[UK-CONTEST] What is the best VHF Radio
John F Wilson
UK-Contest at grebe.plus.com
Tue Sep 9 07:47:59 EDT 2008
The sensitivity of the IC7400 is not bad - I reckon a Noise Figure of
about 3 dB, but I don't think this is an issue, as for serous use you
have to have a mast head preamp anyway.
John G3UUT
Darrell G0HVQ wrote:
> Interesting reading, speaking as a HF/VHF contester and keen VHF op.
>
> Whilst I am a fan of the IC7400, having owned one and used it in HF and VHF
> contests for a couple of years, I only consider it 'adequate' on 2m (and
> HF).
>
> On 2m, I have been fortunate to run it alongside an old Icom IC 251E with
> Mutek front end in several 'lifts' - it doesn't have all the bells and
> whistles, but is significantly more sensitive than the 7400.
>
> A few people I've spoken to think highly of the 847 as a V/UHF radio.
>
> It'd be great if one of the big manufacturers produced a high-performance
> V/UHF radio, but like Joh says I think those days are gone due to lack of
> demand - you only had to listen to 2m yesterday during the biggest contest
> of the year. I've got a reasonable station and struggled to make more than
> 40 QSOs in 6 hours.
>
> I think next time I'll got for a higher-performance HF/6m radio and get a
> decent transverter for 2m.
>
> 73
> Darrell G0HVQ
>
>
>
> ----- Original Message -----
> From: "John F Wilson" <UK-Contest at grebe.plus.com>
> To: "UK-Contest" <uk-contest at contesting.com>
> Sent: Monday, September 08, 2008 3:29 PM
> Subject: Re: [UK-CONTEST] What is the best VHF Radio
>
>
>
>> Neil,
>>
>> I reckon the IC7400 despite one or two issues, is hard to beat, on all
>> round performance, strong signal handling and trasmit noise close to
>> carrier. The problem is that it only covers HF, 50 MHz and 144 MHz.
>> Its high time ICOM produced a DSP VHF/UHF rig as a successor to the
>> IC910 but I suspect they won't due to the smaller market than for HF rigs.
>>
>> On your original point, my feeling is that with the attenuator in and
>> the preamp off, it was the transmitted signal that was at fault unless
>> you just turned your preamp off by removing the supply to it without
>> switching it out of circuit in which case it might be that if the signal
>> was strong enough it could still be driving the off amplifier device
>> into non-linearity.
>>
>> 73 John G3UUT
>>
>> Ian Burns wrote:
>>
>>> Neil,
>>>
>>> The Javornik II can be found here
>>>
>>> http://lea.hamradio.si/~s53ww/xvrt/xvrt.htm
>>>
>>> The page also shows some screen shots of the transverter o/p indicating
>>> why you don't want to use it. With the PA turned off, depending on the
>>> drive control setting (anything over about 1/4 is bad) the o/p has
>>> spurii about 45dB down from the main carrier. These spurs move in and
>>> out with respect to the main carrier as the rig is tuned across the band
>>> and are offset anywhere from zero to several hundred KHz from the
>>> carrier. Filtering is not an option.
>>>
>>> When you have seen how bad the TVTR o/p from the FT1000MP is you won't
>>> want to use it to transvert to any band...
>>>
>>> As Jiri says a pad on the main o/p works well and is clean.
>>>
>>> 73
>>> Ian
>>>
>>>
>>> G3RIR wrote:
>>>
>>>
>>>> Ian,
>>>>
>>>> Thanks for the response. I have never heard of Javornik perhaps you can
>>>> let
>>>> me have a link.
>>>>
>>>> I have an FT1000mp as well as my FT847 and have a DEM transverter for
>>>> 432
>>>> which was used with the FT1000mp. I moved to the FT847 for contesting on
>>>> 432
>>>> as there are not too many very strong signals on 432 from our NFD
>>>> location
>>>> (G3SDC/P on the Norfolk coast (JO02st)) and it is much more convenient
>>>> and
>>>> smaller that the FT1000mp etc!!
>>>>
>>>> I have recently been active on 144 and that is where the FT847 might not
>>>> have a robust enough receiver. However I found only one signal
>>>> splattering
>>>> during the weekend from my home qth in IO92 so I am not blaming the rx
>>>> just
>>>> yet.
>>>>
>>>> What did you find wrong with the FT1000mp transverter output? Could it
>>>> be
>>>> cleaned up with filtering? When using the FT1000mp for a transverter I
>>>> switch off the pa completely from inside the little top lid as this is
>>>> safer
>>>> than someone accidentally running too much power from the pa into an
>>>> attenuator.
>>>>
>>>> Neil, G3RIR
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: uk-contest-bounces at contesting.com
>>>> [mailto:uk-contest-bounces at contesting.com] On Behalf Of Ian Burns
>>>> Sent: 08 September 2008 09:13
>>>> To: uk-contest at contesting.com
>>>> Subject: Re: [UK-CONTEST] What is the best VHF Radio
>>>>
>>>> I can thoroughly recommend the FT100MP and Javornik II transverter
>>>> combination. The receiver is not totally bomb proof but is noticeably
>>>> better than my FT847. We used the setup at G0FBB in the 2m trophy this
>>>> weekend and had no real problems despite some very loud signals on the
>>>> band.
>>>>
>>>> The only drawback of this combination is that the transverter output of
>>>> the FT1000 can be too dirty to use on a crowded band. It's a fair way
>>>> off the VHFCC recommendations of -100dBc... The main o/p is clean enough
>>>> to use via a suitable attenuator though.
>>>>
>>>> 73
>>>> Ian.
>>>>
>>>> Dave wrote:
>>>>
>>>>
>>>>
>>>>> At 20:21 07/09/2008 +0100, G3RIR wrote:
>>>>>
>>>>> There is a useful comparison of HF Tcvrs here
>>>>> http://www.df9ic.de/tech/trxtest/trxtest.html
>>>>>
>>>>> 73 Dave G4RGK
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Earlier today I reported to a station on 144MHz that his signal was
>>>>>> very
>>>>>> wide. I could hear splatter about 12kHz either side of his signal.
>>>>>>
>>>>>> I turned off my mast-head pre-amp, switched in an attenuator and
>>>>>> turned
>>>>>>
>>>>>>
>>>>>>
>>>> my
>>>>
>>>>
>>>>
>>>>>> beam side on so that I only had s7 registered on my s-meter. The
>>>>>> splatter
>>>>>> was still noticeable.
>>>>>>
>>>>>> The station concerned said he was definitely not over-driving
>>>>>> anything.
>>>>>>
>>>>>>
>>>>>>
>>>> He
>>>>
>>>>
>>>>
>>>>>> asked what receiver I was using and on being told it was an FT847 he
>>>>>> suggested that it was my receiver at fault. This may of course be the
>>>>>> problem but he wasn't the only loud signal on the band but was by far
>>>>>> the
>>>>>> widest.
>>>>>>
>>>>>> What are the group members' views on the FT847 in handling such
>>>>>>
>>>>>>
>>>>>>
>>>> situations
>>>>
>>>>
>>>>
>>>>>> and indeed what is the best receiver around for 144 and 432?
>>>>>>
>>>>>> I am also interested to know what is the specified noise figure for
>>>>>> the
>>>>>> FT847; of course the manual only refers to sensitivity!
>>>>>>
>>>>>> Neil, G3RIR
>>>>>>
>>>>>> _______________________________________________
>>>>>> UK-Contest mailing list
>>>>>> UK-Contest at contesting.com
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>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
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>
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