Batboard

I want to make this creation for use in my truck since i think it would be a lot cheaper than buying an XTVA. Lets say I were to take public safety mic and chop off the cord leaving a few inches. Then solder a female BNC onto the end of the PSM coax and put a 1/8" audio jack on the speaker leads. Maybe put it all in a little black project box. Then I could plug an external antenna and speaker into it and have the same performance as a mobile radio. I don't need the mic to work really, I have enough of those already, I just need external antenna and a speaker.

Parts:
- Public Safety Mic
- NTN8327A RF Adapter
- Female BNC
- Female 1/8" audio jack
- Small Project box

Does this sound workable?

I've not any direct expereince with the XTS 3K PSM or XTVA but I understand that you'll need the RF ANTENNA SWITCH P/N NTN8327 as according to the price book:

"The RF Switch has been removed from the XTS radio to provide cost savings on the model. Therefore, the external RF switch must be attached to the radio in order for the PSM to operate. A wrench tool must be used to place the RF switch. These kits must be ordered separately."

On the other hand if you don't plan to swap out the radio very often you could just use a SMA barrel or BNC (f) to SMA (M) adapter in the antenna jack.

Ah, but your performance will not be the same as a mobile.

First, the run of coax will be lossy. That's usually not a problem, except for when the radio only puts out 4 or 5 watts, as portables do. Hopefully your run of coax will be no more than a couple feet, which is not feasible I understand. Second, the radio will only be transmitting 4 or 5 watts, not the 25-110 that mobiles have the luxury of.

Other than that I don't see many other roadblocks

Of course it's not as good as a real mobile, but an external antenna should always be better than an HT inside a car.

nmfire10 wrote:I don't need the mic to work really, I have enough of those already, I just need external antenna and a speaker.

Ok, so will you be transmitting at all while this is hooked up? I'm not sure I'm following the part of you not needing the mic to work.

Grog wrote:Of course it's not as good as a real mobile, but an external antenna should always be better than an HT inside a car.

I don't know about that, especially with UHF and 800MHz radio.

RG58 is nowhere near lossless. You are probably going to be seeing about 3 watts of output at the antenna from a 4 watt UHF radio, and 3.8 to 4 watts of output on a VHF radio. This assumes a run of 12 to 18 feet and SWR of 1. I count the RF running through at least 3 adapters (RF switch, BNC, and antenna) as well.

Hence the should


There are always chances that it will go either way, but maybe he will be using this in an area with signals so strong that it won't matter?


edit...... Gut you also have to consider the gain from an external antenna outweighing the power loss getting to the antenna if a higher gain antenna is used/needed.