Texas Star DX399

[Flex1493]

Hi everyone. I have a Texas Star DX 399 in my mobile.

I have a 1.3 to a 1.7 swr when the amp is on.
But for some reason when I turn on the pre amp the radios internal swr meter spikes to a 4.5 to a 5 and up but on the external Diamond meter stays at 1.5.

Can anyone help or give me some advice

Thanks everyone for any help or advice

 

[nomadradio]

The meter in the radio is not connected to the antenna when the amplifier is keyed while transmitting. The radio's SWR meter reads the impedance between the radio and the amplifier.

Not the antenna.

When the amplifier is turned off, it should act like a barrel connector, and the radio's SWR meter will now read the antenna's SWR. Should be about the same as the antenna-side meter reads between the amplifier and antenna.

The preamp should "unkey" when you use only the preamp and leave the transmit side on standby. The high reading you have suggests that the preamp is not taking itself out of line like it should. Do you hear a "click" from inside the amplifier when you use the preamp alone, without the transmit side active and key the radio?

You should. If not, the preamp circuit is soaking up all your radio's barefoot transmit power.

Not healthy for it.

73

 

[Flex1493]

The meter in the radio is not connected to the antenna when the amplifier is keyed while transmitting. The radio's SWR meter reads the impedance between the radio and the amplifier.

Not the antenna.

When the amplifier is turned off, it should act like a barrel connector, and the radio's SWR meter will now read the antenna's SWR. Should be about the same as the antenna-side meter reads between the amplifier and antenna.

The preamp should "unkey" when you use only the preamp and leave the transmit side on standby. The high reading you have suggests that the preamp is not taking itself out of line like it should. Do you hear a "click" from inside the amplifier when you use the preamp alone, without the transmit side active and key the radio?

You should. If not, the preamp circuit is soaking up all your radio's barefoot transmit power.

Not healthy for it.

73

Hey buddy thanks for the advice

No I don’t hear a click on the pre amp.
What do you recommend o do. I don’t really care for the pre amp only really brings on more nose them anything els. But I just bought it a few weeks ago. So I’m a litttle upset that it’s not working like it should.

Now the power amp works creat and I get out really good and I sounds fine from the reports I get from my friends.

 

[Flex1493]

Thanks for advice should I try to get fix or just use it without the pre amp

 

[9C1Driver]

I think this is what you will need to replace in your amp.

http://stores.goldeneagleradios.com/transistor/

 

[W2EKG]

Bad switching transistor( already mentioned above) IMO. I find those Texas Star pre-amp's useless.

 

[Tallman]

All un-tuned pre-amp's are useless. No selection, all noise is amplified. If it does not have tuned tank circuits or a PLL receiver it is a junk circuit.
Just another way to put their hands on your money.