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. See the plotted chart below:
Comparing 3 transceivers for efficiency.
This table shows the test results. All tests into a 50Ω dummy load, at 13.8v on 7MHz:
It can be seen that the IC-7200 is ever so slightly more efficient than the FTDX1200, but neither is anywhere near the efficiency of the FT-897D. It will be interesting to see how the new Yaesu FT-991 compares to the FT-897D! In all cases, the more RF power you use, the more efficiency you are getting
I have a 100AH Leisure Battery which still provides enough power for an afternoons operating with the IC-7200 at full power, so that will do me, although a bit more efficiency is always nice!
It was a clear evening last night, and the international space station was due to pass almost directly overhead (86º peak). Below is an image of the pass. My antennas are visible (Doublet, 70MHz dipole and X-50).
I’m still yet to receive any signals from all those other solar systems!
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.
I went down to the river Thames a couple of mile from home today for some portable operation and some experimenting with an end fed half wave antenna. I recently built a Parallel tuned coupler for feeding end fed half waves from 7-30MHz and this was tested on a few bands. I wanted to try 15m, but the band was full of contest stations due to the Scandinavian contest, so I cut a piece of wire for a 17m vertical. Below is some video took by Dave M0TAZ of me working Chris SM0OWX on 18MHz.
I have used the coupler on a few different bands now in various configurations with good results. I shall add a post with more results after some more tests and fine tuning soon. Here is a photo of the inside of the unit. 73 John.
Today, I finally built a ½ λ dipole for 4m. I have previously been using a folded ½ λ dipole made out of 450Ω balanced feeder, suspended in the loft, which is not ideal. I still had the coax outside on the roof and the pole which were both used previously for my 2m/70cm co-linear, which has been relocated to the chimney, so once it was built, it was simple enough to put up.
Inside the waterproof box
I was thinking about building an end fed half wave dipole, having previously built a ‘prototype’ which worked well. This requires a matching section at the base, but no boom arm is needed. I also thought about a slim jim / J-pole, but the total length would be 3 metres. So, I decided to go with a trusty ½ λ centre fed dipole. I built it using two 1 metre lengths of 6mm aluminium tube, and all terminations are inside a waterproof electrical box. Inside, I also placed a coax choke balun, which is built out of a 25mm piece of pipe, with 11 turns of RG58 coax wrapped around it.
Coaxial choke balun.
I thought I might have to trim a bit off the 1m elements, but once I put it on the mast, the analyser showed the lowest VSWR of 1:1 at exactly 70MHz, so I left them as they are! The only thing I forgot was to put self amalgamating tape around the PL-259 plug after putting all my tools away! All watertight now though
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.
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. The sea was only 100m or so behind me and Dungeness is a large area of shingle which pokes out of the south coast into the English channel.
Sunset at Dungeness
I operated until after sunset, and it was the night of the ‘supermoon’, which made the location more surreal! I got a few night shots and then headed home about 11pm. It was certainly an interesting place to visit and I will be sure to go back again! Thanks to all those I worked…
Dungeness Lighthouse. This one was built in 1961 because Dungeness A Nuclear Power Station obscured the old lighthouse of 1904 which is behind me here.