From k1px at msn.com Tue Apr 1 09:21:33 2025 From: k1px at msn.com (Jim Monahan) Date: Tue, 1 Apr 2025 13:21:33 +0000 Subject: [Amps] 3CX1500A7/8877 Message-ID: <DM6PR05MB5259C9FD432EA85D9F2EAE0997AC2@DM6PR05MB5259.namprd05.prod.outlook.com> If anyone is interested in a NOS Penta Labs 3CX1500A7/8877 sealed in original packaging, please contact me off list for details and pic. Thanks, Jim, K1PX K1PX at msn.com From jim.thom at telus.net Wed Apr 9 16:14:19 2025 From: jim.thom at telus.net (jim.thom jim.thom@telus.net) Date: Wed, 9 Apr 2025 13:14:19 -0700 Subject: [Amps] 12 KW CCS on 160-15M.... USING the 3CX-6000A7...... PART 24 Message-ID: <CAB4ZMguoo0m7+ED5cw8vCEjGB_v1fAK5UhccrgiYJU3GXvm8mg@mail.gmail.com> 12 KW CCS on 160-15M.... USING the 3CX-6000A7...... PART 24 Some more progress was made. Paralleled mercury contactors and step start resistors installed. Modified step start board installed. Also, a pair of 5AGC fuse holders plus 3 x small breakers. Then the large twist lock for aux items, like the 330 cfm squirrel cage blower for the RF deck etc. A pair of (black) 250 amp CCS rated.. 'supercon' connectors also mounted (for the 240 vac connection over to the pair of paralleled plate xfmrs, that reside in a separate cabinet.... each rated at 5300 vac @ 1.5 amp CCS). The back end of those supercon connectors use a 1/2" stud. The mating plug that goes on the power cable, will handle a max of 250 mcm power cable. At the far left is the pair of red 100 amp supercon connectors..... used for the 79 amp filament xfmr. Those use 5/16" studs on their back ends. The mating 100 amp supercon connector that goes on the mating power cable, will handle a max of 1-0 power cable. It's getting there, albeit slowly, due to time constraints, etc. The previous 20 x 2500 uf lytic assy will be installed in the same cabinet as the fil xfmr, variac, etc. That's what the open space on the chassis will be used for...along with the HV rectifier assy. https://www.youtube.com/watch?v=HDo4ck3iGKA From sp4it.mail at gmail.com Fri Apr 11 03:27:39 2025 From: sp4it.mail at gmail.com (Lukasz) Date: Fri, 11 Apr 2025 09:27:39 +0200 Subject: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band. Message-ID: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> 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? These amplifiers are only 50W, but they are very nice if one wants to bump a -10dBm SDR output to usable power (got 12W from -5dBm at 12V) to use one of the high frequency SDRs like Lime (or maybe Pluto, I use Limesdr). The amplifiers use bipolar transistors in a 5 stage design. First 2 stages are in a little metal can and they are two of BCP54 transistors (45V max) with 3 unable core filter cans between them. Also same transistors are used to switch power to other RF stages. Then there is SGS Thomson 1310 transistor, 1391 and finally 1393. As far as I can tell with my nanovna probing first 4 stages are very wideband (pretty much flat between 300Mhz and 600mhz) and the filter cans are used to narrow the input down. The final transistor uses a tuned input but it's output again is very wideband (3dB bandwidth is again over 300mhz). So all i had to tune were the input cans and anf the input circuit of the final. The thing is powered by an 11 pin plug. First two pins appear to go directly to the final and one prior transistor power supply. Then we have something I called "logic Vcc" it is power for a quad op amp circuit that sets the bias, the 1391 and other transistors thar switch power on/off. This is the voltage I'm mostly trying to find. It works from as low as 5V, but it produces a lot more power at 12V. Then there are tewo enable pins that have to be over 3V for bias and power to be supplied. I haven't discovered the purpose of other pins, but I suspect they might be status outputs. I know all transistors can survive 40V. I believe the final may have run on 24V. But not sure about that logic supply that also powers 1310 transistor and earlier stages. The opamp (3303) is fine with up to 36V (+-18V). But I have no way of knowing how these bias circuits are set (there are smd pots). Can anyone suggest how to find the correct value for that voltage? 73, Lukasz From ka4inm at gmail.com Fri Apr 11 09:32:19 2025 From: ka4inm at gmail.com (Ron W4BIN) Date: Fri, 11 Apr 2025 09:32:19 -0400 Subject: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band. In-Reply-To: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> References: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> Message-ID: <e1efbbc2-e660-475a-b067-67ea1dfbe64e@gmail.com> 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.) 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 From sp4it.mail at gmail.com Fri Apr 11 11:07:09 2025 From: sp4it.mail at gmail.com (Lukasz) Date: Fri, 11 Apr 2025 17:07:09 +0200 Subject: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band. In-Reply-To: <e1efbbc2-e660-475a-b067-67ea1dfbe64e@gmail.com> References: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> <e1efbbc2-e660-475a-b067-67ea1dfbe64e@gmail.com> Message-ID: <CADuTvfr6dKvfTTErD2P1Q=g5CNixd30X9tVTcrvu0ev6-0zcJw@mail.gmail.com> Thanks for the reply Ron. On Fri, 11 Apr 2025, 15:32 Ron W4BIN, <ka4inm at 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 , ?ukasz > From g8gsq at gmx.com Fri Apr 11 11:31:39 2025 From: g8gsq at gmx.com (Steve Thompson) Date: Fri, 11 Apr 2025 16:31:39 +0100 Subject: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band. In-Reply-To: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> References: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> Message-ID: <8cb4bd49-7969-47e6-8a79-58239672fc75@gmx.com> It's almost certainly 24/28V for the main power to the driver and output. I used to work for a company which supplied transistors for other Ericsson base station equipment and everything was 28V (same with Nokia NMT450 gear). To check what the 'logic Vcc' supply input should be, leave power to the driver/output disconnected and use a bench supply to gradually increase the voltage while monitoring the bias voltage going to the input tabs of the driver and output stages. At some point the voltages should stabilise which will be the 'logic Vcc' that you need - probably around either 12V or 24V. Steve G8GSQ On 11/04/2025 08:27, 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? > > These amplifiers are only 50W, but they are very nice if one wants to bump > a -10dBm SDR output to usable power (got 12W from -5dBm at 12V) to use one > of the high frequency SDRs like Lime (or maybe Pluto, I use Limesdr). > > The amplifiers use bipolar transistors in a 5 stage design. First 2 stages > are in a little metal can and they are two of BCP54 transistors (45V max) > with 3 unable core filter cans between them. Also same transistors are used > to switch power to other RF stages. > > Then there is SGS Thomson 1310 transistor, 1391 and finally 1393. As far as > I can tell with my nanovna probing first 4 stages are very wideband (pretty > much flat between 300Mhz and 600mhz) and the filter cans are used to narrow > the input down. > > The final transistor uses a tuned input but it's output again is very > wideband (3dB bandwidth is again over 300mhz). So all i had to tune were > the input cans and anf the input circuit of the final. > > The thing is powered by an 11 pin plug. First two pins appear to go > directly to the final and one prior transistor power supply. Then we have > something I called "logic Vcc" it is power for a quad op amp circuit that > sets the bias, the 1391 and other transistors thar switch power on/off. > This is the voltage I'm mostly trying to find. It works from as low as 5V, > but it produces a lot more power at 12V. > > Then there are tewo enable pins that have to be over 3V for bias and power > to be supplied. > > I haven't discovered the purpose of other pins, but I suspect they might be > status outputs. > > I know all transistors can survive 40V. I believe the final may have run on > 24V. > > But not sure about that logic supply that also powers 1310 transistor and > earlier stages. The opamp (3303) is fine with up to 36V (+-18V). But I have > no way of knowing how these bias circuits are set (there are smd pots). > > Can anyone suggest how to find the correct value for that voltage? > > 73, Lukasz > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps From steve at nr4m.com Fri Apr 11 13:09:12 2025 From: steve at nr4m.com (Steve Bookout) Date: Fri, 11 Apr 2025 13:09:12 -0400 Subject: [Amps] 10 meter amp coil Message-ID: <f3b6d370-306d-40ca-881f-2e71283e1cdc@nr4m.com> Hello all, I'm building a 10 meter mono band amp for my m/m contest station here in VA. What is the group consensus on what diameter the conductor for the plate tank circuit?? I tried looking in the archives, but it's not the best for searching (it's monthly). I'm thinking 3/8 inch should be fine.? Half inch is starting to get 'stupid big', IMO. Will be an 8877 @ 4kv.? Class of operation: not sure of yet.? 12 volt bias is probably fine.? I ONLY run CW. And, looking for a filament transformer for the 8877.? Anyone have one that is not in use? 73 de Steve NR4M From g8gsq at gmx.com Fri Apr 11 17:19:29 2025 From: g8gsq at gmx.com (Steve Thompson) Date: Fri, 11 Apr 2025 22:19:29 +0100 Subject: [Amps] 10 meter amp coil In-Reply-To: <f3b6d370-306d-40ca-881f-2e71283e1cdc@nr4m.com> References: <f3b6d370-306d-40ca-881f-2e71283e1cdc@nr4m.com> Message-ID: <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> On 11/04/2025 18:09, Steve Bookout wrote: > And, looking for a filament transformer for the 8877.? Anyone have one > that is not in use? DC works fine, it might be easier and/or cheaper to find a 5V 10A PSU. Steve G8GSQ From steve at nr4m.com Fri Apr 11 18:17:03 2025 From: steve at nr4m.com (Steve, NR4M) Date: Fri, 11 Apr 2025 18:17:03 -0400 Subject: [Amps] 10 meter amp coil In-Reply-To: <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> References: <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> Message-ID: <41A19AA3-579D-4368-A1F1-C9EB3704DA8C@nr4m.com> Hi Steve, Ya know, I?ve thought about that in the past, but figured since I?ve never heard a bunch of positive comments from those who have done it, it had issues. My first thought was that all that ?switching garbage? would be put on the cathode of the tube. Garbage in: garbage out. Would love to hear any pros and cons to this idea. This first crossed my mind when I wanted to convert an AL-1200 to an AL-1500. Of course, I waited till MFJ folded, so couldn?t get the correct fitting transformer from there. Thanks all Steve NR4M Sent from my iPhone > On Apr 11, 2025, at 5:25?PM, Steve Thompson via Amps <amps at contesting.com> wrote: > > ? > >> On 11/04/2025 18:09, Steve Bookout wrote: >> >> And, looking for a filament transformer for the 8877. Anyone have one >> that is not in use? > > DC works fine, it might be easier and/or cheaper to find a 5V 10A PSU. > > Steve G8GSQ > > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps From john at kk9a.com Fri Apr 11 21:05:24 2025 From: john at kk9a.com (john at kk9a.com) Date: Fri, 11 Apr 2025 21:05:24 -0400 Subject: [Amps] 10 meter amp coil Message-ID: <000b01dbab46$f9314de0$eb93e9a0$@kk9a.com> The archive search goes back to 1997 (not monthly) if you use the search string at the top: http://lists.contesting.com/archives//html/amps/ John KK9A Steve Bookout NR4M wrote: ] Hello all, I'm building a 10 meter mono band amp for my m/m contest station here in VA. What is the group consensus on what diameter the conductor for the plate tank circuit? I tried looking in the archives, but it's not the best for searching (it's monthly). I'm thinking 3/8 inch should be fine. Half inch is starting to get 'stupid big', IMO. Will be an 8877 @ 4kv. Class of operation: not sure of yet. 12 volt bias is probably fine. I ONLY run CW. And, looking for a filament transformer for the 8877. Anyone have one that is not in use? 73 de Steve NR4M From k2vco.vic at gmail.com Fri Apr 11 21:35:52 2025 From: k2vco.vic at gmail.com (Victor Rosenthal) Date: Sat, 12 Apr 2025 04:35:52 +0300 Subject: [Amps] 10 meter amp coil In-Reply-To: <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> References: <f3b6d370-306d-40ca-881f-2e71283e1cdc@nr4m.com> <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> Message-ID: <CAJZhGajv-RQqMed9UD9=jPiYj8ou43iPfWatK=R0k8B8M6in3g@mail.gmail.com> But watch out for noisy switching supplies! Victor 4X6GP On Sat, Apr 12, 2025, 00:27 Steve Thompson via Amps <amps at contesting.com> wrote: > > > On 11/04/2025 18:09, Steve Bookout wrote: > > > And, looking for a filament transformer for the 8877. Anyone have one > > that is not in use? > > DC works fine, it might be easier and/or cheaper to find a 5V 10A PSU. > > Steve G8GSQ > > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps > From k2vco.vic at gmail.com Fri Apr 11 21:42:11 2025 From: k2vco.vic at gmail.com (Victor Rosenthal) Date: Sat, 12 Apr 2025 04:42:11 +0300 Subject: [Amps] 10 meter amp coil In-Reply-To: <41A19AA3-579D-4368-A1F1-C9EB3704DA8C@nr4m.com> References: <7cf6a5b0-3c1f-45da-b872-7bbd244b438a@gmx.com> <41A19AA3-579D-4368-A1F1-C9EB3704DA8C@nr4m.com> Message-ID: <CAJZhGaj6dbCJeHup7AxvyXiaMOWB_qT9F0i4PpSEjoYSShk09A@mail.gmail.com> The problem I had was noise on receive when the amp was in standby. Victor 4X6GP On Sat, Apr 12, 2025, 01:22 Steve, NR4M <steve at nr4m.com> wrote: > Hi Steve, > Ya know, I?ve thought about that in the past, but figured since I?ve never > heard a bunch of positive comments from those who have done it, it had > issues. > My first thought was that all that ?switching garbage? would be put on the > cathode of the tube. Garbage in: garbage out. > Would love to hear any pros and cons to this idea. > This first crossed my mind when I wanted to convert an AL-1200 to an > AL-1500. Of course, I waited till MFJ folded, so couldn?t get the correct > fitting transformer from there. > > Thanks all > Steve NR4M > > > Sent from my iPhone > > > On Apr 11, 2025, at 5:25?PM, Steve Thompson via Amps < > amps at contesting.com> wrote: > > > > ? > > > >> On 11/04/2025 18:09, Steve Bookout wrote: > >> > >> And, looking for a filament transformer for the 8877. Anyone have one > >> that is not in use? > > > > DC works fine, it might be easier and/or cheaper to find a 5V 10A PSU. > > > > Steve G8GSQ > > > > _______________________________________________ > > Amps mailing list > > Amps at contesting.com > > http://lists.contesting.com/mailman/listinfo/amps > > > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps > From steve at nr4m.com Fri Apr 11 22:01:28 2025 From: steve at nr4m.com (Steve, NR4M) Date: Fri, 11 Apr 2025 22:01:28 -0400 Subject: [Amps] 10 meter amp coil In-Reply-To: <000b01dbab46$f9314de0$eb93e9a0$@kk9a.com> References: <000b01dbab46$f9314de0$eb93e9a0$@kk9a.com> Message-ID: <0F0B4F9E-0868-41F9-9147-6D30ED3FFE99@nr4m.com> Hi John, Just looked at the link. I can deal with this! Not sure where I was before. Thank you Steve NR4M Sent from my iPhone > On Apr 11, 2025, at 9:05?PM, john at kk9a.com wrote: > > ?The archive search goes back to 1997 (not monthly) if you use the search > string at the top: > http://lists.contesting.com/archives//html/amps/ > > John KK9A > > > Steve Bookout NR4M wrote: > ] > Hello all, > > I'm building a 10 meter mono band amp for my m/m contest station here in > VA. > > What is the group consensus on what diameter the conductor for the plate > tank circuit? I tried looking in the archives, but it's not the best > for searching (it's monthly). > > I'm thinking 3/8 inch should be fine. Half inch is starting to get > 'stupid big', IMO. > > Will be an 8877 @ 4kv. Class of operation: not sure of yet. 12 volt > bias is probably fine. I ONLY run CW. > > And, looking for a filament transformer for the 8877. Anyone have one > that is not in use? > > 73 de Steve NR4M > > > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps From sp4it.mail at gmail.com Sat Apr 12 03:11:37 2025 From: sp4it.mail at gmail.com (Lukasz) Date: Sat, 12 Apr 2025 09:11:37 +0200 Subject: [Amps] Reusing old 450mhz CDMA base station amplifiers for ham radio on 70cm band. In-Reply-To: <8cb4bd49-7969-47e6-8a79-58239672fc75@gmx.com> References: <CADuTvfqaiG4uL5tY2be=ZbrwymMTocKPcfD+5xrTWqjmVJBNig@mail.gmail.com> <8cb4bd49-7969-47e6-8a79-58239672fc75@gmx.com> Message-ID: <CADuTvfoTQn=Guzpy2Qm+=x=Jx1nwLo_W8W0Bd4e4pmxj4o=L_g@mail.gmail.com> Great. Thank you for the reply. Good tip about the logic Vcc. 73, Lukasz I 8 On Fri, 11 Apr 2025, 17:35 Steve Thompson via Amps, <amps at contesting.com> wrote: > It's almost certainly 24/28V for the main power to the driver and > output. I used to work for a company which supplied transistors for > other Ericsson base station equipment and everything was 28V (same with > Nokia NMT450 gear). > > To check what the 'logic Vcc' supply input should be, leave power to the > driver/output disconnected and use a bench supply to gradually increase > the voltage while monitoring the bias voltage going to the input tabs of > the driver and output stages. At some point the voltages should > stabilise which will be the 'logic Vcc' that you need - probably around > either 12V or 24V. > > Steve G8GSQ > > On 11/04/2025 08:27, 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? > > > > These amplifiers are only 50W, but they are very nice if one wants to > bump > > a -10dBm SDR output to usable power (got 12W from -5dBm at 12V) to use > one > > of the high frequency SDRs like Lime (or maybe Pluto, I use Limesdr). > > > > The amplifiers use bipolar transistors in a 5 stage design. First 2 > stages > > are in a little metal can and they are two of BCP54 transistors (45V max) > > with 3 unable core filter cans between them. Also same transistors are > used > > to switch power to other RF stages. > > > > Then there is SGS Thomson 1310 transistor, 1391 and finally 1393. As far > as > > I can tell with my nanovna probing first 4 stages are very wideband > (pretty > > much flat between 300Mhz and 600mhz) and the filter cans are used to > narrow > > the input down. > > > > The final transistor uses a tuned input but it's output again is very > > wideband (3dB bandwidth is again over 300mhz). So all i had to tune were > > the input cans and anf the input circuit of the final. > > > > The thing is powered by an 11 pin plug. First two pins appear to go > > directly to the final and one prior transistor power supply. Then we have > > something I called "logic Vcc" it is power for a quad op amp circuit that > > sets the bias, the 1391 and other transistors thar switch power on/off. > > This is the voltage I'm mostly trying to find. It works from as low as > 5V, > > but it produces a lot more power at 12V. > > > > Then there are tewo enable pins that have to be over 3V for bias and > power > > to be supplied. > > > > I haven't discovered the purpose of other pins, but I suspect they might > be > > status outputs. > > > > I know all transistors can survive 40V. I believe the final may have run > on > > 24V. > > > > But not sure about that logic supply that also powers 1310 transistor > and > > earlier stages. The opamp (3303) is fine with up to 36V (+-18V). But I > have > > no way of knowing how these bias circuits are set (there are smd pots). > > > > Can anyone suggest how to find the correct value for that voltage? > > > > 73, Lukasz > > _______________________________________________ > > Amps mailing list > > Amps at contesting.com > > http://lists.contesting.com/mailman/listinfo/amps > > _______________________________________________ > Amps mailing list > Amps at contesting.com > http://lists.contesting.com/mailman/listinfo/amps >