It looks like the idea is a goer!
Today I checked the transverter's LO leakage, TX image and harmonics and there's no significant difference in the levels between driving it at 124 to produce 2300 and 144 to produce 2320MHz.
I'm now pressing ahead working out the changes required to the G4DDK Anglian transverter kit so it can produce 124MHz with 28MHz drive.
I've already modelled the main 145Mhz bandpass filter using QUCS and it's looking like a few capacitor value changes to drop it's centre frequency down to 125MHz. Changing the crystal oscillator from 116 to 96MHz will be easy as there's already a 96MHz version of the G4DDK Butler Oscillator in Sam's G4DDK2001 multiplier design that I can copy. I just need to change the second stage values so that it buffers at 96MHz instead of multiplying.
A word of warning if anyone else is considering using 124MHz as a drive frequency drive. You'll need to keep the drive power as low as possible and the leakage to a minimum.
Why?
Because 124MHz is in the air-band!
Be warned!
Monday, February 29, 2016
Sunday, February 28, 2016
How to be a Bad Morse Operator (With apologies to Simon Barnes, “the bad birdwatcher”)
A wise man once said to me
“Don’t worry about what people are thinking of you, because they rarely are”
How many times have you heard that very weak Morse Tropo signal on 23cm or the distant hiss of rain scatter Morse on 3cms and wished you could work it?
I know, you trot out the usual excuses in your head.
• Oh he’s going too fast….
• I used to be a Class B/I’m a new licensee and I never took the Morse test.
• I’ve not operated on Morse since I walked out of my local coastal station in 1972.
• My Morse is not good enough
Maybe you just too “frit” to have a go in case you get in a tangle with the dots and dashes and “make a fool of yourself”?
Wake up… no one really cares about how bad your Morse is.
You’ll miss out on some of the best Microwave DX if you take this attitude, just look at the Terrestrial DX World records.
1.3GHz! 4143km! CW
2.3GHz! 3980km! CW
3.4GHz! 3980km! CW
5.7GHz! 3980km! CW
10GHz! 2079km! SSB
24GHz! 710km! CW
47GHz! 343km! SSB
75/76GHz! 175.3km! CW
122GHz! 114km! CW
134/136GHz! 114.4km! CW
……………Need I go on? 8 out of 10 are on Morse.
Unlike the HF bands you don’t need to be a “good” Morse operator to work Morse DX on Microwaves. There’s no “First Class Operator’s Morse” club for Microwavers, in fact I’m thinking
of forming a “2nd Class Morse operator’s club!
So why not join me and become a bad Morse operator? Don’t sit back and “wish you could do Morse properly”.
Here are the four pillars of being a Bad Morse operator.
• Everyone else is as bad at Morse as you are.
• Never admit how bad at Morse you are.
• Bad Morse operators still work the DX on Microwaves
• On the radio, no one can see you blushing
And here are the rules of Bad Morse Operating
• If you hear someone calling CQ or posting on KST….. CALL THEM!
• If you don’t call them, you won’t work them.
• Call the station at your speed, 99% of people will slow down. If they don’t, then they are likely to be a prat and you wouldn’t want to work them anyway.
• If you miss something, ask them to repeat it.
• Learn to pick out callsigns, reports and locators. The rest of it’s probably boring chatter anyway!
• Don’t be afraid to sign off once you’ve got the above info, blame it on “Deep QSB” (“Heavy QRM” doesn’t cut it on Microwaves, but it’s great for HF!)
• All the Morse you need to know after you’ve learned the alphabet is …
G1XYZ de G2ABC ga (gm/ge) tnx call UR 559(xxx for contests) in?
RRR tnx QSO es 73
• If you’re embarrassed by your poor Morse skills, …LIE!..... and learn...
The “Bad Morse operator’s code”
Here it is.
1. QRS = please slow down
2. QSB = I didn"t read my report because my Morse skills are so bad
3. QRM = (see QSB)
4. PSE ALL AGN = (see QSB)
5. PSE TRY SSB (only if signal is strong enough)
6. TNX QSO es 73 = (see QSB, only to be used after 2, 3, 4 and 5 have failed)
The chances are the only person who’ll know or care that you are a Bad Morse Operator is yourself, the other station has got a new square/country/ initial – that’s all he cares about.
What do Bad Morse Operators do better than non-Morse operators?
They have Morse QSOs! …..AND….. their Morse actually improves!
“Don’t worry about what people are thinking of you, because they rarely are”
How many times have you heard that very weak Morse Tropo signal on 23cm or the distant hiss of rain scatter Morse on 3cms and wished you could work it?
I know, you trot out the usual excuses in your head.
• Oh he’s going too fast….
• I used to be a Class B/I’m a new licensee and I never took the Morse test.
• I’ve not operated on Morse since I walked out of my local coastal station in 1972.
• My Morse is not good enough
Maybe you just too “frit” to have a go in case you get in a tangle with the dots and dashes and “make a fool of yourself”?
Wake up… no one really cares about how bad your Morse is.
You’ll miss out on some of the best Microwave DX if you take this attitude, just look at the Terrestrial DX World records.
1.3GHz! 4143km! CW
2.3GHz! 3980km! CW
3.4GHz! 3980km! CW
5.7GHz! 3980km! CW
10GHz! 2079km! SSB
24GHz! 710km! CW
47GHz! 343km! SSB
75/76GHz! 175.3km! CW
122GHz! 114km! CW
134/136GHz! 114.4km! CW
……………Need I go on? 8 out of 10 are on Morse.
Unlike the HF bands you don’t need to be a “good” Morse operator to work Morse DX on Microwaves. There’s no “First Class Operator’s Morse” club for Microwavers, in fact I’m thinking
of forming a “2nd Class Morse operator’s club!
So why not join me and become a bad Morse operator? Don’t sit back and “wish you could do Morse properly”.
Here are the four pillars of being a Bad Morse operator.
• Everyone else is as bad at Morse as you are.
• Never admit how bad at Morse you are.
• Bad Morse operators still work the DX on Microwaves
• On the radio, no one can see you blushing
And here are the rules of Bad Morse Operating
• If you hear someone calling CQ or posting on KST….. CALL THEM!
• If you don’t call them, you won’t work them.
• Call the station at your speed, 99% of people will slow down. If they don’t, then they are likely to be a prat and you wouldn’t want to work them anyway.
• If you miss something, ask them to repeat it.
• Learn to pick out callsigns, reports and locators. The rest of it’s probably boring chatter anyway!
• Don’t be afraid to sign off once you’ve got the above info, blame it on “Deep QSB” (“Heavy QRM” doesn’t cut it on Microwaves, but it’s great for HF!)
• All the Morse you need to know after you’ve learned the alphabet is …
G1XYZ de G2ABC ga (gm/ge) tnx call UR 559(xxx for contests) in
RRR tnx QSO es 73
• If you’re embarrassed by your poor Morse skills, …LIE!..... and learn...
The “Bad Morse operator’s code”
Here it is.
1. QRS = please slow down
2. QSB = I didn"t read my report because my Morse skills are so bad
3. QRM = (see QSB)
4. PSE ALL AGN = (see QSB)
5. PSE TRY SSB (only if signal is strong enough)
6. TNX QSO es 73 = (see QSB, only to be used after 2, 3, 4 and 5 have failed)
The chances are the only person who’ll know or care that you are a Bad Morse Operator is yourself, the other station has got a new square/country/ initial – that’s all he cares about.
What do Bad Morse Operators do better than non-Morse operators?
They have Morse QSOs! …..AND….. their Morse actually improves!
Getting on the new 2300Mhz NoV band with a 2320 transverter
The threat to our 2320MHz (13cm) band from commercial interests is real, but those nice people at Ofcom have given us a the option of a full power NoV (Notice of variation) to operate between 2300 and 2302MHz. I've already modified by homebrew transverter that I use for terrestrial by adding a switchable LO between 2176 for 2320 and 2156 for 2300, but currently my DB6NT based EME system is stuck on 2320.
This afternoon I've been doing some basic tests on my DB6NT Mk3 13cm 2320MHz transverter to see if it might work on 2300MHz. The MK3 is a PLL locked transverter so simply switching in a different crystal to put the Lo at 2156 instead of 2176 is not an option as it would require a firmware change.
My simple plan is to drive it at 124MHz instead of 144MHz giving an output 20MHz lower.
I've already confirmed that the receive side works at 2304, (the US EME band) with a separate receive converter at 128MHz and I wrote about it in RadCom "GHz bands" last year
Using just a signal generator at + 18dBm as IF drive (my system's standard drive level), I measured the output from the transverter using first 144MHz, then 124MHz at the same level.
The 13cm output at 2300MHz dropped by just 4dB! Result, considering my 2320MHz PA should have more gain at 2300 that is not going to be an issue. Increasing the 124MHz drive by the same 4dB and the 2300MHz output level came back to the 2320MHz level.
I still need to check the LO leakage and the harmonic levels but it's looking really good so far and I'll do that tomorrow.
So my plan will be to build a 124MHz version of the excellent G4DDK Anglian 144MHz transverter kit allowing me to use my Elecraft K3 with suitable IF switchery on 2300 and 2320MHz TX and RX plus cross band combinations and to receive on 2304 by tuning the K3 to 32MHz. I've already verified that the K3 will receive via it's transverter ports at 32MHz with little drop off in performance.
Once it's all complete I'll write up the project for Scatterpoint
This afternoon I've been doing some basic tests on my DB6NT Mk3 13cm 2320MHz transverter to see if it might work on 2300MHz. The MK3 is a PLL locked transverter so simply switching in a different crystal to put the Lo at 2156 instead of 2176 is not an option as it would require a firmware change.
My simple plan is to drive it at 124MHz instead of 144MHz giving an output 20MHz lower.
I've already confirmed that the receive side works at 2304, (the US EME band) with a separate receive converter at 128MHz and I wrote about it in RadCom "GHz bands" last year
Using just a signal generator at + 18dBm as IF drive (my system's standard drive level), I measured the output from the transverter using first 144MHz, then 124MHz at the same level.
The 13cm output at 2300MHz dropped by just 4dB! Result, considering my 2320MHz PA should have more gain at 2300 that is not going to be an issue. Increasing the 124MHz drive by the same 4dB and the 2300MHz output level came back to the 2320MHz level.
I still need to check the LO leakage and the harmonic levels but it's looking really good so far and I'll do that tomorrow.
So my plan will be to build a 124MHz version of the excellent G4DDK Anglian 144MHz transverter kit allowing me to use my Elecraft K3 with suitable IF switchery on 2300 and 2320MHz TX and RX plus cross band combinations and to receive on 2304 by tuning the K3 to 32MHz. I've already verified that the K3 will receive via it's transverter ports at 32MHz with little drop off in performance.
Once it's all complete I'll write up the project for Scatterpoint
Wednesday, February 24, 2016
Yes, system improvements are addictive!
A lot of newcomers to the GHz bands ask me about how to improve the performance of their systems, andI reply that it's down to transmitted ERP and receiver noise figure. While QRO is king, noise figure is an altogether more subtle thing. Improving noise figure does not quite give you the same improvements when your dish is looking at the "hot" horizon as it does when looking at cold sky for EME. The "bible" on this is (The sadly recently deceased) VK3UM's article so read it, I don't intend to repackage it here! Receiver performance depends a lot upon on how much coax/waveguide you have between the input of the preamp/transverter and the dish feed. Remember that every 0.1 of a dB loss between the feed and the front end adds 0.1dB to your noise figure, but a 0.1dB improvement in Noise figure can give you more than 0.1dB improvement in signal to noise under certain circumstances. So your first aim should be to reduce this front end loss as much as possible by putting the preamp/transverter close to the feed. You can get a real feel for all this by downloading VK3UM's) "EMEcalc" and doing some "what ifs" with the RX performance page. There you can change gains, noise figures and antenna temperatures and see how it effects your output S/N ratio.
In my case, my 10GHz transverter/PA is in the loft by the gable end and I have a run of about 5m of FSJ2-50 up to the dish, giving me around 2dB loss. The dish mounted 1dB preamp makes a notable difference, as I can switch it in and out of circuit from the shack.
Dish upgrades are always a good thing, giving you better RX and more TX ERP but remember the narrower beam width will make it all that more difficult to point. I find my 60cm dish is OK with a bog standard G450 rotator on 10GHz but it is a pain on 24GHz. Also make sure that you get the elevation spot on (more difficult) I cheated and used an elevation rotator as well but it's all weight on the pole. EMEcalc allows you to calculate your dish beam width.
See my August 2015 "GHz Bands" column in RadCom for more ramblings about preamps and noise figure.
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