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My KRX3 arrived yesterday and after about 4 hours of work It was fitted into my K3. For those of you that don’t already know The KRX3 adds a second receiver of equal specification to the primary receiver to the K3

Generally sub receivers are useful to help find out where the dx station is listening in the pileup, to search for multipliers whilst ‘running’ in a contest or to monitor a second band.

The K3 with the KRX3 fitted has another ‘neat trick’ up it’s sleeve. If the KRX3 is configured with the same filters in at least some of the slots as the primary receiver it can be used for Dual antenna diversity reception. In this mode the Sub RX tracks the tuning of the main RX. I have been using diversity reception for a number of years for tropical band broadcast Dxing with my Racal RA-3702 however the K3 is the first amateur transceiver I have used that is actually capable of doing diversity reception well.

Icom’s Flagship 7800 fails miserably in diversity on two counts. Firstly the main and Sub RX have a small but constant frequency offset making it very tiring to listen to, secondly the tuning of the main and sub receivers cannot track.

On the Elecraft k3 tuning tracks both receivers (when linked) RIT also applies to both receivers making the k3 very easy to use in diversity mode.

Diversity holds a lot of promise for weak signal DXing where using 2 separate antennas can help reduce the impact of fading, QRM and noise

Diversity is also very useful for enhancing the ability to pull individual calls out of large pileups

Here is a 5 minute audio clip of the K3 in Diversity mode. For a better idea of how useful this is listen with headphones on.

here is the YR2TOP beacon on a noisy 160m with K9AY loops on the left and a beverage on the Right
filter bandwidth is 150hz this time
160m_beacon_k3

Here is a clip of an SSB pileup on 20m Here too diversity reception helps to separate the callers
k3 20m ssb diversity

One of the nice things about the elecraft K3 is the support that it has for a very wide range of microphones. The rear panel mic connector is directly compatible with computer headsets once the bias voltage is enabled to power the electret condenser element.

My normal headset is a home brew one based on the bias circuit that is normally used in Icom hand mics. This simple circuit is published in the user manuals for most modern Icom Radios. The manuals can be found on line on the Icom website.

Recently, however I have been using a little headset that I bought on Ebay for 1 pound Sterling ( about 2 US dollars.)
I have been getting truly fantastic audio reports on this headset when used with the K3. It’s a little bit flimsy but it’s very light and easy to wear, It simply loops over one ear.

Vox on the K3 is fantastic but I prefer to use a footswich for PTT control.

Lots of Ebay vendors have similar products and any computer store will sell you a ’skype’ headset. Before you spend ‘proper’ money on expensive ham radio branded products, try a cheap computer headset. You may be very pleased with the results.

Last October I was at an event organised in Clifden to commemorate 100 years of Commercial radio. On October the 17th 1907 the worlds first commercial point to point wireless link opened for service between Clifden in Ireland and Glace Bay, Nova Scotia. This link remained in service until the Clifden station was destroyed in 1922
You can read some background on the type of transmitter used at Clifden on
OZ6GH’s pages

I recently came across traffic logs for the first few months of the station’s operation, these show that in the first ten months of operation that 129,614 words were sent and 116,633 words received over the radio link, a total of 246,247 words exchanged, approximately 820 words a day.

I expect that in the later years of operation that the data rates were much improved but even assuming that 12 words per minute could have been maintained for 18 hours per day, every day, this works out at approximately 331 Megabytes of data transmitted during the entire lifespan of the station

A little over 100 years later my company commissioned a new 155 Mbs wireless point to point link to connect to our Internet transit provider.
331 Megabytes of data can pass over this link in around 17 seconds. This link is just a tiny sliver of today’s telecoms infrastructure. What a long way we have come in the last 100 years.

I have had the very nice elecraft K3 here in the shack since November 2007. It’s an absolutely fantastic radio and it also has a lot of I/O connections on it’s crowded rear panel.
Elecraft for user convenience sake make all the audio connections using 1/8″ Jack sockets. This is of course very handy in that using a single standard audio connector makes for quick and easy reconfiguration. Unlike DIN or Mini-din connectors 1/8″ Jack plugs are available almost everywhere too.
The downside is that in a permanent shack setup reaching around to the crowded rear panel may be tricky and with the tight spacing it’s easy to remove or losen the wrong mini-jack plug as they do not have much holding force.

I have made access to the K3’s wide range of I/O connectors much easier by connecting all of the Audio keying and PTT lines via a 1/2 Normalised balanced jack Patchbay.

1/2 Normalised is particularly usefull for this purpose in that you can plug into the upper (black) Socket and be connected in parallel with the normal signal path. if you plug into the Lower socket you interupt the normal signal path.
Parallel connections are usefull if you wish to route the line out audio to two devices, or hook up two Morse keys.
The interupting connection is usefull for connecting a different microphone as you would not want to have 2 microphones connected in parallel

One of the problems with patchbays is keeping track of all the connections. I do this by using a simple wordprocessor table which looks like this (click on image to zoom in)

As you can see I have plenty of unused inputs for future use.

Patchbays are easily available new or second hand at low cost on e-bay and make a most usefull addition to the shack.

Well I resisted Having a blog for a good number of years now, Finally it’s time to give in and follow the herd