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October 2nd 03, 01:29 AM

On Thu, 25 Sep 2003 00:31:07 UTC, (N2EY) wrote:

How about,
put a piece of tape over the mike jack. Or even more realisticly,
give up finding a Heathkit 2 prong mike connector.

HAW! That's a good one!

I spent a year looking for that connector. Someone told me that
it's a still in production Amphenol part, or Amphenol sold the
rights to someone, no one knew the part number but that Newark
carried it.

A lot of folks converted the rigs to use something else!

I couldn't figure out what part it was so I asked a vendor at the
Timonium Maryland Hamfest and they had it. It's pricey so I only
got two. Dumb move on my part since I have 5 rigs that need it, an
SB-104A, SB-401, two SB-102's, and an SB-101.

ahhh, Timonium. It's been too many years....

The connector/coax vendor goes to all the mid-Atlantic Hamfests and
is based in Rockville, MD.

None of the rigs are "ready to use". I've been working on my SB-303
collection. The plan is to clean up and restore the radios and
eventually sell them off, keeping one SB-102/SB-303 combination, the
104A, and the CX7A.

oh mama mia!

Seriously, though, that series is a good candidate for conversion to
CW-only,
as you suggest.

Well, I wouldn't actually "modify" the radios. I'm a restorer,
although I'm not a purest. One of my SB-200s has the Harbach soft
key mod in it and I'm getting ready to add the mod to the other.

NICE!

My rules a 1) keep it looking factory stock, 2) if I modify it,
do it out of sight and reversable. 3) no cutting sheetmetal but an
added bracket or board is acceptable. 4) tack solder electrical
mods.

I'll replace components with close-enough and modern. I put a
radial lead cap in place of an axial in an SB-303. The new cap is
about half the size and has more capacity.

The big point is "nothing irreversible".

I always operate with it off! Old trick, makes CW much more fun. AF gain
way
up, RF gain way down, RF gain used as volume control. Try it - you may like
it.

With AGC on, anyhting in the passband makes the gain go up and down. And
since
a CW signal is all ups and downs, having the AGC on can make QRM worse!

Ever use a Drake 2B on slow AGC? It takes a LONG time for the gain
to come back. Of course on fast, it's pumping the noise.

I drooled over the 2-B 30+ years ago but never had one. I know what you mean
about pumping AGC.

W2LYH, master homebrewer and radio operator, had a lot to do with my design
philosophies. Sadly, he passed away in 2000. I wonder what happened to his
rig...

After all these years using homebrew rigs whose tunable oscillators are
built
around variables from ARC-5 transmitters and BC-221s, I'm spoiled rotten. 6
kHz
per turn of the big, skirted solid Bakelite tuning knob. Silky smooth when
you
have a good one. Almost not fit for polite company.

I might have one of those in my basement. Big air cap, like a
transmitter tuning capacitor but with a worm drive?

Not extremely large but very nice. Solid. They show up on eBay once in a while.
Fair Radio used to have them for $4....

Unless your junkbox has a pair of thsoe Heath CW filters, the Inrad may be
cheaper! The Heath filters are only 4 pole, with 5:1 shape factor.

I have lots of Heathkit filters. Most are in radios. I have one
SB-303 with dual cascaded 2.1 filters in it. There is an audible
difference in how fast signals vanish as you tune past them. Never
thought to try that with CW filters.

I got some 500 Hz wide, 1.4 MHz filters at Gaithersburg back about 1988. Built
a rig around them. I only bought four, and the guy had a crate full. Still
kicking myself.

Has to be in the LMO. Maybe they use the sideband-offset thingie.

I found one write up for the HW-101. That has a exposed VFO. The
SB LMO is hard to remove from the radio and is built in layers.
Also, Heath did not publish the internal details.

That's because Heath didn't make the LMOs.

Heath simply wrote up a detailed spec of what the LMO had to do (physical size,
power requirements, output, dial linearity, etc.) and then subcontracted the
LMOs out to the lowest bidder. They were a component to Heath, like the filters
or the power transformers.

You can put an SB series LMO in an HW-101. I did it, and it works great. Made
up a disc dial from plexiglas, and old knob, and a CAD program. Only trick is
that you have to remember which 100 kHz segment you're in...

Looked in a couple radios. Seems that the SB-10x and the SB-30x had
different LMO's. The SB-30x LMO had a RTTY board on it.

FSK

Here's another trick for the scrounger:

Get both a Tempo One and an HW-100 or 101. Remove the often-balky Heath VFO
and
install the VFO from the Tempo. That Tempo (actually Yaesu) VFO is about
the
best thing in the rig, and it tunes the right range (5-5.5 MHz). And it is
all
set up for RIT!

It might tune in the wrong direction. .... Or is that just the
electrical direction?

Electrical. The Heath VFO tunes backwards.

You can always make up an overlay for the Tempo dial disc.

Classic Exchange is this weekend.

I missed it. Work.

The Type 7 is only about 12 years old. Maybe I'll have to drag the Type 6
out
of storage...

That's a conundrum. If you build a new design tube radio, why
is that not a classic? Why is my 1970ish solid state, digital
readout CX7A or SB-104A more a classic?

Good question!

you might be interested in

http://groups.yahoo.com/group/amateur-repairs

About 1,000 of us hang out there and discuss fixing radios.

cool

73 de Jim, N2EY

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