Tag Archives: Presidio of San Francisco National Historic Site (US-7889)

Change Is Good

by Matt (W6CSN)

Recently, OM Witherspoon (K4SWL) wrote a blog here and shared a POTA activation video in which he described the benefit of changing up your operating location within a large park to keep things fresh or simply to be able to activate within a given schedule.

Activation zone looking over the Pacific

That got me to thinking about my own “home” park, Presidio of San Francisco US-7889, a large park which is also part of an even larger reference, Golden Gate National Recreation Area (GGNRA) US-0647. Recently my XYL, who is very patient, has been subjected to my complaining about being bored by doing the same activation over and over.

Classic vistas from the Presidio of SF

My typical POTA outing is after work, I drive ten minutes down to the East Beach parking area, set up a base-loaded vertical on the roof of my car and plug in the trusty FT-818. Mind you, this is not a bad setup. The location combined with repeatable antenna installation reliably produces contacts and I usually have a complete activation in about 30 minutes.

GRA-7350T antenna deployed

The XYL’s suggestion was, “hey, why not play radio somewhere else?” and K4SWL’s blog and video were an inspiration as well. So I left the FT-818 in the shack, packed up a QMX kit, and headed for the high bluffs in the Presidio that overlook the Pacific Ocean to the west. I setup on an out of the way granite bench that was part of a World War II memorial to servicemen who perished in the coastal waters of the Pacific.

World War Two commemorative wall

My plan was to get on 15 meters in the hope of catching some early JA’s or other Pacific rim DX. The vertical antenna deployed easily and though the location was substantially protected from the strong wind gusts, I did stake the tripod down with a pair of tent pegs.

Tent pegs keep the tripod secure

With an SWR of below 2:1 on 21 MHz I set to calling CQ and posted a spot on pota.app advertising that I was in US-0647 GGNRA, even though I was also still in US-7889. Turns out 15 meters was dead, for me at least. Not a single nibble after 15 minutes of calling.

Good SWR on 15 meters

After a QSY to 20 meters, another half hour brought in only four QSOs! This location and radio combo was certainly a nice break from the usual and even though the QSO pace was glacial, it was quite satisfying and refreshing to do something different.

The QMX station ready for action

Since the clock read just after 00 UTC there was plenty of opportunity to gather the needed contacts for a complete activation. If necessary I could even come out the next day before 23:59 UTC. But since I had no particular time constraint for the evening, I decamped for East Beach where I was pretty sure I could wrap up the activation in short order.

Sunset over SF Bay

Even though I was back at my “usual” spot, starting the activation somewhere else was the change I needed to break the routine. Six more QSOs validated the activation in a matter of minutes. I swear being down close to the waters of San Francisco Bay adds at least 3db to my signal. There is a reason I frequent this particular spot.

Sun going down behind the Golden Gate

I feel fortunate to have so many locations within US-0647 and US-7889 that are quite close to home. I plan to take advantage of this diversity of operating spots, knowing that the “East Beach Amplifier” is always available if my QRP is not cutting it.

72 de W6CSN Matt

P.S. I did, in fact, log this activation as a two’fer.

Matt’s Weekend POTA Roundup!

Many thanks to Matt (W6CSN) who shares the following post from his blog at W6CSN.Blog:

Weekend POTA Roundup

by Matt (W6CSN)

It’s been a stormy past several days here in Northern California, but if anything, the weather only amplifies my motivation to go outside and get on the air.

Rather than do a separate writeup for each, this post is a roundup of my last four POTA activations, from Friday, February 2nd through Sunday, the 4th.

A faint rainbow splashes down in front of Angel Island

Thursday and Friday had been wet, with one storm in a series moving across the Bay Area. However, by Friday evening the cold front had passed and there was a break in the rain. This was a perfect opportunity to try an after work activation at the Presidio of SF (K-7889).

I hadn’t used the QCX-Mini in a while, and this activation reminded me why. I believe what is happening is that being so close to the antenna, RF interference causes clicking while keying, nearly to the point of distraction. I need to experiment with RF chokes on the key and audio lines to see if that improves the situation.

Fed up with the RFI on the QCX-Mini, I switched over to the MTR-4B which doesn’t seem to suffer the same issue. I wrapped up the activation after netting 21 QSOs in the cold west wind.

All QSO maps in this post are from http://tools.adventureradio.de/analyzer/

The next bout of rain wasn’t due to arrive until later Saturday afternoon. This was a change in the forecast that subsequently altered my plan to stay in Saturday soldering on my QMX Hi-Bander project.

Initially I went to Fort Point (K-0819) in the hopes of changing it up from my usual activation park but there were just too many people there. So seeking relief from crowds, I crossed the Golden Gate Bridge and went up on the slopes of Mt. Tamalpais.

I parked at Trojan Point at an elevation of approximately 1800 feet. See this post for more views from this location. The temperature was in the mid-40s, which is cold for us coastal Californians. Besides, the winds were picking up ahead of the next storm so I operated from the comfort of my vehicle using the Gabil 7350T base loaded vertical antenna on 15m and 20m.

This activation used the FT-818 and yielded 23 contacts, including JH1MXV from northwest of Tokyo, Japan coming in fairly strong on 21 MHz.

Driving back to San Francisco takes me right through the Presidio of SF (K-7889) and noticing that it was after 00:00 UTC, I made the last second decision to divert to East Beach to see if I could work in another activation before the anticipated rain.

At my usual spot for activating this park, it took only moments to raise the MFJ-1979 20m quarter wave and do a quick deployment of the MTR-4B on the trunk of the car. The wind was picking up, but not nearly as strong as it was up on the mountain.

After seven QSOs, the skies began spitting raindrops, this was going to be close! I closed the cover of the Maxpedition pouch to protect the radio and battery while the Bencher paddles could tolerate a little bit of moisture.

I was happy to have a Rite-In-The-Rain notepad for logging [Amazon affiliate link], because now I was certainly writing in the rain! Three more contacts and the activation was concluded with a hunt of Jim, WB0RLJ, in K-4011. Continue reading Matt’s Weekend POTA Roundup!

W6CSN: Activation 72 of the Presidio of San Francisco National Historic Site

Many thanks to Matt (W6CSN) who shares the following post  from his blog at W6CSN.Blog:

Activation 72

by Matt (W6CSN)

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!

The Bencher is a breeze to operate on the center console.

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.

The trunk lid is where I usually operate from when at this park.

At the same time, I switched radios to the Mountain Topper 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.

The Wolf River coil provides a good match on 40 meters.

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.

QSO map by http://tools.adventureradio.de/analyzer

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.

Matt’s Rainy Day POTA Activation

Many thanks to Matt (W6CSN) who shares the following post  from his blog at W6CSN.Blog:

Rainy Day Activation

by  Matt (W6CSN)

It’s late December and one of a series of winter storms is driving into northern and central California. The previous day, my plans for a combined Summits On The Air and Parks On The Air activation fell apart due to weather. Today most of the UTC day had passed with only light drizzle, and itching to get on the air, I hatched a plan for an activation at my nearby park reference K-7889, the Presidio of San Francisco.

Typically when activating at this park from the “East Beach” area, I will back into a parking space, setup the radio on the trunk lid and run the coax a short distance to a 17 foot vertical telescoping whip antenna which is clamped to a short steel post.

Today however, I chose to operate from inside the vehicle so both myself and the radio equipment would stay dry. Not wanting to leave the coax unsupervised where someone could trip over it, I deployed the Gabil GRA-7350T antenna with a triple mag-mount on the roof of the car.

The CW Morse paddles mounted to a steel clipboard on the center console.

The GRA antenna is a short, loaded vertical with the whip portion maxing out at about 8 feet in length. It works well on 20 meters, but it’s less of a compromise on higher frequencies. On 18 MHz, only a small amount of the loading coil is needed to achieve an acceptable SWR, so with the bands in pretty good shape I brought the Yaesu FT-818 so I could get on 17 meters.

There weren’t many spots for 17m on the POTA web site, but I posted my spot anyway and started calling CQ. It wasn’t long before KX0Y responded, followed by more hunters from across North America and Alaska. The Golden Gate Bridge was visible from my vantage point at the start of the activation, but as the rain intensified the bridge became enshrouded by the incoming weather front.

With 00 UTC approaching, the rain now coming down harder, and 13 QSOs in the log I called QRT. Rather than carefully stowing the antenna and mag-mount, I simply broke it down as quickly as possible and tossed it all the back seat since I would have to bring it inside to dry anyway.

The following equipment was used in this activation:

[Note: All Amazon and CW Morse links are affiliate links that support QRPer.com at no cost to you.]

Thanks to all the hunters that responded and made the activation a success.

73 de W6CSN.

Matt’s “Crackadawn POTA” Field Report

Many thanks to Matt (W6CSN) who shares the following post  from his blog at W6CSN.Blog:

Crackadawn POTA

by Matt (W6CSN)

This is the weekend in October that features the U.S. Navy’s Blue Angels taking to the skies over the Bay Area. The air show takes place over the Bay waters, which means the beaches and shorelines around San Francisco will be packed with people and traffic. Since my usual POTA operating location is right by East Beach, I had pretty much given up on the idea of activating K-7889 this weekend.

Lights of the Golden Gate Bridge reflecting off the still Bay waters.

The airshow is on Saturday and Sunday, but the Blue Angles practice on Thursday and Friday, weather permitting. So here I was on Friday morning, awake at 5AM watching K4SWL on YouTube doing POTA when the idea of getting out for an early activation got into my head.

It was still dark when I tossed my backpack, which was already loaded for POTA from the previous activation, into the car and headed down to the East Beach in the Presidio of San Francisco National Historic Site (K-7889).

The sky getting lighter in the East before sunrise.

Given the early hour and low light conditions I didn’t relish the idea of doing my usual picnic table and tripod antenna setup. Not long ago I had acquired one of those “mirror” antenna mounts with the jaw clamp arrangement, and this was a great opportunity to try it out. Between the parking lot and the beachfront promenade there is low fence constructed of short steel posts and strands of stainless cable. The fence post was a perfect place to attach the clamp and the MFJ-1979 17 foot telescopic whip, which is a quarter wave on 14 MHz.

Close up of the MFJ-1979 whip antenna clamped to steel fencing.

I was ready to string some radials out to give the antenna a ground plane to work against, but wondered if the post, being sunk into the ground by the Bay and the steel fencing cables might provide enough of a counterpoise. A quick check of the SWR on the meter built into the MTR-4B showed a 1.2 to 1 – no need to even bother with radials with an SWR like that right out of the box.

Low SWR on the quarter wave vertical as the Bay wakes up.

The other advantage of this antenna setup was that it is right next to the car. However, I don’t really like operating from my vehicle as it’s not very sporting nor is it comfortable. Instead, I simply set the station on the trunk lid and completed the activation from a standing position. The other advantage of this arrangement was that I could closely guard the RG-316 coax going from the radio to the antenna to keep any humans or canines from getting entangled. Continue reading Matt’s “Crackadawn POTA” Field Report