Universal coil tester

[Alexismex]

With R1 Been 56ohms and yours read 55.4ohms and should be 56k, im surprised it oscillated at all, and no wonder you got all the spikes in your simulation because you have shunted the base almost to deck.
If you look I specified R1= 56kohms which is 56,000 ohms.
I advise you check the other components because its getting late now, but if there ok just substitute R1 to correct value and all should work ok, although I would try getting yourself a 2n2907 because the specs are different as in the 2n2907 application is high speed switching where as the BC337 is general purpose aLso collector base capcitance is 8pf where as yours is 18pf also the 2n2907 frequency is 200mhz where as yours is 60mhz, not that it wont work its just maybe you will suffer with performance when judging it against the build that I posted here.
You live and learn, just keep in mind in the fucture to check and double check component values, not just by what they say on the packet or there markings because its a jungle out there.
When finely installing the components after weeding out the crap, always work with PCB layout and circuit diagram and parts list hand in hand, and marry the three up as you go along.
So its circuit number-part no- value.
By doing it that way your giving yourself a double check on values, making sure your PCB print is working along the same lines as your circuit diagram.
If everything lines up and the design was ok, then it will work.
Regards

I am sure it do not oscillate with 56 ohms

[reiv]

Thank you Dave for catch my childish mistake. I have found BC177B for Tr1 in metal case it has 200MHz freq. and collector base cappacitance 5pF it would be better i think. Now with Rx oscillate ok, but with Tx don`t want to i guess FT1-BF245 could damage because of wrong value of R1 soe i order another few.
Regards

[satdaveuk]

Thank you Dave for catch my childish mistake. I have found BC177B for Tr1 in metal case it has 200MHz freq. and collector base cappacitance 5pF it would be better i think. Now with Rx oscillate ok, but with Tx don`t want to i guess FT1-BF245 could damage because of wrong value of R1 soe i order another few.
Regards

Hi Reiv
It wasnt childish mistake, just overlook, so now you learned something else not to do in the fucture, although will say we all have are moments
The BC177B, if spec as you say here should fit the bill nicely as long as its PNP and the spec was obtained from a reliable source, happy days

The FETS I used were BF245C, should have mention that, although should be ok with bs etc, however cannot varifi them.

Regards

[sido]

What equivalent Fets can be used. The BF245's seem to be obsolete??

Will a FT of 500mhz work as replacement for the oscillator? and can i substitute a RF NPN transistor for the Fets's with the circuit presented??

Sid

[joop]

Grab the datasheet from the BF245 from the internet and look for a replacement with similar specs, e.g. a 2N3819 will do. Since working at high frequencies isn't very important any NPN transistor will do, even audio types like BC557. I have used it's PNP equivalent, BC547 in RF applications up to 30 MHz. Take care of the correct pinouts!

[satdaveuk]

Joop is no doubt right, just try and keep near to spec as possible so in the advent of having further problems you wont be doubting yourself on components you have used as substitutes, otherwise your turning a very simple helpful project into a time consuming heap of crap, that will be no good to man nor beast.
Putting it bluntly that is