On Sat, Apr 19, 2008 at 10:44:26AM -1000, Ken Brown wrote:
> Is there any validity to the notion that deleting CW functionality from
> a rig could make it cheaper?
Yes, IMHO there is.
> For receiving:
>
> Any rig with a BFO and product detector can receive CW. Sure it would be
> nicer to have some narrower filter options available, and perhaps a
> faster AGC than when using SSB. The filters could be add on options, but
> let's include the cost of the PCB space and connectors, and switching
> diodes necessary to accomodate a narrower filter....No on second
> thought, lets not include that, because an optional narrow filter could
> just as easily be used for a narrow SSB filter, so this is not a CW
> specific additional cost to the rig. And you don't need that filter for
> basic CW functionality. How about the cost of a switch and a capacitor
> and resistor for the other AGC speed? Lets say $2.
Wrong. You are assuming that a narrow SSB filter, which COULD be,
WOULD be. Quite simply it would not. So a user would be able to recieve
CW in USB mode with a 2.4 kHz bandwidth. Possible but not likely.
How many CW ops on this list use a 2.4Khz IF filter/DSP bandwidth? I'm not
talking about a 2.4kHz roofing filter, I'm talking a total to your ears
badwidth of 2.4kHz.
> For transmitting:
>
> There are two really simple ways of making an SSB transmitter send a CW
> signal. One is to have an audio tone generator feed the balanced
> modulator, and the other is to apply a DC bias to the balanced
> modulator, unbalancing it and letting carrier through. The second method
> is probably preferable, requiring fewer parts. The purity of the tone
> from a tone generator would be very important and might require
> adjustments or selected value parts in order to work right. So, if we go
> with the unbalanced balanced modulator method, we need a switch and a
> few resistors to get the proper DC bias to unbalance to modulator. We
> could either bypass the sideband selecting filter, or use a different
> BFO/carrier crystal to get the CW carrier well into the filter bandpass.
> So we need a crystal, a couple of resistors, a few diodes for crystal
> switching and a switch of some sort to apply the DC offset to the
> balanced modulator. This might all add up to $8 if the crystal cost is
> $5. We'll use the PTT line on the microphone connector for the key
> input, so we don't need to include the cost of one phone or phono jack.
A matter of opinion. Some people would not mind unpluging their microphone
and plugging in a key some would.
I would also design it differently. I would use a sythesized oscialtor
not a VFO and most likely a channelized digital one.
> So our total is $10. This is for basic CW operation, since we were
> talking about a cheap rig, that seems appropriate. In order to have fast
> QSK operation and a few other nice features for CW, we might need a bit
> more careful engineering, with not many more parts.
$10 in parts adds a lot to the cost of a radio. Depending upon the
retail markup, etc, if sold directly by Ten-Tec, it would add about $25.
If it were to be sold in a store like AES or HRO, it would add about
$50.
> I'm not sure what price range this discussion was centering on for the
> cheap rig, was it $200 or $500? Lets go with $200. Now suppose you have
> two rigs to choose from, a SSB only rig for $200 and a SSB/CW rig for
> $210. Will the $210 SSB/CW rig collect dust on warehouse shelves, while
> the $200 SSB only rig sells like hotcakes?
But if you add your $10 in parts, plus an IF filter, even a 4 crystal one,
your $200 rig is a lot more money than $200. In the computer business it's
called "feature creep", and it just crept up another $50 to $100 depending
upon the filter.
I originally said $200 as that was the figure many non active hams have
told me over the last year as what they could afford. Someone else said
that $500 was ok, something I think is totally wrong.
I chose 20 meters for the rig because of antenna restrictions and the
ability to work DX with it. 40m and 75m are worthless outside of the
Americas. In order to be heard you have to fight SWBC stations and
in order to listen they have to fight digital stations at the high
end of the U.S. CW bands.
I'm not trying to make a cheap rig to sell to CW ops, there are plenty of them,
I'm not trying to make a cheap rig to sell to contestors, it's just not
possbile.
What I am trying to do is to make a cheap rig, as cheap as possible,
to attract hams who are not on the air and want to be. Ones with a limted
amount of money to spend on their hobbies, and who can't copy morse code.
Someone else mentioned that getting them involved in clubs would be a good
thing, but currently they don't. Most of these hams only contact with a
club was at a VE session and they were just as quickly forgetten about
as the club ignored them.
Speaking of clubs, obviously you have never dealt with the Israel
Amateur Radio Club. A ham here tried to start an English language net
on the Jerusalem 2m repeater and was run off, even though he was a
club member and had permission.
For the next month the repeater was shut off from 4pm until 11pm,
except on the nights the person doing it forgot to turn it on again.
To answer another point, would you buy a radio at a hamfest or eBay if
you had no way of evaluating it? If you blew your ham radio budget on a
radio and found out it was broken and the seller disapeared? Would you
still be willing to buy those radios?
If you already have a radio or have the skills or equipment to fix one that
was broken from parts available from Radio Shack (do they still sell parts?),
you are not someone I am trying to reach.
Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM
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