Welcome to NORAC The North Okanagan Radio Amateur Club

September 16, 2021

Our club's affectionately named crank-up tower trailer Cranky needs some attention. This summer, for the unofficial club ARRL Field Day event, technical team members got the trailer back into basic road shape for use up at Island Lake. See the full trip report here.

But there's more to do to get Cranky skookum again. Here is the compiled list of tasks outstanding:

• spare tire replacement (we replaced the main tires, but the spare should be replaced as well - will need some Deep Creep or other penetrating lubricant to unlock the spare tire nuts)
• generator gas swap (2 years ago the generator was filled with Aspen 4 alkalyte fuel which has a opened-bottle life of around 2 years - drain tank into someone's car and re-fill with a new 4L container of Aspen 4, run for a couple of minutes to get new fuel through the system)
• rebuild the wooden blocks (remove the tin, rebuild to same dimensions with treated lumber, re-install the tin)
• antenna feed point rebuild (water and oxidization at the feed point - bring new SO239, tinned wire and soldering equipment to refresh this key connection point on the beam antenna)
• review suspension setup / adjust torsion bars
• repair tower lockout mechanism (bent)
• modify crank-up pulley system (prevent cable from shafing)
• replace trailer to tow vehicle electrical connector (crusty)
• install tire covers for storage (to reduce UV degradation of tires)
• figure out where to store the front support leg when towing

If you would like to volunteer to take on any of these tasks, please contact This email address is being protected from spambots. You need JavaScript enabled to view it. and we can set up a visit to the trailer in its storage location (at Ralph VA7NU's QTH).

Summary

Technical team members went to the VE7RSS site to do the following:

• battery maintenance
• remove defunct power amplifier
• remove unnecessary filtration
• duplexer swap
• full system check
• clean up shack

Attendees

VE7TRZ Terry
VE7KPZ Mike

VE7EIY Garry (remote tester)
VE7JON Jon (remote tester)

Access

By truck (Unimog to haul all the supplies, equipment and ladder) to the top of SilverStar mountain. Route arranged with lead patroller Phil and called using a borrowed HT (channel 1 this visit) from the patrol office.

In preparation for this visit, Mike coordinated with SilverStar operations director Brad to choose the day/time optimal for a proactive site visit. With mountain biking now only happening on weekends that meant we could drive directly up the frontside of the mountain safely (Pinnacles) on a weekday and access through the patrol shack that is now located directly under the VE7RSS radio room.

Events Leading Up To The Visit

COVID-19 delayed this visit by a good year. With Terry and Mike now fully vaccinated (and wearing masks) we could finally visit the site (and work in a very small space) together.

The recent AC power outage for the site that had the repeater on battery for an extended period made us curious about the battery health.

Actions Taken

The first task to tackle was the battery maintenance. Mike ran a quick (10 second) 100A load test on the battery bank (4 x 6V FLA batteries) and it passed with an excellent result. Next an inspection of each cell's electrolyte showed that all cells had electrolyte covering their plates - yay! Each cell was topped up with distilled water to just below the fill tube and then a 25A charge (via Mike's portable charger) was initiated to get the new water and electrolyte mixed. Soon the charger was into absorb and then disconnected to let the 10A on-site charger finish the job.

While Mike was doing the battery maintenance, Terry was removing the coax switching network and defunct power amplifier. The coax from the Daniels exciter will now go direct to the Daniels power amp and then to the duplexer. A shorter piece of coax was also used between the Daniels power amp and the duplexer. This removal of components should cut out 0.2-0.3 dB of insertion loss on the TX-side as we never use this amp and don't currently have another amp to replace it.

Next Terry removed Mike's OCI VHF bandpass filter. We had initially put this filter in as a problem solver... but it didn't solve the specific problem we had, so out it came today and the 0.5 dB insertion loss on both TX and RX it required.

Next the team removed the old 6-cavity ResLok Q duplexer and installed a new-to-this-site 6-cavity ResLok Q. This new duplexer is the old VE7RIP duplexer re-tuned by Ralph VA7NU for VE7RSS frequencies. This duplexer worked very well at VE7RIP and is notable in providing 95 dB of separation, albeit with 2.5 dB of insertion loss on the TX side. Mike will take the old duplexer to Ralph's and have it checked out to see how it compares on the bench.

Aside: Mike would actually love to see a low-insertion-loss-with-high-separation Q-series duplexer installed at this site instead of the compact ResLok Q as space does allow for a larger duplexer model.

Now while the duplexers were being swapped, they were actually also being checked with Mike's RigExpert AA-230 Zoom antenna analyzer and a dummy load on the antenna port. No, the AA is not a service console, but it does give a bit of insight into if the tune is still good (new duplexer was tuned back in 2019 and sat in Mike's basement for the last 2 years waiting to be installed). On both duplexers, the low SWR areas for TX and RX were pretty much on frequency, however, the new duplexer showed slightly lower SWR on TX. We won't share the specifics here as the test is not ideal, but we can confirm the new duplexer is going to let the electrons flow a little bit better on TX, SWR-wise.

Now on to the rest of the checks. Mike also checked the additional RX bandpass filter that we have installed between the duplexer and the Daniels receiver. This filter is still on frequency. Mike checked the antenna and feed line - ok. Mike checked the RX and TX from the repeater position - ok. Mike put an inline frequency counter/power meter/SWR meter in line between the Daniels power amp and the duplexer - the amp puts out 23.1 watts on 146.880 MHz with a VSWR of 1.01:1 - perfect.

In summary, while we have installed a new duplexer that favours separation over insertion loss, we have also removed components and shortened coax to reduce insertion loss. So, on the TX side we expect to be about the same, and on the RX side, perhaps a tiny bit better. And then with the higher separation, the repeater should hear a little better.

Lastly, we did a full shack cleanup. There were construction scraps, old electrical bits (like wire strippings, etc.), dust, dirt, signs of mice, bits of insulation, etc. that all went to the garbage. We vacuumed the shack and the entire attic. We also removed the old batteries that had long been replaced with the set we are currently using. The shack is looking presentable now.