Amps
[Top] [All Lists]

Re: [Amps] hf-2500

To: "Jim W7RY" <w7ry@centurytel.net>, "Amps" <amps@contesting.com>
Subject: Re: [Amps] hf-2500
From: "Jeff Blaine" <keepwalking188@yahoo.com>
Date: Sat, 22 Dec 2012 09:45:08 -0600
List-post: <amps@contesting.com">mailto:amps@contesting.com>
They don't work very well in that implementation (the hf-2500). A guy across town had the exact same failure scenario as David did. Not quite a "china syndrome" but a melt-down none the less.

I think the issue with the shorted turns is overheating due to the coil's flux being jammed into the few turns in use. The argument is that separate band-dedicated coils don't have that issue because the entire core's surface is used and you don't have the localized concentration of heating.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- From: Jim W7RY
Sent: Wednesday, December 19, 2012 7:16 PM
To: Amps
Subject: Re: [Amps] hf-2500

Bill

We already had this discussion on here about a year ago. But I 'm going to
repeat it.

Alpha, Ameritron, Jerry K8RA, myself W7RY, and many others all use toroids
with shorted turns on our "L" coil in a PI-L circuit.  It works just fine.

Do you mean that a shorted turn toroid for the PI network is not good?  Or
are you making a general statement that they don't work at all in an
amplifier?


73
Jim W7RY


-----Original Message----- From: Bill Turner
Sent: Wednesday, December 19, 2012 12:26 PM
To: Amps
Subject: Re: [Amps] hf-2500

ORIGINAL MESSAGE:
On Wed, 19 Dec 2012 17:15:03 +0000, K1TTT wrote:

Agreed, that is why I have modified one to do only 40-10m... removing the
80m and 160m coils from the toroid removes the shorted turns problem and
makes it run very nicely doing rtty on 40m.

REPLY:
As David found out, shorted turns on a toroid or any iron core coil
are a no-no unless you do some very careful design and testing, which
Command obviously did not do. Shorted turns on an air core coil are
usually no problem. A word to the wise.

73, Bill W6WRT
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>