Hi, TR502 is rather expensive even as an used instrument.
There is one TR503 on eBay. (I know it is not the same thing).
Too expensive for my taste.
But there is also tracking generator that is made by DS Instruments.
Unfortunately, the Tek equipment is not listed as a working environment. But maybe it can be adjusted in some way to work with 7L13.
It is not cheap (around 600 USD)? but it is brand new.
Another option is to build your own.
Mr John Miles KE5FX also has its own TG design.
I hope this helps.
With kind regards, Josip Luetich
