[Boatanchors] HQ-180 help???

[Kim Herron]

Hi Eugene,
>how about for keeping dust off? My HQ140X is missing this cover and I am 
>looking for it.  I wonder if the tiny field between the plates could cause 
>a build up of dust attraction?

     No the field won't "cause dust attraction", but it will get dusty just 
because it's open.  MANY older recievers operate this
way for years with no problem.


>Any one have any empirical evidence about sheilding here?

       This is a different story.  The cover was steel and was intended as 
a shield,
and will affect radiation, etc from the receiver.  It will operate just 
fine without it, though you will get some hand capacitance
and some stability issues showing up on higher frequencies.
The covers on the HQ-170/180 series receivers were PLASTIC, and of no 
consequence
electrically, or mechanically.  They just made it look pretty.  The plastic 
drew moisture,
which made the capacitor frame rust and that screwed up the grounding.  BTW,
one of the biggest problems that those two receivers are having is that the 
solder connection
to the frame/chassis is coming loose which is causing all sort of stability 
problems.
This is usually the reason that people are looking for the covers, which 
they think are steel or
aluminum and they figure that this will take care of the problem, which it 
doesn't.
The solution to the problem is to either find a HUGE iron and resolder the 
frame to chassis connection
or drill #6 holes in the chassis, very near the tuning or bandspread 
capacitor and put solder lugs and screws
in them and solder heavy busbar to the solder lug and the grounding fingers 
on the tuning caps, which are there but not used.
That make the receiver rock solid stable.  You can literally take one end 
of the receiver, pick it up while tuned to a station,
and drop it (my test to see if its fixed) and it will not move or even 
warble.
Sorry for the long answer, but sometimes the background info makes the 
answer make sense, and gives everybody a
heads-up when they run into the same problem.


Thanks!!

Kim Herron  W8ZV
1-616-677-3706