The Vector 4000 Antenna

QRM

That afternoon, my radio had been particularly noisy with the usual noisy pest- skip from the continent. All the channels were full of it, just a splatter of constant atonal screeching- the all too familiar FM carriers colliding from people too far away to hear one another. The whine and raspy hash of mashed up signals mixed with Italian and Spanish SSB wobble & warble breakthrough- it was useless trying to get out anywhere “local”.

While clunking the channel selector on the radio I settled on some unusually strong signals. I’d heard POCSAG pagers from the local hospital before but these were entirely different and I could tell that some, but not all were coming in on the skip. I really didn’t know what I was listening to but the tones were pleasant and definitely structured in packets. A header, a data burst and a tail, each one a little bit like the loading sounds from a cassette loaded computer game.

It just so happened that I’d actually been flipping through the Maplins catalogue while sat on the bog. Looking back now, it was probably a bit weird but for me at the time, it was how I chose how to blow all of my saved up birthday & pocket money.

I’d seen the kit several times in the mag already but not really bothered to read the item description before, but I’d got a spark from the idea that it might actually be for this type of signal so I looked it up. A packet radio modem kit, 1200 baud speed. Hmmm.

I had a hunch. After a neatly coordinated bus and train trip to and from the Maplins in Coventry, I’d bought home a pile of components and a plastic box.

After successfully constructing and then setting up the modem with the radio and then configuring the terribly old and slow Compaq Deskpro XT PC with the Baycom software, the first packets decoded floored me.

Readable data traveling through the air from France, the Netherlands, Germany, Italy, Spain and probably more- incredible!

This was gonna be huge for me and my mates. Unlimited “online” chatting, connected so no need to use the mic to talk all night- we could chatter & trollolol on about cheese without any distractions or interruptions or sleep- today in the age of smartphones this is seriously taken for granted.

Ramsey Packet Modem PDF

The BBS

By 1996 ENG01A BBS had served quite a large portion of the Midlands during its four or so years of operation.

The radio also served as a digital packet repeater (digipeater) during frequent radio path openings to the continent as well as a “hotspot” for forwarding mail up to Cannock and across to Birmingham.

Some of my mates even used my system to hop to distant stations on the continent during “sporadic-E”-layer ionospheric propagation– it was awesome to watch in action!

The BBS in its final form was a machine comprised of a “custom built” 486 DX built from 2nd hand scrap, with a Kantronics KPC-3 Terminal Node Controller (TNC) connected to a “Superstar 3900” CB radio- operating on Channel 24. (27.235MHz).

Running inside a shed that would easily spike at over 35°C during the summer months, the gear was punished pretty severely!

Networked to the secondary machine located in my old teenage bedroom via a massive run of RG-213 coaxial Ethernet cable, enabling remote access, saving uncountable trips down to the owl house attached shed during freezing cold or miserably wet British weather.

Fast Moves

By aged 17, having passed the RAE (amateur radio exam qualification), and then diving head first into the internet, it was not long before an online relationship quickly matured to a very real life getting-engaged situation.

A sudden and swift decision on my part to save money on the phone bill and weekly plane tickets- I ultimately quit my job and moved to live in the Netherlands, with some hard graft put in at Ericsson R&D, we finally purchased our first home together in 2001.

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Early Bloomers

CB radio had been booming & blooming in the Netherlands with digital packet radio networks for almost a decade. Dutch legislation had effectively enabled the digital adoption by deregulating the Citizens Band entirely.

This lead the way for manufacturers to legally advertise and sell packet radio equipment to quite a substantially larger market than just radio hams. A stark contrast compared with the UK.

Later, unlicensed usage and the allowance of data over RF would be ratified and somewhat protected in the CEPT specification with several channels/frequencies specifically set aside for packet/data.

The CB and ham packet stations in the Netherlands eventually began to decline beyond a sustainable network in the mid-2000s.

For the CBers, The sunspot cycle had come to an end and so too did the interest in long distance (DX). For the hams, there were fresher new digital-mode pastures to play with now that the internet had most certainly won.

COVID-19

The lockdown due to the COVID-19 pandemic has seen a noticeable increase of activity on amateur radio as people- perhaps likely perturbed by everything going on- have come back to their radios. As a consequence the packet community has been busy helping a number of hams set their packet stations back up again. Yay! 🎉

The idea to put up a new 10 meter band antenna began to gather momentum as personal forecasts for 2021 predicted it likely to be up to another year locked indoors- something we are already quite familiar with due to Ilona’s cancer treatment in 2019.

So I purchased a shiny new antenna from the local ham shop and it was delivered the very next day:

The radiator is the short stub on the lower left that couples to the large vertical in the center.

At the top of the antenna is a wire ball for hypothetically reducing corona discharge- high voltage RF (radio frequency) sparking into the air when running very high power.

Though I suspect this is yet another window dressing feature of CB antennas- its probably for the looks. I operate almost exclusively within my limits and I have consideration for my densely packed in neighbors so it’ll never be presented with more than 100 watts of power.

The circular basket? Probably extra capacitive coupling for the radiator element, though- jury is still out on this one… Looks cool though 😎 📡

If only we could see RF with our eyes… 👀

Performance

Yay! 😁 I’m once again able to work 10 meter band digital modes, so you may hear me on FT8 or WSPR from time to time.

I have checked the packet signals on 11 meters (CB)- there is a bit of “local” FM packet activity from stations about 80-100km away, but it is too weak to decode- unfortunate!

Luckily I am able to log into those packet stations remotely via the internet gateway and can remotely trigger their transmitters, so far I have worked out who I can hear: NL9UTR and NL9SHB – Utrecht and Den Bosch respectively. Bit of a reach to Rijen apparently. 😿

Due to quite high levels of neighborhood interference from power-line networking, solar panels, crappy laptop chargers and ISM band encroachment- its a constant S5 of noise here, even with local phase cancellation mitigation on the packet frequency.

However, during good skip conditions, signals from abroad can easily be 20db+ so its a bit of a mixed bag- now on to some testing ⚡️

Early Signal Reports

Above are a couple of maps showing my experiment on the 10 meter amateur band with FT-8, an insanely narrowband slow digital transmission capable of penetrating signal-to-noise ratios previously only touchable by Morse code. Openings to Africa, Australia, Brazil, Falkland Islands & a large portion of Central Europe within one 24 hour period.

With the use of advanced digital signal processing machine FT-8 can decode signals that are barely perceptible to the human ear.

Read up on WSJT-modes here.

The maps were created with the use of the reverse beacon network– a bunch of automated listening stations. The RBN is mostly unmanned ham equipment left running while the operator is away, decoding and reporting what they can hear to a central database on the Internet, (pskreporter.info for example).

Conclusion

So the Vector 4000 is basically as good as I remember it being back in the 90s. It is limited in use though, as one cannot tune it to anything other than the designed band.

The resonance drops way off after 1.5MHz bandwidth curve so don’t be expecting this to work as a multi band antenna.

For 10 meters, the Vector 4000 is an exceptional performer, the reception across the shortwave spectrum is also decent but not overwhelmingly as you might expect for a vertical.

Weather robustness – this Vector 4000 has happily survived some close-to-gale force winds recently, metal fatigue is a factor I may yet have to contend with as the aluminum joints aren’t all that large or convincingly strong. My previous Vector 4000 back in the 90s suffered from a severe clobbering from an Oak tree, breaking it in half, though if not for that, it probably would have lasted many more years.

All of the bolts, joints and connections have been triple wrapped in “Scotch 23” electrical self amalgamating tape which does offer some extra tensile strength as well as waterproofing, so we will have to see!