[Amps] Old Amps on WARC Bands
Dennis W0JX
w0jx at yahoo.com
Sun Jun 30 13:14:57 EDT 2013
I have had good success with my Collins 30S-1 on the WARC bands. The manual does state that it was designed to operate on a wide range of frequencies. You have to use the next higher bandswitch position, i.e., 17 meters by using the 15 meter position, and 12 meters by using the 10 meter position. I run the Collins at about 600 watts out.
However, when using the older legacy amps this way, you have to keep in mind that the Q of the tank circuit will be much higher with higher rf voltages and currents resulting. My Ameritron AL-800H started arcing its plate capacitor on 17 meters requiring a replacement of the tuning capacitor. I also noticed some discoloration of the band switch.
Ameritron has, from time to time, put a notice in very small print in their amplifier ads that their big amps should be limited to 1200 watts out on the WARC bands.
These old amps won't be around forever, and dialing back the power is a good practice in most situations.
73, Dennis W0JX
--- On Sun, 6/30/13, amps-request at contesting.com <amps-request at contesting.com> wrote:
From: amps-request at contesting.com <amps-request at contesting.com>
Subject: Amps Digest, Vol 126, Issue 46
To: amps at contesting.com
Date: Sunday, June 30, 2013, 12:00 PM
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Today's Topics:
1. Using old amps on WARC query (Charles Harpole)
2. Alert to stockpile parts (Charles Harpole)
3. Re: Using old amps on WARC query (Larry)
4. Re: Using old amps on WARC query (Kevin Stover)
5. Re: Using old amps on WARC query (Pete N4KW)
6. Re: Using old amps on WARC query (Pete Smith N4ZR)
7. Re: Using old amps on WARC query (Joe Subich, W4TV)
----------------------------------------------------------------------
Message: 1
Date: Sun, 30 Jun 2013 11:39:30 +0000
From: Charles Harpole <k4vud at hotmail.com>
To: "amps at contesting.com" <amps at contesting.com>
Subject: [Amps] Using old amps on WARC query
Message-ID: <BLU171-W1462D4B46B4571FE0F3585F7700 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Please anyone can tell me the factors to consider, including burning tank components, when operating old linear amplifiers on the WARC bands, especially 12 meters.
Alpha 76 PAC meaning the 3 tube version.
TenTec Titan One
Dentron DTR-2000
ICOM IC-2KL
All these amps have factory-type conversions to TEN meters already done. The Alpha has the swamping input taken out. Other than that, all amps are stock.
Thanks for all specific info... 73,
Charles Harpole
k4vud at hotmail.com
------------------------------
Message: 2
Date: Sun, 30 Jun 2013 11:49:24 +0000
From: Charles Harpole <k4vud at hotmail.com>
To: "amps at contesting.com" <amps at contesting.com>
Subject: [Amps] Alert to stockpile parts
Message-ID: <BLU171-W335F3AF2B4818B2BFFC8FBF7700 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
As the ham population ages, the idea of not buying new stuff must be increasing; so:
Lets alert folks to parts that will be very difficult to replace now and in the future:
All Alpha amps with front push buttons. Because one button pushed cancels the other gang of push buttons, a simple single replacement switch will not do the job.
All amps with rotary wafer switches with dual actions and/or more than one wafer on one shaft.
Conversions to TEN meters------ICOM is out of the many parts to add ten meters to the IC-2KL, one of which is a rotary band switch.
Add your ideas here......................
All of my old amps are having failures of unique parts. Sad but true. ,73
Charles Harpole
k4vud at hotmail.com
------------------------------
Message: 3
Date: Sun, 30 Jun 2013 08:01:19 -0400
From: "Larry" <lknain at nc.rr.com>
To: <amps at contesting.com>
Subject: Re: [Amps] Using old amps on WARC query
Message-ID: <F7068AF986EB48748451CE2711267C00 at XV2W>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I am no expert on this. I have a Dentron Clipperton-L that I had applied the
10M fix to it years ago. But I fried the parasitic suppressors when working
WARC bands. At the suggestion of several on the group I changed the RFC over
to an Ameritron RFC and suppressor assembly and that fixed the problems.
Apparently the original Dentron RFC was not very effective on the WARC
bands. Not sure that applies to the DTR-2000.
73, Larry W6NWS
-----Original Message-----
From: Charles Harpole
Sent: Sunday, June 30, 2013 7:39 AM
To: amps at contesting.com
Subject: [Amps] Using old amps on WARC query
Please anyone can tell me the factors to consider, including burning tank
components, when operating old linear amplifiers on the WARC bands,
especially 12 meters.
Alpha 76 PAC meaning the 3 tube version.
TenTec Titan One
Dentron DTR-2000
ICOM IC-2KL
All these amps have factory-type conversions to TEN meters already done.
The Alpha has the swamping input taken out. Other than that, all amps are
stock.
Thanks for all specific info... 73,
Charles Harpole
k4vud at hotmail.com
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Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps
------------------------------
Message: 4
Date: Sun, 30 Jun 2013 07:44:32 -0500
From: Kevin Stover <kevin.stover at mediacombb.net>
To: amps at contesting.com
Subject: Re: [Amps] Using old amps on WARC query
Message-ID: <51D02830.4080601 at mediacombb.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
If I'm not mistaken the Titan, model 425, was designed "WARC ready".
It needed a mod to make it work above 23MHz but you say the mod has been
done.
On 6/30/2013 6:39 AM, Charles Harpole wrote:
> Please anyone can tell me the factors to consider, including burning tank components, when operating old linear amplifiers on the WARC bands, especially 12 meters.
>
> Alpha 76 PAC meaning the 3 tube version.
> TenTec Titan One
> Dentron DTR-2000
> ICOM IC-2KL
>
> All these amps have factory-type conversions to TEN meters already done. The Alpha has the swamping input taken out. Other than that, all amps are stock.
>
> Thanks for all specific info... 73,
>
> Charles Harpole
> k4vud at hotmail.com
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
------------------------------
Message: 5
Date: Sun, 30 Jun 2013 09:09:58 -0400
From: "Pete N4KW" <n4kwpete at centurylink.net>
To: "Charles Harpole" <k4vud at hotmail.com>, <amps at contesting.com>
Subject: Re: [Amps] Using old amps on WARC query
Message-ID: <2B496EDBEEA4424DA92BC318D7163EA7 at redlobster>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I have an old Alpha 78, one in the same as the 76 except for the "Bandpass
tuning" I believe. My 78 works fine on 18 meters using the manual tuning
and bandswitch on 21 mhz.
73 Pete N4KW
> Please anyone can tell me the factors to consider, including burning tank
> components, when operating old linear amplifiers on the WARC bands,
> especially 12 meters.
>
> Alpha 76 PAC meaning the 3 tube version.
> TenTec Titan One
> Dentron DTR-2000
> ICOM IC-2KL
>
> All these amps have factory-type conversions to TEN meters already done.
> The Alpha has the swamping input taken out. Other than that, all amps are
> stock.
>
> Thanks for all specific info... 73,
>
> Charles Harpole
> k4vud at hotmail.com
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
------------------------------
Message: 6
Date: Sun, 30 Jun 2013 10:34:57 -0400
From: Pete Smith N4ZR <n4zr at contesting.com>
To: amps at contesting.com
Subject: Re: [Amps] Using old amps on WARC query
Message-ID: <51D04211.3030705 at contesting.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I know it has been reported on this reflector that some old amps made
the mistake (in retrospect) of parking the resonance of the plate RFC at
24 MHz. The Ameritron RFC substitution seems like a good idea, just to
be safe.
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.
On 6/30/2013 8:01 AM, Larry wrote:
> I am no expert on this. I have a Dentron Clipperton-L that I had
> applied the 10M fix to it years ago. But I fried the parasitic
> suppressors when working WARC bands. At the suggestion of several on
> the group I changed the RFC over to an Ameritron RFC and suppressor
> assembly and that fixed the problems. Apparently the original Dentron
> RFC was not very effective on the WARC bands. Not sure that applies to
> the DTR-2000.
>
> 73, Larry W6NWS
>
> -----Original Message----- From: Charles Harpole
> Sent: Sunday, June 30, 2013 7:39 AM
> To: amps at contesting.com
> Subject: [Amps] Using old amps on WARC query
>
> Please anyone can tell me the factors to consider, including burning
> tank components, when operating old linear amplifiers on the WARC
> bands, especially 12 meters.
>
> Alpha 76 PAC meaning the 3 tube version.
> TenTec Titan One
> Dentron DTR-2000
> ICOM IC-2KL
>
> All these amps have factory-type conversions to TEN meters already
> done. The Alpha has the swamping input taken out. Other than that,
> all amps are stock.
>
> Thanks for all specific info... 73,
>
> Charles Harpole
> k4vud at hotmail.com
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
------------------------------
Message: 7
Date: Sun, 30 Jun 2013 10:45:43 -0400
From: "Joe Subich, W4TV" <lists at subich.com>
To: amps at contesting.com
Subject: Re: [Amps] Using old amps on WARC query
Message-ID: <51D04497.6060105 at subich.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I believe the early PA76 series amps *all* had plate chokes resonant
at 25 MHz and will not work on 12 meters. It's been a long time since
I last looked at one.
73,
... Joe, W4TV
>> Please anyone can tell me the factors to consider, including burning
>> tank components, when operating old linear amplifiers on the WARC
>> bands, especially 12 meters.
>>
>> Alpha 76 PAC meaning the 3 tube version.
>> TenTec Titan One
>> Dentron DTR-2000
>> ICOM IC-2KL
>>
>> All these amps have factory-type conversions to TEN meters already
>> done. The Alpha has the swamping input taken out. Other than that,
>> all amps are stock.
>>
>> Thanks for all specific info... 73,
>>
>> Charles Harpole
>> k4vud at hotmail.com
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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