There is a spray product called Midas Spider EX
that is supposed to keep the spiders out of things. I have tested
it for flies and it works very well. I now use it on all box on
the tower. Read the can for precautions. Ideal for outside heat
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On 20/02/2021 15:13, John Quarmby via
For my 3 and 6cm systems the heatsinks are external to the
diecast waterproof box, sealed round the edges with
non-corrosive silicone sealant. The 3cm section has forced air
cooling with a hood over the fans, the heatsink fins are covered
so air is pulled up through the fins from bottom to the top and
then expelled by the two minature fans into the hood which keeps
water off. It does need annual maintenance to remove spiders
webs which tend to gum up the fans. This arrangement has worked
for 20 or so years with the box outside on the tower throughout
that time. The heatsinking is compromised a little by having the
diecast box body in between the PA and heatsink, it wouldn't be
too difficult to calculate the resulting increase in thermal
On 20/02/2021 13:48, DAVID G4ASR via
Has anyone built a masthead SSPA with integral blowers? I'm
just looking for ideas of how to bring air in & out without
bringing in rainwater.
Its actually going to be used on 70cm, bringing my total of
masthead transverter/lna/sspa boxes to a total of 5, up to the
It won't be permanently on the tower. Just fired up for 1-day a
month, maybe on the tower for 3 days or so.
On my 1296MHz masthead transverter/sspa I have 2 blowers and
bring the air in/out on 32mm plastic plumbing fittings that I
can swivel so that the inlet/outlet
As an aside, I'm going to be rebuilding my 13cm masthead system
with a 3xLDMOS sspa and will be shifting a fair bit of air.
Ideally I would love to have the heatsink fins external to the
masthead box but can't see a way of making it waterproof and
able to be easily removed when I blow it up.
Maybe some type of flexible gasket?
Be interested to see how you do it ?
73, David G4ASR