Tvheadend

what version tvheadend are you using? I'm guessing < 3.9 if so update to latest (git master is best).
follow this guide for master
https://tvheadend.org/projects/tvheadend/wiki/Building

for a repository (unstable one is the one you need)
https://tvheadend.org/projects/tvheadend/wiki/AptRepository

I am using a clone from git master dated 20141228 and packaged for centos.

your cards should be defined as separate entries in the TV Adapters tab.
your satellite position should be defined in the Network tab. You give the position a name, e.g., Astra 1.
in the TV Adapters tab, you find the LNB parameter window for each adapter and select the name of the network.
The Mux and Service entries will refer to the Network name, which points to the adapters that have the Network connected.
So you do not reference the adapter in your channel definition screen.

I get the feeling we're not talking the same thing so here goes my stupidity.

I've attached Configuration DVB Inputs TV Adapter Screen
You can see I have two Networks DigitalTV1 and DigitalTV2.
You can also see that the channel screen refers to the Service.
Now a given station WLKY for example is avaialble on both Network1 and Network2.
Should I have two channels for WLKY or one channel with two services?

I want the recorder to use whatever adapter is free when it comes time to record. And since I can get show A from adapter A and show B from Adapter B in the same time slot. Can I record both.

Hope this makes it clearer.

It's your choice. When you map the service to channels, you have the option of merging or keeping them separate. If you keep them apart, you're likely to get two EPG entries and no obvious way of telling the channels apart beyond "tuner 1 always comes first in the list" sort of stuff.

As a rule, I merge identical channels, on the proviso that they're genuinely identical. If there's any difference, I keep them separate and rename them so I can tell them apart.

I've gone thru and merged them where they are identical. It appears that it works fine and will record 2 shows at once.

Hi Bob
Why did you have to create 2 Networks? If both your adapters are going to tune to the same muxes, shouldn't you have just 1 network entry and both your adapters select the same network? That way, you do not have to merge services into each Channel, there will be only 1 service for each of your stations.

I am coming from mythtbv and there I have two nets one for each adapter. I am not quite sure I follow this whole mux, service, adapter, channel lingo yet. I am looking to be able to record channel 32.1 from either adapter whichever is available. Thus I might record 32.1 from digitaltv1 one time and then from digitaltv2 another. For example I might start recording a show on 11.1 thru Digitaltv1 and in the middle of that time start recording a program on 32.1 from digitaltv2. I think this is working the way I set it up. By calling both adapters the same network, I lose the ability to record thru both adapters don't I. The wiki, manuals and google foo I've read don't make this clear.

Rob vh was right - I wasn't thinking, and only have merged channels because I have duplicates across different technologies (DVB-S and -T) or tuner types (SD/DVB-T/MPEG2 vs HD/DVB-T2/H.264).

You need to think about the relationship as one-to-many or many-to-many versus the one-to-one you're looking at now.

One tuner can support multiple networks. One network has multiple muxes, and each mux has multiple services. Channels are then what clients tune to in order to access those services.

So, a DVB-S tuner might be associated with multiple satellites (line of sight or via a rotor), and hence you define multiple networks for that tuner.

In your setup, you have a single network with a single set of mux/service definitions, and associating it with both tuners means that either tuner can lock onto those broadcasts. If you ask for channel "32.1" on network "digitaltv" then either tuner can get that because they both know about "digitaltv"; when you ask for "32.2" then the same thing applies.

An adapter will tune to exactly 1 multiplexer (mux) on the satellite position (or antenna) that it is connected to.
Each mux transmits many services that are multiplexed on the frequency.

If you have 2 adapters, each with the same network, the following happens when you record/view a service:
a. the active (currently tuned) muxes are checked to see if they contain the service you are looking for
b. if the service is part of an active mux, the use count of the mux is increased and the service is taken from the active adapter
c. if the service is not in an active mux, a free adapter is located and tuned to the mux that holds the service
d. if there is no free adapter -> failure

This applies to FTA services and softcams. If your adapters have hardware CAMs, receiving multiple services on one adapter may or may not work depending on your hardware.