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peter oesterle
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Also,?? mobiles? are designed? for freq agility,? therefore a?? wider bandwidth.
The older? GE MII and? MICOR? and? MSF5000 ,? were tuned for? fixed freq operation? as a repeater.
Narrow band???? operation.
Not 138 to 174? as most mobiles? are today.
The eary ICOM? 2m mobiles? had? 4 pole helical filters in them.?? Examples? are? IC22A???? IC25.
They were? pretty selective,? keeping out? non 2m? RF.
GE MII and? MICORs?? also had? great? helical front ends.
Want better? RX , add a? helical filter!?
It's simple !
From: [email protected] <[email protected]> on behalf of peter oesterle <phoesterle@...>
Sent: Sunday, January 17, 2021 4:41 PM To: [email protected] <[email protected]> Subject: Re: [repeater-builder] Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together? ?
Do not forget? the issue? of? phase npise on? a? TX? or? the? RX? local oscillators.
GE MII and? MOT?? are usually?? a? lot cleaner.
?I? have? experienced? RX? desense where? Yaesu? radios?? transmitted? ,? vs??? MOT?? mobiles? TXing on the? same freq.] with similar power levels.
You get what you pay for!?
From: [email protected] <[email protected]> on behalf of Skyler Fennell <electricity440@...>
Sent: Sunday, January 17, 2021 4:32 PM To: [email protected] <[email protected]> Subject: Re: [repeater-builder] Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together? ?
I see no problem with using two mobiles and I do it all the time and the performance is identical to the fancy repeaters.?
Sensitivity: I don¡¯t see much difference in RX sensitivity between most mobiles and purpose built but if need be I can add a pre-amp.?
Selectivity: This is where many mobiles are lacking. BpBr Duplexers seem to give me enough selectivity for an average mobile but if it¡¯s really bad, I will add another pre selector.?
Keep in mind the average Motorola mobile is much more selective than the average Yaesu repeater.?
Duty Cycle: another big issue, you will blow up your mobile if you talk at full power on full duty. I have never had an issue full duty half power with a nice fan on Motorola mobiles. In addition I have often used repeater grade PA¡¯s from old
crystal controlled repeaters like the GE mastr because crystals are more expensive than mobiles.?
Standardization: this is my weak point. I have different configuration of mobiles all over the state of Colorado and if one fails it¡¯s going to have a completely different construction than another. If every repeater was a standard it will save
me time in the future. Hopefully I have all my documentation.?
Intermod: NEVER interface a mobile directly to an antenna at a high RF site, but I think the same would go with repeaters so I don¡¯t think there is any reason a mobile would be worse, a PA is a PA and it¡¯s gonna mix if there¡¯s enough RF coming
back. But some PA¡¯s have built in circulators which I guess would never happen on a mobile.?
I have never had a site owner care about mobiles at a site vs ¡°professional¡± repeaters and I have been able to make pretty nice looking mobile installs and I have seen pretty ugly looking ¡°real¡± repeater installs.?
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