VHF Minitor I reception question

[dwh367]

I recently purchased a VHF Minitor I with the amplified charger/external antenna. The repeater I am toned out on is 25 watts (60 watts ERP) with a ground elevation of the tower at 152 feet. The tower itself it 55 feet and the HAAT is 71 feet. The height to the tip of our antenna is 46 feet. I am located 18 miles away from the repeater with some hills and valleys between us.

If we get toned out, my Minitor seems to very sensitive to the tones as it will alert but the signal seems to be not strong enough to open up the squelch for the audio to come through.

If I have it in the amplified charger, with the external antenna connected, I can hear the audio full quieting. I am just wondering if this would be normal given our tower limitations (lack of height), the power output of the repeater (low powered) and the terrain involved (hills and valleys). If not, I'll have another dealer go through and recheck it.

We are in the process of relocating the repeater. We have purchased 180 feet of tower so far. We still need to get the hardline for it yet and a higher place in the county to erect it.

Thanks!
David H.

[HLA]

the problem is most likely the antennae in your pager. do you have a portable radio on the same frequency? if so set it next to the pager and see if it comes thru there. if you get it in the portable then the problem is your pager. if you don't get it thru either then it's a signal problem.

[ard099]

There probably isn't anything wrong with your pager. Elevation is key and it appears that you don't have much right now which is probably the reason your pager doesn't work sometimes. Also your pager isn't going to be as sensitive as a portable, so if you can hear it on a portable and not on your pager don't sweat it, there probably isn't anything wrong, except a lack of elevation. Also don't forget if you put up a tower and increase your elevation you may need to change your liscense.

[kf4sqb]

the problem is most likely the antennae in your pager. do you have a portable radio on the same frequency? if so set it next to the pager and see if it comes thru there. if you get it in the portable then the problem is your pager. if you don't get it thru either then it's a signal problem.

Jeff, in a way, you're right. It is partly the antenna in the pager. Believe it or not, it acutally has a negative gain. However, I think that ard099 has it right. The problem is more on the transmitter end. With the negative gain antenna in the pager, the handheld sitting beside it will pretty much always receive better than the pager, and the layout David is detailing will most likely make that problem worse.

[stvnd53]

Oh the Minitor 1,Oldies but goodies! When ever I use to get them I would replace the Batt.box,spk.jack on top,volume control,jack on bottom(ant) and alert/monitor switch on top,and it was good to go!
That was then,and this is now.I understand that they don't sell those parts any more.
P.S:don't forget the batts

[WB2IID]

I wonder if the pager antenna is tuned to the exact receive frequency. I have an old housing with holes drilled in it to access the trimmer and tuning slugs. That way you can tune it with whatever effects the case adds to the antenna.

You don't want to tune the antenna trimmer with an antenna connected, rather only with the internal one, because there is a difference in optimum tuning spots between external and internal antennas.

As far as negative antenna gain, at VHF it's probably not more than 3 or 4 dB worse than a quarter wave dipole. I would check the antenna tuning and possibly even the antenna, sometimes they have been known to crack and lose sensitivity.

And the Minitor always did go off even when you couldn't make out the tones through the noise, because of the excellent tone decoder.