[Boatanchors] Plug in coils for Central Eletronics 10 B

[Gary Schafer]

One note on the vfo. When making the coils for it to cover the other bands
don't use small slug tuned forms. Use the B&W or similar coil stock called
for. Smaller coils will not have enough Q and you won't get the output
expected.

73
Gary  K4FMX

> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> bounces at mailman.qth.net] On Behalf Of James M. Walker
> Sent: Tuesday, February 06, 2007 1:33 PM
> To: John King; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] Plug in coils for Central Eletronics 10 B
> 
> Congratulations,
> and welcome to the Central Electronics users "club". First a few
> observations
> You have the 10B, that's good, next if you "intend" to operate it as
> intended,
> Ie; low power, get the RCA 6AG7 tube for the unit, then find, the changes
> to the rig put out by CE, they will allow it to really sing well.
> 
> Find the VFO manual in some of the other manuals, 10A, 10B, 20A like
> that. There are also mods to it. Some are OK, some I found were NOT
> needed. My secret is the use of a spectrum analyzer and RF probes to
> insure signal levels are correct, for injection and the like to each
> stage.
> 
> DON'T solid state the power supply, it won't get you much more than grief.
> The 6AG7 only needs around 200 - 300 max plate volts. So make sure
> you get at least that for the plates and that will be fine for the rest of
> the
> circuitry that uses resistor networks to lower the values they need.
> 
> My VFO458 is per the manual, no extras, coil positioning per the manual
> is OK and if you have an RF probe or analyzer you can determine if it is
> working properly. Above all Don't Panic, if it seems to not be!
> 
> The plate coils can be fabricated from Air Dux or B&W coil stock, or
> if you have a form you can do a handy coil once you settle on the bands
> you
> want to operate. As for number of turns, check out any of the LP
> transmitters
> and see what they used with the same caps as in the 10B, and trim to suit.
> 
> The coild forms are 5 pin for the plate of the 6AG7 and 6 pin for the
> input
> to
> it.The manual in some cases calls for 2 watt resistors across the coils, I
> have
> used 1 watt 5% and had no problems. If you are driving a "tube linear"
> DON'T forget the swamping resistor at the 10B side. If solid state
> amplifier
> turn the output down to the minimum needed to drive the rig and watch the
> linearity of the "system".
> 
> Enjoy, the rig and VFO, I like mine!
> 
> Jim
> WB2FCN
> http://eshop1.chem.buffalo.edu
> 
> ----- Original Message -----
> From: "John King" <k5pgw at yahoo.com>
> To: <boatanchors at mailman.qth.net>
> Sent: Tuesday, February 06, 2007 12:27 PM
> Subject: [Boatanchors] Plug in coils for Central Eletronics 10 B
> 
> 
> > Hello folks!!! I have Central Electronics 10 B serial
> > number 625 and a BC-458 VFO in what appears to be nice
> > shape. That seems to be a real low serial number.
> >
> > I need the mixer plate coils and final amplifier tank
> > coils. If I cannot get the coils, I need the six pin
> > plug in coil forms to make my own. I have the 75 meter
> > coils but I need a 40 meter plate tank coil and the
> > higher band coils eventhough I understand the BC 458
> > moves a lot on higher bands and operation up there is
> > not desirable.
> >
> > I still want the coils and/or coil forms. Thanks for
> > reading, looking and responding. 73, John, K5PGW
> >
> >
> >
> >
> >
> >
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> 
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