APX4000 on 902/927 ham?

[N4KVE]

We are lucky to have quite a few 900 P25 ham repeaters here in SE Florida. For equipment we are using XTL mobiles, & XTS 2500 portables. No 902/927 FPP fix yet, but it's still being worked on. Some of the guys who have APX8000's want to be able to use the APX4000 portable on 902/927, but the rumor was the CPS can not be hex edited to work there. 2 days ago I was at a shop, & there was a 900 MHz APX4000 laying around, & ch 1 was 927.5 MHz simplex. So while the ham freq's can be entered into the radio, when transmitting, the red light on top of the radio blinks on, & off, like the VCO is unlocking. Did not try transmitting on 902 freq's. Whether the VCO can be adjusted or not, who knows. But for now, that's where the APX4000 is on 900 ham. GARY

[d119]

The modifications for APX radios to go out of band have to be performed in the firmware file, and then pushed out to the radio. It's a long, lengthy, dangerous process (or so I've heard, I've zero experience with it), and any time you update the firmware you overwrite what you've previously done.

I doubt the 4000 you saw was actually on the amateur bands, someone was playing with you. Sounds more like it was trying to affiliate to some system rather than transmitting on 927MHz. Did you hear it with another radio?

You can't just "enter the frequencies" in to the radio. I think you were played.

[N4KVE]

No, but the next time I go back I will have another radio to test with. I'll also tx on 927.5 with my 2500 to see if the APX can receive it. GARY.

[d119]

Sounds good Gary, let us know what you find. Perhaps you can do some investigative work and find out what the deal is.

Just yesterday I received the XTL 2500 900MHz mobile I bought, it works great as well, really nice to have a 35W 900MHz P25 mobile. Considering getting another.

P25 works INCREDIBLY well on 900MHz - analog is completely useless IMHO, but P25 is KILLER! (as you know)

[N4KVE]

Was it from Gozillatrade on E-bay? I just got one of his as a spare for under $300. Practically new, & only a few years old. GARY

[d119]

Apparently so... Though (s)he has changed their username to tictech8

[N4KVE]

Ok. I brought mine to a shop on Tuesday, to get flashed for P25, as it came to me as analog only. That's where I saw the 900 APX4000. When I got the radio back, it was a 5000, so I could clone it to my other radio. GARY

[d119]

Must be quite the "shop"... These radios are apparently retired Los Angeles City Department of Water and Power mobiles. Mine came blank, but still had the 0008 system ID in the first trunked system. They have a very large SmartZone system on 900MHz, probably in the process of upgrading it to P25 Phase II as so many utilities seem to be these days.

The other interesting item was that it came with firmware R20.00.00A, whatever that is... Actually I seem to recall that being a legitimate release some time back, could be wrong. Regardless, I upgraded it to R20.50.09.

[N4KVE]

Yup, full upgrade for mine too, including ADP. GARY.

[d119]

I may buy another one for a base station. I'm going to see if this is a direct replacement bracket-wise for the MCS 2000 model 1 that is in the car. I am using an old cellular phone glass mount antenna, seems to work well enough.

[N4KVE]

I use the Laird/Antenex antenna on the trunk lid. Low profile. Works great. When the radio went on the Aeroflex 3920 [part of the upgrade], it passed every test. GARY.

[Number 6]

Sorry guys, no ham 900 on an APX4000.

[d119]

No out of band anything on ANY APX as far as I'm concerned.

[N4KVE]

I'm going back to the shop this week to see if the radio receives on 927.7 from my 2500. The display did say 927.7 in FPP mode. GARY.

[vince7003]

I have 2 Motorola XTS2500 M3 FPP 900 mhz will work just fine on 927/902 Ham with P25. I have ADP too. Love them. We have 3 900 mhz Repeates in Reno, the 2 XTS2500 i got where never issued new in the box Chevron
gas Refinery radios

[N4KVE]

My friend just got one of those NIB radios He had to have his flashed for P25, as they were analog only. Even though they were made in 2009, but unused radios, his failed the Aeroflex 3920 test, & had to be realigned. Tx power output was 2.15 watts, & the reference oscillator test was way off. Now, it's right on. He's happy.

[fineshot1]

Many of those failures are to be ignored since each radio is going to present slight variations to
these canned tests that look for very rigid requirements to pass. You have to learn to read between
the lines of each individual radio test results.

Example - freq error may be slightly low in freq by .01 Mhz and that may be enough to make
it fail.

[N4KVE]

The Aeroflex used allows 10% tolerance before failure is shown. OTOH, my 2500 was putting out 3.1 watts, so the Aeroflex failed the tx setting, & turned it down to 2.5 watts. GARY

[d119]

So what was the outcome of the mystery APX4000?

[N4KVE]

I haven't been back to the shop yet. Maybe next week. but 927.7 was definitely programmed into the rx, & 902.7 was definitely programmed into the tx. This I saw with my OWN 2 eyes. But like the 2500, I could not change the 927.7 freq with the keypad to another 927 freq. The 927 freq was entered with the CPS. When trying to tx, the top light would flash like the VCO was out of lock. When I go back, I will bring my 2500, & transmit on 927.7 to see if the APX will rx my transmission. And before you say this is impossible, this radio belongs to the same guy who wrote the program to enable FPP on the XPR6550. GARY

[escomm]

Sounds like the MTR2000 detailed service manual

[k4vks]

Gary, which shop to do you use? Good to know there's one down here.

[N4KVE]

Gary, which shop to do you use? Good to know there's one down here.

The same place CONRAD goes. GARY.

[Number 6]

I haven't been back to the shop yet. Maybe next week. but 927.7 was definitely programmed into the rx, & 902.7 was definitely programmed into the tx. This I saw with my OWN 2 eyes. But like the 2500, I could not change the 927.7 freq with the keypad to another 927 freq. The 927 freq was entered with the CPS. When trying to tx, the top light would flash like the VCO was out of lock. When I go back, I will bring my 2500, & transmit on 927.7 to see if the APX will rx my transmission. And before you say this is impossible, this radio belongs to the same guy who wrote the program to enable FPP on the XPR6550. GARY

Were you able to verify that his APX4000 can transmit and receive in the 902/927 ham band? Not speculation, but actual verification?

[N4KVE]

No. I've only been back to the shop once, but the radio was not there. I swear, I did see the ham freq in the radio. I can only "speculate" its like the XPR7580e. You can program 900 ham freq's in it, but it will not transmit, while the 7580 works perfectly. The 7580e will transmit perfectly at 901.98750, but will not transmit at 902.000. Its like they specifically don't allow the newer radios to work in the ham band. I'll get by with my 2500. GARY.

[G6VBJ]

Did this ever get resolved, I have a 900Mhz APX4000 that I would dearly love to get onto the 900 Ham Band.

Thanks

Peter
KM4JXP/G6VBJ

[N4KVE]

Nothing has changed since my February post. GARY.

[n9ihx]

There is a guy on ebay thats selling an Apx4000 he claims is modded for ham use and that he will send a drive with the radio with the mod.
I know this is an old discussion but I havent seen any mention of a mod anywhere else yet>
https://www.ebay.com/itm/196555920218?m ... media=COPY

[N4KVE]

There is a guy on ebay thats selling an Apx4000 he claims is modded for ham use and that he will send a drive with the radio with the mod.
I know this is an old discussion but I havent seen any mention of a mod anywhere else yet>
https://www.ebay.com/itm/196555920218?m ... media=COPY

Sent from my iPad Someone figured out how to modify the APX to do 900 ham. [902-927 MHz] I have 2 radios from the guy. The seller of the radio is not the guy who modifies them. The drive is the DLL file that’s installed in the radio owner’s CPS so the mod stays in the radio after it’s programmed. The radio MUST be programmed with the EXACT SAME CPS that programmed it last for the DLL file to work. TX was measured in spec from 896-941 with no gaps. RX was measured in spec from 925-941. Below 925 the radio gets deaf pretty quick. Since my radios are full keypad radios, FPP works in the ham band. The guy figured it out last November, & I was one of his first Beta testers. I’m guessing the seller of this radio got it from the same guy. He will also mod someone’s radio if they send it to him. And he does APX mobile radios too. If you have the 03 head, it’s FPP anywhere the radio works. There’s a fee, but he also tunes the radio. So it’s real. GARY