Since you mention the Sierra Wilderness, can I post a cry for help that I recently posted on the Sierra Yahoo Group? Perhaps someone who reads this might have some advice.
I bought a Sierrs Wilderness rig off Ebay about 5 years ago, (not because I intended to use it at that time, but because this rig had such a good reputation, was rare to find on Ebay, and I knew that I would use the rig at some time in the future).
The rig came with band modules for 3.5MHz, 7MHz, 10MHz, 14MHz, 18MHz and an unbuilt/partial band module kit for 21MHz. A quick on-air test for each band produced signals, except for 14MHz, where the seller offered the suggestion that the band module crystal was faulty. (I still need to replace it).
A transmit test into a power meter confirmed that the rig was putting out a few watts on each of the bands.
So all looked OK and the rig was stored in a box.
I have been living on the island of Phuket, Thailand since 2002, and finally got round to installing an antenna for the low bands. I imported, (at great expense!), the DX Engineering Thunderbolt 80/40 vertical antenna, with 30mb add-on kit. This antenna was installed with 64 radial wires in the middle of my plot. A check with my antenna analyser showed low SWR (1.1 - 1.2) on the three bands of interest.
So I connected up my Wilderness rig and ... hmmm. I could hear signals for all band modules, but the rig seemed, well... a little deaf. This was especially so because I have an old Icom HF rig in my car, connected to a screwdriver antenna. That installation was producing many signals on the same band and at the same time of my tests.
My initial thought was that there was a problem with my Thunderbolt antenna/coaxial lead etc. So I connected the Wilderness rig to my screwdriver antenna in my car to confirm my theory.
But the result was similar to that for my Thunderbolt antenna. Some CW signals (and SSB on 40m), but nothing like what my Icom rig was receiving.
This problem of 'deafness' seemed to apply for all band modules. I 'tweaked' the pre-mixer and receiver capacitors for maximum signal on each module, but they were generally already at their optimum.
So what could be the problem?
Let me say that all aspects/controls of this little rig seem to be working correctly. It just seems deaf when doing comparisons with my short, screwdriver antenna and old Icom rig. (ie, I can hear a strong CW station on my HF rig, but the same station is weak or almost inaudible when I swap the Icom for the Sierra rig.
I have resoldered the centre connection of the antenna connector socket, in case the joint was dry, but that hasn't solved the problem.
I do have the manual and circuit diagrams for the rig, and would appreciate advice as to what measurements/tests I could perform to identify where the problem might lie.
I would start by checking the RF Gain control. It is labeled R1 on the schematics and connects to the band module connector at pin 7 and 8. When turned fully up there should be a short or a few ohms between pins 7 and 8, and around 1 kohm to ground from either pin.
Bueng Kan, Thailand