Topband: 470Khz transverter

Mon Nov 6 12:11:43 EST 2017

472kHz Transverter - G3XBM QRP WEBSITE

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472kHz Transverter - G3XBM QRP WEBSITE

A page about lower powered (QRP) amateur radio with details of simple circuits to build, operating and much more...
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There are many designs out there to choose fromThis one works well and I built two of them 
73John

Digitally signed mail - John  M0ELS

“The further a society drifts from truth the more it will hate those who speak it.”
George Orwell

    On Monday, 6 November 2017, 17:00:53 GMT, <topband-request at contesting.com> wrote:  

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Today's Topics:

  1. Re: what does it take to get on new band 600 meters
      (Raoul Coetzee)
  2. Re: Rotator creating spur on 1820- results (k8gg at voyager.net)
  3. Re: Rotator creating spur on 1820- results (K4SAV)
  4. Re: what does it take to get on new band 600 meters (Eric NO3M)

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Message: 1
Date: Sun, 5 Nov 2017 20:15:05 +0000 (UTC)
From: Raoul Coetzee <raoulcoetzee at yahoo.com>
To: Kevin Adam <n9iww at LIVE.COM>,     "topband at contesting.com"
    <topband at contesting.com>,     Jeff Kincaid <w6jk at sbcglobal.net>
Subject: Re: Topband: what does it take to get on new band 600 meters
Message-ID: <1101447823.2488569.1509912905487 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

 I have been playing with a few ideas, one was to mix a 6 Mhz Xtal oscilator output with a 6.474 MHz signal from my ft817 (into a small 50 ohm load)the difference, 474 KHz was amplified with tubes (valves for the UK ) and I ended up driving an old 813.Why? because I wanted a job for the tubes that was in the garage.It worked fine, I also used the Ft1000 MP, one vfo set to rx on 474 KhZ? and the other to TX on 6.474 MHz using the same valve mixer/amplifier/ driver/PA setup.That project took up space, I had no one to talk to, and ended in? the garage with other projects !
The current project is using two? TTL decade counter chips (74LS192)? to divide a 13.77 MHz signal by 100 , ending with 137.7 KHz, this is amplified by two transistors, and those drive a FET PA.So far getting 47 watts output , nice sine wave after the output filter.Efficiency is a bit poor, I am looking to go class E.
If I use one decade counter, (tap the ouput signal from the first counter) )? and only divide by 10, I could put a 4.74 MHz signal in to it, and get 474 KHz out.Again using the dual VFO's to tx on on 4.74MHz? and RX on 474Kc.
Of course, I could use a cheap DDS module and an Ardiuno to generate the signal too, but now? I use the rig's switching and keying, no RX/TX antenna relays etc.
I will? bottom load the 160m vertical with 5400uH coil and a suitable tap to match.
Maybe this may stimulate some further thoughts and ideas.
Raoul ZS1C

    On Thursday, November 2, 2017, 8:40:34 PM GMT+2, Jeff Kincaid <w6jk at sbcglobal.net> wrote:  

 I've been trying to get Heathkit to produce a dual bander of some sort for the two new bands.? Why not start by dropping them a line supporting the idea?
Regards,Jeff W6JK 

? ? On Thursday, November 2, 2017 10:35 AM, Kevin Adam <n9iww at LIVE.COM> wrote:

 What does it take to get on 600 meters radio antenna transceiver? power requirements

N9IWW
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Message: 2
Date: Sun, 5 Nov 2017 18:45:33 -0500 (EST)
From: k8gg at voyager.net
To: "K4SAV" <RadioXX at charter.net>
Cc: topband at contesting.com
Subject: Re: Topband: Rotator creating spur on 1820- results
Message-ID: <2943.174.230.141.90.1509925533.squirrel at webmail.core.com>
Content-Type: text/plain;charset=iso-8859-1

Hi Jerry & Topbanders,

Doing the math from the info below:

AM 890 x 2 = 1780 KHz + 1730 KHz = 3510 <- - your 80 meter birdie.

I hope this makes sense and helps solve the puzzle.

As I noted before, it is probably generated off site by some rusty
connection in a radio tower that is a nasty diode as well.

73,  George,  K8GG...

> *I put the strap around the rotator today.  I no longer have a birdie on
> 1820.  Not a trace of it on any antenna.  Based on symptons, I can only
> conclude it was caused by intermittent contact at the rotator bearings
> or by intermittent contact at the bearing on top of the tower.  Diodes
> inside the rotator do not seem to be a problem.**
> **
> **The strap had no effect on my 3510 spur, which means the mixer for
> that one is somewhere else.  That one is not a big problem because it
> goes away at nighttime due to one of the stations being daytime only.**
> **
> **The strap is 1/4 inch diameter twisted (not braided) stranded tin
> plated wire, very flexible. Length is about 16 inches.**
> **
> **Special thanks to Lloyd N9LB and Hank K7HP who had the correct answer.**
> **
> **Jerry, K4SAV - happy camper*
>
>
> On 11/2/2017 5:27 PM, K4SAV wrote:
>> Likely all the spurs you see on 160 that are caused by AM stations
>> will land on 10 kHz increments because the stations are spaced on 10
>> kHz increments.  I identified one of the stations that was a big
>> contributor to my problem and that was on 1730.  I haven't found the
>> other station yet.  I expected the station on 890 to be a contributor
>> since it is only 1700 ft from my antenna but I don't think it is the
>> one.  (It is a contributor to the spur that happens on 3510).
>> Regardless of which stations are involved, the main problem is that
>> the mixing is being created near my rotator, and probably inside it
>> somewhere.  I have to kill the mixer somehow. More than likely the
>> stations are clean.  It will be interesting to see if the same mixer
>> is causing both spurs, 1820 and 3510. Fortunately the 3510 spur goes
>> away at night because one of the contributor stations is daytime only.
>>
>> Interesting video by N8PR, but he is fighting a different problem from
>> what I have,
>>
>> I do not have a strap around the rotator.  That's worth a try. Thanks
>> Lloyd and Hank.
>>
>> Jerry, K4SAV
>> _________________
>> Topband Reflector Archives - http://www.contesting.com/_topband
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>

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Message: 3
Date: Sun, 05 Nov 2017 21:23:36 -0600
From: K4SAV <RadioXX at charter.net>
To: topband at contesting.com
Subject: Re: Topband: Rotator creating spur on 1820- results
Message-ID: <59FFD5B8.1040204 at charter.net>
Content-Type: text/plain; charset=utf-8; format=flowed

Thanks George

"AM 890 x 2 = 1780 KHz + 1730 KHz = 3510 <- - your 80 meter birdie."

Yep, that works, except I had a typo when saying one of the contributor 
to the 160 problem was 1730.  No station on 1730. Copied the wrong 
number off my notes.  Sorry.  I should have said 1310.

My 80 meter problem is also due to that 1310 station, (1310 + 890) + 
1310 = 3510.  Both very strong local stations.

The really tough question is where is that mixer. Can't do much about 
the stations.  Only hope is to find the mixer.  There are lots of 
possibilities.  Might be close, or maybe not.  That 1820 problem was 
generated on my tower and radiated to my receiving antennas located 550 
ft from the tower.  Very glad to get rid of that one.

Guess I will have to see if I can track the 80 meter problem by using a 
portable 3510 receiver.  I can locate the general direction using my 
receiving antennas and it's not in the direction of either of those two 
stations.  Funny thing is the 3510 birdie is minimum when the antenna is 
pointed at the 890 tower and I know that is one of the contributors.  
When pointed at that station. my receiving antenna has a null at 96 
degrees to that station and that is the direction to the mixer.  That 
direction passes very close to my tower so I was expecting to maybe see 
some change in the 80 meter problem when I put that strap on the 
rotator, but it didn't happen.

Jerry, K4SAV

On 11/5/2017 5:45 PM, k8gg at voyager.net wrote:
> Hi Jerry & Topbanders,
>
> Doing the math from the info below:
>
> AM 890 x 2 = 1780 KHz + 1730 KHz = 3510 <- - your 80 meter birdie.
>
> I hope this makes sense and helps solve the puzzle.
>
> As I noted before, it is probably generated off site by some rusty
> connection in a radio tower that is a nasty diode as well.
>
> 73,  George,  K8GG...
>
>

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Message: 4
Date: Sun, 5 Nov 2017 23:20:37 -0500
From: Eric NO3M <no3m at no3m.net>
To: topband at contesting.com
Subject: Re: Topband: what does it take to get on new band 600 meters
Message-ID: <8c43fd0a-740a-91ed-4f5c-38de915e9126 at no3m.net>
Content-Type: text/plain; charset=utf-8; format=flowed

Quite a loaded question... for every 10 guys on the band, there will be 
20 ways they went about getting on (including some things going up in 
smoke and fire).

Power requirements depend on your antenna's efficiency... for an 
explanation of EIRP, see here:

http://www.472khz.org/pages/technical-topics/eirp.php

Using the formula method, you'll need to model your antenna to figure 
out it's radiation resistance.? Unless you know your local ground 
characteristics to get an accurate model, assume a vertical has 4.77 dBi 
gain, which is a gain factor of 3, in the calculations.

As for an antenna, most put up a vertical (inv-L, Tee, etc.) with some 
form of top-loading and coil to resonate it.? Lots of ground wire helps 
mitigate ground losses.? Lots of top-loading helps reduce the required 
inductance to resonate it and reduces coil losses. Construct and mount 
coils for high-Q and minimal stray coupling. But if you understand EIRP, 
it's not necessary to go crazy with height, top-loading, radials, etc., 
since you can just increase transmitter power.? It all depends on 1) how 
much power you can generate, 2) how much you are willing to waste, 3) 
are prepared for obscene RF voltage at the base if using a lot of power 
into a very short vertical (this means a good insulator, NOT cheap 
PVC!).? Guys in backyard lots can be just as loud as someone with a 
200ft (max height) top loaded vertical... again, it all comes back to EIRP.

Transceiver can be just about anything if you use a transverter, 
otherwise, something like the TS590, K3S, etc. can natively operate down 
there.? SS amp.... tube amp.... etc, etc, etc.? Of course, you can also 
homebrew something from start to finish.? Some guys are using lashed 
together setups with signal generators, etc.? There are also vintage 
Navy and other rigs that can go down there... old 500kc type stuff.

Don't forget an RX antenna... sure you can get away with using the TX 
antenna, but you'll be missing out on a lot of stuff.? Loops, EWE, 
beverages, BOGs, vertical arrays, etc....

I've been QRV on 630M since 2012 under both the ARRL's group Part 5 
grant (WD2XHS/46) and my own grant (WG2XJM).? I've used a number of 
different configurations over the years, but currently have a 67ft. 
vertical w/ 8 top-loading wires over 22,000 ft radials.? K3 to a 
transverter with dual RX channels for diversity and a 100W SS amp. I did 
modify a SB-1000 for 630M, but no longer need it.? For RX I use my 160M 
broadside beverage arrays and a dedicated full-sized 630M 8-circle BSEF 
array (1150ft diameter).? Some links:

http://no3m.net/antennas/630m-antennas/
http://no3m.net/antennas/630m-8-circle/
http://no3m.net/shack/630m-station/

I have also homebrewed a bunch of antique style gear for down there, 
including a 1930s rack transmitter which I use almost every night:

http://no3m.net/2017/10/1930s-rack-transmitter/

For general info, technical articles, and daily activity updates, see:

http://www.472khz.org/
http://500kc.com/
http://njdtechnologies.net/category/630-meters/

GL CU 630M
73 Eric NO3M

On 11/02/2017 01:34 PM, Kevin Adam wrote:
> What does it take to get on 600 meters radio antenna transceiver  power requirements
>
>
> N9IWW
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband

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