Re: Digest for larcan-6m-amplifiers@googlegroups.com - 3 Messages in 1 Topic
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Stephen Gregory
Jun 5, 2013, 3:32:16 PM6/5/13
to larcan-6m-...@googlegroups.com
larcan circuitry had all the protection outboard.
Singel carrier operation of larcan modules has been an ongoing issue
ever since this forum started fet after fet blown out the door.
I sent a module to 0JJJ he blew the fets, sent him a second blew the fuses.
Its called over driving.
hams are great at overdriving.
LOL
To the extent that a big red flyer was included with the TE0552G..
RF Concepts always warns against overdriving FET amps
and the original Larcan circuits are no exception and used a low power
B/B video rf driver 0 dbM then an IPA 2 B/B twin fet modules splitting
6 ways.
Unless you are really good with RF levels people will suffer the
inevitable over drive and blown fet indicators.
As for halving a dual driver yes and lose 3db.
The IPA2s at 500w are a comfortable way of achieving power or as 5PJ
has done buy in dumping resistors and attenuate you input.
On 6/6/13, larcan-6m-...@googlegroups.com
<larcan-6m-...@googlegroups.com> wrote:
> =============================================================================
> Today's Topic Summary
> =============================================================================
>
> Group: larcan-6m-...@googlegroups.com
> Url: http://groups.google.com/group/larcan-6m-amplifiers/topics
>
> - Repair help Larcan Lo-Lo 6m [3 Updates]
> http://groups.google.com/group/larcan-6m-amplifiers/t/945667fb45a8a9ce
>
>
> =============================================================================
> Topic: Repair help Larcan Lo-Lo 6m
> Url: http://groups.google.com/group/larcan-6m-amplifiers/t/945667fb45a8a9ce
> =============================================================================
>
> ---------- 1 of 3 ----------
> From: tkr...@azci.net
> Date: Jun 04 10:54AM -0700
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/3b0a7102fce6ed0a
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
>
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB
> and drove it to 700 watts on CW with the same driver radio. As near as I
> can see SWR is okay with the antenna, very little reverse power as measured
>
> with bird meter and 250 watt slug.
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
> ---------- 2 of 3 ----------
> From: "Dave Olean" <k1...@metrocast.net>
> Date: Jun 04 08:22PM -0400
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/3f934ba723f5b070
>
> I suspect that some kind of input peak power problem may have occurred.
> What mods were done to the Larcan before you used it on 50.2 MHz? Were the
> output combining networks re worked or are they stock? They have a high VSWR
> at 50.0 MHz. If you are using an Icom 746 as a driver, that is way too much
> power as well. It is best to run the driver into a high power pad at full
> output to avoid any chance of instantaneous peak problems. The Larcan will
> deliver big power with just 6 or 7 watts.
> I see MRF151Gs on EBay for a bit over $100. I have popped a few myself.
> I think you need all the FETs running for good efficiency.
>
> Dave K1WHS
>
> From: tkr...@azci.net
> Sent: Tuesday, June 04, 2013 1:54 PM
> To: larcan-6m-...@googlegroups.com
> Subject: Repair help Larcan Lo-Lo 6m
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB and
> drove it to 700 watts on CW with the same driver radio. As near as I can
> see SWR is okay with the antenna, very little reverse power as measured with
> bird meter and 250 watt slug.
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
> ---------- 3 of 3 ----------
> From: "Kevin Hobbs" <ve...@cogeco.ca>
> Date: Jun 04 08:27PM -0400
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/ebdeb9e7c4d665f1
>
> Hi Dave
>
>
>
> The Larcan in question was mine . sold to Tom. No mods were done as my
> efficiency was excellent stock, and as such didn't seem to warrant any
> optimization (I did consider adding some C to output combiners only per
> your
> article). It ran JT fine here for many many hours at 1KW (drive was 7W from
> K3/10). I also suspect an input power spike occurred as those Icoms are
> known to do that!
>
>
>
> 73 Kevin
>
>
>
> From: larcan-6m-...@googlegroups.com
> [mailto:larcan-6m-...@googlegroups.com] On Behalf Of Dave Olean
> Sent: June 4, 2013 8:23 PM
> To: larcan-6m-...@googlegroups.com
> Subject: Re: Repair help Larcan Lo-Lo 6m
>
>
>
> I suspect that some kind of input peak power problem may have occurred.
> What mods were done to the Larcan before you used it on 50.2 MHz? Were the
> output combining networks re worked or are they stock? They have a high
> VSWR
> at 50.0 MHz. If you are using an Icom 746 as a driver, that is way too much
> power as well. It is best to run the driver into a high power pad at full
> output to avoid any chance of instantaneous peak problems. The Larcan will
> deliver big power with just 6 or 7 watts.
>
> I see MRF151Gs on EBay for a bit over $100. I have popped a few myself.
> I think you need all the FETs running for good efficiency.
>
>
>
> Dave K1WHS
>
>
>
> From: tkr...@azci.net
>
> Sent: Tuesday, June 04, 2013 1:54 PM
>
> To: larcan-6m-...@googlegroups.com
>
> Subject: Repair help Larcan Lo-Lo 6m
>
>
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
>
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB
> and
> drove it to 700 watts on CW with the same driver radio. As near as I can
> see SWR is okay with the antenna, very little reverse power as measured
> with
> bird meter and 250 watt slug.
>
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
>
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
>
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
--
Steve Gregory
First Response
Cell-Phone: 0410006899
Singel carrier operation of larcan modules has been an ongoing issue
ever since this forum started fet after fet blown out the door.
I sent a module to 0JJJ he blew the fets, sent him a second blew the fuses.
Its called over driving.
hams are great at overdriving.
LOL
To the extent that a big red flyer was included with the TE0552G..
RF Concepts always warns against overdriving FET amps
and the original Larcan circuits are no exception and used a low power
B/B video rf driver 0 dbM then an IPA 2 B/B twin fet modules splitting
6 ways.
Unless you are really good with RF levels people will suffer the
inevitable over drive and blown fet indicators.
As for halving a dual driver yes and lose 3db.
The IPA2s at 500w are a comfortable way of achieving power or as 5PJ
has done buy in dumping resistors and attenuate you input.
On 6/6/13, larcan-6m-...@googlegroups.com
<larcan-6m-...@googlegroups.com> wrote:
> =============================================================================
> Today's Topic Summary
> =============================================================================
>
> Group: larcan-6m-...@googlegroups.com
> Url: http://groups.google.com/group/larcan-6m-amplifiers/topics
>
> - Repair help Larcan Lo-Lo 6m [3 Updates]
> http://groups.google.com/group/larcan-6m-amplifiers/t/945667fb45a8a9ce
>
>
> =============================================================================
> Topic: Repair help Larcan Lo-Lo 6m
> Url: http://groups.google.com/group/larcan-6m-amplifiers/t/945667fb45a8a9ce
> =============================================================================
>
> ---------- 1 of 3 ----------
> From: tkr...@azci.net
> Date: Jun 04 10:54AM -0700
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/3b0a7102fce6ed0a
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
>
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB
> and drove it to 700 watts on CW with the same driver radio. As near as I
> can see SWR is okay with the antenna, very little reverse power as measured
>
> with bird meter and 250 watt slug.
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
> ---------- 2 of 3 ----------
> From: "Dave Olean" <k1...@metrocast.net>
> Date: Jun 04 08:22PM -0400
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/3f934ba723f5b070
>
> I suspect that some kind of input peak power problem may have occurred.
> What mods were done to the Larcan before you used it on 50.2 MHz? Were the
> output combining networks re worked or are they stock? They have a high VSWR
> at 50.0 MHz. If you are using an Icom 746 as a driver, that is way too much
> power as well. It is best to run the driver into a high power pad at full
> output to avoid any chance of instantaneous peak problems. The Larcan will
> deliver big power with just 6 or 7 watts.
> I see MRF151Gs on EBay for a bit over $100. I have popped a few myself.
> I think you need all the FETs running for good efficiency.
>
> Dave K1WHS
>
> From: tkr...@azci.net
> Sent: Tuesday, June 04, 2013 1:54 PM
> To: larcan-6m-...@googlegroups.com
> Subject: Repair help Larcan Lo-Lo 6m
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB and
> drove it to 700 watts on CW with the same driver radio. As near as I can
> see SWR is okay with the antenna, very little reverse power as measured with
> bird meter and 250 watt slug.
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
> ---------- 3 of 3 ----------
> From: "Kevin Hobbs" <ve...@cogeco.ca>
> Date: Jun 04 08:27PM -0400
> Url:
> http://groups.google.com/group/larcan-6m-amplifiers/msg/ebdeb9e7c4d665f1
>
> Hi Dave
>
>
>
> The Larcan in question was mine . sold to Tom. No mods were done as my
> efficiency was excellent stock, and as such didn't seem to warrant any
> optimization (I did consider adding some C to output combiners only per
> your
> article). It ran JT fine here for many many hours at 1KW (drive was 7W from
> K3/10). I also suspect an input power spike occurred as those Icoms are
> known to do that!
>
>
>
> 73 Kevin
>
>
>
> From: larcan-6m-...@googlegroups.com
> [mailto:larcan-6m-...@googlegroups.com] On Behalf Of Dave Olean
> Sent: June 4, 2013 8:23 PM
> To: larcan-6m-...@googlegroups.com
> Subject: Re: Repair help Larcan Lo-Lo 6m
>
>
>
> I suspect that some kind of input peak power problem may have occurred.
> What mods were done to the Larcan before you used it on 50.2 MHz? Were the
> output combining networks re worked or are they stock? They have a high
> VSWR
> at 50.0 MHz. If you are using an Icom 746 as a driver, that is way too much
> power as well. It is best to run the driver into a high power pad at full
> output to avoid any chance of instantaneous peak problems. The Larcan will
> deliver big power with just 6 or 7 watts.
>
> I see MRF151Gs on EBay for a bit over $100. I have popped a few myself.
> I think you need all the FETs running for good efficiency.
>
>
>
> Dave K1WHS
>
>
>
> From: tkr...@azci.net
>
> Sent: Tuesday, June 04, 2013 1:54 PM
>
> To: larcan-6m-...@googlegroups.com
>
> Subject: Repair help Larcan Lo-Lo 6m
>
>
>
> I am new to the group so forgive me if I am repeating questions previously
> posted.
>
>
>
> It appears I have blown two of the modules in a newly acquired amp. I was
> testing it out on JT65 at about 200 watts out when I heard a crack and saw
> flash of light. Found two fuses blown. Replaced fuses and now can get max
> of 60-80 watts output. Driver is Icom 746 which I previously checked for
> spikes and could see none. Earlier in the evening I used the amp on SSB
> and
> drove it to 700 watts on CW with the same driver radio. As near as I can
> see SWR is okay with the antenna, very little reverse power as measured
> with
> bird meter and 250 watt slug.
>
> 1. Does anyone have spare MRF 151Gs for sale? ( Yes, I have scanned
> over the info on MMRA page and understand RF Parts has them).
>
>
>
> 2. Is it possible to un-fuse these two modules and run with what are
> hopefully two good modules? Not necessarily looking for 1 Kw out at this
> time, just more than the 200 watt brick I have.
>
>
>
> Thanks for any helpful feedback. 73 Tom NQ7R Casa Grande,AZ
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Larcan 6m Amplifiers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to larcan-6m-amplif...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
--
Steve Gregory
First Response
Cell-Phone: 0410006899
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