[Amps] Amps Digest, Vol 101, Issue 33
K3vw at aol.com
K3vw at aol.com
Mon May 23 15:34:16 PDT 2011
Carey, the GS-35B tube is NOT a high mu triode. It is a medium mu triode
the requires a very well built, input circuit, for the "flywheel" effect.
More plate voltage will also lesson drive requirements. It is a MEDIUM MU
triode, not to be compared with an 8877.
K3VW-Vaughn "Willy" Worth, Sr.
In a message dated 5/23/2011 3:00:23 P.M. Eastern Daylight Time,
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Today's Topics:
1. Re: load resistor (Carey Lockhart, KC5GTT)
2. arrrrgggg!! (Carey Lockhart, KC5GTT)
3. Re: arrrrgggg!! (TexasRF at aol.com)
4. Re: arrrrgggg!! (Carl)
5. Get access to my pictures and more (Shon Edwards)
6. Re: arrrrgggg!! (Steve Thompson)
7. Re: Get access to my pictures and more (Peter Frenning [OZ1PIF])
8. Re: Get access to my pictures and more (Shon Edwards)
----------------------------------------------------------------------
Message: 1
Date: Sun, 22 May 2011 14:49:05 -0500
From: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
Subject: Re: [Amps] load resistor
To: <TexasRF at aol.com>, <amps at contesting.com>
Message-ID: <6E51FE3972F84985B4F36A6E4F18B54D at careychbqjio7i>
Content-Type: text/plain; charset="iso-8859-1"
thanks very much for that info. it is most usefull. i having tons of fun
building the amps. sadly in my 20 years of being a ham there is still so
much i still have to learn.
Carey, kc5gtt
----- Original Message -----
From: TexasRF at aol.com
To: kc5gtt at gmail.com ; amps at contesting.com
Sent: Sunday, May 22, 2011 11:10 AM
Subject: Re: [Amps] load resistor
Carey, you can confirm resonance with the plate tuning capacitor. If you
see a peak in output power while adjusting the control, there is resonance.
A slight increase in C will lower the frequency of resonance and the power
will drop. A slight decrease in C will raise the frequency of resonance
and the power will also drop.
The plate loading can be confirmed in a similar manner. Maximum power
output happens with optimum load C. When the load C is adjusted up or down in
value and the plate tune is adjusted for resonance, the power output will
drop relative to the optimum load C adjustment.
As load C is increased in value, the plate load impedance is lowered and
there will be a resulting increase in plate current.
Strip line designs are not noted for having highest efficiency. The
primary cause of this is unequal rf currents flowing between the strip line and
various parts of the tube anode connection. The strip line is basically
connected to about 1/3 of the tube anode and the other 2/3 of the anode has
very little current flow.
There are losses in all parts of the plate circuit, including the anode
cooler where it connects to the strip line. If most of the current flows in
1/3 of the area, two things happen: 1> the loss resistance is 3X and 2> the
rf current in this area is also 3X.
Loss being related to current squared times resistance, then the total
loss becomes 3X3X3 or 27 times greater than a truly balanced anode to
resonator rf current flow. What could be a low loss of say 10 watts, quickly
becomes a 270 watt loss and this shows up as lower power output and efficiency.
The designs using parallel resonators, such as the W6PO design, will have
far better rf current balance and associated power output and efficiency. A
cylindrical coaxial resonator design is the best of all but few 2m designs
have been published. A coaxial resonator for 144 MHz is not small!
There are a number of 2m GS35B amplifiers documented at
www.nd2x.net/base-1.html if you haven't been there. Operating conditions are shown and you
can compare your results.
Others have mentioned the measurement accuracy of both the dc metering and
rf output power. These factors can cover quite a range of performance
discrepancy. It may well be that your amplifier is working as well as it ever
can!
73,
Gerald K5GW
In a message dated 5/22/2011 9:42:25 A.M. Central Daylight Time,
kc5gtt at gmail.com writes:
Hey guys,
before i fire my amp back up i think i need to check the stripline
resonance. i have 4100 volts on the plate of the gs35. what formula should i use
to come with a resistor value?
or am i going about it wrong. it was working before but not like it
should. i had very poor efficency. which we have more than covered HI. any
suggestions? at that voltage 1500 out with 100 watts drive was a reach. i feel i
should be able to get that with much less drive. i just dont know where to
start
Carey, kc5gtt
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------------------------------
Message: 2
Date: Sun, 22 May 2011 22:19:12 -0500
From: "Carey Lockhart, KC5GTT" <kc5gtt at gmail.com>
Subject: [Amps] arrrrgggg!!
To: <amps at contesting.com>
Message-ID: <BB90496446AA4FBB91CF0ABFE3961ED1 at careychbqjio7i>
Content-Type: text/plain; charset="iso-8859-1"
ok guys i have the amp back together in the yu1aw lazy builder. now i am
getting much lower efficent
plate 3400 full load
current 1.2a
drive 100w
output according to my cheap meter 1600 and my other cheap meter 1900
eff. around 35%
now i am wondering how to determin actual output from these values. is
there a way? also is the flapper capacitor a bad way to go?
Carey
------------------------------
Message: 3
Date: Mon, 23 May 2011 08:16:58 EDT
From: TexasRF at aol.com
Subject: Re: [Amps] arrrrgggg!!
To: kc5gtt at gmail.com, amps at contesting.com
Message-ID: <5c8a.631b9679.3b0baa3a at aol.com>
Content-Type: text/plain; charset="US-ASCII"
Hi Carey, flapper tuning is the best (maybe only) method for resonating a
strip line plate circuit.
There are always losses in these circuits due to unavoidable resistance in
the metal parts and rf currents flowing through them.
For the lowest loss, highly conductive metal, such as copper, is used.
Brass is often used but the inherent resistive losses are much higher than
copper unless the brass is silver plated.
Losses are related to rf current squared. Using the minimum possible
tuning
C will correspond to minimum rf current. The flapper should have a wide
spacing at the strip line and be well grounded at the cold end. The wider
the
spacing, the lower the C and resulting rf current. If the flapper is too
closely spaced, the strip line length is too short.
The rf field around the strip line is very intense at the power levels
involved here. It is important for all metal joints in the strip line and
the
enclosure be rf tight. Lots of screws are needed and everything has to be
clean and tight. Screw spacing of 2 inches is not excessive.
Your figures of 3400 volts and 1.2 Amps yield a dc input power of 4080
watts. If the output power is 1900 watts, that is 45% plate efficiency
ignoring
feed through power. The actual power output may well be higher and a
better calibrated wattmeter will tell. Maybe a friend can loan you one
for a
test.
73,
Gerald K5GW
In a message dated 5/22/2011 10:19:26 P.M. Central Daylight Time,
kc5gtt at gmail.com writes:
ok guys i have the amp back together in the yu1aw lazy builder. now i am
getting much lower efficent
plate 3400 full load
current 1.2a
drive 100w
output according to my cheap meter 1600 and my other cheap meter 1900
eff. around 35%
now i am wondering how to determin actual output from these values. is
there a way? also is the flapper capacitor a bad way to go?
Carey
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------------------------------
Message: 4
Date: Mon, 23 May 2011 09:16:24 -0400
From: "Carl" <km1h at jeremy.mv.com>
Subject: Re: [Amps] arrrrgggg!!
To: <TexasRF at aol.com>, <kc5gtt at gmail.com>, <amps at contesting.com>
Message-ID: <5C7B89692E2248FDB68F22435C7C10F1 at computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
----- Original Message -----
From: <TexasRF at aol.com>
To: <kc5gtt at gmail.com>; <amps at contesting.com>
Sent: Monday, May 23, 2011 8:16 AM
Subject: Re: [Amps] arrrrgggg!!
> Hi Carey, flapper tuning is the best (maybe only) method for resonating a
> strip line plate circuit.
Its not the only method Gerald, I use a small vacuum variable; never did
care for the mechanical problems of a flapper. Im also using the split
line
tank.
Carl
KM1H
------------------------------
Message: 5
Date: Mon, 23 May 2011 16:08:16 +0000
From: Shon Edwards <noreply+A73169060 at netlogmail.com>
Subject: [Amps] Get access to my pictures and more
To: <amps at contesting.com>
Message-ID: <19.F3.04202.DB38ADD4 at mail03>
Content-Type: text/plain; charset=utf-8
Hey,
I have created a Netlog profile with my pictures, videos, blogs and events
and I want to add you as a friend so you can see it. You first need to
register on Netlog! When you log in, you can create your own profile.
Take a look:
http://en.netlog.com/go/mailurl/-bT0xODAyMjQ4ODkxJmw9MSZnbT0xMiZ1PSUyRmdvJTJ
GcmVnaXN0ZXIlMkZpZCUzRC1ZVzF3YzBCamIyNTBaWE4wYVc1bkxtTnZiUV9fJTI2dWlkJTNEMTY
1NTQzNTI2
Cheers,
Shon
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------------------------------
Message: 6
Date: Mon, 23 May 2011 17:22:36 +0100
From: Steve Thompson <g8gsq72 at gmail.com>
Subject: Re: [Amps] arrrrgggg!!
To: amps at contesting.com
Message-ID: <4DDA89CC.3050106 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Hi Carey, flapper tuning is the best (maybe only) method for resonating a
> strip line plate circuit.
>
I think Carey said he was using the YU1AW 'lazy builder' circuit. That's
not the usual resonant stripline with capacitive coupling design.
Visualising it on Smith chart is the easiest way for me to think about
how it works. Probably long before YU1AW, N1BUG built a 4CX1000 amp that
way, with stripline instead of the lumped inductor YU1AW uses.
Carey - what value capacitors are you using, and what are they set to at
max. output. Some pictures might help. The series one at the output
connector is like a loading control. The figures you mention suggest
that the anode impedance is too low. Less capacitance should give you a
higher anode load impedance, and thus better efficiency - but if the L
and other C aren't right you might never be able to hit a pure resistive
anode load and things won't come right.
Steve
------------------------------
Message: 7
Date: Mon, 23 May 2011 20:03:49 +0200
From: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
Subject: Re: [Amps] Get access to my pictures and more
To: Shon Edwards <sre.1966 at gmail.com>
Cc: amps at contesting.com, Shon Edwards
<noreply+A73169060 at netlogmail.com>
Message-ID: <4DDAA185.7020206 at frenning.dk>
Content-Type: text/plain; charset="ISO-8859-10"
------------------------------
Message: 8
Date: Mon, 23 May 2011 12:23:25 -0600
From: Shon Edwards <sre.1966 at gmail.com>
Subject: Re: [Amps] Get access to my pictures and more
To: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
Cc: amps at contesting.com, Discussions of Antennas and Related Topics
<antenna-discussion at antennex.com>, antennaware at contesting.com
Message-ID: <BANLkTi=kDi8ghCDovd-2RHc7pF93awLmoQ at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Sorry all! Someone apparently hacked into my account and sent a message to
everyone in my gmail account. I do apologize for the inconvenience. I
have
had this happen once before and it is not very fun!
2011/5/23 Peter Frenning [OZ1PIF] <peter at frenning.dk>
> Den 23-05-2011 18:08, Shon Edwards skrev:
>
> Hey,
>
> I have created a Netlog profile with my pictures, videos, blogs and
events and I want to add you as a friend so you can see it. You first need to
register on Netlog! When you log in, you can create your own profile.
>
> Take a
look:http://en.netlog.com/go/mailurl/-bT0xODAyMjQ4ODkxJmw9MSZnbT0xMiZ1PSUyRmdvJTJGcmVnaXN0ZXIlMkZpZCUzRC1ZVzF3YzBCamIyNTBaWE4wYVc1bkxtTnZiUV9f
JTI2dWlkJTNEMTY1NTQzNTI2
>
> Cheers,
> Shon
>
> ----------------------------------------------------------------
> Don't want to receive invitations from your friends
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yRmludml0ZSUyRmVtYWlsJTNELVlXMXdjMEJqYjI1MFpYTjBhVzVuTG1OdmJRX18lMjZjb2RlJTN
EMTU1NDE1Mzg_
> _______________________________________________
> Amps mailing
listAmps at contesting.comhttp://lists.contesting.com/mailman/listinfo/amps
>
> More spam - stay away!
>
> --
> Vy 73 de OZ1PIF/5Q2M, Peter
>
> *****************************************
> ** Genius is one per cent inspiration, **
> ** and ninety-nine per cent **
> ** perspiration. **
> ** -- Thomas A. Edison **
> *****************************************
> email: peter(no-spam filler)@frenning.dkhttp://www.frenning.dk/oz1pif.htm
> Ph. +45 4619 3239
> Snailmail:
> Peter Frenning
> Ternevej 23
> DK-4130 Viby Sj.
> Denmark
> *****************************************
>
>
>
--
Shon R. Edwards,
Amateur call: K6QT
1039 N 2575 W
Layton, UT, 84041-7709
USA
e-mail: sre.1966 at gmail.com
phone: (801) 444-3445
cell: (801) 336-7635
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End of Amps Digest, Vol 101, Issue 33
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