to drive it.  Yes there is another wire going inside. I have used  No.12 enameled copper wire covered with Nylon Sleeves through it and the the dia of copeer tube is 3/8 inch.

 Regards
Jayaprakash
VU2JLH

From: Hari <harigee@yahoo.com>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Friday, 26 April 2013 6:57 AM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Jayaprakash,
  
    Thanks for the link , i plan to use only two tubes so that i can be driven with my SDR which gives out 20W.
This idea seems interesting and i have copper tube with me , iam assuming that there is another wire going inside the copper tube is that right ?

73
Hari   

From: JAYAPRAKASH NAIR <vu2jlhktm@yahoo.co.in>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Friday, April 26, 2013 12:01 AM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Hello Hari

              If you are getting difficulty to obtain ferrite rods please follow the link for an alternate solution. My present Linear is with 4x811A and I am using this tuned Bifilar cathode input .  SWR of 1:1 is easily  obtained and the only problem is that an SWR meter is necessary at the input for tuning. Also it is tunable from 40 to 10 mtrs. Actually it was for an 813 Amp but it is doing a good job with 811A's. I am using it for the past four years without any problem.

http://www.lu1dma.com.ar/lineales/813%20Amplifier.htm


Warm regards
Jayapraksh
VU2JLH

From: Hari <harigee@yahoo.com>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Thursday, 25 April 2013 10:50 PM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Pramod,

   No not an SMPS iam planning to use a transformer for filament , these days getting a ferrite rod is difficult hence the idea to go for a toroid.I had look at the SMPS design for the HT but yet to make up my mind to do that ! 

73
Hari 

From: Pramod <vu2ttp@gmail.com>
To: HamBrewers@yahoogroups.com
Sent: Sunday, April 21, 2013 6:37 PM
Subject: [HamBrewers] Re: 811 Filament choke value

 
Hari,
You cannot use a ferrite torroid if the filament supply is DC as it would result in core saturation thereby rendering it useless. I have never seen a torroid used in this application, universally in almost all GG hf amps people use bifilar wound 20 to 30 turns on a 1\2 inch dia 5 inch long ferrite rod with a mu of 125. Basically this choke has to just feed dc bias to the filament while simultaneously blocking the rf excitation from getting into your filament pwr supply, really needed if you are using the SMPS there....
73
Pramod








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Re: [HamBrewers] Re: 811 Filament choke value

 

Jayaprakash,
  
    Thanks for the link , i plan to use only two tubes so that i can be driven with my SDR which gives out 20W.
This idea seems interesting and i have copper tube with me , iam assuming that there is another wire going inside the copper tube is that right ?

73
Hari   

From: JAYAPRAKASH NAIR <vu2jlhktm@yahoo.co.in>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Friday, April 26, 2013 12:01 AM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Hello Hari

              If you are getting difficulty to obtain ferrite rods please follow the link for an alternate solution. My present Linear is with 4x811A and I am using this tuned Bifilar cathode input .  SWR of 1:1 is easily  obtained and the only problem is that an SWR meter is necessary at the input for tuning. Also it is tunable from 40 to 10 mtrs. Actually it was for an 813 Amp but it is doing a good job with 811A's. I am using it for the past four years without any problem.

http://www.lu1dma.com.ar/lineales/813%20Amplifier.htm


Warm regards
Jayapraksh
VU2JLH

From: Hari <harigee@yahoo.com>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Thursday, 25 April 2013 10:50 PM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Pramod,

   No not an SMPS iam planning to use a transformer for filament , these days getting a ferrite rod is difficult hence the idea to go for a toroid.I had look at the SMPS design for the HT but yet to make up my mind to do that ! 

73
Hari 

From: Pramod <vu2ttp@gmail.com>
To: HamBrewers@yahoogroups.com
Sent: Sunday, April 21, 2013 6:37 PM
Subject: [HamBrewers] Re: 811 Filament choke value

 
Hari,
You cannot use a ferrite torroid if the filament supply is DC as it would result in core saturation thereby rendering it useless. I have never seen a torroid used in this application, universally in almost all GG hf amps people use bifilar wound 20 to 30 turns on a 1\2 inch dia 5 inch long ferrite rod with a mu of 125. Basically this choke has to just feed dc bias to the filament while simultaneously blocking the rf excitation from getting into your filament pwr supply, really needed if you are using the SMPS there....
73
Pramod






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Re: [HamBrewers] Re: 811 Filament choke value

 

Arvind,
  
  Thanks, no i have not tried that options.I checked with some local shops and few shops in ritchie street.

No i have not fixed the Hex till now, AKW talked to me some time back but was QRL with MQ now slowly back to radio !

73
hari 

From: Aravind Balasubramanian (VU2ABS) <vu2abs@gmail.com>
To: HamBrewers@yahoogroups.com
Cc: Hari <harigee@yahoo.com>
Sent: Friday, April 26, 2013 12:55 AM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Hari: Longish ferrite rods are available if you scout in the Lily pond complex shops of Moore Market. I got one for kindoff free there. Or you can check out the Friday market @ Pallavaram.

I can give you any number of 10 cm long Ferrite rods all you have to is epoxy them lengthwise.

Have you got the replacement FG tubes for your Hex?

Aravind

On 4/25/2013 10:50 PM, Hari wrote:
   No not an SMPS iam planning to use a transformer for filament , these days getting a ferrite rod is difficult hence the idea to go for a toroid.I had look at the SMPS design for the HT but yet to make up my mind to do that ! 




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Re: [HamBrewers] Re: 811 Filament choke value

 

Hari: Longish ferrite rods are available if you scout in the Lily pond complex shops of Moore Market. I got one for kindoff free there. Or you can check out the Friday market @ Pallavaram.

I can give you any number of 10 cm long Ferrite rods all you have to is epoxy them lengthwise.

Have you got the replacement FG tubes for your Hex?

Aravind

On 4/25/2013 10:50 PM, Hari wrote:
   No not an SMPS iam planning to use a transformer for filament , these days getting a ferrite rod is difficult hence the idea to go for a toroid.I had look at the SMPS design for the HT but yet to make up my mind to do that ! 


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Re: [HamBrewers] Re: 811 Filament choke value

 

Hello Hari

              If you are getting difficulty to obtain ferrite rods please follow the link for an alternate solution. My present Linear is with 4x811A and I am using this tuned Bifilar cathode input .  SWR of 1:1 is easily  obtained and the only problem is that an SWR meter is necessary at the input for tuning. Also it is tunable from 40 to 10 mtrs. Actually it was for an 813 Amp but it is doing a good job with 811A's. I am using it for the past four years without any problem.

http://www.lu1dma.com.ar/lineales/813%20Amplifier.htm


Warm regards
Jayapraksh
VU2JLH

From: Hari <harigee@yahoo.com>
To: "HamBrewers@yahoogroups.com" <HamBrewers@yahoogroups.com>
Sent: Thursday, 25 April 2013 10:50 PM
Subject: Re: [HamBrewers] Re: 811 Filament choke value

 
Pramod,

   No not an SMPS iam planning to use a transformer for filament , these days getting a ferrite rod is difficult hence the idea to go for a toroid.I had look at the SMPS design for the HT but yet to make up my mind to do that ! 

73
Hari 

From: Pramod <vu2ttp@gmail.com>
To: HamBrewers@yahoogroups.com
Sent: Sunday, April 21, 2013 6:37 PM
Subject: [HamBrewers] Re: 811 Filament choke value

 
Hari,
You cannot use a ferrite torroid if the filament supply is DC as it would result in core saturation thereby rendering it useless. I have never seen a torroid used in this application, universally in almost all GG hf amps people use bifilar wound 20 to 30 turns on a 1\2 inch dia 5 inch long ferrite rod with a mu of 125. Basically this choke has to just feed dc bias to the filament while simultaneously blocking the rf excitation from getting into your filament pwr supply, really needed if you are using the SMPS there....
73
Pramod




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