Re: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band.

[Lukasz <sp4it.mail@gmail.com>]

Thanks for the reply Ron.

On Fri, 11 Apr 2025, 15:32 Ron W4BIN, <ka4inm@gmail.com> wrote:

> On 4/11/25 03:27, Lukasz wrote:
>
> > I've recently got my hands on some ancient mobile phone base station
> > amplifiers which I've managed to retune to 435Mhz +- 5MHz but I need some
> > help with choosing the voltage to run them at.
>
> > Does anyone in this group have any knowledge of such old cellular
> hardware?
> > Specifically power and logic voltages used?
>
>    I am sorry I can't help you directly, but "435Mhz +- 5MHz" has never
> been a
> cell band*, in fact it is well within the American 70. CM band.
> (420-450 MHz.)
>

I've retuned it for our 70cm... The original frequency was claimed by the
seller to be 450MHz. But it was actually 460MHz.

430 to 440MHz is the European 70cm band. That's why I've retuned it for
that frequency :-)


>    It might have been designed as a pager transmitter and some HAM has
> adjusted for amateur use.  The manufacturer and model number would be
> very helpful in helping you further.
>
>   * as far as I know
>
>    Ron W4BIN Youvan   W.C. Florida
>

It was a part of Ericsson branded CDMA base station. We used to have them
here in my part of Europe even before GSM. Unfortunately there are no
device types or numbers. There are some pcb assy numbers, but the Internet
came blank when I searched them.

Here is how they look:
[url=
https://ibb.co/fdpwXqfH][img]https://i.ibb.co/whWmdBV4/IMG-20250328-WA0001.jpg[/img][/url
]

The picture is not the best, but that's what I have on my phone now when
away. The numbers are not readable, but I did Google them and I found
nothing .


I know newer hardware used 48v as system voltage. But I have no idea about
these ancient systems.

Still the one board I managed to power up worked very nicely indeed.

73 ,
Łukasz

>
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