w6csn’s outdoor amateur radio

Today’s activation of the Presidio of San Francisco National Historic Site K-7889 was pretty standard for a mid-winter POTA outing. Normally I wouldn’t bother to write it up on this blog. After coming here 72 times there is not much new to say about it. Nevertheless, maybe somebody will find value in this field report.

Even though the weather was dry this afternoon, the radio operating began in the car where I used the FT-818 to net 14 contacts on 17 meters. I must admit being warm while doing a POTA activation is not bad!

After a while the calls started to dry up so I extended the antenna fully to get on 20 meters, but the best SWR I could get was 3:1. I suppose the lack of good bonding of the coax shield to the car body, which I’ve read about in other blog posts on qrper.com, was responsible for the less than optimal antenna match.

After taking down the badly matched roof mount antenna , I flipped the car around and backed into the parking space to set up my usual 20 meter station on the trunk lid with the antenna clamped to a steel post.

At the same time I switched radios to the Mountaintopper MTR-4B. Previously the current draw of the FT-818 had dropped the battery voltage to 12.6v, but with the lighter load of the MTR, the voltage rebounded above 13v. The MTR-4b is designed to accept 13v, something the other radios in the MTR series are not recommended for. However the SWR in this antenna configuration was 1.0 to 1 so I felt okay to run the radio at the full 5 watts with the higher voltage.

Unfortunately 20 meters wasn’t performing all that great, yielding a mere four contacts. The POTA website showed several JA’s activating parks on 40 meters, so I added the Wolf River coil to the base of the antenna in hopes of hearing them. Alas, no copy, so I put out a few CQ POTA calls of my own on 7.062 MHz. W6OOD responded from Southern California, but my report was not particularly strong. And, with the light fading I decided to call it a day.

Activation #72 netted a total of 19 QSOs on three different bands, coast-to-coast. Not bad for an unremarkable Friday afternoon ham radio outing.