Topics

One question only...


Timothy Fidler
 

Kees et al  - Virgil at "HF projects for radio amateurs" in the Old Glory has a relay switched filter board rated 100W for $90 as a kit.  V used to offer a 50W compact filter with a rotary switch .. possibly still has the PCBs for it.

Fred at Far circuits can sell you the PCB for the filter from the Kossor 40W HF amp for $11 but with no other parts. Diz, AKA  the toroid king in FL can make up the difference  (Fred is pretty flexible and not US amateurs may  be able to get him to ship the PCB to Diz and then Diz ships the whole works including Silver mica caps to you ).  Fred May be able to sell you the rotary switch . If you want relay control you would have to build a daughter board to interface to the switch wire in points .

Fred also sells the 200W LPF filter board from the Sabin amp. That uses switched relays from a jejeune cct. Ie rotary switch switching one in at time.. There No default relay set ie if the switch is parked then the Tx sees an open cct. He has the relays to suit.  He can send you out an excel spreadsheet of the LPF component settings.

There are plenty of "maybe dodgy" Russkies etc on Ebay offering stuff but whether it turns up once you have paid ?? 

Baruch Z, RF engineer in Israel may offer LPF sets to go with his super high power amps. (as in 2.2kW RF out S/state) . He does not seem to advertise them separately.  https://www.ebay.com/str/4z4rb/   ie. what is inside those fully made up amp cabinets ??  But these Filter sets are of course overkill for the task at hand if they can be had.


Kees T
 

QRP Labs offers some nice LPF filter kits (good for up to 10W) for all the bands for $4.60 each. Sounds like an excellent solution to me. Go Hans !

73 Kees K5BCQ


n2vdy
 

Can't speak about all the Russians on eBay but after seeing some stuff there I ended up buying from https://www.rv3yf.store and got everything I expected to get.

One thing to note. The filter kits I bought don't use toroids for the coils. They use slug tuned coil forms.

On Sun, Aug 5, 2018 at 09:22 PM, Timothy Fidler wrote


There are plenty of "maybe dodgy" Russkies etc on Ebay offering stuff but whether it turns up once you have paid ?? 


ajparent1/KB1GMX <kb1gmx@...>
 

Kees,

Better or more low pass filters do not solve the 10M problem and may reduce
power for the CW problem while making it passible.

There are several band pass filters available including your site when placed before the
amp will clean it up to the limits of the ground loops.

It will need switching for each band.  

Allison


Glenn
 

There seems to be a rather unfortunate placement of the LPF output from K3, running right back along the common of each LPF switching relay common point. Possibly causing less than optimum LPF responses.?


Gordon Gibby <ggibby@...>
 

Yet another thing to fix, in the long list that Alyson and others have been making.  


On Aug 5, 2018, at 22:10, Glenn <glennp@...> wrote:

There seems to be a rather unfortunate placement of the LPF output from K3, running right back along the common of each LPF switching relay common point. Possibly causing less than optimum LPF responses.?

<uBITX_LPF_RELAYS_BOTTOM.JPG>


Mike Short <ai4ns.mike@...>
 

I have had one of the HFProjects lpf boards, and they are very nice.

--
Mike
AI4NS


Tom Cooper
 

I promise to let everyone here know if the FCC informs me of poor harmonic control.  Until then, I will assume that not being heard on any band by a RBN skimmer means that I am not interfering with anyone.  

Perhaps we should worry about how many angels can dance on the head of a pin with a head diameter of .01234455".  


Gordon Gibby <ggibby@...>
 

While we expectantly wait on much desired circuitry and layout improvements, (which will no doubt come in time,)....

.....bright moves would be to use some sort of antenna tuner that adds a bit of selectivity, or any of the several band pass etc filters available, as appropriate, (I think for some of the higher band problems these don’t completely solve the problem); avoid over driving the mic input. 

I’m still wondering if just a series tuned, variable capacitor/inductor filter might not do a good bit of good


We’re building several of these in just a few weeks time as a club project,  and after we get them built, and working, we will probably employee some of the simple wire-moving-around solutions, band pass filter’s etc.   most of our usage will be on the Lower bands ; almost nobody can hear you on the higher ones anyway! 

Just EXPLAINING  some of these issues to many of our club members will be extremely educational.... which is one of our big goals







On Aug 5, 2018, at 22:36, Tom Cooper via Groups.Io <w1eat@...> wrote:

I promise to let everyone here know if the FCC informs me of poor harmonic control.  Until then, I will assume that not being heard on any band by a RBN skimmer means that I am not interfering with anyone.  

Perhaps we should worry about how many angels can dance on the head of a pin with a head diameter of .01234455".  


Gordon Gibby <ggibby@...>
 

And while it’s not easy, I have soldered RG 174 many times in my life!! I have a roll of it upstairs right now.  




On Aug 5, 2018, at 23:43, Gordon Gibby <ggibby@...> wrote:

While we expectantly wait on much desired circuitry and layout improvements, (which will no doubt come in time,)....

.....bright moves would be to use some sort of antenna tuner that adds a bit of selectivity, or any of the several band pass etc filters available, as appropriate, (I think for some of the higher band problems these don’t completely solve the problem); avoid over driving the mic input. 

I’m still wondering if just a series tuned, variable capacitor/inductor filter might not do a good bit of good


We’re building several of these in just a few weeks time as a club project,  and after we get them built, and working, we will probably employee some of the simple wire-moving-around solutions, band pass filter’s etc.   most of our usage will be on the Lower bands ; almost nobody can hear you on the higher ones anyway! 

Just EXPLAINING  some of these issues to many of our club members will be extremely educational.... which is one of our big goals







On Aug 5, 2018, at 22:36, Tom Cooper via Groups.Io <w1eat@...> wrote:

I promise to let everyone here know if the FCC informs me of poor harmonic control.  Until then, I will assume that not being heard on any band by a RBN skimmer means that I am not interfering with anyone.  

Perhaps we should worry about how many angels can dance on the head of a pin with a head diameter of .01234455".  


WaltR <waltrseiler@...>
 

I’d love to have a spectrum analyzer, but fortunately my wife has other ideas, happy wife happy life,
However, I have a friend that is a Motorola service specialist, and has a Rhode and Schwartz FSP spectrum analyzer. According to his evaluation of the ubitx version 3 board it falls short of meeting the criteria here in Canada. This is very disappointing to me and because I don’t want to run afoul of the regulatory bodies here, It would be best for me to put the whole thing through the shredder and be content with using the Harris, and Wolfsburg equipment That are on board my ship, It’s been a slice! but if I tried to mortgage the house to buy one of those, I fear I may end up on the obituary page in the local paper! I think I’ll get a part time job when I’m on leave, to support my bad habits.

Cheers and 73

WRS


m5fra2@...
 

Thanks Tom!

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Tom Cooper via Groups.Io
Sent: 06 August 2018 03:36
To: BITX20@groups.io
Subject: Re: [BITX20] One question only...

 

I promise to let everyone here know if the FCC informs me of poor harmonic control.  Until then, I will assume that not being heard on any band by a RBN skimmer means that I am not interfering with anyone.  

Perhaps we should worry about how many angels can dance on the head of a pin with a head diameter of .01234455".  


Virus-free. www.avast.com


Bill Cromwell
 

Hi Walt,

I will attach to this thread along about here. There is a lot of tail chasing and obvious disappointment among uBitx owners. I admit that I have felt some discouragement, too. But practical remedies are contained in the fog being spewed.

In the "good olde dayes" outboard filters were added between a (naughty)transmitter and the antenna. That approach can help a receiver as well. That was before we had CAT or even computers to support CAT. My approach won't support Cat. Or will it?

When there are several pieces of gear working as the ham station and each has it's own bandswitch we quickly get into the habit of checking all those bandswitches whenever we change bands. Newfangled hams don't have this experience and maybe are not even aware of the possibilities. I will be building the needed filters - bandpass models because of the uBitx sins - and adding them into the lashup immediately after the antenna terminal on the uBitx. Next will be the SWR bridge and tuner to the antenna so that the 50 ohm filter is assured of a 50 ohm load. That renders the uBitx impractical for some kinds of field operation. Too many googaws in the kit to drag up a steep hill or out into the forest. The local park might not be quite so bad. If the people who are working on mods for the radio get a good solution then I will probably make those modifications to mine. Meanwhile I am going to use it with external filters.

And now back to computer control of the station with those bandswitched filters living outside the radio. The VFO and Raduino are NOT going to accommodate that. But that is not where CAT originates. Make your Willie Gates special computer change the bands in your external filter for you while it is changing the bands in your uBitx. I see a lot of bragging about computer skills. So just do it. The old mechanical bandswitches still work for me:)

I hope this helps some people get past the disappointment and enjoy their radios on the air - free of worries over regulatory issues or being *bad* neighbors. As for me - I have already used my uBitx GQ receiver to help me troubleshoot another broken radio so I am keeping it:) And using it on the air.

Spectrum analyzers are great for quickly making graphical plots and even drawing them 'on-the-fly'. The same measurements can be made by plodding through a series of measurement steps and putting the results on graph paper (or in a PC spread sheet). It takes longer but most of us are NOT manufacturing radios or working on other folks' gear for pay. So the time required is much less critical.

Good luck and 73,

Bill KU8H

On 08/06/2018 01:54 AM, WaltR wrote:
I’d love to have a spectrum analyzer, but fortunately my wife has other
ideas, happy wife happy life,
However, I have a friend that is a Motorola service specialist, and has
a Rhode and Schwartz FSP spectrum analyzer. According to his evaluation
of the ubitx version 3 board it falls short of meeting the criteria here
in Canada. This is very disappointing to me and because I don’t want to
run afoul of the regulatory bodies here, It would be best for me to put
the whole thing through the shredder and be content with using the
Harris, and Wolfsburg equipment That are on board my ship, It’s been a
slice! but if I tried to mortgage the house to buy one of those, I fear
I may end up on the obituary page in the local paper! I think I’ll get a
part time job when I’m on leave, to support my bad habits.

Cheers and 73

WRS
--
bark less - wag more


ajparent1/KB1GMX <kb1gmx@...>
 

Gordon,

I have a 1k spool of it...  Doesn't mean I expect others less experienced to find it easy.
For some it might be the first time.  

Allison


ajparent1/KB1GMX <kb1gmx@...>
 

Glenn,

Yes that one of many.  Your pointing out the specifics of the general issue of board layout.

For example if the indicated line was moved to the area more centered and had
ground copper on both sides its not an issue.

Allison


Gordon Gibby <ggibby@...>
 

yup --- agreed.   Need to have a pair of hemostats or something to protect the center insulation.   But somehow I did it as a teenager causue heathkit used those a lot.   


we seem to have a lot of hams today who aren't even up to the level of heathkit assemblers, and it is good to improve onthat!!!!


this forum has taught me a ton...


I saw the price of a Rigol 700....I might be able to swing it....   the 800 's seem to have the tracking generator but then the price is $500 higher..... is it worth it?    Or can I somehow use a si5351 below 100 MHz?


I am getting a little unit that is supposed to let me tune duplexers ($100 cheapie system from china)



gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of ajparent1/KB1GMX <kb1gmx@...>
Sent: Monday, August 6, 2018 8:45 AM
To: BITX20@groups.io
Subject: Re: [BITX20] One question only...
 
Gordon,

I have a 1k spool of it...  Doesn't mean I expect others less experienced to find it easy.
For some it might be the first time.  

Allison


G8HAV
 

I know it is off topic but I used a DG8SAQ VNWA  for the duplexers.


Depends on whether they are pass. reject or a mixture of these, on how you proceed


SA &  tracking gen is easier but five or more times expensive.


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: 06 August 2018 14:14:38
To: BITX20@groups.io
Subject: Re: [BITX20] One question only...
 

yup --- agreed.   Need to have a pair of hemostats or something to protect the center insulation.   But somehow I did it as a teenager causue heathkit used those a lot.   


we seem to have a lot of hams today who aren't even up to the level of heathkit assemblers, and it is good to improve onthat!!!!


this forum has taught me a ton...


I saw the price of a Rigol 700....I might be able to swing it....   the 800 's seem to have the tracking generator but then the price is $500 higher..... is it worth it?    Or can I somehow use a si5351 below 100 MHz?


I am getting a little unit that is supposed to let me tune duplexers ($100 cheapie system from china)



gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of ajparent1/KB1GMX <kb1gmx@...>
Sent: Monday, August 6, 2018 8:45 AM
To: BITX20@groups.io
Subject: Re: [BITX20] One question only...
 
Gordon,

I have a 1k spool of it...  Doesn't mean I expect others less experienced to find it easy.
For some it might be the first time.  

Allison


ajparent1/KB1GMX <kb1gmx@...>
 

Gordon,

The Rigol DSA815T I bought one to back up my HP8568B because the HP does not
have a tracking generator and finding a working one was approaching the price of a Rigol.
While I still prefer the HP the Rigol does work well has modern interefaces for remote
control and screen capture/storage.  Being an easy 60 pounds lighter is portable. 
I've even run it on a small 200W inverter and 33ah battery in the field (it uses maybe
50W).

The tracking generator that was the desired feature and it makes the instrument
a good second place for things I'd want a PNA like the Agilent 8357A for.  That
is things like  SWR analysis, 1 and 2 port network analysis. 

The tracking generator is worth the cost difference.
That's a lot of capability in a small box.

When you consider that many hams spend 1000-2000 for a mid range radio
and more the 1560$ (via amazon) was a reasonable ham purchase and a
dirt cheap professional one.

Allison


WaltR <waltrseiler@...>
 

Thanks Bill,

I, as many others enjoyed assembling the bitx40 and the ubitx, for my purposes, dragging around a bag full of outboard filters and other accessories will not work. Perhaps to some degree I am spoiled by having access to high end gear, but I am aware that it’s not prudent to compare a Harris to a ubitx. I wish not to besmirch Harris by putting the ubitx in the same sentence.

my understanding is the bitx was designed and built as a kit for those that wish to assemble, experiment, dabble in Arduino sketches etc, and by the number that have been sold obviously has a large following.
There is a need for a simple solid rig that doesn’t require a lot of fiddling about, and is reasonably priced and meets regulatory criteria.

There should be some warning or reminder that if you plan on doing any modifying or hacking that you should ensure that you don’t produce any transmitted products that may interfere with other services, especially any that might fall in the spectrum allocated to government agencies and services, as well as commercial, and international interests. You might get away with it in the ham bands but you certainly won’t if you cause superfluous transmissions in other spectrum allocations.

Buy filters, there are some great little devices available at QRP LABS.

Cheers and 73

WRS

IF THE PROCESS IS FLAWED, THE OUTCOME MOST SURELY WILL BE FLAWED


ajparent1/KB1GMX <kb1gmx@...>
 

I used to use a signal generator (analog), frequency counter, and a diode load
so adding even a digital oscillator DDS or NCO was a giant step forward in
making basic measurements.

If a SA at ~1500$US is out of reach the lowly 9850 DDS and arduino plus a
RF power sensor (8307 or one of the many others) will allow many of the
same measurements at a fraction of the cost in exchange for time to plot
the points.

It is also possible to use the above to plot to a graphic display 
by taking the power sensor output to the analog input of the arduino
allowing graphic display of the results. 

The 5351 is good but the square wave output will mess you up for many
measurements due to the rich harmonic output.  Two common measurements
are SWR and filter bandwidth/cutoff are hard to do with harmonics present.

Allison