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Search found 11 matches

by VA3HF
Mon Feb 29, 2016 3:36 pm
Forum: Base Stations, Repeaters, General Infrastructure
Topic: RFS Model 0185417U02 parts
Replies: 10
Views: 1071

Re: RFS Model 0185417U02 parts

Did you find one yet? They are common to those who play with duplexers.
by VA3HF
Mon Jun 29, 2015 9:11 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Intermod Product On My Rx Freq
Replies: 20
Views: 1370

Re: Intermod Product On My Rx Freq

Also make sure you don't have some LMR type foil transmission line in the system. It has poor PIM in the presence of strong carriers. Use only silver plated RG214/U or solid copper hardline. Copper over aluminum centre conductor like that of LDF4-50A is acceptable but don't nick the copper plating. ...
by VA3HF
Sat Jun 27, 2015 5:42 pm
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Intermod Product On My Rx Freq
Replies: 20
Views: 1370

Re: Intermod Product On My Rx Freq

Intermod problems depend on the actual power levels at the non-linear junction. If the source of the IM is in your RX antenna system, the trick is to reduce the level of one or more of the offending transmitters getting received at the antenna or improve your PIM of your system. Vertical separation ...
by VA3HF
Fri Jun 26, 2015 4:42 pm
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Intermod Product On My Rx Freq
Replies: 20
Views: 1370

Re: Intermod Product On My Rx Freq

That is actually the point of using a scanner and/or portable. If you have three different receivers all agreeing, it's real, and will be fairly easy to locate. If they don't agree, but each has their own problems, it's still there, it's more complicated, and more difficult to locate, but not impos...
by VA3HF
Thu Jun 25, 2015 10:58 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Intermod Product On My Rx Freq
Replies: 20
Views: 1370

Re: Intermod Product On My Rx Freq

The 3 transmitters are local so a scanner or even a portable outside will receive the signals and produce the IM product in its fromt end. You will need a low IM antenna connected to a bunch of bandpass cavities tuned to the RX frequency an the whole setup needs to be a LOW PIM system too to be able...
by VA3HF
Mon Jun 22, 2015 10:02 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Intermod Product On My Rx Freq
Replies: 20
Views: 1370

Re: Intermod Product On My Rx Freq

This sounds like you have a 3 transmitter 3rd order intermod product where the 2 Broadcast transmitters are also 3.4MHz apart. You say you are on a Master RX antenna - is this just an antenna with a preamp and power dividers with maybe a wide band preselector? Likely cause is the amplifier or any ni...
by VA3HF
Sun Jun 14, 2015 1:35 pm
Forum: Base Stations, Repeaters, General Infrastructure
Topic: MTR2000 repeaters
Replies: 6
Views: 1088

Re: MTR2000 repeaters

Take it out of repeat and key the transmitter externally is one way.
by VA3HF
Sun Jun 14, 2015 8:05 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: MTR2000 simplex TX interfering with RX (TX idle frequency problem?)
Replies: 4
Views: 860

Re: MTR2000 simplex TX interfering with RX (TX idle frequency problem?)

The TX idle frequency was originally set to 50KHz below the simplex frequency when we noticed it was actually on the TX frequency which was also the RX frequency. We then changed the idle frequency to -300KHz below the simplex frequency and it still was on the RX frequency causing the receiver to un...
by VA3HF
Wed Jun 10, 2015 11:50 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: Horrible Wireless Internet Site Noise Everywhere
Replies: 13
Views: 1334

Re: Horrible Wireless Internet Site Noise Everywhere

Shielded CAT 5 cable with grounded RJ45 shield connectors into metal boxes if equipment is plastic. I've seen very noisy consumer grade Ethernet switches and routers used at some places that radiate noise everywhere. Unlikely the actual RF signal from the antennas are the cause - too far away in fre...
by VA3HF
Wed Jun 10, 2015 10:51 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: IP Radio Gateway suggestions requested
Replies: 11
Views: 1934

Re: IP Radio Gateway suggestions requested

One box to consider for multiple radios is the Vocality Basics Radio Relay line. I used them to link three MTR2000 radios over 2 dialup analog modems using MLPPP because there were no digital services available and they worked! Mind you, you need to take some training to set them up properly and the...
by VA3HF
Wed Jun 10, 2015 6:12 am
Forum: Base Stations, Repeaters, General Infrastructure
Topic: MTR2000 simplex TX interfering with RX (TX idle frequency problem?)
Replies: 4
Views: 860

MTR2000 simplex TX interfering with RX (TX idle frequency problem?)

Hello, I have a VHF MTR2000 problem I'm trying to see if it has been a problem elsewhere - recently found 2 stations causing this problem. The TX side of the MTR2000 is generating a carrier (when not transmitting) on the RX frequency when set to simplex even thought the TX idle is 50kHz off the TX f...

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