[NLRS] Transverter use with 756Pro or Orion

[Mike King - KM0T]

Hi Jon and all,

I ran one for a few years, loved it with a few exceptions.  Hence the reason 
I am trying the SDR-1000 route.

The power output is adjustable from the front panel gain control in both CW 
and SSB, however, the levels are not equal for the CW and SSB modes.  This 
is also experienced by K0AWU with his 746 Pro, as it appears to be a problem 
with the Icom radio brand.  I posted this question on my website article on 
this issue, and got essentially no responce, so I dont know if its an issue 
with just me and Bill, or if everyone else just deals with it.

The issue was that when say for instance, you set the xverter output from 
the 28 Mhz IF to drive the 144 Mhz transverter to get 3 watts in CW, then 
the SSB will be about 50 to 60 percent of this.  So, if your drive level is 
touchy to your microwave transverters, this could be a problem.

I was always turning the gain up a bit in SSB to get full output and when I 
would switch to CW, then the 144 Mhz xverter would be putting out to much 
drive to the microwave transverters.  I never blew up anything, but it was a 
pain and I always agonized over it during the heat of battle during contests 
and such.

In addition, the transverter output level from the 756 Pro II seemed to be 
temp dependent.  Sometime I would hardly get any output when left on for a 
long time, would have to turn the gain up with no help, always seemed to be 
ok when I just first turned stuff on.

Now, Im not sure this was the 756 Pro II or the actual 144 Mhz transverter. 
However, never had problems with the transverters any other time.  (LT2S 
mark IIs)

I asked Icom about the xverter output between SSB and CW, they said 
something was wrong.  Send it in....uhg....I do not believe that anything 
was wrong, its just the way it is.

I then talked to Bill, and he said he had the same problem.  So I tested my 
Icom at the HF connector with 100 watts output on CW into a dummy load at 28 
Mhz.  Switched to SSB and got about 65 watts on whistle peaks!  Bill said he 
dealt with it by only using SSB for both CW and SSB.  He just send a CW tone 
to thur the mic jack or something to generate CW while in the SSB mode. 
(Sorry Bill, your secret is out...) Works great and if he never told ya, you 
would never know....That way he gets consistent power in both modes. 
Perhaps Bill can comment here on the reflector for his real facts, hopefully 
I dont have the info wrong.

I even was looking at switched in attenuator schemes to level the output 
based on mode, however, that would take some more head scratching, and I 
never got around to it.

This pretty much made me upset, I have two FT-1000MP radios and have 
extreamly consistant CW and SSB level control from the front panel when 
driving the transverters, so Icoms version is bogus if you ask me.  One way 
to solve it is to get the new FT-9000DX, but man......I have to send my kids 
to college some day!

Hence, I sold the 756 Pro II and trying the SDR-1000 for the 20 Khz 
bandscope function.  The jury is still out, but I am getting closer...it has 
been a learning experience, but I am making headway and it shows some 
promise.

In fact, dont know if you heard me last night or not, but I checked into the 
NLRS net with the SDR-1000 radio running it into my LT2S Mark II - running 
20 watts QRP.  If it sounded ugly, Matt would have been sure to tell me :)

The link on the interfacing is on my website for the 756 Pro II to the 
transverter....If you have a split TX / RX transverter on the IF, it gets a 
bit complicated as the transverter port on the 756 Pro II is combind TX/RX.

http://www.km0t.com/pages/sept2002.htm

The operation of the 756 Pro II was great for microwave IF, and I do miss 
it.   If to be used for virgin 144 Mhz use, the noise blanker does not match 
up with the FT-1000MP units...not in the same league for sure.  However, the 
DSP noise reduction was killer, much better than the FT-1000MP as that was 
technology that was about 10 years older.

Hope this helps...gota run.

73
Mike - KM0T

----- Original Message ----- 
From: <W0ZQ at aol.com>
To: <nlrs at mailman.qth.net>
Sent: Monday, February 14, 2005 6:25 PM
Subject: [NLRS] Transverter use with 756Pro or Orion


>
>
> Does anyone on the reflector use a Icom 756ProII or a TenTec Orion with a
> VHF transverter ?  If so,
>
> 1)  What transverter are you using ?
> 2)  Can you control the drive level (CW and SSB) via front panel  controls
> and get 0 to full power out ?
> 3)  How do you like it ?
>
> 73, Jon
> W0ZQ
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