[Boatanchors] Boatanchors Digest, Vol 200, Issue 15
JAMES HANLON
knjhanlon at msn.com
Fri Sep 25 13:55:50 EDT 2020
Ron,
The first comment I'd make is that both of those transmitters were definitely home-brew and designed by their constructors, not copied from any magazine or handbook that I'm aware of.
The 1946 transmitter would have started off with a 6L6, a medium-power beam tetrode that was originally introduced by RCA in the mid 30s as an audio output tube but which hams quickly found worked well as a crystal controlled or variable frequency oscillator or RF power amplifier. The 807 was a very famous and widely used RF amplifier, pretty much a 6L6 with the plate connection brought out via a plate cap which came out about a year after the 6L6, also originally by RCA. The T-55 was a Taylor product, a triode. A pair in push pull were rated for as much as 450 watts input on CW and would require 12 watts of drive, well within the capability of an 807 which could run as much as 75 watts input. The 579x report indicates that the contact was on CW. The "x" means that the other station's note had a crystal-like character, stable and with no problems like chirp or click. If there had been a chirp, the report would have been 579c; if a click 579k.
The 1948 transmitter started with a 6J5, a low-power receiving triode often used for a vfo. The 802 is a pentode that could run as much as 33 watts input, a good choice for a buffer/doubler amplifier following the vfo. The 814 is a beam tetrode that could run as much as 225 watts input and requires 1.5 watts drive in CW service. For the final, there was not an 819 tube used by amateurs, but there was an 810 which I suspect was used. The 810 is a high-power triode. A pair of 810s could run as much as 1500 watts input with 38 watts of drive in CW service and 1 KW with 70 watts of drive in AM phone service. They would be loafing along at 700 watts. The 57 report was a typical one for phone, the last tone-report number was normally omitted for phone. The SX-28A was the 1944 to 1946, top-of-the-line, Hallicrafters Super Skyrider receiver. It has 2 RF stages, 2 IF stages, a very flexible crystal filter, a Lamb noise silencer, 8 watts of audio output from a pair of 6V6s, and more. It sold for $223. The pre-war SX-28 version sold for $159.50.
Jim, W8KGI
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Subject: Boatanchors Digest, Vol 200, Issue 15
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Today's Topics:
1. Re: rigs from antique QSL cards (JAMES HANLON)
2. Re: rigs from antique QSL cards (Ron VE8RT)
3. .DOC TO DJVU CONVERSION (Walt Cates)
4. Boat anchors recevers (dle9480907 at aol.com)
----------------------------------------------------------------------
Message: 1
Date: Tue, 22 Sep 2020 17:49:01 +0000
From: JAMES HANLON <knjhanlon at msn.com>
To: "boatanchors at mailman.qth.net" <boatanchors at mailman.qth.net>,
"ve8rt at yknwt.ca" <ve8rt at yknwt.ca>
Subject: Re: [Boatanchors] rigs from antique QSL cards
Message-ID:
<DM6PR20MB3018F66859CED02207EE3547A03B0 at DM6PR20MB3018.namprd20.prod.outlook.com>
Content-Type: text/plain; charset="iso-8859-1"
Ron,
I should be able to comment on the rigs from your QSL cards - I was licensed in 1952 and my rig was an HRO-50 and a home-brew 6AG7 tri-tet crystal oscillator driving a brand new 6146 to the 75 watt limit for novices in those days. Please let me know what the cards say about those two rigs. And yes, in those days people talked about their transmitters in terms of power input to the final amplifier rather than to RF power output. Power input could easily be determined by multiplying the DC plate voltage by the DC plate current, both measurable by readily available meters of the era. Output was harder to measure directly. There were RF ammeters, usually thermocouple types, but we didn't know what the resistance of the load was that we were working into. I remember loading my tx into a light bulb and comparing its output to a bulb driven from the 60Hz line voltage through a Variac variable voltage transformer and using a photographic light meter to set both bulbs to the sam
e brilliance. 50 ohm loads, SWR meters and power output meters were still a few years away at that point.
Jim Hanlon, W8KGI
------------------------------
Message: 2
Date: Tue, 22 Sep 2020 19:22:41 -0600
From: Ron VE8RT <ve8rt at yknwt.ca>
To: JAMES HANLON <knjhanlon at msn.com>
Cc: "boatanchors at mailman.qth.net" <boatanchors at mailman.qth.net>
Subject: Re: [Boatanchors] rigs from antique QSL cards
Message-ID: <20200922192241.7760d0e9f4db2acd878d7993 at yknwt.ca>
Content-Type: text/plain; charset=US-ASCII
Hi Jim,
thanks for reply, what I see on the 1948 card for the TX
6J5-802-814-PP819s 700W input receiver SX-28A
on the 1946 card the edge of the card is missing but I read ?L6-807-?
P-T55s ?60W part of the other side of the card with the receiver
missing, only SX-
The newer card doesn't say if it was CW or Phone, the report was 57,
the second does say CW with a report of 579x, was the x to indicator
crystal like stability?
Sadly they're likely long gone, I was trying to imagine what they
may have looked like, and maybe what publication they would have gotten
the design from.
73 Ron VE8RT
On Tue, 22 Sep 2020 17:49:01 +0000
JAMES HANLON <knjhanlon at msn.com> wrote:
> Ron,
>
> I should be able to comment on the rigs from your QSL cards - I was licensed in 1952 and my rig was an HRO-50 and a home-brew 6AG7 tri-tet crystal oscillator driving a brand new 6146 to the 75 watt limit for novices in those days. Please let me know what the cards say about those two rigs. And yes, in those days people talked about their transmitters in terms of power input to the final amplifier rather than to RF power output. Power input could easily be determined by multiplying the DC plate voltage by the DC plate current, both measurable by readily available meters of the era. Output was harder to measure directly. There were RF ammeters, usually thermocouple types, but we didn't know what the resistance of the load was that we were working into. I remember loading my tx into a light bulb and comparing its output to a bulb driven from the 60Hz line voltage through a Variac variable voltage transformer and using a photographic light meter to set both bulbs to the s
ame bril
liance. 50 ohm loads, SWR meters and power output meters were still a few years away at that point.
>
> Jim Hanlon, W8KGI
--
Ron VE8RT <ve8rt at yknwt.ca>
------------------------------
Message: 3
Date: Fri, 25 Sep 2020 15:15:10 +0000
From: Walt Cates <cateswa at msn.com>
To: "HallicraftersRadios at groups.io" <HallicraftersRadios at groups.io>,
BOATANCHOR QTH <boatanchors at mailman.qth.net>
Subject: [Boatanchors] .DOC TO DJVU CONVERSION
Message-ID:
<DM5PR08MB249167A0E997F0ED054D4DB8B3360 at DM5PR08MB2491.namprd08.prod.outlook.com>
Content-Type: text/plain; charset="iso-8859-1"
Has anyone had experience with any of the online .doc to djvu conversion sites?
Walt Cates, WD0GOF
https://wd0gof.com/Hallicrafters
The root of most anger is FEAR.
https://wd0gof.com/bible-study/commentaries/
------------------------------
Message: 4
Date: Fri, 25 Sep 2020 10:38:49 -0500
From: dle9480907 at aol.com
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] Boat anchors recevers
Message-ID: <b70c25a0-a465-49eb-9382-56f086b29a90 at email.android.com>
Content-Type: text/plain; charset="utf-8"
------------------------------
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