Charlie: Pete & Bob are absolutely right: you do NOT need a peak-reading
wattmeter to tune your Alpha. Thousands have been tuned up just fine (and
have survived up to 40 years!) using only the internal metering.
Here's an easy procedure that works fine: basically, you start with low
drive power, Tune and Load for maximum RF Pfwd, an
5) I'm sure many of us would then hold the key DOWN for 2-3 seconds to see
what the real numbers look like.
d check grid current. Increase drive and repeat.
1) Preset Tune & Load from a chart. The first time, without a Tune/Load
chart? Start with very low drive, maybe ~5W, fast dits.
2) Alternate adjusting first Tune then Load, for maximum Pfwd. After the
initial adjustment, Load first then Tune.
3) Watch grid current and don't let it rise beyond ~50 mA while increasing
drive power in small steps, then Load, Tune for max Pfwd.
4) Repeat (3) until Plate Current indicates ~300-350 mA. This is
approximately HALF actual key-down current, so if HV is ~2200V, DC input
power is ~2200V x 0.6-0.7A = ~1.3-1.5 kW during each dit.
Efficiency typically should run 60-65 percent, and RF forward power output
in the range of 800-1000 watts. This isn't "wide open" but it's a reasonable
way to run the amp while you get used to it. After tune-up it's common to
hold down the key for 2-3 seconds to confirm results.
Numbers that result when using the bandpass ("no-tuneup") positions
shouldn't be greatly different from those from using manual tune-up. NOTE:
When feeding a dummy load or other load with VSWR near 1:1, Pfwd is nearly
the same as RF output. But actual RF output is Pfwd-Prefl. Keep that in mind
if reflected power is greater than 1-2% of Pfwd. Also note that Prefl/Pfwd
of ~10% corresponds to load VSWR ~2:1 which is the maximum rating for most
power amplifiers. It's probably unwise to use the no-tune-up mode if
Prefl/Pfwd is more than 3-5%.
My 1977 (?) era ALPHA 76A is a 2-tuber and the above is based on it.
3-tubers in the same series, like the '78 or '76PA, generally can be tuned
up and operated at 1.5 kW "dit" (or "PEP") output without worry... if your
antenna system can take it.
BTW, it wouldn't be a bit surprising if I've missed something significant
above... been a long time. Hope you other guys will step up and correct any
error(s). ~{ ;-)>
73 & great DXing all!
Dick W4ETO
Forest, VA
-----Original Message-----
From: towertalk-request@contesting.com
Sent: Thursday, April 21, 2011 12:10 PM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 100, Issue 52
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Today's Topics:
1. slightly OT - Wattmeter suggestion? (Charlie Gallo)
2. Re: slightly OT - Wattmeter suggestion? (Steve Hunt)
3. Re: slightly OT - Wattmeter suggestion? (Robert Harmon)
4. Re: slightly OT - Wattmeter suggestion? (Paul Christensen)
5. Re: slightly OT - Wattmeter suggestion? (Jim W7RY)
6. Re: slightly OT - Wattmeter suggestion? (bob finger)
7. Re: slightly OT - Wattmeter suggestion? (Pete Smith)
8. Re: slightly OT - Wattmeter suggestion? (bob finger)
9. Re: slightly OT - Wattmeter suggestion? (Charlie@thegallos.com)
10. Re: slightly OT - Wattmeter suggestion? (Jim W7RY)
----------------------------------------------------------------------
Message: 1
Date: Thu, 21 Apr 2011 06:48:17 -0400
From: Charlie Gallo <Charlie@TheGallos.com>
Subject: [TowerTalk] slightly OT - Wattmeter suggestion?
To: towertalk@contesting.com
Message-ID: <489232199.20110421064817@TheGallos.com>
Content-Type: text/plain; charset=us-ascii
Hi Gang,
Over the next couple of weeks, my shack (including tower/antennas) will be
getting a MAJOR upgrade
Right now, I've got a A-D DX-EE for 10-40m, an SB-230amp, all being driven
by an FT-1000 MkV field (and an at-1000pro tuner)
Well, the radio and tuner are staying the same, but that's it
Antenna wise, there is a Glen Martin going on the roof (I live on a small
lot), and a C3SS and DX140 going on that (antennas will be delivered on
Friday)
Anyway, the other big change - a freshly re-tubed/caped an Alpha 78 - for
those bands where I don't need the tuner (or turned down for when I do)
Think is, everyone says "You MUST have a peak reading watt meter to safely
tune them".
OK - No problem, I buy a meter. I love the Alpha meter (friend has one),
but no way is that in the budget at a grand. I could get a peak reading kit
for my bird 43, but
So, what do you guys think?
I'm thinking the Array Solutions looks good - others? Just put a peak kit
in the bird?
--
73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)
My Website: http://www.thegallos.com
------------------------------
Message: 2
Date: Thu, 21 Apr 2011 13:16:47 +0100
From: Steve Hunt <steve@karinya.net>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: towertalk@contesting.com
Message-ID: <4DB0202F.5030108@karinya.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Charlie,
Not sure what your budget is, but I've been very happy with my LP-100
from Telepost. Not only will it read peaks, it'll estimate the amount of
compression on your signal, and it'll give you the complex impedance of
the load. SWR is properly computed over a wide range of powers, 50mW to 3kW:
http://www.telepostinc.com/lp100.html
That nice new station deserves a quality meter:)
73,
Steve G3TXQ
On 21/04/2011 11:48, Charlie Gallo wrote:
> Hi Gang,
> Over the next couple of weeks, my shack (including tower/antennas) will be
> getting a MAJOR upgrade
>
> Right now, I've got a A-D DX-EE for 10-40m, an SB-230amp, all being driven
> by an FT-1000 MkV field (and an at-1000pro tuner)
>
> Well, the radio and tuner are staying the same, but that's it
>
> Antenna wise, there is a Glen Martin going on the roof (I live on a small
> lot), and a C3SS and DX140 going on that (antennas will be delivered on
> Friday)
>
> Anyway, the other big change - a freshly re-tubed/caped an Alpha 78 - for
> those bands where I don't need the tuner (or turned down for when I do)
>
> Think is, everyone says "You MUST have a peak reading watt meter to safely
> tune them".
>
> OK - No problem, I buy a meter. I love the Alpha meter (friend has one),
> but no way is that in the budget at a grand. I could get a peak reading
> kit for my bird 43, but
>
> So, what do you guys think?
>
> I'm thinking the Array Solutions looks good - others? Just put a peak kit
> in the bird?
>
>
>
>
------------------------------
Message: 3
Date: Thu, 21 Apr 2011 05:26:59 -0700
From: Robert Harmon <k6uj@pacbell.net>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: Steve Hunt <steve@karinya.net>
Cc: towertalk@contesting.com
Message-ID: <D340E8FC-0CC4-41F2-B3A4-D4C5FE675517@pacbell.net>
Content-Type: text/plain; charset=us-ascii
I have an LP-100 also.
Very hapy with it. As Steve says it will give you
impedance data also. I used my old trusty Bird wattmeter
before, but I had to change slugs for low range and for higher
ranges when looking at the output from the amplifier.
The LP-100 is auto ranging, nothing to change.
Bob
K6UJ
On Apr 21, 2011, at 5:16 AM, Steve Hunt wrote:
> Hi Charlie,
>
> Not sure what your budget is, but I've been very happy with my LP-100
> from Telepost. Not only will it read peaks, it'll estimate the amount of
> compression on your signal, and it'll give you the complex impedance of
> the load. SWR is properly computed over a wide range of powers, 50mW to
> 3kW:
>
> http://www.telepostinc.com/lp100.html
>
> That nice new station deserves a quality meter:)
>
> 73,
> Steve G3TXQ
>
>
>
>
> On 21/04/2011 11:48, Charlie Gallo wrote:
>> Hi Gang,
>> Over the next couple of weeks, my shack (including tower/antennas) will
>> be getting a MAJOR upgrade
>>
>> Right now, I've got a A-D DX-EE for 10-40m, an SB-230amp, all being
>> driven by an FT-1000 MkV field (and an at-1000pro tuner)
>>
>> Well, the radio and tuner are staying the same, but that's it
>>
>> Antenna wise, there is a Glen Martin going on the roof (I live on a small
>> lot), and a C3SS and DX140 going on that (antennas will be delivered on
>> Friday)
>>
>> Anyway, the other big change - a freshly re-tubed/caped an Alpha 78 -
>> for those bands where I don't need the tuner (or turned down for when I
>> do)
>>
>> Think is, everyone says "You MUST have a peak reading watt meter to
>> safely tune them".
>>
>> OK - No problem, I buy a meter. I love the Alpha meter (friend has one),
>> but no way is that in the budget at a grand. I could get a peak reading
>> kit for my bird 43, but
>>
>> So, what do you guys think?
>>
>> I'm thinking the Array Solutions looks good - others? Just put a peak
>> kit in the bird?
>>
>>
>>
>>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 4
Date: Thu, 21 Apr 2011 08:48:45 -0400
From: "Paul Christensen" <w9ac@arrl.net>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: <towertalk@contesting.com>
Message-ID: <008f01cc0022$74228850$1d3ca8c0@office>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
The only other current design on-par with the LP-100 is the Alpha 45xx
series, although the Alphas do not offer complex impedance measurements.
However, both units offer exceptional directivity as well as temperature
compensation, and each will read accurately down to 50mW. The other
significant competitor's meter cannot achieve the same level of accuracy
over a wide power range. Run power down to less than 1W and see what
happens. Granted, not many folks on this list are operating at QRPp levels,
but it speaks volumes concerning the design of these meters.
I use both the LP-100 and Alpha 4510. I like the LP-100's ability to
display complex Z and power in a digital format, but I also like the Alpha
4510's digitally-sampled, high-resolution moving-coil meter.
Paul, W9AC
------------------------------
Message: 5
Date: Thu, 21 Apr 2011 06:23:08 -0700
From: "Jim W7RY" <w7ry@inbox.com>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: "Charlie Gallo" <Charlie@TheGallos.com>,
<towertalk@contesting.com>
Message-ID: <E9ED91A56D51452497C0D2B0803EA52A@Laptop>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
>
> I'm thinking the Array Solutions looks good - others? Just put a peak kit
> in the bird?
>
I have 2 of them. They work great!
73
Jim W7RY
>
>
>
> --
> 73 de KG2V - Charles Gallo
> Quality Custom Machine-shop work for the radio amateur (sm)
>
> My Website: http://www.thegallos.com
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1321 / Virus Database: 1500/3586 - Release Date: 04/20/11
>
------------------------------
Message: 6
Date: Thu, 21 Apr 2011 09:42:42 -0400
From: bob finger <finger@goeaston.net>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: towertalk@contesting.com
Message-ID: <4DB03452.3030400@goeaston.net>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
I have two Array Solutions Power Master watt meters. I'm very happy
with them. The old Drake W4's are bulletproof if you prefer analog. 73
bob de w9ge
Jim W7RY wrote:
>>I'm thinking the Array Solutions looks good - others?
>>
>
>
------------------------------
Message: 7
Date: Thu, 21 Apr 2011 09:45:10 -0400
From: Pete Smith <n4zr@contesting.com>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: TowerTalk <TowerTalk@contesting.com>
Message-ID: <4DB034E6.1030000@contesting.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Charlie, I don't believe that you need a peak-reader at all. A few
things you can do.
1. Begin your tune-up at reduced output from the radio. Go to full
drive only for the final touch-up.
2. Keep your key-down periods short and let the tubes cool for an equal
interval.
3. Send a string of fast dots while tuning; your Bird will display an
average value due to meter mechanics but the duty cycle will be about 50
percent, which is nice to the tubes.
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000
On 4/21/2011 6:48 AM, Charlie Gallo wrote:
> Hi Gang,
> Over the next couple of weeks, my shack (including tower/antennas) will be
> getting a MAJOR upgrade
>
> Right now, I've got a A-D DX-EE for 10-40m, an SB-230amp, all being driven
> by an FT-1000 MkV field (and an at-1000pro tuner)
>
> Well, the radio and tuner are staying the same, but that's it
>
> Antenna wise, there is a Glen Martin going on the roof (I live on a small
> lot), and a C3SS and DX140 going on that (antennas will be delivered on
> Friday)
>
> Anyway, the other big change - a freshly re-tubed/caped an Alpha 78 - for
> those bands where I don't need the tuner (or turned down for when I do)
>
> Think is, everyone says "You MUST have a peak reading watt meter to safely
> tune them".
>
> OK - No problem, I buy a meter. I love the Alpha meter (friend has one),
> but no way is that in the budget at a grand. I could get a peak reading
> kit for my bird 43, but
>
> So, what do you guys think?
>
> I'm thinking the Array Solutions looks good - others? Just put a peak kit
> in the bird?
>
>
>
>
------------------------------
Message: 8
Date: Thu, 21 Apr 2011 10:01:03 -0400
From: bob finger <finger@goeaston.net>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
Cc: TowerTalk <TowerTalk@contesting.com>
Message-ID: <4DB0389F.4020301@goeaston.net>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Charlie: I have an old Alpha 78 on the bench. It retains the original
tubes and has seen many a contest over the years. Puts out 90%+ of what
it would do with new tubes, and I have never ever tuned it using a peak
reading wattmeter. I usually keep a Drake W4 in line and I tune for
maximum output when I need to tune it....which is rare. I keep a cheat
sheet on the amps with the tune and load cap settings on it, one set for
cw and one for ssb. In the heat of battle it is a 5 second band change
and maybe maybe a 2 second tweak if the wattmeter says I need to.
(assuming I am not using the passband settings). 73 bob de w9ge
Pete Smith wrote:
>Charlie, I don't believe that you need a peak-reader at all.
>
>
>
------------------------------
Message: 9
Date: Thu, 21 Apr 2011 11:34:28 -0400
From: Charlie@thegallos.com
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: "bob finger" <finger@goeaston.net>
Cc: TowerTalk <towertalk@contesting.com>
Message-ID:
<605c467b9d9b923dc41fb1403a728f4d.squirrel@emailmg.ipower.com>
Content-Type: text/plain;charset=iso-8859-1
Thanks All - I didn't even know about the LP100 till a bunch of you
recommened it - an order has been placed - looks like a useful toy^h ol.
Now to actually go GET the A78 - it's oh, 1/8 mile from home at a friends
place (it's his SPARE Alpha), but he dislocated his shoulder last week,
and my leg started acting up. so between us, we can't carry it the 10-15
ft to my truck, and from the truck to my desk. Probably another week or
so.
Back onto topic
The C3SS and D140 get delivered tomorrow (along with the 11 ft of mast) -
I'll have a spare MA-33 sitting in the yard after that ;)
Coax ships tomorrow, so should have it Tuesday or so
All the rest of the 'toys' should be in by the end of the weekend or so.
Then it's a matter of scheduling the work (hi John) and renting the
cherrypicker - and arranging for delivery on the same day. 1 Ground rod
is in, for at least a minimal ground (want to put in more, but that can be
done during/right after the antenna install)
First big test of the system will be field day - even if that will only be
at 100 watts - I like to run class 1E, and I'm GUESSING that the C3SS/D140
should give me signals a BIT better than my DX-EE ;) (they will also be
about 10 ft higher) I'll still be VERY limited on 80m (small lot), but
that antenna's average height will be going up another 6-7 ft at the same
time, (high side from circa 28 to circa 32, LOW from circa 8 to 33)
Only antenna that gets "worse" is my 2m/440m stick, which will have to be
lowered about 4 ft, and will still be line of site to the few repeaters I
do use - for the 1-2 times a year I use them from home
My goal on this whole project has been "the best I can put up in the space
I have" - particularly the antenna system. I hope I made the right
choices. Budget wasn't a huge issue (wasn't going to spend what I didn't
have to, but doing what I did do RIGHT, not cheap out)
------------------------------
Message: 10
Date: Thu, 21 Apr 2011 09:10:37 -0700
From: "Jim W7RY" <w7ry@inbox.com>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
To: <Charlie@thegallos.com>, "bob finger" <finger@goeaston.net>
Cc: TowerTalk <towertalk@contesting.com>
Message-ID: <F10E52355FD94045819F24035E8FA9FA@Laptop>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I had a LP-100. Sold it and bought another Array Solutions. Didn't like how
the peak reading worked. And it was difficult to tune an amplifier with it.
For my use, the Array was better for this.
73
Jim W7RY
--------------------------------------------------
From: <Charlie@thegallos.com>
Sent: Thursday, April 21, 2011 8:34 AM
To: "bob finger" <finger@goeaston.net>
Cc: "TowerTalk" <towertalk@contesting.com>
Subject: Re: [TowerTalk] slightly OT - Wattmeter suggestion?
> Thanks All - I didn't even know about the LP100 till a bunch of you
> recommened it - an order has been placed - looks like a useful toy^h ol.
>
> Now to actually go GET the A78 - it's oh, 1/8 mile from home at a friends
> place (it's his SPARE Alpha), but he dislocated his shoulder last week,
> and my leg started acting up. so between us, we can't carry it the 10-15
> ft to my truck, and from the truck to my desk. Probably another week or
> so.
>
> Back onto topic
>
> The C3SS and D140 get delivered tomorrow (along with the 11 ft of mast) -
> I'll have a spare MA-33 sitting in the yard after that ;)
>
> Coax ships tomorrow, so should have it Tuesday or so
>
> All the rest of the 'toys' should be in by the end of the weekend or so.
> Then it's a matter of scheduling the work (hi John) and renting the
> cherrypicker - and arranging for delivery on the same day. 1 Ground rod
> is in, for at least a minimal ground (want to put in more, but that can be
> done during/right after the antenna install)
>
> First big test of the system will be field day - even if that will only be
> at 100 watts - I like to run class 1E, and I'm GUESSING that the C3SS/D140
> should give me signals a BIT better than my DX-EE ;) (they will also be
> about 10 ft higher) I'll still be VERY limited on 80m (small lot), but
> that antenna's average height will be going up another 6-7 ft at the same
> time, (high side from circa 28 to circa 32, LOW from circa 8 to 33)
>
> Only antenna that gets "worse" is my 2m/440m stick, which will have to be
> lowered about 4 ft, and will still be line of site to the few repeaters I
> do use - for the 1-2 times a year I use them from home
>
> My goal on this whole project has been "the best I can put up in the space
> I have" - particularly the antenna system. I hope I made the right
> choices. Budget wasn't a huge issue (wasn't going to spend what I didn't
> have to, but doing what I did do RIGHT, not cheap out)
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1321 / Virus Database: 1500/3586 - Release Date: 04/20/11
>
------------------------------
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