October 25, 2005

Power Supply-Voter updates


Today saw the long awaited upgrading of the repeater power supplies and the new voter for the six meter receivers.

The two Astron RS50 power supplies which have been doing a yeomans job for years were finally replaced by two Astron RS70M supplies. Finally we have meters to indicate the loading on the supplies-- much easier to judge loading than the 'finger-on-heatsink' test.

With these new supplies, the 2mtr remote base and the packet station are now on battery backup. The only portion of the site that is not on battery backup is the 6mtr gear and the second 449.725 receiver at the site.

With just the 'exciters' running, the current draw is negligible and at most an amp on either supply. The 6mtr power amp appears to draw about 10amp (a bit low I think-- will have to look at that later), the 440 power amp appears to draw about 23 amps (more like it). The SyntorX on 2meters draws about 9 amps when it's transmitting.

The installation involved moving many items around in the rack, thankfully everything fit. As I left the site this evening the backup battery was accepting a charge from my portable charger.

I also installed the new LDG RVS-8 voting receiver controller. The first four ports are wired to the KK standard 9pin connectors for use with my 6mtr receivers. The present two receivers were setup with the new voter and appear to be functioning properly. I will add an additional receiver (or two) to the voter in the coming weeks.

While dealing with alignment issues on the new voter (which went easily and well it seems) I also touched up the setup on the 440 side with it's Doug Hall voter.

Since the installation was going well, I decided it was a good time to add the extra circuits to the special 'Benzie PL one-shot' circuit so that it only functioned when the remote base was dialed up on the 147.04 repeater. After a bit of soldering and a few parts, the added circuitry was in place and now the annoying 'squelch burst' when non-Benzie repeaters (or simplex) was dialed up on the remote base is gone. The Benzie circuit is only functional when the Benzie repeater is selected-- the way things aught to be.

More improvements to follow shortly.

73 KF8KK

October 12, 2005

Benzie Link on PL decode


Today I've installed a small 'one shot' in the COS line of the 2mtr remote base transceiver. The purpose of this is to allow the use of 'PL decode' when linked to the 147.04 repeater for the Wednesday net. By using PL decode, stations connected into the system via Echolink will no longer have to wait for all the repeaters to drop carrier before they can transmit. Sadly, when we first setup the 147.04 repeater to encode (100hz) PL during incoming signals only, it turned out that the oddball 'beat' (a heterodyne/IF mix from something at the Empire site) that appears on the 147.04 frequency interferes with reliable PL decode-- causing dropouts.

The small 'one shot' delays the closure of the carrier (or PL) sense line and masks any PL decode dropouts.

At present, this delayed COS closure is manifest on ALL frequencies used in the 2mtr remote base (it will appear as a burst of open-squelch noise when distant repeaters unkey). I plan to install the circuitry needed to restrict the delay to just the 147.04 frequency within the next few weeks. Please pardon the squelch bursts in the interim.... it makes linking in Echolink connections considerably better.

73 John KF8KK

PS... the new power supplies and new LDG voter (to replace the current 6m voter) have arrived and will be placed in service before the end of the month.

Packet node NOT diplexed


While the test of the packet node diplexed with the six meter repeater antenna was a huge success for the packe node (reliable connections to TAWAS and Midland) it turned out that in the field the small loss in transmitted signal on 52.92 produced a VERY noticeable loss in downtown Traverse City and other fringe areas.

The packet station was returned to it's former configuration, mutually exclusive with the 2mtr remote base transceiver. During the winter I will work on designing and building an appropriate diplexer to use to diplex the packet node with the six meter antenna.

Because the small (3w) power loss on 52.92 made such a dramatic change to the coverage 'downtown', I will bump up the plans to raise the repeater output power to 250w to a higher position on the 'list'. While I have the GE 'Power Mate' amplifier, I need some parts to complete it's operation-- and to rebuild the 6m duplexer to withstand the higher wattage.

Progress on this project will likely become noticeable in the spring/summer of 2006.

73 KF8KK

October 09, 2005

Packet Node diplex with 52mhz rpt antenna


Tonight I have put in place an experiment to determine how desireable it would be to feed the 52mhz antenna at the 330' level (the main 6mtr rptr antenna) with a diplexed feed that included the 145.09 packet node along with the 52mhz repeater.

Initial experiments show that the Comet Triplexer exhibits acceptable insertion loss (36.9w reduced to 34.0w on 52.92) and that the 145.09 packet node (using the SyntorX remote base) has a dramatically improved connectivity to known distant packet stations. The observed SWR shown at 145.09 (using the 52mhz DB products folded dipole) is roughly 3:1. While the SWR is not very good, the apparent transmission/reception range is noticeably better and that makes me stand up and wave at the standing waves.

If the experiment proves succesful, a seperate packet transceiver will be placed on site to use this higher antenna and the 2m SyntorX remote base will be returned to the dualband antenna at 100' where it has been operating from. During the test, however, the 2m remote base is also using the antenna at 330'.

Film at eleven...
73 KF8KK

October 03, 2005

Aux 449.725 rx preamp


Today I installed another ARR GasFET preamp in the 440 repeater. This preamp is feeding the second 'main site' 449.725 receiver with amplified RF off the former repeater antenna (the Super Stationmaster at 100'). This should improve reception in areas which have poorer coverage due to the tower shadow (downtown Glen Arbor, for example).

Simultaneously with the installation of the preamp is the installation of a single Motorola bandpass cavity in this second receivers antenna line.

73, KF8KK