HF amplifiers, antennas, batteries and more

In reply to G8ADD:
Those who can, or those who think they can? I’ve been working on morse on and off since 1981 and have only recently tried a few chases. I’ve done a lot of listening, and there are some operators who send awfull, almost unreadable, morse, compared to (or with?) whatG4FON churns out. Lots of self-belief not matched by ability.

I’ll get off my hobby-horse before someone kicks it!

Regards, Dave, G6DTN

In reply to MW6AQU:

Hi Gerald,

There’s no right or wrong way when it comes to activating.

Find out what works you.

Experimenting is one of the best parts of Amateur Radio.

73 Mike
2E0YYY

In reply to MW6AQU:

“That looks like a simple set up, maybe just substitute a linked dipole for the bands I want in order to miss out the tuner?”

A linked dipole would be lighter and probably a little more efficient. I only use a W3EDP because it lets me change bands without abandoning my operating position and messing about with the antenna, which on a rocky summit can be a bit uncomfortable. I trade a little efficiency for a saving in time and effort. A nest of parallel dipoles would do the same job with higher efficiency but also with higher wind resistance. Swings and roundabouts!

73

Brian G8ADD

In reply to 2E0YYY:
Good advice Mike.

I am enjoying experimenting, but I want to avoid any expensive mistakes in kit choices. I don’t mind spending money if it will turn out to be useful.

I’m actually getting exactly what I wanted (and expected) when I kicked this discussion off i.e. quite a lot of differing opinions, each of which reflect different peoples experience and needs.

I want to absorb all of this before I decide where to go next, which will be my decision based on what I think will suit me.

I’m grateful to everyone expressing an opinion and their findings from their chosen operating methods.

Keep it coming folks.

73
Gerald
2W0GDA

In reply to G8ADD:
Another good point Brian.

Although for me getting up and about might be a good idea to stop getting stiff and cold.

73
Gerald
2W0GDA

In reply to MM0FMF:

365days x2.25years x10mins/day = 137hrs approx.

I suspect that’s actually an under-estimate. Wish I’d been paid for that time… :wink:

You’re doing it wrong! :slight_smile:

Probably misled by Koch et al., then… :wink:

In reply to M0DFA:

there are some operators who send awfull, almost unreadable, morse,

I’m glad I’m not entirely imagining that. I don’t expect to be able to pick callsigns out when the pile-up’s calling in, but there’ve been cases when I’ve been unable to pull anything (except, perhaps “5NN”) out of the responses…

In reply to G8ADD:

some of these QRP CW types consider an 817 too heavy to bother with!

I weighed up my rig before my last walking holiday in the Lakes, and decided that as I’d be carrying everything almost every day, and I’d be away long enough that I’d have to take a battery charger, that the extra kilos (plus the antenna pole) were more than I wanted to carry. I might have taken a rig if I could have got the total rig weight below a kilo…

73, Rick M0LEP

In reply to M0DFA:

… the 817 weighs 1.2 kg with internal batteries. No idea what a amplifier weighs…

Just weighed my amps: BNOS 50-3-50 (6M, 3w in 50w out) 1.3kg; BNOS 144-3-50 (2M, 3w in 50w out) 1.26kg; Microset RU45 (70cm, 5w in 45w out) 0.7 kg

I use these with a FT817 off a 7AH slab for 2.5 hours in the UKAC’s

Pete, M0COP

In reply to M0COP:
Well, that answers that, there is basically not much in it for weight.

I think the 857 has more features and has the ability to do at least 50W on all the bands I want (HF to 2M) and 20W on 70cm.

So that leaves batteries. SLAB’s or LiPo’s.

73
Gerald
2W0GDA

In reply to MW6AQU:

So that leaves batteries. SLAB’s or LiPo’s.

If you’re carrying the stuff up hills, LiPo batteries every time.

I used to lug a couple (and sometimes more) of 4Ah SLABs up hills but not any more - a couple of 2.2Ah LiPos are not equivalent but I find are more than enough. One would be enough if it’s just the 817 and no transverter. The lowered voltage of the 11V ones is not really a problem, though I know some people use higher voltage ones and lower it with diodes etc.

It’s well worth getting a proper balance charger though - in fact probably essential. Read up about the care and feeding of LiPos - they don’t like all sorts of things. Especially being stored fully charged :frowning:

There’s masses of discussion on LiPos on this reflector - hunt through the old threads.

73
John GM8OTI

In reply to MW6AQU:

Consider how many activators made Mountain Goat using an FT817, SSB, link dipole or similar and possibly a Li-Ion battery with an all-in weight of less than 2Kg when the sun was less active. Then ask yourself if the extra complexity and weight of what is being proposed is worth a maximum of 2 S points at the Chasing end?

Remember being rare DX apparently adds about 4 S Points to your signal without any effort on your part!!! Also see what results have been gained in the last week on 28MHz SSB and then make a decision about increasing your pack weight.

Then, as others have said, there is CW also with absolutely minimal impact on your pack weight.

My twopenn’orth, YMMV as my children keep telling me

73

Barry GM4TOE

In reply to GM4TOE:

I think you are oversimplifying, Barry. You are looking at a possible 10 dB difference on V/UHF, which will make a considerable difference on outlying or difficult summits. Even on 40 metres life is much easier with the bigger rig, you get found and spotted more quickly. It can be done with an 817, no doubt of that, but it is easier with an 857 if you don’t mind the extra weight. I use both, the difference is obvious to me.

10 metres is great at the moment, but even now when the solar radio flux drops to near 100 the band goes rather quiet, in a few years time we will be back to waiting for Es openings!

73

Brian G8ADD

In reply to G8ADD:

With greatest respect I’m going to disagree with you on this Brian. My operating has been almost exclusively /P - most of it non-SOTA, without the benefit of spotting - which in my view gives a fairer comparison of the real advantages of power. Rigs have included the 817, 857, 897, Alinco DX-70, PRC-320, Elecraft KX1 and a couple others…
All have their pros and cons - and there’s something masochistically fun in taking a 15kg Clansman kit up a hill or a 100W rig with a couple 12Ah SLABs for a full day operating. Honestly though, I found there were very very few occasions where upping the power got me a QSO when QRP didn’t. One is busting a pile-up, the second is when you’re right in the noise floor and need that extra few dB to make you readable. A few dB below that and the extra power makes no difference, a few dB higher and you’re already legible.
To me the real advantage the 857 has over the 817 (and the reason I consider it the second best rig for SOTA after the 817) is the bigger knobs - much better for use with gloves. Therefore Gerald I would say that rather than getting the amp you’re considering, if HSUs allow go for the 857 instead. Far less faffing with cables, power, etc and the 857 is easier to use on the hill. If, however, you want effectively a lot more dBs for the price of a key, the Koch trainer is the way to go!

In reply to MW6AQU:
Hi Gerald!

Checkout my www.QRZ.com listing to give you a flavour of what I use up on the hills.

73 es gd activating

Jack (;>J
GM4COX

In reply to 2W0NNN:

there were very very few occasions where upping the power got me a QSO when QRP
didn’t. One is busting a pile-up, the second is when you’re right in the noise floor
and need that extra few dB to make you readable.

Working from Kenya last year (when anything much above 15 metres was dead) I found that 5W from an FT-817ND was mostly a struggle, but 100W into the same antenna using an Icom 706MkIIG, pulled in ten times as many contacts. Obviously, from there, almost all the contacts were over the 1000km line. Best DX on the 817 was Canada (~12,000km) and best on the 706 was Hawaii (~17,500km). That was, however, from near Nairobi, and the noise floor was… interesting… Electric fences and arc-welders do not nice RF neighbours make…

73, Rick M0LEP

In reply to MW6AQU:
Well this thread is fascinating!

I am enjoying all the differing views.

73
Gerald
2W0GDA

In reply to GM4COX:
Thanks Jack, that all looks straightforward. Just one question. Why carry both the VX-8 and the FT817 and two separate batteries?

Is it so you can monitor 2m and HF at the same time?

73
Gerald
2W0GDA

In reply to MW6AQU:

Why carry both the VX-8 and the FT817 and two separate batteries?

All real men carry 2 radios with them. And 3 or 4 batteries. Don’t you? :wink:

Yes, it’s so you can monitor VHF and play on HF. Also you can sometimes chat to fellow activators/chasers as you walk between summits. In my case it’s normally on the way down rather than up for obvious reasons!

Andy
MM0FMF

In reply to MW6AQU:

"Why carry both the VX-8 and the FT817 and two separate batteries?

Is it so you can monitor 2m and HF at the same time?"

Spot-on Gerald - especially S2S on 2M. Also it’s a back-up in case I have a problem with either rig - especially if you are on one of the remote Scottish summits. Likewise with the extra battery packs.

Cheers

(;>J

In reply to 2W0NNN:

If, however, you want effectively a lot more dBs for the price of a key

Just how many more?

Well we can do some very crude power spectral density (PSD) maths. This is the “back of a fag packet” version not the proper PSD. It’s 30 years since I last had to work one out and I’m a bit rusty at the hard sums involved.

But an informative value of the benefit of CW can be had doing the following for an 817. Output = 5W, CW TX b/w = 100Hz, SSB TX b/w = 2700Hz

CW: 5W/100Hz = 0.05 W/Hz
SSB: 5W/2700Hz = 0.00189 W/Hz

So CW has approx 27 times higher PSD. This assumes the power is spread linearly across the TX b/w and it certainly isn’t for voice. But I did say it’s the informative not accurate version.

Or in simple terms to sound as “loud” as a 5W CW signal you need to have about 135W of SSB. We’ll round things about and say 5W CW approx. 100W SSB.

There’s no doubt that 20W for SSB makes noticeable difference over 5W even though it’s only 1S point. The real problem of low power SSB is that it’s hard to protect your frequecny from an alligator who’s all mouth and no ears and splats all over you. This is mitgated if you’re lucky enough to get a well equipped chaser who will come on your freq. and drive the encroaching stations back.

A speech processor is a noticeably missing from the 817 and having an outboard one makes a big difference as it ups the PSD. I’d add one of those before I’d add an amp. Not very heavy and doesn’t need a big extra battery.

For the higher bands, more antenna gain is reasonably easy to get. A vertical Moxon for 15/12/10m is not a massive antenna and gives good improvement. It weighs less than an amp and improves RX as well as TX.

If you have an 817 the improvements in order in my view would be

  1. learn enough (*) Morse to have SOTA QSOs
  2. make a better antenna
  3. add an outboard speech processor.
  4. make an amp
  5. sell the 817 buy an 857 and new batteries

For those who aren’t aware, the MX-P817 is a 50W addon HF amp which interfaces to the 817 and uses the automatic bandswitch data to follow the 817. It’s got filters unlike that RM CB trash and uses a nice Motorola FET. You can get them for between £135-£170 depending where you look.

In the meantime Gerald, how did your 1st CW lesson go last night?

Andy
MM0FMF

  • My CW skills are sufficient to get a callsign and report and the GA ANDY at about 18-20wpm. If someone wants to send me plain text then we need to drop to about 10wpm or slower. You don’t need to be character perfect for extended receiving at 30wpm for SOTA.

In reply to GM4COX:
Thanks Jack, that all looks straightforward. Just one question. Why carry both the VX-8 and the FT817 and two separate batteries?

Is it so you can monitor 2m and HF at the same time?

73
Gerald
2W0GDA