| |
GM7HUD > FT-817 07.01.07 03:01l 158 Lines 6671 Bytes #999 (0) @ WW
BID : AE4281GM7HUD
Read: GUEST DL1RX VE7HFY DG4IAK
Subj: Re: Green wire mod,empty cell
Path: DB0FHN<DB0RGB<DB0MRW<DK0WUE<DB0RES<F5GOV<F4BWT<ON0BEL<VK4TRS<VK6HGR<
VK7HDM<GB7ESX
Sent: 070106/2313z 48400@GB7ESX.#31.GBR.EU $:AE4281GM7HUD [Witham, Esx]NNA V3.1
G4XNH wrote:-
> I wonder what aerial you use for the FT-817ND? I have not yet used it on
> HF as I do not have a suitable aerial and was\am content to use it just
> for 2 & 70 for the moment
(EBT sized bull coming up!)
The gear was designed for SOTA (Summits on the Air) and so is lugged by
yours truly. So it has to be light as everything has to be carried along
with any mountain/walking/survival equipment.
Currently I'm only operating on 60m for HF on SOTA. I've done some 2m VHF
activations but VHF is not terribly popular up here North of the Border!
Sure there's activity, but as you need 4 QSOs to claim a hill, I want to
guarantee those contacts after all the effort. So 60m guarantees several
things, almost 100% success of inter-G contact during daylight hours, quiet
bands (unlike 40m), large group of gentlemanly SOTA operators all striving
for the same goal.
So I have a dipole cut for 5.3985MHz. This is supported in an inverted V
configuration by a 5m telescopic fishing pole. The apex ends up about 4.25m
AGL. The ends of the dipoles have lightweight plastic egg insulators
finished off with about 4m of nylon cord. The dipole centre is a small
piece of paxolin board with 2x 4mm binding posts and a captive coax feeder
made from 10m of RG174 terminating in a BNC plug. I use the front
connection for HF as this saves 20mA or so current in having to operate the
internal relay that selects between rear and front sockets. There are two
strain relief mounts and the dipole element weight is supported on these
with some quick release hooks attached to the elements. The connections are
made to the binding posts and have no strain on them. The element wire is
7/32 multistranded PVC covered. Thin, light and bright yellow so you can
see it on the heather!
The dipole centre is supported from the fisihing pole by a small metal
loop.
A choke balun made from 6 turns of coax is just below the dipole centre.
This is attached to the pole with double sided velcro cable ties. Another
tie holds the feeder near the base of the mast.
The hills around here are all covered with wire fences. A fence post makes
a brilliant support for the fishing pole, just lashed on with some
lightweight nylon rope. I normally try to find a fence running E-W and tie
the ends of the dipole off to more fence posts. The fence wire running
underneath a low mounted inverted V helps the NVIS radiation. I'm not after
DX, I want to be able to hit the UK.
Everything has been designed for strength yet light weight. 10m of RG174
weighs a hell of lot less than RG58. But it's much more fragile, so you
have to treat with serious respect when handling it. In addition, it gets
very cold when you get above 1500ft in the Winter. So I'm trying to avoid
anything fiddly to setup that needs gloves removing. I've not got there yet
and setup and take down still needs gloves off. But slowly I'm getting to
the point where gloves on setup is aproaching.
The elements are wound figure of 8 style onto some easy winders. These are
available commercial to hold kite string. They are designed to easily
deploy the string without twisting and are easy to wind back onto. Now I'm
not going to spend 6ukp for some plastic. I made my own. Initially I used
some heavy corrugated cardboard. But they soon wore out/got soggy. So now I
have used a material suggested by Brian, G4ZRP. This is the corrugated
plastic used in Estate Agent FOR SALE signs. This is very light and almost
indestructible, yet easily worked. Best of all you can find it as rubbish
in the streets or in skips when people are moving house.
If there are no fences, I've got a collar to drop over the mast and three
2m guys. I could use the antenna itself to guy the mast. But that is likely
to increase the mechanical load to point where things will break sooner. I
carry a bag of lightweight metal tent pegs to use if I'm operating with a
fence.
So the complete radio side carried is:
In the first heavy duty transparent plastic bag:
FT817+NiCds+softcase
Rubber duck
Standard microphone
pencils/paper
The bag is thick and clear. If it's very wet the 817 can be operated
through the plastic with ease. The external battery cable is left connected
all the time and the cable is coiled and held in place with the funny
little cord on a pop fastener that is part of the softcase. I use pencils
because I can resharpen them with a penknife and a pen is less reliable.
Next bag:
Dipole centre / feeder
2x Elements on easy winders.
spare doublesided velcro.
pole guying gear.
tent pegs
Next bag:
lightweight DVM (size of packet of 20 cigarettes)
Leatherman style multitool
small screwdriver
spare fuse, battery lead
Wrapped in a large piece of bubble wrap
12V 2.8AH SLA cell.
The bubble wrap makes a nice cushion to sit on and keeps your bum warm and
dry.
Rucksack contents:
Compass
OS map for region
whistle
Swiss army knife
Windup 5 led torch (no need to worry about batteries)
Survival bag
Water, fruit, carbohydrate rich food
Spare socks
Clothes (may be worn or carried):
Woolly hat
Gloves
Goretex X-treme jacket
Goretex clone waterproof overtrousers
Boot gaiters
Fleece coat
Sweatshirt
and finally a pair of Goretex boots (not suitable for crampons though).
My NOV for 60m says I'm conducting experiments into NVIS propagation. And
that's exactly what my SOTA activations are all about. Setting up QRP
simple gear and proving I can use it contact about the UK. I've plans to
try some other antenna designs but first I'm baselining performance with a
well known antenna, low mounted inverted-V.
The whole 5MHz experiment is a bit of a joke really. If you want to know
about 5MHz propagation ask the people who use it professionally, the MoD
etc. I'm not sure what we'll achieve other than confirming what the pros
already know and do! However, it does give us a nice clear band that people
aren't using for DXing and that seems to keep people behaving nicely. I
wouldn't like to try working with just 5W SSB on 40m or 20m due to high
incidence of LIDS.
What I can tell you (at the present time) is that operating an hour either
side of midday is around the best time for consistent QSOs on 60m. By 1430
(and it gets dark around 15.30 up here at this time) the propagation is
getting very iffy for shorter contacts with significant QSB, as the MUF
starts to drop no doubt.
Best DX with this setup is 350miles to Devon. Shortest contact is 31m. Both
about S5 reports each way. I could do with more people nearby to check on
performance but that shows so far I can work to the extremeties of the UK
and closeby stations.
Who can guess what's missing from all the gear being carried?
73 de Andy GM7HUD
Read previous mail | Read next mail
| |
