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G0FTD > FT817 08.10.06 18:17l 154 Lines 5187 Bytes #999 (0) @ WW
BID : 080127276PZT
Read: GUEST VE7HFY
Subj: Realising a walkabout shack ?
Path: DB0FHN<DB0RGB<DB0MRW<DK0WUE<CE8FGC<SP7MGD<SR1BSZ<ON0DXC<TU5EX<XE1FH<
GB7TUT<GB7COV<GB7MAX<GB7PZT
Sent: 061004/1956Z @:GB7PZT.#24.GBR.EU [Kidderminster] #:12708 XSERV410h
Date: Wed, 04 Oct 2006 20:56:34 +0000
From: g0ftd@gb7pzt.#24.gbr.eu (Andy)
To: ft817@ww
Subject: Realising a walkabout shack ?
Greetings to all you FT817 owners and those just being nosey ;-)
I've had an FT817ND now for just over a year.
It replaced a bunch of VHF/UHF handhelds, cheapo scanner and the second
faulty Sony SW100 all in one go.
And it was nice not to have to faff about with so many batteries and chargers
of the aforementioned !
Of late I have been attempting to make it all into a very compact
amateur radio station come listening post when out on long walks,
or down the beach.
I've been doing a lot of antenna tests here, and I thought they might be
of interest to others.
For rx'ing:
* 5m random wire. Next to useless.
* 25CM BY 13CM loop. These were made from some scrap "Hi Fi" MW antennas.
I seem to have collected trhree of the things without realising it.
Tuned with a 0-1000pf and a single 1 turn coupling loop the performance
on 160/80m is brilliant. Not tried them on any other frequency yet.
* The PA0RDT Mini Whip. This uses a J310 FET driving a 2SC5109. The description
for this antenna is that it's an "E" field antenna. In this design a simple
plate antenna measuring only 45mm by 30mm acts as the antenna feeding the pre-amp.
The original design shows the antenna powered via the feeder,the antenna being
located at the bottom of the garden.
I homebrewed the PCB within an hour and tried it out.
Well I suspect it's the feeder/dc line acting as the antenna !
When I isolated the antenna using a battery supply and fed it's output to the
FT817 via about 100mm of coax the performance was poor !
* I then investigated using the pre-amp as a conventional active antenna, with a
1.5metre whip and with a short length of wire about 5m long.
Performance is pretty good up to 30MHz.
AM broadcast seemed quite good down to 500KHz even with only the 1.5 metre
whip being used.
Below this either the antenna or the more likely the FT817's rx sensitivity
goes down the "plug hole" and it's pretty useless. BBC Radio 4 on 198KHz
is only registering S4 and theat with the 5m wire in use.
For tx'ing:
* I made a 28MHz "rubber duck" which is about 600mm long.
The antenna rod is made from a luminous plastic rod, used for tying garden plants
to, and of course it glows in the dark.
These are approx 10mm in diameter and fit nicely into an RG8 size PL259.
You can get these rods in the UK from a garden centre.
Performance is excellent. I've worked upto 2500Km with it and the 5w output.
Highly recommended.
It does help greatly if you have some form of antenna measurement system that
can quickly scan a wide range of freqs for the best SWR or match otherwise
it would take forever.
I used a Palstar ZM30 which can scan 0-30Mhz in 3 seconds.
(I wouldn't touch an MFJ if you paid me!)
* I made a 1m "rubber duck" for 14MHz and it performs superbly.
I can hear WWV and WWVH and CHU on 14.670Mhz almost 24/7 here.
* I've also been playing with a simple ATU + 1.5m telescopic.
Seems OK so far but definatly not happy with it below 10Mhz.
On 1.8Mhz I can shout farther than this antenna works.
More work needed.
I'm most keen to have a good rx capability down to 100Khz with my FT817 so
I'm going to make further tests, but it all takes time. I'm gonna try a
small loop antenna with the aforemention pre-amp in line and see how that
works.
(I wonder if Felix has the answer?) !
Trying to use MW to listen to broadcasts at night with a non directional
antenna is a disaster at night, at least here in the UK so a compact loop
looks attractive. I also wish to receive the aero beacons around 300Khz
and try the amateur 136Khz band too.
Does anyone else have anything to add regarding putting the FT817 to good
use when "pedestrian mobile".
I'm really interested in 0-50Mhz stuff. Repeaters and stuff bore me stupid.
Onto a different subject - the mini DIN connectors used on the rear of the FT817
are impossible to use with the rig in it's leather case.
Unless you make the required hole in the leather case.
I don't want to do this as it weakens the leather case.
Has anyone come across a compact (perhaps right angled) connecter that allows
easier use of the rear sockets ?
Lastly a cautionary tale.
Be careful of that top BNC antenna connector !
It's splits the internal diecast chassis.
In the UK you'll pay about £35ukp for a replacement. It's not that hard to
change a broken one.
Regretfully at least here in the UK both Yaesu and Kenwood have no proper
repair facilites, and as such your left to the mercy of anyone who decides
to take on the repair :-(
In the UK this is where Icom score lots of extra points, as not only do they
import the rigs, but they have a full on site repair facility. That's why I prefer
Icom rigs.
I've found Castle Electronics (here in the UK) to be the place to send Yaesu's and
Kenwoods for replair.
So has anyone got anything useful to add about getting the best out of the FT817
when pedestrian mobile ?
- Andy -
(Did you know that 9 out of 10 amateurs can't spell Yeasu correctly ?)
G0FTD @ GB7CIP
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