Tag: Portable

RSGB 2nd 70MHz Contest


M0UKD/P – 70MHz

We had some great September weather today for the 2nd 70MHz contest. We setup at the Kelvedon Hatch ‘Secret Nuclear Bunker’ as seen above, using my new 70MHz amplifier at 160w and my 4 element DK7ZB 12.5Ω Yagi.



Conditions seemed quite normal, we worked no Scotland or Ireland but our best DX (as many others) was PA4VHF at 449km. Other highlights were GJ3YHU in Jersey and M1CJN/P in the North York Moors. Total contacts was 46.

A very enjoyable day of operating and testing the new amplifier. Next week, it’s the Practical Wireless 70MHz contest, so lets hope for the same weather and some band openings perhaps? Maybe I’m asking too much 🙂

The Claimed Scores are available. Thanks to Dave M0TAZ, George M1GEO, Dave M0YOL and Chris G8OCV for help & company, and of course everyone we worked (or tried to work!).

RSGB 2nd 70MHz Contest at Kelvedon Hatch

RSGB 2nd 70MHz Contest at Kelvedon Hatch

Working a few on 10m (28MHz) with a half wave vertical

28MHz has been in good shape recently, so I wanted to go out portable and try my end fed half wave parallel tuned circuit coupler as I have not tried it on 10m before. The band was in good shape (unlike the weather) and it seemed to work well. I managed to work some good DX whilst I was there, the log can be seen below.

November 2014 10m log

I also took a little video of me working VA3AQB – Alan in Canada. The coupler seemed to work well on 10m and with a bit more bandwidth than other bands, perhaps because very little capacitance was needed. I’m enjoying making the most of the higher bands whilst they are open! John.

Loaded Quarter Wave Antenna on Topband

We went out for some portable operating today, as the weather was nice. Our club has a topband net each Saturday at 2pm and I wanted to try an antenna for the upcoming 160m AFS Club Calls contest. Using Dave M0TAZ’s 18m spiderbeam fibreglass pole as a loaded quarter wave, with an inductor (340μH) towards the top of the antenna. It makes it all a bit critical having the inductor so high, but the big advantage is that the bottom 15.5 metres has a lot of current in it, leaving only the 2.5 metres above it at a high impedance, making a better radiator. Ground was provided by a chicken wire fence, which I have used many times before with good results.

Below is a short video showing the antenna first on 24MHz where Dave is working Bahrain where the vertical was set up close to a ⅝ wave, then afterwards, it’s fully extended with the loading coil 15.5 metres up, making it a loaded ¼ wave for 160m. The antenna was resonant at 1830kHz, a bit low, so the ATU was used. I calculated for 1900kHz, so I guess 70kHz off isn’t bad! It would be easy enough to fine tune it. Lovely day for it, a bit breezy towards the end though!

Portable operating on 24MHz

I was operating portable on 12m (21MHz) today. It’s a band which I have hardly ever used, so I cut a half wave length of wire and used my End Fed Half Wave Coupler to match it at the base of the fibreglass pole. Conditions seemed good and I was able to work Chicago, Massachusetts, California, New York and Texas in a short time. Below is a short video and photo of the setup.

Operating on 12m beside the river Thames.

Operating on 12m beside the river Thames.

Transceiver efficiencies (FT-897D, FTDX1200 and IC-7200)

The FT-897D is a very efficient transceiver for portable use, perhaps because it is designed for use with battery power in mind. As I recently purchased an Icom IC-7200 to replace it for HF use whilst portable, I thought I would do some tests on the efficiency of them both, and also my FTDX1200 for comparison. The IC-7200 is comparable to most other HF desktop transceivers, using up to 20A with a 100W carrier. (more…)

Portable on 40m with the End Fed Half Wave

I went out for a little bit of /P operating this afternoon for just over an hour as the weather was OK. Had a nice chat on 40m with some UK stations using the end fed half wave set up as a kind of sloper. The end was up 8m on a fibreglass pole just resting against a tree, and the feed end came down to a low tree branch and then into the coupler. It seemed to perform really well on TX and RX. Below is a little clip recorded by Dave M0TAZ. Running 100w from the Icom IC-7200.

Operating HF from Dungeness ☢

I just got back from a couple of days on the South coast. I spent a day at Birling Gap and walked up the chalk cliffs at Beachy Head, then on Monday, I spent the afternoon at Dungeness. My plan was to do some photography during the day and some HF operating at night.

After a day of strolling around this strange landscape, I finally got round to setting up the HF station. I used an 85AH Leisure Battery, Yaesu FT-897D at 100W and the antenna was an inverted V for 80m up on a 9m fibreglass pole. I was facing a fantastic sunset (and the two nuclear power stations) as can be seen below.

Parked up at Dungeness for some HF operating whilst watching the sun go down.

Parked up at Dungeness for some HF operating whilst watching the sun go down.

I used a few different bands, 40m, 60m and 80m. Conditions on 60m and 80m were great for local contacts and I got good signal reports.  It was an interesting spot to operate from. (more…)

Using a fence as an antenna

I always wanted to try something other than an antenna as an antenna, so I decided to try to join our clubs topband net, whilst out portable and using a wire fence. I spent the morning modifying my MFJ-971 portable tuner, by adding an extra inductor in the form of a T130-2 torroid, with 29 turns, in series with the main inductor inside. This is only in circuit when the tuner is in the highest inductance setting, where it will use the whole wire inductor and my torroid. MFJ say this tuner is for 1.8-30MHz, but its really 3-30MHz, unless youre tuning a 50Ω load! It now works nicely with most things on 1.8MHz.

So, over to the country park I went, set up this tiny station, clipped my feed to the top piece of galvanised wire, and my ground to the lowest piece, and the mesh. To my surprise, it tuned easily, and worked ok to the local contacts. This fence is 1 metre high, and around 150 metres long. Now, i’m wondering what I can use next! John.

FT-817ND and Tuner


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