The LCD view-angel can be adjust in menu . Which have high rx dynamic, and good Agc design, so sounds very smooth. The service manual very hard to find.
I would hate to be a killjoy but this was a very superficial description. Just listening to the radios is no guide as to how pleasant (or unpleasant) they are to tune and operate. I have the 3701 and 3791 in immaculate condition. Both came with a good copy of the operating manual and the thick maintenance manual. All three have virtually the same controls and they are all highly intuitive, even digging down through five layers of software. The tuning feel is the same in the 3701 and 3712. Very solidly made with no backlash or shake and a lovely tuning feel, similar to an old Eddystone receiver. My 3791 uses a fairly small HP rotary optical coupler and has a bit more shake but the knob is nicely weighted. For me the tuning knob must free free-running with finger tip tuning. The 3701 and 3712 usually have the same filter fit, though be aware that quite a few 3712s were used by military stations (mounted in robust waterprrof cabinets) and employed the excellent Piccolo data system, and may have a special Piccolo crystal filter. The 3712s also tune up to 40MHz and have a higher 1st IF than the 3701. The 3791 has very sophisticated DSP and different IFs. The DSP provides 100 bandwidths - from about 75Hz to 12 kHz! These give brick wall selectivity and just as importantly, have far less differential phase distortion. One outcome is the ability to receive CW in a 75Hz BW without the usual distracting ringing of a tight crystal filter. Switching the filters is very easy as bandwidths are grouped to the mode and have up / down switches, and can be stored in the system. All three detect AM with a sophisticated type of product detector with minimal distortion. There is no selective fading as with a traditional envelope detector. The AGC on my receivers is excellent with a fast attack and slow release. On the 3791 these times can be adjusted. The only receiver I know with a slightly better AGC response is the old R&S EK 070. All three receivers have sophisticated BITE, able to trace faults to component levels - eg "2 LO level low". The build quality on all three is excellent. Be aware that the 3701 and 3012 have many modules bolted to a robust frame. On the 3791, there are only two huge double sided circuit boards running the length of the chassis. One is RF and the other for digital and the susceptible circuits are fully shielded. The other big difference is that the 3701 and 3712 have chunky linear PSUs whereas the 3791 has a bought-in switched mode PSU. It is well built and shielded and filtered but there are a few odd squeaks at around 60kHz and below. In fairness the PSU was a replacement for the original. There are no circuits for these PSUs sadly. On all three the brightness and tilt angle of the displays can be changed from the front panel. You need to read the operating manual for the details. It's actually pretty intuitive. BTW the manuals are on the internet. Google will locate them. Not sure about the 3712 as they are rare beasts. Finally, adjusting the internal crystal standards on the 3701 and 3791 is a delicate screwdriver job. On the 3791 it's done in software via the front panel. And you can feed in external standards of 1, 5 or 10MHz for even better stability - eg from a Rb or GPS.
The LCD view-angel can be adjust in menu . Which have high rx dynamic, and good Agc design, so sounds very smooth. The service manual very hard to find.
I would hate to be a killjoy but this was a very superficial description. Just listening to the radios is no guide as to how pleasant (or unpleasant) they are to tune and operate. I have the 3701 and 3791 in immaculate condition. Both came with a good copy of the operating manual and the thick maintenance manual. All three have virtually the same controls and they are all highly intuitive, even digging down through five layers of software.
The tuning feel is the same in the 3701 and 3712. Very solidly made with no backlash or shake and a lovely tuning feel, similar to an old Eddystone receiver. My 3791 uses a fairly small HP rotary optical coupler and has a bit more shake but the knob is nicely weighted. For me the tuning knob must free free-running with finger tip tuning.
The 3701 and 3712 usually have the same filter fit, though be aware that quite a few 3712s were used by military stations (mounted in robust waterprrof cabinets) and employed the excellent Piccolo data system, and may have a special Piccolo crystal filter. The 3712s also tune up to 40MHz and have a higher 1st IF than the 3701.
The 3791 has very sophisticated DSP and different IFs. The DSP provides 100 bandwidths - from about 75Hz to 12 kHz! These give brick wall selectivity and just as importantly, have far less differential phase distortion. One outcome is the ability to receive CW in a 75Hz BW without the usual distracting ringing of a tight crystal filter. Switching the filters is very easy as bandwidths are grouped to the mode and have up / down switches, and can be stored in the system.
All three detect AM with a sophisticated type of product detector with minimal distortion. There is no selective fading as with a traditional envelope detector.
The AGC on my receivers is excellent with a fast attack and slow release. On the 3791 these times can be adjusted. The only receiver I know with a slightly better AGC response is the old R&S EK 070.
All three receivers have sophisticated BITE, able to trace faults to component levels - eg "2 LO level low".
The build quality on all three is excellent. Be aware that the 3701 and 3012 have many modules bolted to a robust frame. On the 3791, there are only two huge double sided circuit boards running the length of the chassis. One is RF and the other for digital and the susceptible circuits are fully shielded.
The other big difference is that the 3701 and 3712 have chunky linear PSUs whereas the 3791 has a bought-in switched mode PSU. It is well built and shielded and filtered but there are a few odd squeaks at around 60kHz and below. In fairness the PSU was a replacement for the original. There are no circuits for these PSUs sadly.
On all three the brightness and tilt angle of the displays can be changed from the front panel. You need to read the operating manual for the details. It's actually pretty intuitive. BTW the manuals are on the internet. Google will locate them. Not sure about the 3712 as they are rare beasts.
Finally, adjusting the internal crystal standards on the 3701 and 3791 is a delicate screwdriver job. On the 3791 it's done in software via the front panel. And you can feed in external standards of 1, 5 or 10MHz for even better stability - eg from a Rb or GPS.
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Never problems ;with the dislay s ? good compare tu 73,
They can be tricky to adjust, but the menus have a couple of options that make them easier to see.