RadioBanter - View Single Post

November 24th 05, 08:45 AM posted to rec.radio.amateur.boatanchors

On 23 Nov 2005 22:32:37 -0800, wrote:

Maybe not a Galaxy 5 itself, you could be right. Besides, it was a
hybrid rig, not an all- tube rig anyway.

But, what about this lineup for receiver:

1) 3 sets of switchable preselector filter with ganged variable
capacitor with a single dual triode amp, half of which are placed
between each filter.
2) Single dual triode as cascode IF converter, rather than a pentagrid
converter which are hardly made anymore.
3) Single dual triode as differential VFO, glass equivalent of recent
QEX circuit, with oscillator variable capacitor ganged to the
preselector capacitor as part of same set.
4) Single dual triode as pre and post amps to lattice crystal IF
filter.
5) Single dual triode as cascode baseband converter.
6) Single dual triode as differential BFO, similar design to VFO.
7) Push-pull audio power amp... reuse this in transmitter.

Transmitter lineup:

1) Single sweep tube operated class E for CW, modified to class H with
aid of receiver's push pull power amp.
2) Share the preselector for use in postfiltering of the power amp.
3) Use the same differential VFO as the input to the class E amp.

This isn't really SSB: it is more quick and dirty DSB/CW transmitter
with SSB receiver. (If anyone can modify a class E amp for SSB service
I would love to hear about it).

So, this lineup uses a single sweep tube, 6 dual trodes, and a pair of
6L6 equivalents.

Shuguang 807 as sweep tube: $16 retail
Shuguang 6SN7 (VFO) $11 retail
Shuguang 6SN7 (BFO) $11 retail
2 Shuguang 6L6 (Amp/Mod) $25 retail
4 CH-12AX7A $48 retail
-----------------
$111 retail ==
$55 wholesale if I can establish a dealer relationship with supplier.

Tubes: (presumed wholeale) $55
Resistors (NOS wholesale): $10
Caps (NOS wholesale): $10
Power transformer: $5 sheet metal stack
made in LDC
4-gang variable $25 (Soviet make
from EBAY)
Chassis: $20 sheet metal
Planetary gear drive: $15 (cast iron gears
from LDC)
Crystals (NOS wholesale) $5
Rotary Band Switch (NOS EBAY) $10
---------
$140
Labor (20 hours at $1/hour in an LDC) $ 20
---------
$160
Murphy Factor (20%) $ 32
----------
COGS w/labor $192

======================

OK, you are likely right that the wholesale cost is high. But I only
worked this out in 20 minutes using recent surfing, reading, and other
communication. Perhaps with further refinement I can get the cost
down. I added a murphy factor for amortized taxes, freight, and
customs.

BUT: I think I made it with $7 to spare, including labor, so long as I
do not rely on the US for a lot of things.

Maybe $250 would be a more realistic retail price... Not much profit
margin, though, but not much needed for mail order sales if I am only
intending to supplement income rather than support myself.

Thoughts?

What sort of volume will be needed to get the figures mentioned above?
At those numbers a run of a thousand kits will cost $192,000,
probably all up front.

In any case your margins will be quite thin and your hourly rate will
be thin as well.

73 de n4jvp
Fritz