LA2YUA - RF and related projects

On a whim I bought some pole mount GPS receivers. Being unable to find any real details on what's inside I mostly bought them blind, so I took some photos of the insides to help others out.

I bought a chinese made 3-cavity bandpass filter and decided to measure it and compare it to some home-made modified duplexer filters. Updated: VHF information below

The Spectracom Epsilon Clock EC2S and similar devices are fairly high end GPS clocks/timing receivers. I've spent a few days with one and I wrote a utility to program the device that is available for download.

A Procom VHF cavity band-pass filter was donated to the shack, and some work was done to retune it to 145 MHz.

I bought some Ascom SE-140s and figured out how to program them without buying a 386 computer and floppy disks.

I picked up a 18 year MiniDisc recorder and restored it a bit, and added some optical I/O to it.

I bricked my DCX2496 while updating the firmware, but I got it back.

I modified my IC-775DSP with backlighting and thought you might want to as well.

I looked in to modifying the IC-V200T for use with modern repeaters with 2.5 kHz deviation.

I looked in to modifying the IC-H16T for use with modern repeaters with 2.5 kHz deviation.

  In this article I desribe how you can upgrade your H16T to use the Super-150 custom firmware developed for Icom V200T LMR radios. Be warned that some hardware modding and EPROM programming is required.

I've designed a 3D printable solution for rack mounting Lucent RFTG-u receivers on cheap 2U shelves.

To support my pile of Icom IC-H16Ts I decided to upgrade my original Ni-Cd packs to newer cells.

Recently we became aware of a failure in one of our VHF repeaters, users claimed the output power was significantly worse while the sensitivity was the same.

In the interest of public service and guarding against future failures, I pulled the EPROMs from my Wavetek/Schlumberger Stabilock 4015 Service Monitor, and Fluke 6060B RF generator.

This page describes how to convert a VXR-9000 VHF C repeater to a VHF A version.

I try an epoxy technique to repair the front panel attachment points in the Icom IC-V200T.

I acquired several Icom IC-H12 radios, and some IC-H16Ts including original issue Service Manuals for them. Here are links to some scanned documentation. The H16T service manual is widely available, but I scanned the foil pages since Icom official scans are useless there. Several notes on adjustments and mods  Note:…

This page has some info on the MC349 VCXO, that has been available on eBay in large quantities at low cost.

To investigate a simple way of generating local oscillators for my UHF transmitter, the CDCR83 was put on a 4 layer board and fed with frequencies from 10-150 MHz at various multiplication settings. As usual a bag of these was found on eBay and as such there was some incentive to find a use for them.

Background: a set of 110.51 MHz filters were acquired on eBay per usual, and I ended up with around 400 of them. Part number was 110E39. No data sheet was available, though a potentially related data sheet for 90 MHz filters in the same package was available from NDK. Here…

The 8802A transmitter is a 50W continuous 450 MHz modulator, exciter and PA with good performance.

The 8801A receiver is very similar to the F955 receiver, so a lot of the technical documentation can be referenced: http://www.jancorver.org/en/ombouw/ericsson/f955/ The main manual is in Dutch, but it’s still somewhat understandable due to the excellent diagrams drawn by PA0IB.

This is an overview of my documentation for the Magnetic AB/Ericsson NMT 450 base station transceiver system.