Topics

Front end interference on the TM-D700E?

k5qq@...
 

In a message dated 4/23/2001 6:30:48 AM Mountain Daylight Time,
g1lkj@... writes:

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

Does setting AIP ON prevent the problem?

Unless you are working weak signal simplex operations, the decrease in gain
vs the increase in intercept point should help your problem without causing
any decrease in performance from local repeaters.

Another person wrote in to comment on the Par notch filters and I can attest
to the outstanding results they provide for earlier radios's where the AIP
feature is not available. As a series notch, they provide no problem to
dual band amateur operations but sure get rid of the annoying 152 MHz pagers.

Jim K5QQ

Phil Manning <g1lkj@...>
 

Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).

Michael Virgilio <mikev@...>
 

YES! Defintely. I live about 3 miles from a building that has numerous paging transmitters at 152 and 158 MHz at 200+ watts, and whenever I drive by that building, I constantly get paging interference. Mostly on VHF - I don't tend to listen to UHF as much, but can't say that I've had any major interference there when I am listening.
 
Another local ham recommended the Par paging notch filters - attenuating 152-153 MHz over 50dB. They also have one that does 158-159 MHz as well as 152-153. They live a lot closer to that building, and they haven't heard a peep of paging noise since they put the filter in.
 
  - Mike, KG4JNA

-----Original Message-----
From: Phil Manning [mailto:g1lkj@...]
Sent: Monday, April 23, 2001 8:27 AM
To: TMD700A@...
Subject: [TMD700A] Front end interference on the TM-D700E?

Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).



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k5qq@...
 

In a message dated 4/23/2001 10:06:11 AM Mountain Daylight Time,
rick@... writes:

Anyone have a URL or other information on the PAR filters?


Thanks!
http://www.rf-filters.com/

They work great for me!

Jim K5QQ

Doug Bade <dbade@...>
 

In general I have found NO amateur radio's with 130-174 rcvrs, and 10-11 mhz IF's with .2uv sensitivity (130-174), (basically all new current models ) which do not get overloaded with paging RFI when near site's.. It is a tradeoff of sensitivity and lack of selectivity for intermod rejection, it seems to be a cost effective solution trade-off... AIP should block a lot of overload with minimal impact to local repeaters... That is their solution..... :-).. Doug KB8GVQ

At 12:26 PM 4/23/01 +0000, you wrote:
Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).



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Michael Virgilio <mikev@...>
 

Info on the PAR filters is available from their web site:
 
 
Information available includes loss vs. frequency graphs, as well as VSWR graphs for 2M.
 
They do also have a 450MHz filter, if you're having problems with paging in that area as well.
 
Their filters are available at both Amateur Electronic Supply (www.aesham.com) and Ham Radio Outlet (www.hamradio.com), as well as other retailers.

-----Original Message-----
From: Rick Giguere [mailto:rick@...]
Sent: Monday, April 23, 2001 5:18 PM
To: TMD700A@...
Subject: Re: [TMD700A] Front end interference on the TM-D700E?

Anyone have a URL or other information on the PAR filters?


Thanks!


....Rick

Brian Davies <briandavies@...>
 

Hi All

As a matter of interest this specific problem is not restricted only
to the D700 series, it happens on many different makes of amateur
radio. The problem is the front end is wide band and will let in lots
of unwanted frequencies.

The cure is to fit a bandpass filter in the antenna lead. These are
readily available from the major dealers - I got mine from W&S.

Should anyone require further information I will be pleased to supply
it. Surrey Raynet made careful technical investigation into this
problem some years ago and as I wrote a piece about for Radcom, I
suppose that would have been 18 months or more back.

73

Brian G3OYU

-----Original Message-----
From: Phil Manning [mailto:g1lkj@...]
Sent: Monday, April 23, 2001 1:27 PM
To: TMD700A@...
Subject: [TMD700A] Front end interference on the TM-D700E?

Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).

Jim Andrews <jim@...>
 

Surrey RAYNET made careful technical investigation into this
problem some years ago and as I wrote a piece about for Radcom,
I suppose that would have been 18 months or more back.
Leicester RAYNET have also used the DCI filters mentioned, purchased from
Waters & Stanton.

They are pretty-well guaranteed to stop all paging / PMR interference and
have proved very effective, including in a control room with no less than 12
other PMR radios (mobile sets) being used on the same mast as our aerial and
coax (all 150-160Mhz area) and not a peep of interference!

Radio used in this instance was a TM-732, probably the worst of all the
Kenwood 'wide' front end sets, with no advanced AIP control.



Jim, G1HUL


-----Original Message-----
From: Phil Manning [mailto:g1lkj@...]
Sent: Monday, April 23, 2001 1:27 PM
To: TMD700A@...
Subject: [TMD700A] Front end interference on the TM-D700E?

Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).

Gregor <link@...>
 

http://www.parelectronics.com/

I did buy 2 filters, they work realy well. I had bad problems here in Houston.

Good luck, the par filter will probably fix it

Gregory

At 05:17 PM 4/23/01 -0400, you wrote:
Anyone have a URL or other information on the PAR filters?


Thanks!


...Rick



On Mon, 23 Apr 2001 k5qq@... wrote:

In a message dated 4/23/2001 6:30:48 AM Mountain Daylight Time,
g1lkj@... writes:

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

Does setting AIP ON prevent the problem?

Unless you are working weak signal simplex operations, the decrease in
gain
vs the increase in intercept point should help your problem without
causing
any decrease in performance from local repeaters.

Another person wrote in to comment on the Par notch filters and I can
attest
to the outstanding results they provide for earlier radios's where the AIP
feature is not available. As a series notch, they provide no problem to
dual band amateur operations but sure get rid of the annoying 152 MHz
pagers.

Jim K5QQ


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Rick Giguere <rick@...>
 

Yep. I have the same problem all the time.

I really love the rig, but confess that it's all but useless when I'm in
Boston proper.

The thing is incredibly bad at handling intermod .... I have three other
mobile rigs, and none is this bad ... actually none of my HTs is as bad!


....Rick

On Mon, 23 Apr 2001, Phil Manning wrote:

Anybody had problems with their 700E or 700A when in close proximity
to paging systems ( 154Mhz )etc on VHF and also breakthrough on UHF?

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

I have one but do not use mine in a RF interference area as a base
radio. So I have no complaint.

Phil Manning G1LKJ ( in the UK ).



Community email addresses:
Post message: TMD700A@...
Subscribe: TMD700A-subscribe@...
Unsubscribe: TMD700A-unsubscribe@...
List owner: TMD700A-owner@...

Shortcut URL to this page:
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Rick Giguere <rick@...>
 

Anyone have a URL or other information on the PAR filters?


Thanks!


...Rick

On Mon, 23 Apr 2001 k5qq@... wrote:

In a message dated 4/23/2001 6:30:48 AM Mountain Daylight Time,
g1lkj@... writes:

A friend of mine bought a 700E at the weekend and it seems to be
somewhat susceptible to this. AIP is set to off, putting it on acts
as a 10dB attenuator or so it seems.

Does setting AIP ON prevent the problem?

Unless you are working weak signal simplex operations, the decrease in gain
vs the increase in intercept point should help your problem without causing
any decrease in performance from local repeaters.

Another person wrote in to comment on the Par notch filters and I can attest
to the outstanding results they provide for earlier radios's where the AIP
feature is not available. As a series notch, they provide no problem to
dual band amateur operations but sure get rid of the annoying 152 MHz pagers.

Jim K5QQ


Community email addresses:
Post message: TMD700A@...
Subscribe: TMD700A-subscribe@...
Unsubscribe: TMD700A-unsubscribe@...
List owner: TMD700A-owner@...

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Phil Manning <g1lkj@...>
 

Since the manufacture of modern radios using SMD technology and
trying to cram as much as possible in to as small as space as
possible intermod problems have been around. An Yaesu FT847 used on
board HMS Belfast GB2RN suffers chronic breakthough on 2m from the
pagers on Guy's Hospital Tower at London Bridge, whereas a older
FT726R seems to be less susceptable used in the same room.

I had a Icom tribander handy recently when used on 2m in a local park
was swamped by pagers and pmr equipment and I disposed of it in
favour of a older two band Yaesu FT51R radio which gets a bit but not
as bad.

In the case of the TM-D700E I do not use the 2m side for VHF phone
but data only and that is why I bought the rig. For voice ops I have
other older model radio's.

As I said in my earlier comment I do not have a problem with 2m
intermod because I use it for Data only.

I found out how to correct the time problem press REV+LOW and switch
on, rather then disconnecting the lithium battery lead and I like the
radio very much, except for the microphone which I do not like but
that is a purely personal preference. it does not effect the ops.

I have not tried any of it's other ops yet SSTV and Pac Sats, doppler
shift and 5Kz working so I am told could be a problem.

Thanks for all the replies by the way from the US and the UK. My
friend is taking note.

Phil Manning G1LKJ
Surrey Raynet