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Discovery TX500 (Part 2)

What mode? I have been thinking about getting an AX1 but I don’t know CW.


SSB, I don’t do CW. On one of my uses I got lots of euro traffic then realised I hadn’t fitted the counterpoise. It’s not a primary use but good as a backup when I’m out


I would love to see your SSB contacts on the AX1. I know it’s not the best of antennas, but I want to have something that I can use Incase I don’t have the ability to use anything else. Also I want to go do all the DC POTAs with the smallest footprint

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Here’s my two QSO’s from Mon using the AX1

I understand they’re bringing out an AX2 next year. I’m after the extension for 40m but they’re out of stock over here.

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Sorry I misspoke or misunderstood, I thought you were saying you had used it in SSB more than just the 2 contacts.

Hi Paul,

Thanks for elaborating about your last activation and welcome to this addictive hobby!

For a comparison, I used as well the TX-500 and SSB, but made the following contacts one day before you did, by using a different antenna.

First I activated DM/BW-348 on 40m and 20m (54 contacts during 48 Minutes):

Afterwards I activated DM/BW-854 on 20m, 40m and 17m (48 contacts during 50 Minutes):

On this second summit, Sara @MW7SRA tried to chase me like you with an AX1 antenna on 20m but unfortunately, I couldn’t hear her. Since the same happened to me when I started more than two years ago with SOTA, me and others proposed Sara to use a more efficient antenna (see my comment).

Don’t get me wrong, I think the AX1 for its size is great and may be the only feasible solution on a very small summit, but definitely can’t be comparable with a bigger (wire) antenna.

In my case, I was using both times my compact 12m long backup EFHW antenna, because the usual 20m long full size EFHW antenna was faulty (still have to check it out). The setup time of both antennas is usually below five minutes, as can be seen on one of my YT videos.

There are so many different antennas to use and the current propagation condition is probably the most important success factor. I just want to propose to play and build different antennas, since you learn a lot and to me it’s great fun to experiment with the component that radiates your RF. Enjoy the hobby!

73 Stephan


It’s definitely a compromise, but as always, whether something is worth it comes down to what is important to you at the time.

To be fair to the AX1, though, I would like to point out that it in this case it could be just as much down to user error, as both the radio and the antenna are new to me, and I only tried TXing a couple of times as I didn’t want to worry the other visitors. :smiley:



After a long break with ham radio and the start of SOTA, I watched some YT videos and got the wrong impression, that during my radio pause physics had changed. Obviously, this was not the case :wink:

And yes, I remember my learning curve at the beginning, not only with antennas.
In theory all looks easy, but along the way until the summit, there may be obstacles that you didn’t take into account. But exactly that is what makes SOTA so interesting, e.g. to deal with an unplanned situation.

Fortunately, after the initial couple of activations and when I experimented with different antennas, I always took at least one proven antenna as spare with me.

73 Stephan


I would never use the AX1 as a replacement it would be for a summit with no room / POTA that I need a small foot print. I have thought about getting a Buddistick Pro, but they are pricey and heavy. I had a WRC but it would upset me while I was using so I sold it. I love the ease of using EFHW and not having to change anything with the antenna when switching bands.


The second batch of TX-500’s have now landed in the UK - mine arrived this morning. First impressions after a little CW chasing is very positive, and it’ll certainly save some weight and space in the rucksack and I really like the design and engineering. A quick A/B rx check against my IC-705 showed it was equally able to pick out very weak signals.

A quick heads up though for anyone else upgrading the firmware to 1.12.0, as well as the improvements to AGC this also introduces a new menu item “32 Tune Ref” which allows you to trim the TCXO DAC setting. On mine, after the upgrade I couldn’t hear the same stations anymore compared to my IC-705 but I guessed fairly quickly the problem - the firmware update had initialised the TCXO DAC value to +1000, putting the radio several kHz off the indicated frequency.

Simply setting the “Tune Ref” parameter back to zero fixed it, so worth checking after you’ve done the upgrade.

73, Jonathan


Interesting, after updating the firmware last week, mine was on zero.

Last Saturday, I met @HB9ZAP and updated the firmware of his TX-500 in a restaurant, after we did a joint activation. But I didn’t check the menu “32 Tune Ref”.

Maybe we’ll have a TX-500 S2S in the near future :smiley:
Enjoy your new toy!

73 Stephan


I suspect it might depend on whats been in the EEPROM before (they usually default to all 1’s). I know how easy it is to get tripped up on bugs like that, where your development boards have had lots of previous releases running on them and might not behave the same as a new radio. On our automated test systems at work we routinely erase all the flash to try to avoid this, but it can still bite :slight_smile:

Done a bit more testing and I’m really liking it. There’s the occasional very weak internal spurious on RX, but because its easy to switch between direct conversion and low IF modes thats absolutely no problem (and once on a better antenna I think they’ll disappear into the noise).

The user interface is very well thought out and I think will be quite useable in poor weather conditions.

Looking forward to that contact Stephan :grinning:

73, Jonathan


I have. Each time I take it out I get contacts on 20m and all in Europe. No UK or Irish QSO’s. I just loaded up todays activation and got 6 contacts, Spain, Switzerland, Germany, Austria. No ones more surprised than me. I did try to get a chum up a hill 20 or so miles away and we could barely hear each other. I carry it in a wee Maxpedition pouch as a secondary and backup antenna.

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Cheers Stephan, normally I use a Bandspringer or a Bandhopper for HF. The AX1 is heavily compromised but it’s small enough to give me something to use for an aerial. It’s not my primary aerial but a wee handy one.

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Price of everything’s going up even secondhand cars. Our car’s now worth over £1,000 more than what we paid for it last year. I was in the market for an Acom amp for Xmas - price has gone up by £400 overnight - you can forget it. They’re putting down to a shortage of semi-conductors and lack of drivers. Certainly a shortage of semi-conductors - I struggled to get a couple of shift registers and a 555 time at work the other week!!

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HRO replied to my query: An order placed for a TX-500 now won’t likely be fulfilled until mid-January.

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I’ve had my TX-500 for a couple of weeks now and thought I’d post a quick update on my thoughts so far.

As you may know I don’t have any hills nearby so haven’t activated with it yet, but have done quite a lot of chasing. I wanted to get a feel for how it would work in poor weather, so have done a few sessions chasing with the sota antenna and TX-500 in the back garden. Temperature was around 3degC on the last couple of occasions, cold enough to need gloves.

Its worked out very well, the user interface on this radio is excellent. Easy to use with gloves on, and the display has always been very readable without taking any precautions (admittedly we haven’t had much sun, but enough to indicate its unlikely to be a problem). I’ve grown to like the GX12 connectors - they are very quick to attach+remove with a quick spin of the locking ring.

Bought some spare connectors and will be making up better key cable as the supplied cable feels too thin - one clumsy cable trip I’m sure will break it. Otherwise everthing else feels really good. The tuning knob turns smoothly with just enough weight and friction, no adverse effects at 3deg C.

I’m amazed how it appears to sip power - my LiFePo4 battery hardly seems to need much charging after hours on receive. I’ll make up a breakout cable soon to measure it properly, but its very noticeable the battery needs much less charging than after using the IC-705.

My intention is to use the IC-705 as my home radio and for data modes where it excels. The noise reduction works much better on the 705; I don’t use it on the TX-500 as it sounds horrible, but its not a noisy radio anyway. But so far I’ve been reaching for the TX-500 first as I just like the user interface and feel of the controls better - I’ll let you know if that changes after the ‘new radio’ syndrome has worn off :wink:

So thats a few thoughts after a couple of weeks, its definitely a keeper.



I think I have used mine enough in the last two months to make a comment or two.
It arrived very quickly indeed. and was on test very shortly. It took me a while to locate spare GX12 connectors; as soon as they arrived I wired up a pair of spare power leads (no internal battery to fall back on) and a variant of the headset/ptt adaptor I use with the KX3. Essential spares for multi-day trips.
A quick look around the shack/workshop revealed a plastic case just the right length and depth and wide enough for the T1 AMU as well - not as neat as the one I found for the KX3 but providing good protection - not that I think it really needs it. The case goes in a jiffybag to protect the waterproofs etc in the sack from the hard plastic case.
Seager Hill, G/WB-022, is a short drive and very short walk, so off we went on a not very nice day - but its waterproof so why worry. That has been my greatest benefit after a rather paranoid approach to the KX3 in bad weather.
Half a dozen contacts on 60m with varying reports, including suggestions of RF in the audio. (I now keep the T1 at arms length from the TX500 which seems to be better.) On 40m with 19 contacts the comments were more favourable and reports mostly 59 58 or better! Then a couple of quick contacts with the HH on 2m as Ian and Esther,AZA/B, were on May Hill, G/WB-019 (1 point towards Ian’s recent MG :smiley: ) and then home for lunch well satisfied with the new radio.
The TX500 has now been on 19 activations resulting in 325 contacts in the log and I have got very cold and fairly wet using it without detectable effect on the radio. (EDIT - the conditions do seem to have killed my phone battery.)
Points of concern:-
the ptt switch lead is very light and seems vulnerable - however it did survive being pulled fairly hard to extract it from a clump of heather. (It did not come as I was standing on it :open_mouth: ) I am not confident in it and still carry the speaker/mike supplied - just in case.
the connectors are stiff and difficult to extract with cold hands. I have considered leaving them in place (but then there is the effect on the emerging cable to consider.)

In conclusion, I am very happy with the TX500 to the extent that Vicki, M6BWA/P, is asking what I am going to do with the KX3 :pensive: EDIT - this is not a request for suggestions :unamused:


Sell it and buy an IC705

Why would I even consider doing that?