AOR8200B S-meter alignment

[wa8vzq]

Does anyone know if the AGC/S-meter calibration for the 8200B is a software setting? My measured sensitivity is fairly good but it seems to take a lot of signal to get S-meter to begin to register.

The settings on my VR-500 are tweakable via a maintenance procedure and I was hoping to do the same with this 8200B.

Also does anyone know of any mods to shorten up the AGC time constant? Sure is awfully darned slow.

Dan
Apple Valley, MN

 

[DaveIN]

Dan, did you try the AOR workshop program? It has a built in S-Meter calibration:
http://www.aoruk.com/software/workshop_v2.0.6.zip

How do you like your VR-500 by the way?

 

[wa8vzq]

Thanks Dave, well I've played with that a little. It seems to affec the display on the PC more than the actual 8200B s-meter. Someone on the 8200B list on yahoo sent me this link.

http://www.aoruk.com/8200bulle.htm#s-meter_full_scale_corrupt_data

It talks about the s-meter data getting corrupted. The service bulletin shows how to "peek & poke" the values held in a register for the s-meter. I did find that my settings were different and poked in new ones. I haven't had the opportunity to check the results yet. I'm planning on experimenting a little to see what happens if I poke in values other than those mentioned. Could be that I can get the results I'd be happy with.

As far as the VR-500 goes, it's a real gem. I'm almost half tempted to trade off this AOR for another one. Not that there's anything technically wrong with the AOR. It seems to meet all advertised spec's but spec's obviously aren't everything. I specifically was interested in the narrower IF for SSB. It is narrower than the VR-500 BUT I haven't seen that much of a performance improvement. Definitely much less than anticipated. I think that it's reputation far exceeds its performance.

I'd be happy to send you a fairly lengthyy composite of a review and some other messages of interest that I'e posted on the VR-500 group on yahoo. If youre interested, drop me an email at wa8vzq@yahoo.com

Dan

 

[DaveIN]

Ok, I didn't realize that it was for the program S-meter, but that makes sense now.

I had an 8200 and then an 8200MKIII, the MKIII was a definite improvement over the original released version. The only thing I didn't like about it was that the extra features were in a card and you could only use one at a time. Other than that the performance was outstanding. I did sell it off and purchased an Icom R-20 and have been pleased with the performance and features of the R-20. As for shortwave utilities, you just can't beat a dedicated shortwave receiver with USB/LSB, or BFO.

I guess I a little surprised to hear you would use the VR-500 over the 8200, but I've never used a VR-500, only a VR-120.

 

[wa8vzq]

Dave,

Well, I have several govt version MKIII's here at work which involves VHF & UHF aircraft comm & that's what how I use them. They are pretty nice but I had never used any for HF use.

For personal use, I have BC785's & BC205D's for aircraft monitoring. Didn't have any intent to use this 8200B for that since it doesn't cover enough channels fast enough.

The VR-500 uses a 16 KHz IF on SSB and does not have single signal reception. Its front end performance is mediocre and it does overload easily. It seems to receive a lot of off-channel signals that are not related to the IF bandwidth. I'm going to guess that it is a synthesizer phase noise issue.

I latched on to this original B version on the spur of the moment. It does have good sensitivity but I haven't been overly impressed with the HF performance. I was expecting a lot quieter receiver since it has a 3 KHz IF (which I did measure). The 8200B seems to have similar synthesizer phase noise issues. So there's a lot of underterminate backgorund noise that definitely is not adjacent channel.

Also as mentioned in my earlier post, the AGC time constant is very long, too long for my tastes for reception.

That's how this unit is shaping up in my evaluation so far. From what I can see, I didn't gain as much as I thought I would and that's why I made my comment. I'll probably play with this unit for a few more months before making a decision.

Dan

 

[wa8vzq]

Do need to correct myself.

The VR-500 bandwidth is 8 KHz in any of the SSB/CW modes.

Dan