Varying Frequencies

Reminder
Please note that the blog now is continued at
https://oz9qv.blogspot.dk

My main radio blogging activity will, from now on be at the blog for my Danish call, OZ9QV : http://oz9qv.blogspot.dk/.

See you there .

Got myself moved safely back to Denmark, and got a bit of antennas in the garden.

 1) 3 band vertical for 6m, 2m and 70cm. Worked local on 2/70FM, and a bit of sporadic E this summer on 6m.

 2) Lately I got myself a multi-dipole for 80/40/20/15/10. Works on 30/17/12 as well. SO I got started doing a bit of CW QSOs ...

 3) Decided that 10m might have it last really good winter season, so I set up a half wave vertical (shortened 27 MHz Half wave). Just moved it into the garden and elevated the feed point to about 5m. Came in late in the afternoon and 10 was open to South America and South Africa. Worked CE, CX, ZW (ZS) and PY. Not bad for a first day with the new antenna. Given the opportunity the feed point will get up to about 7m with some good guy wires.

 Winter is coming, and I would like to try getting a bit more antennas up, possibly for 4m, and a wide band receiving antenna (active whip (Dressler) or a PA0RDT "mini whip" E-probe). This should work from

The Double Dutch grabber has disappeared forever, due to a move. As soon as time allows, the "Thor's Hammer" grabber will come up running. Some antenna is necessary. The grabber will likely, over time, be renewed to cover more than one or two bands.

In less than a year the Double Dutch (PA9QV) grabber is going to disappear, and Thor's Hammer will probably be expanded to more bands when time to get the hardware running allows. Thor's Hammer will still be unattended for that year, but after that it will be mostly attended.

The Grabber is down, again.

It is running unattended, so will be restored when someone can attend to it.

It still needs some recovery program if a reboot should occur (e.g. due to a power failure).

Thor's Hammer has been down for a while due to a thunderstorm putting it offline.
The grabber is on line again.

If I have sufficient time one or two new bands will be added to TH when I go there next time. 80m is a likely candidate, since I have a 80m RockMite built and ready. However, I may have to add another low powered PC to take the load off the current one. SpectrumLab is not the easiest on processor load.

I may see if Argo or Spectran is better in that respect. Tests needed, or, if anyone has experience, please tell me.

During some work at the place the PC had been switched off.

The "Hammer" is running nicely again since Christmas.

It is running on 10MHz and 500kHz as before. Possibly with an extension in a few months. Some antenna work and some soldering needed.

Next band will probably be 80 (3500kHz). and a simpler receiver for 10MHz. The original receiver will then be set to yet another band. Some wideband antenna work will be necessary for this to work out.

Time to get the soldering iron warmed up again.

On the PA9QV front the next soldering project should be the FA-SDR. All components including the housing have arrived, only a PA (1W) is missing yet. I may build a small wideband PA myself.

Still a lot of kits to build, but slowly getting started again.

I have noticed that Thor's Hammer has stopped uploading. Reason unknown, but could be the Inet connection has been lost, or the PC has been rebooted due to a power outage. I will have to wait and see.

Since I cannot just go there and back again in a day It will have to wait till I can go there for it to be updated

It took a while, but I now have "a few" kits to build.

Some SoftRock II kits, different bands, each can be made directly for 160,80,40,30 or 20m, all components in the kit. Some SMD soldering necessary, but should be possible, even with my eyes.

Some "Funkamateur" single frequency kits, among those a 10.7MHz kit to connect to my VHF-UHF RX (R7000, possibly AR-8600).
Two kits for 9MHz, one will be modified for use on 10MHz

the other 9MHz might be made "wideband", so a multitude of LO signals could be used, possibly a Si570 synthesizer or the DDS60 kit

Two lower band kits, to be decided

The FA wideband SDR TRX, will need a PA and a programmable LO, not yet ordered. Covering 1.7 - 30 MHz with preselection, so seems quite usable.

The "standard" 1W PA could probably easily be replaced by a home made solution, but I will see if I do not get to order the standard one at some stage. The local oscillator, the so-called FA-SY may be the way to go for full band coverage. A housing is also available, I may order that one, too.

Update :
The FA-SY oscillator has been ordered, along with a housing fit for the FA-SDR TRX
More Update :
The FA-SY kit and the housing have arrived

Lots of kits to build, not too much time, so let us see what comes up here.

The intention is to use some of the fixed frequency stuff for simultaneous WSPR and QRSS monitoring.

Since I visited the QTH of OZ9QV last month I have been monitoring the WSPR reception there.

The WSPR receiver is of course the same as the one for QRSS, with WSPR running concurrently on the PC.

With the tiny indoor tuned multi turn loop (diameter 22cm) the following stations have now been received successfully on 600m .

PA0A, PA0O, G3XIZ, PE1GRL and EI0CF being 1225km from there.

For such a simple setup I am quite happy with the results, even though I know that improvements are certainly possible.

During a holiday (and being there for other reasons) in Denmark I have made an update to the "Thor's Hammer" QRSS grabber. More will happen later at another visit.

The grabber can, as usual be found at :
Thor's Hammer

The grabber now works on two bands, a more stable receiver (old TRX with defective TX) has been installed for 10 MHz and the viewable frequency range reduced. Still using an older low powered PC

10 MHz Grabber :
RX range : 10139.880 - 10140.120 kHz
SpectrumLab set for display of 3 stripes of consecutive periods
Antenna : indoor dipole

500kHz Grabber :
RX range : 502.700 - 505.500 kHz - some noticeable frequency drift, but acceptable
SpectrumLab set for 3 strips as above
Antenna : indoor multi turn tuned loop

The 500kHz RX seems to have some problems with receiving WSPR, only once or twice the WSPR signals from PA0A and PA0O have been received.
The signal from (I think) G3XIZ was visible, but no decodes.

All in all I am fine with the improvements, but more is needed. I would like to add more bands, e.g 80m, 40 and 20m, possibly 136kHz but things do take time to get running, and new antennas will be necessary.

I may experiment with a wide band active loop antenna (H-probe) or an E-probe (short active whip).

Next time I will visit the OZ9QV grabber "Thor's Hammer" there will be another band active in grabbing : 80m

I have finished encasing a modified RockMite 80 (RX only)

Frequency drift is acceptable :
10 deg C : 3499.955
23 deg C : 3499.915

Yes - negative temp coefficient.

Since the temperature is expected to be within that range (most likely 15 - 25 for the majority of the time, and I expect to put the RX and PC into a cupboard, I would expect the local oscillator to stay within 3499.925 +/- 10 Hz for most of the time, quite acceptable.

The addition of another band to the grabber is worth it alone, I think.
New antenna needed as well.

I know that more activity is on 40m by now, but the winter should be good for 80m experiments.

The grabber is expected to run with an older, low powered PC, together with the 10 MHz grabber.

The new grabber receivers should be installed before the end of the year.

I am playing with an idea for a more stable grabber receiver for 3500/7000/14000 kHz, more on that later.
It will be a bit more complicated to build, so I will be taking my time.

Yet another alignment,

The receiver is drifting quite a bit, so the 'window' has been widened to 550 Hz, at least some signals are visible.

Further improvements to the grabber will happen later.

The receiver has a considerable frequency drift, even more than I expected.

When I visit next time I may have a better RX at hand. - if there is enough time to ge one going.

I was visiting the house of OZ9QV and got the 10 MHz grabber realigned.

I broadened the viewing frequency window, since the receiver has some temperature drift. In any case, QRSS signals are now visible again on the grabber.

Thor's Hammer, by OZ9QV :

QTH JO65cp
Frequency 10.140 MHz
Cheap transistor synthesized receiver
Older low spec PC

URL :
http://www.xs4all.nl/~jgander/qrss-p/

After having made a study of the IC-703 manual I see that there is a high pass filter in the TX path , cutting off at 1.6 MHz.
This is most probably for avoiding the IF frequency (455kHz) reaching the TX output.

A switch - switching in a 500kHz bandpass filter (alt 136kHz filter for LW) or bypassing the filter - would probably be possible, but the *tiny* SMD components at this place in the radio makes me think twice about making the attempt.

It *may* be possible to tap the signal out to an external amplifier, but then there is still 30mW out of the TX at 500kHz, so that could as easily be used.

Conclusion : 500kHz looks possible with the 703, but I doubt the internal filter mod is worth the risk of ruining a perfectly good TRX.

Ham radio manufacturers are funny (funny-strange, I mean).

They make 100 W radios needing lots of cooling, yet the PA's work through.

On the other hand, making QRP radios, PA transistors go KAPUT, drivers go KAPUT (FT-817 and IC-703 respectively)

SInce I have a FT-817 with a PA that died, I know it is just a matter of time before it happens again, unless the correct mods are made.

This week end ( with temperatures up around 30 C) I got to do the necessary mods for the IC-703

1) Driver modification. This one is not too bad, a matter of cutting a single PCB track and rerouting a piece of wire on the accessible side of the PCB, no need to remove the PCB. When at it, I adjusted the bias to the driver down to the recommended .5V, so the driver should be safe even with high temperatures now. In the original IC-703 the driver is connected directly to the full supply voltage, now it is connected to the 8V supply line.

2) CW Keyer input. For some obscure reason the keyer jack is grounded through a choke, giving rise to RF making it impossible to release the TX key. The solution, connecting the keyer jack ground directly to RF ground can be made provisionally outside the radio, but the more elegant solution requires the main board PCB to be lifted from the housing. Not too tricky, but beware of the flat cables (connectors).

3) 500 kHz TX option. This one required moving a *tiny* SMD diode. I managed to do it with a "normal" small solder tip, but the result is not that pretty.
The mod does open for TX on 500 kHz, but max output is about 40mW, and it looks like something is heating up, because the output reduces a bit after key-up, then stabilizes. I would probably not try to use the max output, but reduce it a bit, them make a power amp.

All in all not too bad for a hot summer's week end.

Just picked up a Maritime transceiver, the IC-M710.
The station operational from 1.6 to 30MHz, so TX on all bands 160 - 10m.

Now I need to learn to operate the thing, it is not quite the same as a normal HAM transceiver, but there will be time for playing, the set tunes in 100Hz steps, but with a clarifier.

Capable of running 150W out continuously (I have heard), the radio can be used for heavy duty operation

Now for some playing...

For some time I just had a few boxes full of crystals and oscillators- some found at ebay, others at rallys etc - not very practical when trying to find a particular one, or know which ones I have.

So the last week I have sorted out a bit, so that crystals with standard values (and in large quantity) have been separated into their own drawers. Others have been grouped in similar frequencies. some are still left unsorted, but that will have to wait.

Now to make a list of what I really have.

The idea is to write a small program for calculating possible uses of the crystals I have - for simple single frequency (or vxo controlled) receiver or transmitter circuits. After all, not all TX/RXs need to be DDS controlled. Yes - I know that there are lists out there with frequency combinations from standard crystals, but I have some additional frequencies in my stock, so will have to figure those out myself.

At least I got a *little* bit more order in my very messy shack ;) - even if I could use some more sorting out - that will have to wait.