I've updated the 160m amp schematic...
http://www.wd8das.net/160m-GI7B.JPG
Steve WD8DAS
sbjohns...@aol.com
http://www.wd8das.net/
-
Radio is your best entertainment value.
-
m: Edward Swynar
To: Discussion of AM Radio in the Amateur Service
; glowb...@piobaire.mines.uidaho.edu;
sbjohns...@aol.com
Cc: amradio@mailman.qth.net
Sent: Fri, 1 May 2009 12:23 pm
Subject: Re: [AMRadio] Filament choke
Hi Steve,
What kinda fixed padder capacitors are you placing in para
re the hard way...! Hi Hi.
~73~ Eddy VE3CUI - VE3XZ
*
- Original Message -
From:
To:
Cc:
Sent: Thursday, April 30, 2009 9:36 AM
Subject: Re: [AMRadio] Filament choke
>
> Here's my schematic so far for the 160m amp:
>
> http://www.w
I hope I did this right as I've never posted or replied to this list before.
FWIW: On the topic of filament chokes, in Orr's 1959 Handbook, on page 628,
there is a discussion of a "Practical Cathode Driven Amp" based on 803 Pentodes.
All three grids are grounded, and the cathode driven.
He doe
: glowb...@piobaire.mines.uidaho.edu
Cc: amradio@mailman.qth.net
Subject: Re: [AMRadio] Filament choke
Here's my schematic so far for the 160m amp:
http://www.wd8das.net/160m-GI7B.JPG
This one won't be a as pretty as some... I'm going to build it on a
steel chassis that has been used b
Here's my schematic so far for the 160m amp:
http://www.wd8das.net/160m-GI7B.JPG
This one won't be a as pretty as some... I'm going to build it on a
steel chassis that has been used by others for at least four other
projects and is literally swiss-cheesed with useful holes. (more holes
than
Tonight I ransacked my parts bins and found a 3/8" dia ferrite rod
about 4 inches long. I covered it in two layers of quality electrical
tape, and wound a bunch of pairs of turns from two spools of identical
enameled magnet wire about #18 or#20. Covered about 3 inches with
close turns, with a
Excellent ideas today, guys - thank you very much. I 've got 100 watts
+ of drive, so I don't believe I'll use a tuned input in this design,
instead I'm going to swamp the input to the cathode with 15 1.5k 2W
resistors as was successful in the SB230. So the
cathode/filament/heater power circu
circuit, that why I suggested the wire in the copper tube. Bernie W8RPW
- Original Message -
From:
To:
Sent: Wednesday, April 29, 2009 2:32 PM
Subject: [AMRadio] Filament choke
> I'm building a 160m grounded-grid amp around the GI-7B tube
> (it worked so well in my SB-2
One way to make an under-sized filament choke (from an inductance
point-of-view) work is to parallel-resonate it at the desired frequency of
operation with a capacitor. Practically, you can do this by adding the
required capacitance to the input tuned circuit. On the two GG amps I
built I use switc
options!
~73~ Eddy VE3CUI - VE3XZ
***
- Original Message -
From: "rbethman"
To: "Discussion of AM Radio in the Amateur Service"
Sent: Wednesday, April 29, 2009 2:47 PM
Subject: Re: [AMRadio] Filament choke
> From reading past messag
From reading past messages from 2007, the FC-30 by B&W doesn't have
enough inductance for 160M. The specs are from 3.5MHz and up.
You'd be better off checking some of Orr's Handbooks for the correct
ferrite rod and wind your own.
I know I have a home-wound one here, BUT - I don't know if it w
I'm building a 160m grounded-grid amp around the GI-7B tube
(it worked so well in my SB-230 retrofit project:
http://www.wd8das.net/SB230.html)
Anyone know of a source for a filament choke appropriate for this tube?
The filament draws only 2 amps, so the 30-amp ones I see available
online
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