This afternoon I decided to build a 14MHz OXO transmitter. As is often the case, I like to re-use old boxes and project parts, so the FETer box was photographed for posterity, then gutting and used for the OXO transmitter. In this version I did not go for full break-in and instead used a simple changeover switch, but added a push button net function to allow me to net the VXO without the PA being keyed. A small toroid in series with the crystal allows about 15kHz VXO range around the 14.060MHz QRP frequency. I used a 2N3904 for the oscillator and 2N3906 for the keying transistor and a 2N3866 for the PA, but may change this for 4 x 2N3904s in parallel for lower cost. My output is a little low at around 500mW.
It works fine with reverse beacon reports from Iceland and Slovenia and a nice 2-way QRP QSO with IK2RGV who was running 5W.
The OXO really is a classic circuit: you just build it and it works. Another version is on the QRPkits page.
Thanks for all the many comments both here an in private emails. Basically I am looking for a good second QRP transceiver to work along side my existing 12 year old FT817 that continues to work perfectly. There are times when I'd like to WSPR on one band whilst operate CW or SSB on another. Also, the second transceiver allows me general coverage RX whilst TXing on the first unit. Since I sold my IC703 to a friend the year before last, this has not been possible.
At the moment, I am still inclined to buy an FT817ND rather than the KX3. As YO9IRF said in the earlier post and on his blog, the FT817 is close to the ideal for a portable QRP radio, even after 12 years. Although it does not match the RX performance of the KX3, it does perform remarkably well, and of course it also covers the 144 and 432MHz bands and with all modes. And it is half the price.
As someone who gets around 50-60emails a day, sometimes more, even though I am supposed to be retired, the link below offers us all some good sound advice on how to manage emails well. A good half of the emails I get are about projects on this blog or my main websites, so it's my own fault, HI.
My PC or iPod Touch tend to be on for a lot of the day and am almost addicted to reading the emails. Usually I reply promptly but occasionally emails get filed waya having forgotten to reply, for which I make a general apology.
People who own the Elecraft KX3 generally rate it very highly as it is a very feature rich product with an excellent receiver. However to buy one with all the features such as the auto ATU and the internal battery box is EXPENSIVE. For the price of one fully loaded KX3 one could buy 2 well proven FT817ND transceivers.
One has to question whether the KX3 truly is worth the extra cost. Although a trail friendly radio, the KX3 does have a messy cabling interface with wires everywhere, it would appear, from both sides! By contrast, the FT817 has simple, clean interfaces and is as happy in the field, in your hands or on a desktop. The KX3 looks functional, but hardly a thing if beauty.
I'd be interested to hear the views if others.
This video, by Jim Mullen, is the first part of 2 that compare the RX of the KX3 and FT817.
DJ8WX's VLF signal received by G3ZJO (frequency is Hz)
This last week or so Uwe DJ8WX has been active again on VLF from his location near Hamburg. Uwe was the strongest signal I ever copied on the so called "Dreamers Band" a few years ago and his signal is being well received again now. To copy these signals at 8.97kHz requires a quiet antenna location and a very stable, frequency locked receiver. You will NOT be able to hear anything and signals take hours or days to appear on the PC screen using a package like Spectrum Laboratory. Getting a very very stable receiver is actually easy as Spectrum Lab can lock onto one of the strong MSK VLF commercial signals and use this, or a GPS signal, as a very accurate reference. Much more details on the Sub-9kHz Amateur Radio pages.
G3XBM operating pedestrian portable in South Devon
The latest edition of Practical Wireless carries my article on pedestrian portable HF DXing. Getting out of doors in a noise free location with a simple HF rig and using it handheld - not with a large semi-permanent antenna, but with a whip on the rig - is one of the great pleasures of QRPing. With a good location, such as a clifftop site with a slope towards the sea, DX can be worked easier than might be expected even with a few watts of SSB. Nothing quite beats talking to a station thousands of miles away with a small radio in the hand. A small counterpoise wire is a must to get the best results. Especially in the summer Es season when signals can be S9, this can bring a whole new dimension to the hobby. Forget that plasma TV interference and get out there in the great outdoors! Best bands are 15m, 10m and 6m (when open).
A nice Pixie transceiver and tuner on the PD7MAA blogsite
Graham G8NWC has just told me about a very nice blog site with some useful QRP information. See http://pa-11019.blogspot.co.uk/. It is surprising how much GOOD data there is out there when you look around!
Today for a change, and whilst waiting for the family and grandchildren to arrive for half term holiday, I simply went on 20 and 15m and just operated using the 2.5W pep SSB from the FT817. No great DX, with the best contact being OY, but a few nice enjoyable contacts in the log. The speech processor certainly helps.
It is tempting now to build a multi-band VXO controlled QRP CW transmitter to use with the FT817 (on receive) as it is a while since I operated QRP CW on 40 and 20m. With the EF-10/20/40 antenna now up it is an ideal time to do this and enjoy the simple pleasures of operating QRP on the HF bands again. In my mind I think a 2N3904 VXO and buffer followed by an IRF510 PA at around 2-3W.
This afternoon I decided to take down my 10m halo for a while and replace it with a lower antenna: the LNR Precision (was Par) EF-10/20/40 end fed wire antenna, which I've owned for some years but not used recently. As it suggests, it covers 10, 20 and 40m with a very low SWR, although it is a reasonable match on several other HF bands too.
On 40m I did a comparison between the horizontal EF antenna and the earth-electrode antenna. A series of transmissions was made with each antenna in turn, then I compared WSPR spot S/N received from a number of stations.
The conclusion is the earth-electrode antenna is around 9-16dB down on the EF antenna on 40m, so averaging about 2.5 S-points down. The test is not too accurate as conditions change, the earth-electrode and EF have some directivity and the reports sample size was small.
