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562pbt_af-if_align [2015/03/20 00:00]
n1eu
562pbt_af-if_align [2015/03/20 00:01]
n1eu
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 ====== Omni V PBT & IF/AF Alignment ====== ====== Omni V PBT & IF/AF Alignment ======
-**from the factory** 
- 
 {{562_pbt_if-af_align.jpg?​800|}} {{562_pbt_if-af_align.jpg?​800|}}
 ---------------------- ----------------------
 //(the following info was posted to the Omni V Yahoo Group by AA8VE)// //(the following info was posted to the Omni V Yahoo Group by AA8VE)//
- 
-This is good info Don, in my own opinion there are several "​mods"​ talked about in regards to the Omni V which may be very good for many other rigs however the Omni V is such a fine rig to begin with that it just doesn'​t need many mods to improve it!  Over the years my Omni V has had a number of  mods done to it but they were all done either by T*T when it was in for repair or it was information I got from T*T that I did myself. ​ I haven'​t done any mods to it that effected performance which weren'​t from T*T except for the N4PY V.9 chip. 
- 
-I've heard others say the same thing about Inrad filters, for the most part the stock T*T filters are plenty good in the Omni V.  Other brands of HF rigs may very well benefit for Inrad and there are some hams who live in an area that has a lot of RFI problems and the Inrad filters reduce their problems by having a steeper skirt shape to the filter. ​ My only complaint to the T*T filters and the Omni V is that the Omni V is set up for a 600 Hz CW offset for some strange reason but the CW filters are all made with a their standard 750Hz center for the filters band pass.  So the PBT needs to be adjusted every time it's changed to CW from SSB.  Inrad filters can be bought with the 600Hz center so there'​s no need to adjust the PBT.  This in fact may be the reason a ham will think the Inrad is a better filter, because the filter is centered for 600 Hz and they seem to get a better receiver with them!  This CW offset thing use to really bug me but i got use to it, I was thinking about changing the rigs CW offset to be 750 but just never got round to it.  Actually if I just found the true center of the filters I could just adjust the CW BFO to match that.  I think the CW offset is only the shift of the BFO oscillator and since it has a trimmer cap just for that I think it would work to just change it.  ​ 
  
 My experience with the Omni V has been to keep the rig in it's best possible condition for the best performance. ​ Cleaning all the plug in connections on all the boards will reduce internal noise and improve performance and make sure every running oscillator is in perfect alignment. ​ Get all the BFO oscillators aligned per the manual and getting the PBT oscillator set to 15.3MHz when centered so all the crystal filters are centered. ​ For the best receive and sig to noise ratio the slugs for L18, L19 and L20on the PBT board must be peaked and then fine tune L19 for the best sig to noise ratio. ​ All the slugs and trimmers on the 9MHz filter board should be peaked and centered first. C11 and C13 trim caps can be fine tuned for sig to noise as well but most are just peaked and it's good enough, if the receiver is too hot for weak signal work C11 and C13 can help but only a couple db of drop should be used.  ​ My experience with the Omni V has been to keep the rig in it's best possible condition for the best performance. ​ Cleaning all the plug in connections on all the boards will reduce internal noise and improve performance and make sure every running oscillator is in perfect alignment. ​ Get all the BFO oscillators aligned per the manual and getting the PBT oscillator set to 15.3MHz when centered so all the crystal filters are centered. ​ For the best receive and sig to noise ratio the slugs for L18, L19 and L20on the PBT board must be peaked and then fine tune L19 for the best sig to noise ratio. ​ All the slugs and trimmers on the 9MHz filter board should be peaked and centered first. C11 and C13 trim caps can be fine tuned for sig to noise as well but most are just peaked and it's good enough, if the receiver is too hot for weak signal work C11 and C13 can help but only a couple db of drop should be used.  ​

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