Batboard

Hello,

I have access to 2 VHF MSF 5000's from two different sites and they both have the same error when keyed up. Everything works fine all lights come up except the PA Full light. I get the dreaded two beeps in my Diagnostic Panel and the RW2 PA bit is set.

Ok I know I need to be using a dummy load or a suitable antenna, but I don't have one available at the site I'm testing things. Does it require a dummy load or anything of the such just to have PA Full stay on and not trip the trigger?

I tried adjusting the PO Power Set and take it to a lower setting and even completely CCW on one of the MSF's but it didn't help at all.

Can anyone point me to the appropriate method to test the power supply on the MSF with the TLN2419A(my manual scan hurts my eyes to read)? If I key the transmitter then plug the RJ45 into the amps P603 connector and set the DMP to meter knob to 2, I get a reading of about 14 microamperes. Is the normal? I get nothing out of the P604 on transmit but I dont know if I should

Sweet Jesus Almighty...

Forgive me. I'm warning you now I'm going to come off like a jerk, so be ready.

YES, you MUST have the PA (station output) terminated into a 50 ohm load capable of handling the station's power (125W) continuously, or for at least the duration of the test.

Keying the station into no load will result in EXACTLY what you are seeing. The station is sensing an SWR (Standing Wave Ratio) problem, and cutting the PA off to prevent DAMAGE TO IT that WILL RESULT from transmitting into an open with no/improper load on it.

This is very basic, very rudimentary radio knowledge. With all due respect, I would hope you would have known this if you are in possession of this type of equipment. The fact you don't know this and have an MSF 5000 is a recipe for disaster...

Get a dummy load or properly tuned antenna for the band (NOT A MOBILE ANTENNA!) and then continue with your tests.

D119 IS correct on this one.......

You should have known this. NEVER work on a transmitter without a good dummy load rated for the power AND frequency of the transmitter you are working on.

Proper tools are required.

It's ok...that's what I get when I ask questions that I already know the answer to. I offered the answer to my problem in the question, it's not as if I said oh my what do I hook to this thing. If you noticed in my post I said "Ok I know I need to be using a dummy load or a suitable antenna, but I don't have one available at the site I'm testing things. Does it require a dummy load or anything of the such just to have PA Full stay on and not trip the trigger?"

I know what a dummy load is and what's it's for, but the functionality of an MSF 5000 is something that is new to me.

d119 wrote:Sweet Jesus Almighty...

Forgive me. I'm warning you now I'm going to come off like a jerk, so be ready.

YES, you MUST have the PA (station output) terminated into a 50 ohm load capable of handling the station's power (125W) continuously, or for at least the duration of the test.

Keying the station into no load will result in EXACTLY what you are seeing. The station is sensing an SWR (Standing Wave Ratio) problem, and cutting the PA off to prevent DAMAGE TO IT that WILL RESULT from transmitting into an open with no/improper load on it.

This is very basic, very rudimentary radio knowledge. With all due respect, I would hope you would have known this if you are in possession of this type of equipment. The fact you don't know this and have an MSF 5000 is a recipe for disaster...

Get a dummy load or properly tuned antenna for the band (NOT A MOBILE ANTENNA!) and then continue with your tests.

If the load (feedline and antenna) is correct and proper for the band and power you're running, then the station will transmit with the PA FULL LED illuminated, and you won't get the two beeps or the RW2 error. However, if the PA is seeing high VSWR it will fold back and not give you full power. If that happens you have no idea if the PA is bad or the load is bad. So you need a known good dummy load and wattmeter attached to verify if the station is at fault or the load is at fault.

Depending on the power rating of the PA, some metering positions may not give you any indication. For example, on a 75w UHF PA there are three amplifier modules and the metering jack will give you an indication on three positions plus probably one more for the driver. On a 40w UHF PA there are two amplifier modules so you only get an indication on two positions plus the driver.

Bob M.