Question about connections between circuit boards on radio

I have built a 40M transceiver of my own design. The local oscillator and another oscillator are on seperate circuit boards. I used twisted pair wire to connect the oscillator signals to the board with the mixers, and the modulated signals to antenna , etc. I don't have a fast enough o'scope to look at what is happening in those circuits but with a frequency counter it seems that there is interferance between the signals. Would I get better results if I used coaxial cable instead of twisted pair? If so , what kind of coax would I use between circuit boairds?

George

any signal above 30MHz should be used by coax interface

So, you think I am OK with twisted pair if my highest frequency is 10MHz?

Interference is unavoidable both coax and twisted pair.But coax have more immunity to interference because of the dielectric that it has.If you suffer from just interference try to use coax.

If the oscillator outputs were all single ended, would this have any effect on the decision of whether to use coax or twisted pair? Wouldn't the shield normally go to earth ground? I don't have earth ground available in the transceiver. Just circuit common. Is it OK to connect both the negative lead and the shield to circuit common?

Added after 3 minutes:

Sorry. I forgot the there's just the inner core and the shield.

Added after 36 minutes:

I don't know if it's just interference. I get measurements on the mixer where the oscillator connects that are less than 10% low (frequency). Could that also be caused by interference? What do you mean by just interference?

not really

I wouldnt be using anything but coax or some other screened lead for anything over a couple of MHz particularly in a RF enviroment. you could end up with all sorts of weird mixing products with various RF signals bouncing around inside the box.
Which leads to my next comment ... individual (separate) stages, should really be in shielded enclosures :)

cheers
Dave
VK2TDN

There is interference as you guess that twisted pair is the cause then if you change this twisted pair to coax interface the interference will go off.

If the interference is still present then there could be another cause not just twisted pair.