GenComm GC7105B base station analyzer - Page 1
Forum section: electronics / testgear

author: Sinager
author_rank: Newbie
timestamp: March 06, 2018, 11:04:55 am
content: Hi,I just got one at a reasonable price for my VHF & UP radio enthusiast thinkering.While planned for the cellphone industry, it's indeed a nice instrument packed with general purpose features and I'm very satisfied of the purchase.I understand GenComm became JDSU and eventually Viavi and through these handovers it's hard to find resources on older models.In particular I'm after:- firmware CD or download, in case one day reflashing is needed- (reasonably priced) keys to unlock 2 ports VNA and bias-T functions- any other useful information beyond what is available on Viavi website and user manual, which I found on the web.The plan is now to run a port scan on it and see if it runs some standard OS.Thanks for your timeStefano IZ0MJERome, Italy

author: Sinager
author_rank: Newbie
timestamp: March 08, 2018, 11:55:53 am
content: Sharing some updatesAppears to run a 2.6 kernel Linux.There's open TELNET and FTP ports but no luck in brute forcing them viancrack.Next step will be to crack it open and make a disk image for backup and playing.Connecting via usbJDViewseems to work (http://sg.celladvisor.updatemyunit.net/) no luck with the other software.

author: Sinager
author_rank: Newbie
timestamp: March 09, 2018, 09:39:52 am
content: Got it open and turns out the o.s. is stored on a 2Gb SD-card: better making a backup in case it gets corrupted.Sometimes software is protected by associating it to a specific card serial number, but there may be ways around.Getting a clone is trivial under Linux.Pulling out the SD-card requires removing meany screws and the SMA bolts, but you don't need to pull the board all the way out: just slide it enough to give the SD enough clearance to exit.Now let's just hope it still works when I close it back...

author: Wolfsky
author_rank: Newbie
timestamp: March 31, 2018, 05:00:49 am
content: Wow! thanks for your information! i have this too,and i also have a firmware version :JD7105B FW 4.085. looks like this machine also surpported USB-TMC protocol.Do you have some idea hacking this machine to 7.2GHz? or unlock options ?here is the firmware :https://mega.nz/#!vrxGVDCR!7_S8z4Qaq4jgfKd-YK5rGs8kCxcLUnIdZA_SNCAYMsMhappy hacking!

author: Sinager
author_rank: Newbie
timestamp: April 01, 2018, 09:32:14 pm
content: Hello Wolfsky,thank you for the reply.Unfortunately not much progress so far, as the SD card doesn't contain a full OS image but just a few files I'm trying to understand.I've seen the JD fw images on a couple of sites and I'm not clear yet whether the JD branded one would work without issues on the GenComm branded hardware. They look identical in pictures but specs are indeed different, with the crucial 7GHz coverage you talk about. I'll check the fw # on my unit and compare.Will post here any update.Cheers

author: Sinager
author_rank: Newbie
timestamp: April 01, 2018, 09:58:19 pm
content: my machine shows:model GC7105bfirmware 4.061Is yours GenComm or JDSU branded?

author: wavebits
author_rank: Contributor
timestamp: May 03, 2018, 05:23:38 pm
content: Were you ever able to get a login to a telnet session? I have a JD746A RFanalyzer with the same Gencomm lineage and relly need to get a command propmt in order to do some diagnostics on the USB "A" host port. My unit has both "A" and "B" (client) ports. The client is working and I can connect with the JDViewer software, but the A host port does not recognize flash drives or a JDSU USB power sensor.BTW, did you happen to notice how the USB was being implemented internally; ie with an small USB interface chip or directly from a large chipset? I'm trying to get an idea of how difficult the hardware would be to repair if that turns out to be the issue. I did some probing and 5V is present on the port and there is about 5K ohms to ground on the two data pins so it's not a broken connector pin, unfortunately.Thanks.

author: Vit G
author_rank: Regular Contributor
timestamp: December 31, 2019, 07:00:20 pm
content: Is it possible to correct the CW generator in this device? It is strange that the creators of this device did not foresee its synchronization with the spectrum analyzer. In my JD746A it has a difference of 800 Hz at a 300 MHz freq.

author: on7yi
author_rank: Contributor
timestamp: January 07, 2020, 07:00:25 pm
content: Quote from: Sinager on March 06, 2018, 11:04:55 amI own an older GC7105A all I had to do to unlock the SMITH chart is to press on the "Amplitude" button after pressing selecting "Antenna" in the "Mode" menu. Then a new menu item appears offering the choice between VSWR, RL and Smith Chart. No need for any hack or firmware upgrade.I am running version of the firmware 3.133.505 on my GC7105A, If you have more recent version of the firmware that you are willing to share with me, please send me a PM.I am also looking for a version of JD Viewer < 5.3 as currenrt recent versions available from VIAVI/JDSU do not work well with my old GC7105A