Thread: SB-303 heathkit repairs
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Old July 20th 14, 04:30 PM posted to rec.radio.shortwave
dave dave is offline
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Default SB-303 heathkit repairs
On 07/19/2014 11:26 AM, wrote:
On Saturday, July 19, 2014 10:04:10 AM UTC-4, dave wrote:
On 07/18/2014 05:36 PM, wrote:

On Friday, July 18, 2014 12:29:27 PM UTC-4, Michael Black wrote:

On Fri, 18 Jul 2014, dave wrote:







On 07/17/2014 04:49 PM, Michael Black wrote:



On Thu, 17 Jul 2014, Scott Smith wrote:







SB-303 heathkit repairs, I bought a heathkit SB-303 radio off ebay,



all it gets are various tones when I tune the dial, any idea on



repairs, thanks in advance, email .







Does it have the crystals? If that's the ham band one (rather than the



one for shortwave), the crystals are the same frequency as used in the



full SB line of ham band equipment. Buying crystals these days has



become quite expensive, so if someone needed the crystals for whatever



reasons, they may have stripped a receiver, rather than buy the crystals



new, or find a set of crystals on the used market.







It's a receiver that tunes a 500KHz segement (I think around 3MHz) with



a crystal controlled converter ahead of it, a crystal needed for each band.







Michael











Anybody roll their own quartz crystals? You need an oven. Big bucks for



energy.







I gather the radio magazines did show how to make your own crystals, back



in the thirties.







I'm sure they started with a slab of quartz, and cut it down and started



grinding.







Michael



Very , very difficult. Even after it is close enough(!)in resonant frequency- there are a few MORE extremely critical parameters involved ... This is why true "Crystal Filters" were so expensive,even when they were mass produced ...





You can get nice 5 pole filters for about a hundred bucks can't you (I

haven't checked for a few years). For relatively wide band SWL cascaded

ceramic resonators should suffice).
The current production from Inrad or Icom are around $150 and even higher for the really sharp ones...Insofar as the ceramic resonators go- yes,the prices are extremely low,but so is their Q factor.


amplify cascade amplify?
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