XTS5000 III XTVA portable base linear amp problem

[ka0nhh]

I have an XTS5000 type III and an XTVA portable base with 50 watt linear. In theory I should just put the radio in and it will boost the 5 watt radio signal. But it doesn’t work. It’s a brand-new, old stock XTVA that was completely unused (kept in reserve) so there’s nothing wrong with it. But for some reason the XTS will not trigger the amplifier. When transmitting through the XTVA with the “PA” switch off, I read 5 watts into a dummy load. If I turn the PA on, I get 2.5 watts into the load. I do not get any amplification. I have removed the PA and hooked it up directly to the radio, powered it, and the same thing happens. 5 watts unplugged, 2.5 watts plugged in.

I tried the same test with a NOS Motorola N1274A linear I also have, same story except when plugged in I get close to zero watts out into the dummy load.

I have no idea why the RF from the HT isn’t triggering either of the linear amplifiers.

I have CPS and programmed the radio for HAM in a conventional personality. It seems to work fine, I talked to someone atop Pikes Peak on the rubber duck antenna, so it’s putting out signal.

Does anyone have any idea why the linears won’t trigger? Both are for VHF and I’m testing on 146.520, which is within their coverage.

Is there some CPS trick I’m missing?

I’d like not to have to spend a bunch sending the radio and XTVA to the Motorola shop if I can help it.

 

[ResQguy]

1) You didn't mention that you have a properly installed RF adapter on the radio.
2) What is the firmware of the radio?

 

[RFI-EMI-GUY]

What is the frequency range stamped on the N1274A amplifier?

 

[MTS2000des]

1) You didn't mention that you have a properly installed RF adapter on the radio.

Yup, sounds like no RF adapter.
Is this present in the antenna jack and your antenna screwed into it?

If not, grab one. You'll also need the special wrench to properly tighten it down. There is a cheaper version but I don't have the part number in front of me.

 

[ka0nhh]

Yes, I have two adapters (the switch), and have physically tested both of them for proper operation in the XTVA base as well as an XTVA vehicle mount. Both operate to switch RF from the ducky to the external antenna. The darned wrench was supposed to be in the XTVA kit but it got filched before I bought it. I’m having the local radio shop quote me on the price. Used to be able to find them on eBay. Should have bought one then.

The frequency on the 1274 (as I recall, I don’t have it in front of me) is 136 to 150, and the XTVA is 136 to 174.

I’ll have to get back to you on the firmware, the radio and Software are in my communications command post trailer which is 15 miles away.

I’ll check on it tomorrow. This was not a surplus radio, it was purchased new from a dealer about six years ago. It’s always worked fine, but I never tried to use the PAs before.

I can’t troubleshoot the PAs because I don’t have another VHF radio to test them with, I sold almost all my gear some years ago when I was unemployed and needed money. The only one I still had, a Kenwood commercial mobile I used when I was a firefighter turned out to have gotten fried somehow and wouldn’t boot up.

But I can see no reason why the PAs shouldn’t work, so I’m down to something in the radio programming.

Thanks for the replies.

 

[RFI-EMI-GUY]

Being that the XTS5000 and the N1274A were designed decades apart, is it possible that due to trunking capabilities of the XTS5000 and the conventional lineage of the N1274A might require a modification and perhaps a TX indicate signal from the XTVA to properly switch the relays in the N1274A?

 

[kb4mdz]

And for Pete's sake, you don't have to put 'ham' in ALL CAPS!


Sorry, rant over.

 

[ka0nhh]

The 1274 PA was just a test unit to troubleshoot the XTVA PA. I thought if the 1274 worked I could isolate the problem to the XTVA PA as being faulty. When I hooked it up and plugged it in I could hear a relay click inside the 1274, but no amplification, and a drop to near zero power through the 1274 when plugged in, and 5 watts when unplugged.

I then removed the XTVA PA from the case and connected it directly to the radio and antenna to see if the XTVA portable base circuit board might be faulty. Still dropped output from the PA to half what it was through the PA when the PA was connected but not powered.

Thus I conclude the problem is likely in the radio.

I’ll check the firmware and codeplug and get back to you.

 

[ka0nhh]

Okay, finally got back to the radio. Model Number H18KEH9PW7AN, Flashcode 5A9008-101F87-7, Firmware R15.00.08
Codeplug 0021, Tuning R01.09.07, Bootloader R01.04.10, DSP R15.00.05, UCM R05.05.00, PSDT R04.00.00, Nautilus N/A

Feature set:
H38
Q806
Q173
Q361
H14
Q498
Q52
H46
H43
G857
Q947
Q182
Q387
Q53
Q667
Q446
Q445