[JMS] James_Millen_Society Digest, Vol 103, Issue 6
Wilson Lamb
infomet at embarqmail.com
Fri Nov 26 11:36:58 EST 2021
Right about the title...it was late and I must have just looked at the 801 manual.
I'll be firing it up to try the Variarm patched to the 807 soon.
I have gobs of B&W five pin coils, so will likely mount a socket in place of the final tank jack.
I also have a shoebox full of metal 6L6, including my first novice use, 1957.
73,
WL
-----Original Message-----
From: james <james_millen_society-request at mailman.qth.net>
To: james <james_millen_society at mailman.qth.net>
Date: Friday, 26 November 2021 11:27 AM EST
Subject: James_Millen_Society Digest, Vol 103, Issue 6
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Today's Topics:
1. Re: 90801 (90800) (Don Buska - The Radio Lab Works)
2. Re: 90801 (90800) (Don Buska - The Radio Lab Works)
3. Re: 90801 (Don Buska - The Radio Lab Works)
----------------------------------------------------------------------
Message: 1
Date: Fri, 26 Nov 2021 09:58:51 -0600
From: Don Buska - The Radio Lab Works <don at radiolabworks.com>
To: james_millen_society at mailman.qth.net
Subject: Re: [JMS] 90801 (90800)
Message-ID: <30b91c85-d6da-3219-7107-bdcbfb7d5c2d at radiolabworks.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Hi Wilson,
I think your title was suppose to state the 90800, as the 90801 used the
5763-6146 line-up.? Sorry can't provide much insight into the 90800, but
there are many in service with the group members.? From our webpage the
90800 was "based on a transmitter published in QST November 1940 by Don
H. Mix, as "A Simple Two-Tube Exciter". It also made its appearance in
several editions of the ARRL Handbook for the early 40's.? So yet again,
this was essentially a QST project made into a product by the Millen
company.
73
Don N9OO
On 11/25/21 7:58 PM, Wilson Lamb via James_Millen_Society wrote:
> Do we have any actual operators of the 807 exciter?
> I have one now and am planning to drive it with my Variarm.
> Does anyone know where to find a genuine Millen schematic?
> I have one from the web, but it's not stamped, so I don't know if it's accurate.
> It's been interesting to start looking at the exciter, which seems strangely designed, to me.
> Why a 6L6 first stage? It's not a great osc tube and is WAY too big for driving an 807!
> Even going down to a 6V6 seems more reasonable.
> And how strange the rig throws away bands by not being able to run the 6L6 straight through.
> If one has a Variarm, 90700 version, one cannot operate 80m, because of the 6L6 problem.
> Looking at the schematic, it seems I can jump3 and 5 on the 6L6 socket, with the B+ disconnected from the tank coil, and plug a B&W coil into the xtal socket.
> I don't have the coupling unit for the Variarm, so I could feed it to the link on the B&W coil and be all set.
> My Variarm puts out a solid 2W on 80m, which should be more than enough to drive the 807.
> And is the 807 reliably stable? They are notorious oscillators and the 90800 has no neutralization or even a parasitic suppressor in the plate!
> I want to run the 807 with fixed cutoff bias, as recommended in the manual, but with osc keying, so it has to be stable key up.
> And why in the world would anyone bury all those components in a skinny chassis, with very poor access? Any serious work around the osc socket will require removal of components! Using a removable top plate on the chassis would solve this problem.
>
> Speaking of design, my unit has a variable coupling cap, but it's shown as fixed on my schematic.
> The manual talks about changing it if more drive is needed, so I expect mine is a retrofit?
>
> I don't have a lot of time for this stuff, but will plug along until it's working reliably, so I can use it in CX.
>
> Any operational experience or voltage measurements would be appreciated.
>
> BTW, the Variarm is quite stable and has a fine note, very usable.
> I've talked to SC, IL, MA, NY, and PA, mostly with good reports and I have good reports, amazing really, from NH and VT on the Reverse Beacon Network, amazing!
>
> Wilson
> W4BOH
>
> ______________________________________________________________
> James_Millen_Society mailing list
> Home: http://mailman.qth.net/mailman/listinfo/james_millen_society
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:James_Millen_Society at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
--
------------------------------
Message: 2
Date: Fri, 26 Nov 2021 10:02:32 -0600
From: Don Buska - The Radio Lab Works <don at radiolabworks.com>
To: james_millen_society at mailman.qth.net
Subject: Re: [JMS] 90801 (90800)
Message-ID: <733f52c5-d828-355a-4e1c-200a317edc48 at radiolabworks.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Another thought on Post WWII projects is that tube selection was
governed by availability of military surplus.? So perhaps there were
better tubes that could be used, perhaps 6L6'es were a dine a dozen at
the time.
73
Don N9OO
On 11/26/21 9:58 AM, Don Buska - The Radio Lab Works wrote:
> Hi Wilson,
>
> I think your title was suppose to state the 90800, as the 90801 used
> the 5763-6146 line-up.? Sorry can't provide much insight into the
> 90800, but there are many in service with the group members. From our
> webpage the 90800 was "based on a transmitter published in QST
> November 1940 by Don H. Mix, as "A Simple Two-Tube Exciter". It also
> made its appearance in several editions of the ARRL Handbook for the
> early 40's.? So yet again, this was essentially a QST project made
> into a product by the Millen company.
>
> 73
> Don N9OO
>
> On 11/25/21 7:58 PM, Wilson Lamb via James_Millen_Society wrote:
>> Do we have any actual operators of the 807 exciter?
>> I have one now and am planning to drive it with my Variarm.
>> Does anyone know where to find a genuine Millen schematic?
>> I have one from the web, but it's not stamped, so I don't know if
>> it's accurate.
>> It's been interesting to start looking at the exciter, which seems
>> strangely designed, to me.
>> Why a 6L6 first stage?? It's not a great osc tube and is WAY too big
>> for driving an 807!
>> Even going down to a 6V6 seems more reasonable.
>> And how strange the rig throws away bands by not being able to run
>> the 6L6 straight through.
>> If one has a Variarm, 90700 version, one cannot operate 80m, because
>> of the 6L6 problem.
>> Looking at the schematic, it seems I can jump3 and 5 on the 6L6
>> socket, with the B+ disconnected from the tank coil, and plug a B&W
>> coil into the xtal socket.
>> I don't have the coupling unit for the Variarm, so I could feed it to
>> the link on the B&W coil and be all set.
>> My Variarm puts out a solid 2W on 80m, which should be more than
>> enough to drive the 807.
>> And is the 807 reliably stable?? They are notorious oscillators and
>> the 90800 has no neutralization or even a parasitic suppressor in the
>> plate!
>> I want to run the 807 with fixed cutoff bias, as recommended in the
>> manual, but with osc keying, so it has to be stable key up.
>> And why in the world would anyone bury all those components in a
>> skinny chassis, with very poor access?? Any serious work around the
>> osc socket will require removal of components!? Using a removable top
>> plate on the chassis would solve this problem.
>>
>> Speaking of design, my unit has a variable coupling cap, but it's
>> shown as fixed on my schematic.
>> The manual talks about changing it if more drive is needed, so I
>> expect mine is a retrofit?
>>
>> I don't have a lot of time for this stuff, but will plug along until
>> it's working reliably, so I can use it in CX.
>>
>> Any operational experience or voltage measurements would be appreciated.
>>
>> BTW, the Variarm is quite stable and has a fine note, very usable.
>> I've talked to SC, IL, MA, NY, and PA, mostly with good reports and I
>> have good reports, amazing really, from NH and VT on the Reverse
>> Beacon Network, amazing!
>>
>> Wilson
>> W4BOH
>> ? ______________________________________________________________
>> James_Millen_Society mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/james_millen_society
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:James_Millen_Society at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
--
------------------------------
Message: 3
Date: Fri, 26 Nov 2021 10:27:07 -0600
From: Don Buska - The Radio Lab Works <don at radiolabworks.com>
To: james_millen_society at mailman.qth.net
Subject: Re: [JMS] 90801
Message-ID: <37071334-129e-aec7-03a2-2d5a08d3a7fc at radiolabworks.com>
Content-Type: text/plain; charset=utf-8; format=flowed
I have a smile on my face when I read your comment "And why in the world
would anyone bury all those components in a skinny chassis, with very
poor access?". Just a head-up, don't ever look at the underside of the
later 90801 transmitter.? It's makes the 90800 look like a open field of
far apart components, especially around the 5763 oscillator/multiplier.?
Thankfully I never had a problem in that area of my 90801 as it would
require removing a great deal of components just to get at a defective part.
The current discussions on "Built To Repair" relating to modern
electronics, would be pleased to know even Millen ignored that
repairability back in the 40's, hi hi.
73
Don N9OO
On 11/25/21 7:58 PM, Wilson Lamb via James_Millen_Society wrote:
> Do we have any actual operators of the 807 exciter?
> I have one now and am planning to drive it with my Variarm.
> Does anyone know where to find a genuine Millen schematic?
> I have one from the web, but it's not stamped, so I don't know if it's accurate.
> It's been interesting to start looking at the exciter, which seems strangely designed, to me.
> Why a 6L6 first stage? It's not a great osc tube and is WAY too big for driving an 807!
> Even going down to a 6V6 seems more reasonable.
> And how strange the rig throws away bands by not being able to run the 6L6 straight through.
> If one has a Variarm, 90700 version, one cannot operate 80m, because of the 6L6 problem.
> Looking at the schematic, it seems I can jump3 and 5 on the 6L6 socket, with the B+ disconnected from the tank coil, and plug a B&W coil into the xtal socket.
> I don't have the coupling unit for the Variarm, so I could feed it to the link on the B&W coil and be all set.
> My Variarm puts out a solid 2W on 80m, which should be more than enough to drive the 807.
> And is the 807 reliably stable? They are notorious oscillators and the 90800 has no neutralization or even a parasitic suppressor in the plate!
> I want to run the 807 with fixed cutoff bias, as recommended in the manual, but with osc keying, so it has to be stable key up.
> And why in the world would anyone bury all those components in a skinny chassis, with very poor access? Any serious work around the osc socket will require removal of components! Using a removable top plate on the chassis would solve this problem.
>
> Speaking of design, my unit has a variable coupling cap, but it's shown as fixed on my schematic.
> The manual talks about changing it if more drive is needed, so I expect mine is a retrofit?
>
> I don't have a lot of time for this stuff, but will plug along until it's working reliably, so I can use it in CX.
>
> Any operational experience or voltage measurements would be appreciated.
>
> BTW, the Variarm is quite stable and has a fine note, very usable.
> I've talked to SC, IL, MA, NY, and PA, mostly with good reports and I have good reports, amazing really, from NH and VT on the Reverse Beacon Network, amazing!
>
> Wilson
> W4BOH
>
> ______________________________________________________________
> James_Millen_Society mailing list
> Home: http://mailman.qth.net/mailman/listinfo/james_millen_society
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:James_Millen_Society at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
------------------------------
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