Re: 10 ghz lash up test

Alan G0XBV

It certainly does, Mike - many thanks!  I have found the relevant datasheets now too.


-----Original Message-----
From: 'Michael Scott' g3lyp@... [ukmicrowaves]
To: ukmicrowaves
Sent: Wed, 18 Mar 2015 16:09
Subject: Re: [ukmicrowaves] 10 ghz lash up test


Hi Alan
The device I used was a TC622 which comes in various packages. The most convenient is a TO-220 because it can be bolted to the chassis/case etc. It is also available in an 8 pin DIP package. It is designed to have a degree or so of hysteresis which prevents the control device, relay or power MOSFET, from hunting around the set point.
There are other ICs such as the LM135/235/335. The basic LM35 temperature sensor could probably also be used.
I use the TC622 to control the temperature and an LM35 to monitor the temperature on a remote LCD.
Hope this helps.
Mike, G3LYP
----- Original Message -----
Sent: Wednesday, March 18, 2015 3:03 PM
Subject: Re: [ukmicrowaves] 10 ghz lash up test

Thanks, Mike (and all) - that's most helpful.  I will keep that in mind about the IC - I'm sure I can find the info by searching, but if you can recall what the device was off the top of your head, that would be good to know (please don't go to any trouble though).  I know someone who built something similar to prevent a GCH header tank from freezing-up, but alas he has passed on now (motto - ask people whilst they're still on the planet!).  Fortunately, I have both a used and a new gasket-style dc housing, so at least I have the chance to 'learn' before drilling holes in a brand new one!!


-----Original Message-----
From: 'Michael Scott' g3lyp@... [ukmicrowaves] <ukmicrowaves@...>
To: ukmicrowaves <ukmicrowaves@...>
Sent: Tue, 17 Mar 2015 16:06
Subject: Re: [ukmicrowaves] 10 ghz lash up test


From personal experience, I think it is best to have a breather hole and also incorporate some sort of heater to keep the contents of the box above the dew point.
A metal clad resistor makes a simple heater, the value and wattage needed will have to be found by experiment. There are a number of ICs available which can be used as a thermostat to conserve energy. I set mine at about 28 degrees C, and this has worked well for over 20 years on my masthead 10GHz preamplifier.
I gave a talk at Crawley many years ago on it, and could possibly dig up some information if you are interested.
73, Mike G3LYP

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