How to improve MTR2000 receiver?

[arlojanis]

I have heard that there is a modification to greatly improve the receive sensitivity in a VHF MTR2000. I can not find the details. Does anyone know?

[escomm]

How much better do you need it? I just did a PM on a UHF model 2 days ago and going through the duplexer the receiver opened up at .15uV and would stay open to about .1uV. It's almost too good to be true

[RFguy]

You don't get something for nothing. You may be thinking about a pre-amp, but with those you give up performance in other areas and introduce other issues such as potential for intermod, increased site noise, desense etc.

[Bill_G]

I think the key is you "heard" about a way, but the guy telling you didn't give you any details. If you can get -120db direct into a VHF MTR2K, you're doing pretty good especially after you factor in site noise which may eat several / lots / tons of your sensitivity. I'm feeling really good if I find a high band site with less than 6db of noise these days.

[d119]

You might also be confusing the MTR2000 with the GR1225, I think there's a key combination in the 1225 RSS to varactor-tune the GR1225's front end, and that results in receiver sensitivity improvement...

Am I forgetting something?

[Birken Vogt]

I also find that all the MTR200s under my care have receivers that are almost too hot if that were possible. I have heard of total site noise factor improvements by padding the receiver, and I believe it.

GR1225s at noisy sites I have not had any luck with. Even with good input filtering they still pick up all sorts of garbage that when replaced with a real repeater was not even evident. I think they are good for a single repeater site with maybe a flat pack duplexer if you are trying to keep cost down. But they still have transmit duty cycle problems.

[MTS2000des]

I run an MTR2000 high power UHF R1 into a DB-4076 and still get amazing sensitivity. If you are having problems I would suspect a filtering issue or something else. It ain't the radio.

[Bigred]

Do you have a preselector? Maybe that needs attention.

[PETNRDX]

If you have the preselector, and it is tuned wrong, that could be a problem.
OR if you are using an MTR as a repeater, AND you have TRUE PASS filtering (duplexer, NOT reject only or multicoupler with pass filters.)
Then you could remove the preselector. Won't do much but maybe a couple dB.
I am not convinced the preselector is needed IF you have good external filtering. Depends on your environment.
Meaning REAL pass cavities. Not a "pass / reject" duplexer that is REALLY just a reject duplexer.
As others have said, those things have a pretty hot receiver.
Almost too hot.
With a pseudo pass/reject duplexer, there is virtually NO protection as close as several Mhz off your frequency.
TV, FM broadcast, paging several Mhz up or down rides right in and blocks or desenses your receiver.