“If I would buy new antenna tuner for FT-817 ND, which would be the most appropriate? My requirements are small size, accurate SWR display with 5W.”
I googled and found two MFJs: MFJ-904 and MFJ-971. I am just wondering if they need external power for working? When I look schematic of MFJ-971 I understand that its SWR meter works without external power, so the 12V is only for meter lamp - have I understood correct?
Third interesting model is Elecraft T1. It is very small, but needs 4,5V battery and does not show any numerical value of SWR. I am old school boy and have such an understanding that antenna tuner should show some numerical values (I can be wrong). Base reason is that I would have rough estimate how good or bad SWR is that I would not destroy power amplifier.
Let me know how are your opinions and experiences?
In reply to MM0FMF:
+1
I have been using an elecraft T1 for several months (no battery replacement) and it’s quite fast and its range wide enough. Very small and light -at least compared with the other ones I’ve seen- and a lot of memories (can be connected with the 817 thru port). The 9v battery, which is used just while coupling, can be stored disconnected inside the tuner (a thing less to lose). I think the design was made for one who knew what you need out there.
My favourite. Ad for free, I dont work for the company
Third interesting model is Elecraft T1. It is very small, but needs
4,5V battery and does not show any numerical value of SWR.
Let me know how are your opinions and experiences?
73, Saku OH2NOS
Hi Saku,
I have used a T1 with the FT817 on about 40 activations, I think it is very good.
It takes a 9v PP3 battery, and draws current only whilst it is tuning, as it uses latching relays.
There is an FT817 interface cable, which allows it to tune to the last settings used on the band you select, but I haven’t bought one of those. I think it would be of limited use to me, and is something else to lose / break on the summit!
The SWR LEDS represent 1:1, 1.5:1, 2:1, 2.5:1 and 3:1 which is close enough for me to feel happy for my PA FETs.
It is nicely made, but not waterproof. I am also careful with the connectors, as they don’t feel mechanically strong.
Overall, though, I think it is a good piece of equipment. I’d buy another if I had reason to.
I have the T1 for my FT817 and it does have a SWR indication either as a light or CW. It is crude but adequate and is enough to save your final amp from sudden demise!
The SWR meter on the 817 is fine as Andy implied by his reply. Once again it is crude but adequate. Any SWR below about 2:1 is pretty good and my T1 always does better than that with my doublet.
It is not as good as the KX3 gets with its ATU (or the KX1 for that matter) but is smaller and faster than any mini manual tuner.
Read the following interesting article and you will find out what is wrong with it.
Specifically, at lower output powers, it can give a very misleading indication. When cutting my dipoles to resonance I used my FT817 at low power to generate a signal, but I always used a conventional outboard VSWR bridge for the tests.
I’m fully aware of that Walt. Tune for best match using the 817’s display at low power then advance the power and readjust until best match is displayed at high power.
Almost all simple SWR meters are inaccurate at low power levels due to the diodes not seeing enough voltage to work properly. Good designs have a small current flowing through the diodes to (mostly) overcome this problem. Really good ones characterise the diodes and provide on-the-fly compensation.
Of course inaccurate does not equate to useless. But if you see a few bars on your FT817 don’t worry overmuch. Anything 2:1 or less at the radio in a 50 Ohm system is mostly fine (exceptions apply).
I have used an FT-817 quite a lot in portable situations. My experience has been consistent with the following observation from over the years:
0, 1 or 2 bars showing on FT-817’s SW display: All working well.
3 or 4 bars showing on FT-817’s SW display: Still working OK, but perhaps not getting out as well as with the lower indications.
5 bars showing: System doesn’t seem to be efficient even though comms still possible.
6+ bars showing: Didn’t fancy that, so didn’t try!
All my resonant VHF and HF portable antennas give me a zero bar SWR indication on the FT-817. So even if I get, say, 3 bars showing up, I check for problems even though the system will still work. Simple things like slightly adjusting the croc clips (feeder connection to VHF beam) or raising the dipole ends (80m) usually improve this kind of situation.
If when using a EFHW + tuner system, if I can’t find a setting to give me lower than 4/5 bars, then I prefer not to use that band. I tend to find I can tune most bands to give a zero bar reading on the FT-817.
The FT-817’s SWR meter indicator is not perfect and has limitations in what it is actually able to tell you. When you are used to using it though, with your chosen familiar antennas, you soon get to know how to interpret the display, so it remains a very useful feature.
Specifically, at lower output powers, it can give a very misleading
indication.
That article is very old and is almost certainly about the non-ND version of the 817. Do you have any up to date information that states that the same problem exists on the 817ND?
I use the MFJ-971 with my 817. As well as coax it will take ladder line, end fed and can be configured for QRP by moving a couple of jumpers inside the ATU (doesn’t affect warranty) and the twin needle meter enables you to see exactly what’s going on.
The description in the 817ND service manual matches an 817 (nonND) circuit diagram. Either the text hasn’t been updated or nothing has changed in the SWR function. 30years of dealing with Japanese companies on a professional level makes me think it’s that later of those 2.
The problem is all amateurs (and engineers) demonstrate some level of Autistic Spectrum Disorder and have to pendantically analyse everything written or said.
The 817 SWR indication is good enough. Stop bloody worrying about getting 1:1 matches and adjust for maximum smoke out and minimum smoke in. Either by having well matched antennas, in-situ antenna matchers or faffing about with the wires on the summit.
Seriously, it really isn’t hard to do or comprehend.
Well, well, well - have I put my fingers to wrong place? ;-D
Thank you for excellent comments. They all are very valuable for me!
Andy MM0FMF, you are right. It is possible operate FT-817 without tuner if you know that your antenna is quite good tuned beforehand and it is not necessary to have any tuner.
But, like I said before, I am old school boy and also an engineer. Now with 5W output power I would get all to air if possible. Also if some cases I should tune my antenna (a new one) I would know, should I lengthen or shorten it? Then I need more accurate SWR value. Also in the field when I move the end of antenna I will know what it makes to SWR. But these are personal needs only.
Very interesting models are Elecraft T1, LDG Z-11 and MFJ-971. Two first are small, electronic, need (internal) power supply and have led view for SWR. Third is biggest, works without (internal) power, but is manual (like my existing).
Decission making is difficult. All these three models fullfil my needs. My last arguments is which would we most appropriate far from civilization if internal battery end? Question for Chris M0RSF is, how good MFJ’s SWR meter is with qrp power? Is it accurate or not?
Coming weekend (perhapse on Saturday afternoon) I am going to make new summit with FT-817 and my link dipole, but without any antenna tuner. Hopefully I could get qso with some of you!
just to add a little more noise…
I own two QRP tuners:
LDG Z817: electronic and autotuner. Connects to the FT-817 and tunes super fast and in very differente impedance conditions. A good small tuner for the 817.
Emtech ZM-2: manual tuner, lightweigh, no SWR display, so that I use the FT-817 indicator… Deal with parallel feed (doublets…) or coaxial. Easy to tune “by ear”. http://emtech.steadynet.com/zm2.shtml
Good luck with your choice. Take the one that fits best your pocket and portable size/weight and any of them will be all right.
In reply to EA2BD:
Hello Saku,
I use a HB Fuchs Tuner from QRP Projects:
Works very well with wire cut to half wave on 40 meters and no counterpoise, very easy to put up even on heavily treed summits. Follow the tuning directions for max noise. Then fine tune with key down. I start with 500mw to save batteries, and get close, then I go to 5wts for the final bit. Use the radios SWR meter, it may not be spot on, but its close enough. I operate (CW Only) at 2.5 watt setting. With a full charge on internal battery, and an 8 pack of AA’s plugged into the rear jack (essentially running 12v in parallel and nearly doubling your amp hrs) I get much better battery life than on internal battery alone. I’ve come across a few tips for power conservation, and they seem to work very well:
Back Lite off saves 27 mA
Using front BNC antenna saves 20 mA
Noise Blanker off saves 13 mA
Just the above will give you a 20% reduction.
I only use CW so that will also help, the IPO ON (Pre Amp OFF) will also save 2.5 mA, but not enough to really worry about. Keep it on, you might get a S2S you would otherwise miss. Here is a site where I found the above info. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB0QFjAA&url=http%3A%2F%2Fwww.ka7oei.com%2Fft817_pwr.html&ei=TFmjU7baF6Kd8QHW04DoCA&usg=AFQjCNEBbVhUNSUXLw9SgYgi1t7XBsfDKw&bvm=bv.69411363,d.b2U&cad=rja
The link refers to the 817, but the 817ND is identical aside from the addition of the 60 meter band, and an update to the PA to keep it from self oscillating to death.
It’s a great little rig…a bit of an amp hound…but good none the less.
Good luck,
Bob W2CKL
The MFJ-971 is a 300W ATU though there are two internal jumpers that are easily moved to make it a 6W ATU. Therefore I think the readings on the cross needle meter will be more than reasonable. Also, with the display you can monitor SWR and Power out.
The MFJ-971 is a 300W ATU though there are two internal jumpers that are easily moved to make it a 6W ATU.
The jumpers change the sensitivity of the meter. The ATU itself is fine at QRP-ish levels, but sometimes does interestingly unhelpful things when presented with higher power signals.
In reply to OH2NOS:
Today I made my first summit to Venalaisvuori OH/JS-067. SWR meter did not view any reflecting power so I could concentrate to working. Chasers’ signals were very strong and it was huge pile up after first cq! Also I used first time new mini paddle - time to time I had small problems with it, but I believe that training makes master. FT-817 worked excellently - I think it is much better what I thought beforehand! Its loadspeaker is so good and clear that I did not need head phones which I have used so far. Only one station come weaker and then I had to listen more careful. It seems to be such a situation that FT-817 and I will became good friends and this is good for future.
My visit to Venalaisvuori was less than two hours because it was raining on the morgning and estimation for rain was high during UTC 11.00 and later. This year Midsummer celebration in Finland is coldest during last 30 years. When I reached Venalaisvuori its was +7 C. Raining had just stopped and sun started to shine. Station up and cq on the air. After halve an hour I saw very dark clouds on the sky which were coming towards me. Couple of qsos and station down and quicly to car. When I had driven less than two kilometer started heavy rain. Inside the rain temperature was lowest 3,5 C. It come lot of water and grains also, which is very untypical in Finland this time of year, but this Summer seems to be different.
Life goes on and me and FT-817 will be on the air time to time. Keep in touch!
