The Lamphouse Hikers and it derivatives
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Other
Hiker
Related Pages
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Hikers article
Peter Lankshear's excellent history and background,
Hikers Two by John Bauman, KB7NRN, Oregon, USA,
Hikers Two (2 of) by Bill Meacham, Puerto Rico,
USA (check Bill's other sets at
www.sparkbench.com)
Hikers by Mike Peebles, Vancouver, WA, USA
(check Mikes site at
http://www.peeblesoriginals.com )
Winner of NZVRS Hikers comp. (that I was too lazy to
enter!), Well done to Bryan and runner up's
Seven quality scans
from 1936-1938 Popular Mechanics of the flashlight battery series of
regens that started it all, thanks to John Bauman |
 Introduction
The Hikers One first appeared in
the 1937 Lamphouse Annual BUT was
based directly on the "One-Tube Set Works on Six Flashlight Cells"
from
Popular Mechanics,
September 1936 and appears to be an off-shoot (space
charge) of the "Oscillodyne" by J. A. Worcester, Jr. as can be seen in
the 1934 Official Shortwave
Radio Manual; Pg 59 - thanks Phil)
A conventional grid leak regenerative
circuit using a 49 dual grid power triode with 6V on both the plate and the control
grid with the screen grid used as the control grid. In 1938 Lamphouse
published the Improved Hikers One, which used 9v on the plate and 1.5v for
both grid bias
and filament. Incidentally the amp that followed also in 1938 was
taken from "Amplifier Added to Flashlight Battery Set" Popular
Mechanics, October 1937!.
This section contains scans of original details for the infamous
receiver known as the "Hikers One" (49 space charge mode) and the
"Improved Hikers" (49, then changed 1Q5), the "Hikers Two" (2x 49's),
the "Improved Hikers Two or Octal Hikers Two (2x 1Q5's), the Shortwave
Hikers (49) with its plug in coils, the Hikers 'Lunch Bag' One with self
contained aerial and lastly the "Electric Hikers" (12A7) and the
Electric Hikers Amp ( ).
In the Hikers amplifier another 49 tube is used as a low
gain triode with just 15v on the plate, though the center tap of a 45V
battery was often used for greater output (22.5v). The Hikers Two, combined both
units an was capable of driving a small
speaker. Just how many radio electronics careers were kicked
started by this little set, but thousands were sold and thousands more
were, and are still are (hopefully!), homebrewed.
 What is space charge?
basically the first grid closest to the cathode is used to accelerate
electrons toward the low voltage anode (plate) by accumulating a surplus
charge in an electron cloud around itself providing more readily
available electrons for the weakly charged anode.
Many triodes, some tetrodes and a few pentodes may be used in
space-charge mode. These and most tetrodes have an inherently high capacitance between
suppressor grid and anode making them poor cousins to tubes designed
for space charge operation. If the suppressor grid is physically
connected to the filament, forget about space charging it effectively
tho to some extend they will work if B+ is raised. I have used a 12K5 tetrode with
as little as a 9v plate voltage, I'm sure there's plenty more so go
experiment with low voltage hollow state designs that can't electrocute you!.
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Circuits and original Lamphouse
scans (500kb each). Several scans should be examined
as every few years illustrations, testimonials and accompanying text
changed slightly. Use thumbnails or filename link to enlarge
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1
9
3
7 |
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 1937 Hikers One 49
- The set that started it all.
First time published in The Electric Lamphouse Annual, 15yrs later in
the 1952 Issue it was the last time it was published.
This was built on a basic board with no front panel.
hikers/37hikers1.jpg
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1
9
3
8 |
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1938 Improved Hikers One
(lower grid bias, HT raised to 9v, front panel added)
hikers/38hikers11.jpg
hikers/38hikers12.jpg
Hikers One Amplifier
hikers/38hikers1amp.jpg add-on 49 a.f amp (3:1 |
1
9
3
9 |
 |
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1939 Shortwave Hikers
hikers/39swhikers/hikers.jpg
plug in coils
Improved Hikers
hikers/39hikers11.jpg
hikers/39hikers12.jpg
Hikers One Amplifier
hikers/39hikers1amp.jpg (use 2x PP9 batt's for B+) |
1
9
4
0
1
9
4
1 |
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1940 The Electric Hikers
Mains powered 12A7 diode pentode
hikers/40ehikers1.jpg
Hikers Kitset Prices for 1940
Improved Hikers One, Hikers Amp, Shortwave Hikers
hikers/40hikerkits.jpg
1941 Hikers Lunch Bag One
with self contained loop antenna
hikers/41hikerslb.jpg |
1
9
4
2
1
9
4
8
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1942 Hikers Two by Skycraper
built on miniature aluminum chassis
hikers/42hikers21.jpg
hikers/42hikers22.jpg
hikers/42hikers23.jpg
1948 Octal Hikers Two, 1Q5x2
gee they could have cut the shafts down first!
hikers/48octalhikersa.jpg
hikers/48octalhikers/hikersb.jpg |
1
9
5
1 |
 |
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1951 Improved Hikers
hikers/51hikers11.jpg
hikers/51hikers12.jpg
Easy Built Octal Hikers Two
hikers/51octalhikers21.jpg
hikers/51octalhikers22.jpg |
1
9
5
2 |
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 |
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1952 Octal Amp hikers/52octalhikers/hikersamp.jpg
hikers/52hikerkits.jpg
1952 Lamphouse One
This is a variation using an iron cored miniature
coil and is included for interests sake. BTW This was the
Annual's last
issue.
hikers/52lamphouse11.jpg
hikers/52lamphouse12.jpg |
Hikers Build Notes: under
construction, comments and additions welcome
Substitutes: Nothing too critical here, particularly if
your willing to experiment with number of coil turns or optimum
performance or smoothest regeneration is not sought, but
at least it gets you going out of your junk box!. Some guidelines then,
tuning condenser can be anything from 300 to 500pf, choose something
with the lowest min C, rather than max. The grid leak resistor can be
anything from 1meg to 3megs, the capacitors can be any type from .00005
(50pF) to .00025 (250pf) and the pot can be 500k to 1.5megs just make
sure it's a log.
Valve
Info: European equivalents (Philips) DL36=1Q5 , DL35 =1C5,
(but they don't work as well as there American counterparts) a Mullard PM2A
or E344H work well and look good.
If you have a 3Q5 (DL33), 3C5 (DL34) or 3A5 (DCC90) these will also
work to if the two filaments are paralleled or a 3v heater supply can be
provided and there's dozens more practical substitutes if your willing
to change sockets and experiment. If you want to stick with the 5 pin
socket so you can put a 49 in later perhaps, use the
33 or sim
battery pentode, it'll work weakly with 9v B+ due to having
a suppressor grid but nicely with 18v or more. Suits Hikers Two also -
actually I believe the 33 is as good if not better in the o/p stage than
a 49 unless longest poss. battery life is your aim..
49 &1Q5
data (from
download area) Adobe PDF Reader may be required.
Doesn't
work?: No regeneration?, reverse the reaction winding
leads. Remember, no matter how well you built it or how good it looks,
for best results
you will need a good antenna, pref a good earth (not the cold water tap,
the pipes are likely PVC!)
and high impedance crystal headphones or crystal set ear plug of 2,000 ohm or greater . |
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Above: Various Original Incarnations of
Hikers, Improved Hikers & Hikers Amplifier
Below: My first attempt at a Hikers using a 1C5, stock
coil (35,100 & 40 turns) on an original lossy phenolic former (although
baked in hot wax, probably a
rather 'Q'less thing to do but damn those ugly PVC coils!). The 6.8k
resistor between B+ and grid is a cheat to provides the bias, just make
sure filament polarity is correct. Regeneration is very smooth and
doesn't break easily into unwanted oscillation with 18V or even 27V on the plate,
which of course it enjoys, but bear in mind that you will sacrifice
sensitivity with higher plate voltages, the gain you get is in audio
amplitude only.(PP9 batteries in series will last a very
long time and of course draws no current when filaments are off).
The
condenser is about 50pf too large at the top end of the band so turns
could do with reducing, or easier yet pull a vane or two out of the
rotor (not stator). Received about 8 or 10 audible stations, another 3 or 4 more
after dark at v.good
volume into 3k phones,. |
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