[AMRadio] AMRadio Digest, Vol 132, Issue 7


Wade Staggs tvman1954 at gmail.com
Tue Jan 13 07:32:23 EST 2015


*Good Morning All,*
*                                       Well, it's the first 500 Watts that
makes the difference! If I had a Nickel for every time we have heard that.
Unfortunately I don't own a Heavy ( Big ) Iron and Plate Modulated
Transmitter ... NOW ..Although I have owned several in the past.  All we
have to run on AM is the Ten Tec Jupiter and my Heathkit SB-220 Amplifier.
When the band is quiet, we can get away with a 20 Watt Carrier and then the
PEP Output is about 100 Watts. When using the SB-220 Amp, that 20 Watts of
drive nets me about 180 to 200 Watts of Carrier and then the Properly
Modulated Envelope says that the PEP Output is about 1000 to 1100 Watts.
Even when we get the Heathkit TX-1 Scratchy Apache restored. I don't
believe it should be operated with much over about 25 to 30 Watts Carrier.
Everybody in the AM Window tells me that I have a Great Signal and Great
Audio. Please, tell me which AM Transmitter will do a 100 to 150 Watt
Carrier and still have the Headroom to sound good when fully modulated. Am
I missing something here? Two 6146 tubes at 150 Watts Carrier would need to
Output 600 Watts PEP when 100% Modulated.... And I would like to see
someone do this and not Kill the Tubes and or the Power Supply. Yes, I am
an Old Timer but still young for a Ham at 60 years old. Please, tell me
what Collins Transmitter using 6146 tubes which can output a 150 Watt
Carrier and 600 Watts PEP overall and Not Melt Down like the Witch in
Wizard of Oz when drenched with water? Could somebody please answer this
question? This is an honest question guys because we have never been well
off enough to own Collins gear. I can however tell you what would happen if
we tried this with the FLdx400 Transmitter, TX-1 Scratchy Apache and can
you imagine how quickly the Glass would ... Suck into itself with the sweep
tubes in my Yaesu FT-101E? And I don't want to even think about what would
happen to my SB-200 at 600 Watts Carrier or the SB-220 at 1 KW Carrier.
Well, the 3-500ZG tubes in the SB-220 might last a while but the Power
Supply probably wouldn't.*

*                             73 and May God Bless from Wade/KJ4WS*

On Tue, Jan 13, 2015 at 5:39 AM, <amradio-request at mailman.qth.net> wrote:

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> Today's Topics:
>
>    1. Re: Using an old Collins amp for AM (Rob Atkinson)
>    2. Re: Using an old Collins amp for AM (Meir WF2U)
>    3. Re: Using an old Collins amp for AM (Paul Baldock)
>    4. Re: Kenwood MC-50 mike with AM gear (Gary Schafer)
>    5. 30S-1 and AM (CL in NC via AMRadio)
>    6. Re: Using an old Collins amp for AM (Collin via AMRadio)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 12 Jan 2015 18:42:18 -0600
> From: Rob Atkinson <ranchorobbo at gmail.com>
> To: FRANK HUGHES hughes <frsahu0003 at embarqmail.com>
> Cc: Discussion of AM Radio in the Amateur Service
>         <amradio at mailman.qth.net>
> Subject: Re: [AMRadio] Using an old Collins amp for AM
> Message-ID:
>         <
> CALWD7Z5kvYpocUteygL+68wO6hsk5WTee3X74w5ZEOo5HU_bhw at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Just run the collins rig into the antenna.  It should put out at least
> 100 w.  You might need to change the 4D32.
>
> 73
>
> Rob
> K5UJ
>
> On Mon, Jan 12, 2015 at 6:09 PM, FRANK                     HUGHES
> hughes <frsahu0003 at embarqmail.com> wrote:
> > Hi,
> > I would like to be able to participate in some of the AM nets.
> > My 32V-2 only makes 70 watts of carrier. (low voltage selected)
> > I have a good condition Collins 30S-1 that I normally use for SSB.
> > If the power is kept down to about 150 watts of carrier, could I drive
> the amp w/ the 32V-2?
> >
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 12 Jan 2015 20:10:30 -0500
> From: "Meir WF2U" <wf2u at ws19ops.com>
> To: "'FRANK                     HUGHES hughes'"
>         <frsahu0003 at embarqmail.com>,    <amradio at mailman.qth.net>
> Subject: Re: [AMRadio] Using an old Collins amp for AM
> Message-ID: <6F7CCCE6C3CC440EBF95011F96C7DAE9 at MBDCONSULTING.LOCAL>
> Content-Type: text/plain;       charset="us-ascii"
>
> Raising the carrier from 70W to 150W means about gaining 1/2 of an S-point
> on the receiving end. 1 S-point is 6 dB increase in power, which is
> quadrupling it, as if you increased from 70 to 280 W carrier. Doubling the
> power is 3 dB, which is a half S-point.
> It's not worth the effort.
>
> 73, Meir WF2U
> Landrum, SC
>
> -----Original Message-----
> From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of FRANK
> HUGHES hughes
> Sent: Monday, January 12, 2015 7:10 PM
> To: amradio at mailman.qth.net
> Subject: [AMRadio] Using an old Collins amp for AM
>
> Hi,
> I would like to be able to participate in some of the AM nets.
> My 32V-2 only makes 70 watts of carrier. (low voltage selected)
> I have a good condition Collins 30S-1 that I normally use for SSB.
> If the power is kept down to about 150 watts of carrier, could I drive the
> amp w/ the 32V-2?
>
>
> My first homebrew amp is under construction, but until it is ready, I am
> hoping to find a temporary
> solution.
> 73
> Frank
> KJ4OLL
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>
> ------------------------------
>
> Message: 3
> Date: Mon, 12 Jan 2015 17:42:21 -0800
> From: Paul Baldock <paul at paulbaldock.com>
> To: amradio at mailman.qth.net
> Subject: Re: [AMRadio] Using an old Collins amp for AM
> Message-ID: <mailman.996.1421149195.16640.amradio at mailman.qth.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> It's definitely worth the effort, 3dB is very significant for a
> marginal signal. However with your 30S1 you should be able to easily
> get 250W carrier and 1000W PEP which is 5.5dB more than your 70W. If
> you have modified your 30S1 for higher screen voltage, then you can
> get 1500W PEP and 375W carrier which is legal limit in the USA.
>
> You will only need 30W or so of  carrier drive for, so for best
> modulation characteristics you should put an attenuator between the
> the driver rig and the 30S1 and then tune the driver for 70W (or 100W
> if that really is the spec).
>
> Don't forge to tune the linear for maximum PEP and NOT for maximum
> carrier. The carrier level should be 25% of the PEP.
>
> - Paul   KW7Y
>
>
> At 05:10 PM 1/12/2015, you wrote:
> >Raising the carrier from 70W to 150W means about gaining 1/2 of an S-point
> >on the receiving end. 1 S-point is 6 dB increase in power, which is
> >quadrupling it, as if you increased from 70 to 280 W carrier. Doubling the
> >power is 3 dB, which is a half S-point.
> >It's not worth the effort.
> >
> >73, Meir WF2U
> >Landrum, SC
> >
> >-----Original Message-----
> >From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of FRANK
> >HUGHES hughes
> >Sent: Monday, January 12, 2015 7:10 PM
> >To: amradio at mailman.qth.net
> >Subject: [AMRadio] Using an old Collins amp for AM
> >
> >Hi,
> >I would like to be able to participate in some of the AM nets.
> >My 32V-2 only makes 70 watts of carrier. (low voltage selected)
> >I have a good condition Collins 30S-1 that I normally use for SSB.
> >If the power is kept down to about 150 watts of carrier, could I drive the
> >amp w/ the 32V-2?
> >
> >
> >My first homebrew amp is under construction, but until it is ready, I am
> >hoping to find a temporary
> >solution.
> >73
> >Frank
> >KJ4OLL
> >______________________________________________________________
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> ------------------------------
>
> Message: 4
> Date: Mon, 12 Jan 2015 21:41:27 -0600
> From: "Gary Schafer" <garyschafer at largeriver.net>
> To: "'John Coleman'" <jc at pctechref.com>, "'John Neeley'"
>         <w6zkh at att.net>,        <amradio at mailman.qth.net>
> Subject: Re: [AMRadio] Kenwood MC-50 mike with AM gear
> Message-ID: <BD5C009D8BEA4E1B96D3F2DF39684982 at garyPC>
> Content-Type: text/plain;       charset="us-ascii"
>
> Hello John,
>
> A little story about mikes. A long time ago I had a heath SB100 transceiver
> that I had a dynamic mike hooked to. The mike had a transformer in it.
> Everything worked fine.
> I decided to hook up a D104 crystal mike to the rig. It had low and
> distorted audio. I went to the radio store and got a new element for the
> D104, same thing. Took the element back for another one and it was the
> same.
> I finally swapped out the first audio tube and everything worked great.
> Turns out that the first audio tube (6U8 I think) had grid leakage. With
> the
> transformer mike it held the grid at ground (the grid was direct connected
> to the mike jack thru a resistor) and the bias was correct.
> With the crystal mike it allowed the bias to drift up and put the tube into
> saturation and killed the audio.
>
> 73
> Gary  K4FMX
>
> > -----Original Message-----
> > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of John
> > Coleman
> > Sent: Monday, January 12, 2015 3:33 PM
> > To: 'John Neeley'; amradio at mailman.qth.net
> > Subject: Re: [AMRadio] Kenwood MC-50 mike with AM gear
> >
> > Hi John, A lot of the old rigs did not even have a coupling capacitor to
> > the
> > grid of the preamp stage.  This is of no consequence when using a
> > crystal/ceramic microphone, but other mics may drain your grid bias on
> > the
> > preamp tube and cause a lot of distortion.  If the coupling cap is not
> > there
> > put one in. .01 to .05 is good.  Also a lot of the modern microphones
> > have
> > way to much bass response for the old rigs modulator and modulation
> > XFMR. A
> > coupling capacitor in series with the microphone cable and a resistor
> > across
> > the cable on the rig side of the coupling capacitor will reduce the low
> > frequency response. Start with a .05 uf and 100K resistor. Decreasing
> > the
> > value of either will reduce low frequency output and vice versa.  Don't
> > worry about matching impedance.  The 1 or 2 meg resistor at the preamp
> > grid
> > is there for what is known as contact bias. And it works well with the
> > crystal/ceramic microphone as they actually  have their best response
> > with
> > no load or very high resistance.
> >
> > Good Luck,
> > John, WA5BXO
> >
> > -----Original Message-----
> > From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of John
> > Neeley
> > Sent: Tuesday, January 06, 2015 11:25 AM
> > To: amradio at mailman.qth.net
> > Subject: [AMRadio] Kenwood MC-50 mike with AM gear
> >
> > I have a Kenwood MC-50 mike and am wondering if I can use it with my
> > older,
> > tube type AM gear, like the HT-32a, Valiant or DX-100?  Otherwise if
> > not,
> > will need to get a old D-104, etc.  Any info would be greatly
> > appreciated.
> >
> > John W6ZKH
> > ______________________________________________________________
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> ------------------------------
>
> Message: 5
> Date: Mon, 12 Jan 2015 20:19:36 -0800
> From: CL in NC via AMRadio <amradio at mailman.qth.net>
> To: amradio at mailman.qth.net
> Subject: [AMRadio] 30S-1 and AM
> Message-ID:
>         <1421122776.39799.YahooMailBasic at web160605.mail.bf1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> It takes a linear amplifier to amplify AM and this amp qualifies.  It is
> rated at 1KW input power, CW has a 50% duty cycle, and takes 60-100 watts
> to drive to full output.  You won't be able to run it at the  AM current
> legal limit on output power of 350 watts, but you should be able to load it
> up to 350 watts input and expect around 200+ watts out for 800 or so watts
> peak output.  Please use a scope to set you modulation though.
>
> Charlie, W4MEC in NC
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 13 Jan 2015 06:39:39 -0500
> From: Collin via AMRadio <amradio at mailman.qth.net>
> To: AM Radio Reflector <AMRadio at mailman.qth.net>
> Subject: Re: [AMRadio] Using an old Collins amp for AM
> Message-ID: <FB765373-3E93-4ECB-8622-21EB6E952721 at aol.com>
> Content-Type: text/plain;       charset=us-ascii
>
> The 32V-2 is what I use most of the time on the AM nets with very good
> reports.
>
> Thank You, Collin
>
> > On Jan 12, 2015, at 19:20, wa9vrh <wa9vrh at wildblue.net> wrote:
> >
> > Hi Frank,
> > Have you tried using the 32V-2 on AM. For the Collins Collectors 1st
> Wednesday
> > AM net I have been using an Elmac AF-68 which runs less power than
> > your 32V-2. Might give the 32V-2 a try.
> > 73 Larry WA9VRH
> >
> >> On 1/12/2015 6:09 PM, FRANK HUGHES hughes wrote:
> >> Hi,
> >> I would like to be able to participate in some of the AM nets.
> >> My 32V-2 only makes 70 watts of carrier. (low voltage selected)
> >> I have a good condition Collins 30S-1 that I normally use for SSB.
> >> If the power is kept down to about 150 watts of carrier, could I drive
> the amp w/ the 32V-2?
> >>
> >>
> >> My first homebrew amp is under construction, but until it is ready, I
> am hoping to find a temporary
> >> solution.
> >> 73
> >> Frank
> >> KJ4OLL
> >> ______________________________________________________________
> >> Our Main Website: http://www.amfone.net
> >> AMRadio mailing list
> >> Archives: http://mailman.qth.net/pipermail/amradio/
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> >> the word unsubscribe in the message body.
> >>
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> >>
> >
> >
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of AMRadio Digest, Vol 132, Issue 7
> ***************************************
>


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