Hauppauge quadHD problems

[Graham]

Looks like the Hauppauge dualHD (USB) has the same issue.  It's dropping a lot of packets, when another tuner running in parallel is dropping none.

Apologies if I am suggesting the obvious ... What happens if you swap the coax between the two tuner devices?

[NumberFive]

Apologies if I am suggesting the obvious ... What happens if you swap the coax between the two tuner devices?

No problem.  Yes I've tried this, no difference.

[NumberFive]

Martin

I've seen this comment across the web quite a bit, but you 100% definitely can engineer for this.  It's kind of trivial as far as radio circuits go.  The first components after the antenna socket should be an amplifier and impedance matching circuits, then into the tuner ICs.  About 6 dB of amplification is needed, as each time you split the signal in two you lose 3 dB.  This amplification and matching stage would mostly consist of printed components on the PCB (i.e. PCB printed inductors, capacitors), just like you can see in masthead amplifiers, so minimal cost in terms of production.  Pennies/cents for a transistor or two.  

Some of the tuner ICs even have a buffered pass through for such daisy-chaining applications, but I don't know how the costs of those compare against the conventional approach above.

Just came across this Youtube video about a HDHomeRun dual tuner.  https://www.youtube.com/watch?v=fUc4Hvo1N-g

You can see clearly here that from the UHF connector at the bottom, the first 8-pin IC (tiny) is an RF amplifier with two outputs, and then into the two tuner ICs at the top.  The video goes on to show above these are the demod chips, then the CPU.  The RF amplifier and the tuner chips would normally be in a metal can (you can see the solder pads for it).  Lots of little resistors ®, capacitors ©, and inductors (L) presumably for various filters and matching circuits.  Nice piece of engineering.

Lots of close-ups in the video.  Worth a watch.

Anyway, I'm sure other brands with dual/quad/octo tuners will have similar designs with an RF amplifier up front.