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'Mass Matters' (G4YSS)


#1

………Strange you should mention a composite outer casing, because I was just wondering if it would be an idea to replace the one on the 817 with an aluminium replacement. Did you construct the casing yourself or buy it somewhere?

Regards Steve GW7AAV

Hi Steve,

As for home-brew rig casings, much time and effort has been expended here, reducing the weight of rigs for remote /P work since the mid 80’s. I started with a CIR Astro 200 (5 band, 12V-100W, HF/M) using folded 26 SWG & 24 SWG alloy sheet to replace steel, an FT77 using 3mm honeycomb composite and a Yaesu 4m FM PMR, using corrix board. The CIR was further lightened by first removing all the PCB’s and punching 87 one-inch diameter holes in the internal steel chassis, then adding-back the screening with aluminium foil. I also rebuilt the thick steel PA box in an otherwise relatively lightweight FT747, using alloy.

The IC706 2G was the most difficult and it took a week of work because the bottom casing is not straightforward but has a compound shape in the form of a bulge. Into this projects internal components. The top was made in 3mm honeycomb composite, with added screening. It accommodates the speaker and cooling holes. The bottom was re-manufactured in 0.4 inch thick two-skin epoxy honeycomb used in aircraft floors / bulkheads etc. This was internally ‘relieved’ to clear the circuitry, screened with self-adhesive aluminium foil to ‘pick up’ on the chassis; then meshed-over cooling holes were incorporated. Sure the rig’s a bit bigger now but using relatively thick honeycomb composite is a way of decreasing weight while retaining strength and some of the impact resistance. The combined weight saving over the conventional casings was 12.2 oz (347gm) as follows:

Standard steel top panel, 9 oz; new top 3.5 oz (both inc speaker).
Standard steel bottom panel, 8.5 oz (inc feet & prop-up frame); new bottom 1.8 oz (no feet or prop).

There were further savings as a result of a modified power lead (incorporating rev-pol. protection and a resettable circuit breaker) plus the fact that a CW key (if it’s worthy of the name) is incorporated into the mic case.

I have not considered mods for the 817 as it is not yet a year old. As is normal, Yaesu have fitted a steel case, presumably on the basis of material cost and ease of manufacture but there’s the attraction of relative simplicity in this casing, apart from clearance for the battery box etc. At least the internal chassis is cast in aluminium. However, the 817 is a lot smaller than a 706 so I could not see savings greater than perhaps 5 or 6oz. I can’t see that any high-tech composite approach would be worth the bother on an 817 but around 26 SWG (or thinner) bendable alloy might be worthy of investigation.

Any small weight saving (especially when added to many others) is worth the effort if the time and materials are available. I for one, have ‘groaned’ many times after seeing ‘boastful’ ads for the latest compact all band-all mode rig without my first interest, a weight figure given in the short-spec. I groan even more loudly when I buy one, take it out of the carton, rush it into the workshop and run a magnet over it! It’s been frustrating that for 2 decades nobody sold what I wanted forcing me to invest 200 hours on a home-brew 10W, 3 band SSB/CW HF rig with low receive current and 1.8kg. Until the 817, I don’t think it crossed the designer’s minds that someone might actually be taking their compact rig out of the car to be so cruel as to stick it in a rucksack and lug it across the Cairngorms or down a cliff.

There are expeditions where weight is not particularly important, except perhaps to comfort. In others, it’s central to getting the job done.

Weight saving applies to all equipment of course and it’s review should be an ongoing activity as technology advances. The first place to start is with battery technology. I never feel that I’m doing enough but one important (if low-tech) component of this overview is my own body mass, especially around Christmas time! All the meticulous, time-consuming effort in other areas does thankfully concentrate the mind somewhat in that particular direction.

Hope you succeed with the 817 case.

73, John G4YSS.


#2

In reply to G4YSS:

A very good and informative read John, very interesting stuff and I enjoyed every minute of it.

73 Mike GW0DSP


#3

In reply to G4YSS:

Seems a little bit extreme John! I cant see it catching on. Some pictures on Flickr would be interesting.

See also:

http://www.qsl.net/g3cwi/weight.html

73

Richard


#4

In reply to G4YSS:

Food for thought, John!

My thinking went something like this;
Why am I lugging the internal batteries in the FT-817 up every hill when I use a SLA?
Why don’t I leave the microphone at home and make a light weight head set?
If I use a head set I don’t need the internal speaker, so why not remove it?
Then, I could lighten everything further if I replaced the case with some light alloy.

About five minutes after thinking these thoughts I read your activation report and was curious. The only answer to the above questions is that I would loose the flexibility of being able to use the rig both in the shack and the car as well as on the hills, but it is certainly a path worth pursuing.

Examining my rucksack my main source of weight is the coax feeders for the antennas so maybe I should throw away the two 50m lengths of 10.5mm mil spec RG213U and replace it with shorter lengths of 2.5mm RG174U mini coax before I try tin bashing an aluminium case;o)

Regards Steve GW7AAV

Just joking about the RG213U, I wouldn’t use that it’s too lossy. I’m now using this 22mm stuff but I couldn’t remember the number. It’s a bit heavy but it will stand up on it’s own so you don’t need a mast;o)


#5

In reply to G4YSS:

Good Day John,

It is very refreshing to discover that there are people out there who take this important matter sufficiently seriously.

I too have for many years been pioneering the use of advanced technology to reduce the burden of carrying over-engineered equipment to inaccessible places.

Of late I have had particular success with the use of materials such as Waspalloy, which you no doubt are more familiar with in it’s role in aero-engine turbine blades; it does however have a strength to weight ratio second to none. Admittedly not every amateur workshop contains the ultra-high temperature reduction furnace necessary to deal with this material, nor indeed the somewhat specialised machine tooling to work it but the rewards are tremendous, it being possible to shave 30 grammes off the weight of an '817 by casting the chassis in this material and removing unnecessary material with a carburised tungsten reamer.

Not radio-related but perhaps of interest to those who do spend a lot of time in the hills, I have fashioned a set of camping cutlery from this material and have reduced the weight by a further 35% by boring holes in strategic places: experience has however shown that it is unwise to extend this treatment to the bowl of the spoon.

Finally, do not overlook lower-tech methods of weight reduction; for instance by drilling strategically placed holes in the boom of your SOTA beam you can reduce it’s weight by a staggering 5%; and by operating 20m instead of 40m you can save almost 50% of the weight of the radiating portion of your dipole.

Have fun out there,

73 de Paul G4MD


#6

In reply to GW7AAV:

Just joking about the RG213U, I wouldn’t use that it’s too lossy.

Steve, you’re a wind-up - or are you? I used to use 5m of RG-213 and as part of the ERP-encouraged lightening of the kit, I changed this for 5m of 5D-FB cable. I made losses in two ways - weight and cable loss and as a result of the latter I gained an improvement of 0.2dB on my 2m noise figure. Nice cable 5D-FB - hard to get hold of and it needs special diameter BNC’s. Anyway, ask Richard ERP about his light blue RF string…

73, Gerald


#7

In reply to G4OIG:

In reply to GW7AAV:

Steve, you’re a wind-up - or are you?

73, Gerald

I reckon AAV has been having lessons from HJD :slight_smile:

73 Mike GW0DSP


#8

Paul, I’m going to send you the bill for cleaning of a vdu, IC-7400, Watson PSU and various other equipment.

I had unfortunately just taken a rather large swig from a mug of tea at the same time that I read your posting, hi.

Superb Paul!!

73 Mike GW0DSP


#9

Is it important to get the pack weight down? No. Whenever I am carrying a heavier-than-usual pack, I just remind myself that it is good for my fitness. Pack weight up keeps my weight down.

Besides, in my experience, if you feel uncomfortable with the weight of your pack, you don’t necessarily need to reduce that pack weight. Usually problems can be solved by properly adjusting the shoulder straps and waist strap of the rucksack.

Surely the quality and set-up of your rucksack, and what size/how many SLABs to take, how much water etc are considerations that will have far more effect on the overall load than mods to radios.

Then again I could always take that new CW filter back out of my 817…


#10

In reply to M1EYP:

Is it important to get the pack weight down? No.

Therein lies the difference between a radio amateur carting gear up a hill and a backpacker. I seem to recall that you adopted a different philosphy on the Pennine Way! I find a long walk in far more pleasurable with a light pack - so next time we go on a joint activation you can carry my gear and we will both be happy :wink:

73

Richard


#11

In reply to G3CWI:

so next time we go on a joint
activation you can carry my gear and we will both be happy :wink:

Are you sure you’ve read the rules?

Steve GW7AAV


#12

In reply to GW7AAV:

Good point! Tom can carry my spare SLABS and water.


#13

In reply to G4YSS:
Hi, John. I used to carry quite large loads up the hills in the days when I used to do Scottish winter climbing: the minimum load was about 15 kg for a simple snow gully, at grade III and above with the extra racks of pitons, screws, hammer etc it approached 20 kg. Weight cutting was not considered, the gear was essential and its strength could not be compromised, you couldn’t even jettison the camera as it cost you bragging points! What made a big difference was a decent pack frame, a properly adjusted pack frame such as a Karrimor made you feel as if you were carrying half the weight. I don’t see people using them nowadays, either they are obsolete or they are not considered “cool”! I still have mine: if it hasn’t deteriorated (like me!) it would be interesting to modify it to mount the rig and slab onto - remove the sack and slot in the rig and it would hold things clear of the ground and provide a stable platform even on a pile of loose boulders. Just a thought!

73

Brian G8ADD


#14

Is it important to get the pack weight down? No.

Therein lies the difference between a radio amateur carting gear up a hill and a backpacker. I seem to recall that you adopted a different philosphy on the Pennine Way!

Indeed. I was, of course, talking complete rubbish. My ‘heavier-than-usual’ pack is probably lighter than some other activators’ ‘lighter-than-usual’ packs. I do find though that extra weight in my pack can be almost nullified by putting it at the top, and tightening the waist strap.

The Pennine Way, of course, is a completely different proposition to a day walk, and indeed what exposed the previously unseen inadequcies of my old cheapo rucksack.

so next time we go on a joint activation you can carry my gear…

I already get the fitness boost I require by carrying some of Jimmy’s and Liam’s gear for them, so I am afraid I will be unable to help.


#15

In reply to GW7AAV:

Are you sure you’ve read the rules?

It says (something like) the method of final ascent must be person powered, and that all equipment must be carried to the summit by the activating team. I don’t think it specifies who has to carry what. If it did, I would lose a load of points, where we have arrived on summit in poor wx and just activated it on Jimmy’s handheld!


#16

In reply to M1EYP:

My ‘heavier-than-usual’ pack is probably lighter than some other
activators’ ‘lighter-than-usual’ packs.

Oi, talking about me behind my back while I was doing some work, eh? I would have you know my total pack weight (including mast and antennas) of 22kg, as taken up Great Rhos MW-002, has now been reduced to 15kg. The problem is I need to go out twice as much to get fit with less weight… well, that’s what I keep telling the XYL!

73, Gerald


#17

In reply to 2E0HJD:

…but if you eat all your buttys before you leave, it could put a strain on one’s hip :slight_smile:

Tin hat on for reply!!


#18

In reply to 2E0HJD:

Mmmmmm bacon !


#19

In reply to 2E0HJD:

I usually leave mine in the car and eat them when I have returned that way they can still be nice and fridge fresh from the cool bag. I always have a nice cold drink there to re-hydrate me too.

I was thinking of using a pack horse to ascend summits but I still need to lighten the load and make room for the paraglider to get down, with my weight it won’t take long ;o)

Steve GW7AAV

Is that static or bacon frying?


#20

In reply to 2E0HJD:

it`s simple realy eat your buttys before setting off

So you like indigestion do you Mick? Don’t you know eating yer scran before you ascend requires the blood to go to yer stomach, but it will be used for fuelling yer leg muscles instead, hence indigestion, big time! Besides, the litre of water being carried weighs more than the sarnies… mind you I haven’t seen yer scran!

73, Gerald