[HBR] So i'm gonna build an HBR-XX

Wed Feb 18 19:41:57 EST 2009

What would be the going price for an Eddystone dial?   I talking about 
the horizontal one, that everybody who builds HBR wants.

David

Marvin Match wrote:
> On 18 Feb 2009 at 12:00, xjakobx at gmail.com wrote:
>
>   
>> Hello List!
>>
>> I'm starting to gather together parts for my HBR-styled construction  
>> project. It's a long way from being started, but hey, i gotta get the parts  
>> together sometime, right?
>>     
>
> ---snip---
>
> A dial mechanism will be difficult. I've been looking for some time, 
> and I have a National or two, but I really want an Eddystone. At this 
> point I don't expect to find one.
>
> So, I'll be making my own slide-rule mechanism. I'll share it all 
> with the list, but I don't expect to make much progress for another 
> month or so. I really wanted a gear-reduction dial made with anti-
> backlash gears, but the gears themselves are expensive, so I found a 
> variable cap made by TRW with an integral 6:1 ball reduction built 
> into the shaft and I'll put a 6:1 Jackson ball reduction drive in 
> front of it. That'll get me 36:1 reduction. I'd prefer about twice 
> that, or three times that with a two-speed reduction, but I won't 
> live long enough to find the parts to build it that way.
>
> BTW, the National and Jackson reduction units are not all the same 
> either. Line up 10 identical Nationals and each one will feel 
> different. The Jacksons are more consistant and generally feel better 
> than the Nationals, but the same holds true. The best that i've found 
> are the ball reduction drives that you see on some military equipment 
> that have threaded parts that you can take apart. Not sure who made 
> them. Next is the Jackson like found in Heathkits, last is (most) of 
> the Nationals, although like I said, once in a while you find a 
> National that feels really good.
>
> Another thing that will be difficult is the power transformer. Fair 
> Radio Sales has one that might work. It's their TR180 for $18 here:
>
> http://www.fairradio.com/catalog.php?mode=view&categoryid=1545
>
> You'll need to add another transformer for the tube heaters if you 
> choose this one as 1 A. @ 6.3 V. is not enough.
>
> Coil forms are near impossible to find for reasonable money.
>
> **Note to list: Anybody have spare coil forms?
>
> I've been making my own out of 5-pin tube bases and 1 1/4 inch 
> acrylic tubing with 1/8 inch wall thickness (I think that a 3-foot 
> remnant piece was $12 from the plastics store). I tested all of my 5-
> pin tubes and any that didn't test into the "good" range on my 
> Jackson tube tester were sacrificed for coil bases. I chuck the base 
> in my lathe and cut them down to .6 inches in height. Then if it's a 
> fat base I machine the inside to accept the 1 1/4 inch tubing. If 
> it's a skinny base, I machine the 1 1/4 inch tubing to fit over it. 
>
> **Note to list: Anybody have some 5-pin tube bases or 
> weak/dead/shorted 5-pin tubes they would be willing to pass along to 
> me? I still need about a dozen for the two projects I'm working on.
>
> Then, you'll need an enclosure to put it in. They too are hard to 
> find. I found a B&K 1077B TV Analyst for only a few bux and after 
> gutting it and making a new front panel I have nice enclosure with a 
> hinged flip-top lid! In fact I bought two... one for my HBR and one 
> for a matching transmitter. I think I paid $20 for the first one 
> (locally) and $35 (total including shipping off e-bay) for the 
> second. Watch e-bay, check around town. These were never all that 
> useful, but they're entirely useless now, so a local repair shop 
> might just give one to you if you make friends with them.
>
> There's one on e-bay now if you want to see what it looks like. It's 
> auction number is 230325967. The enclosure is worth the $30 starting 
> bid on this one, but maybe not after the $40 shipping is tacked on, 
> at least not to me. There's also a 1076 on e-bay that could be 
> another possibility for an enclosure. These come up for auction all 
> the time, so don't be in a hurry. Sooner or later one will be listed 
> on e-bay that's close enough for you to pick it up.
>
> A good variable cap is essential. Most anything out of a tube-type FM 
> radio will work, but they're not all the same, and actually they're 
> just a tad too small anyway, an extra pf or two at the top end or a 
> pf or two less on the bottom would be better. I can't speak for the 
> one you've found, it might be fine, but if you ever get the chance to 
> get the one Ted specified... GET IT! 
>
> I've thought about using one of the AM-FM caps like the one you've 
> found, and using the two larger sections to cover 160 with no RF amp, 
> but to do this easily you'd need 6-pin coils so that there's an extra 
> pin for the 160 coils to catch those big tuning cap sections, and 
> I've already invested a lot of time building 5-pin coils.
>
> WOW! Am I long-winded or what?
>
> Keep us posted, Jake.
>
> Marvin
> KA7TPH
>
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