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Minitor Band Change

Posted: Thu Jan 04, 2018 6:25 pm
by Elkland1
Looking to take some 151-159 minitors (iv and/or v) to the 143-151 range. Will be putting them on 147.000 and possibly 148.1xx area at a later time. Has anyone done this with success and little to no ‘tuning’ needed? Just want to make sure they are able to before committing. Thanks

Re: Minitor Band Change

Posted: Tue Jan 30, 2018 4:17 pm
by Karl NVW
Unless you are talking about Minitor 5 or 6 you are out of luck. The entire PC board is built for the specific sub-range, so it could easily be deaf as a fencepost if youtry to move them too far. You may also experience 'birdies' or 'self-quieting' frequencies which will degrade audio quality that wasn't all that great fresh out of the factory.

Re: Minitor Band Change

Posted: Tue Jan 30, 2018 5:18 pm
by rainbowpenguin
I've done exactly this successfully with a couple III and IV pagers. One needed a bit of tuning, there's a pot accessible thru a hole on the vco shield.

Re: Minitor Band Change

Posted: Tue Jan 30, 2018 5:29 pm
by W3AXL
I've done this several times successfully with Min IV's. I can't say if the V would follow a similar process as I haven't had one apart.

Your receive will be attenuated as the antenna is tuned for a very narrow bandwidth and can't be (easily) changed, but the VCO can be tuned to work over a much wider range.

An easy way to align the pager is to program it for the new frequencies (once you've changed the band range - doing that is described on other sites in detail) and feed a signal through a small wire close to the pager. Then adjust the VCO tuning cap on the mainboard until your signal comes in clear. Again, not a very empirical method of aligning the pager but if you're using it on the ham band odds are you're not looking for public-safety grade performance either.

151-159 Minitor IV's will work fine from 144-148. I've got two tuned to local repeaters that broadcast NOAA tones during severe weather.