On Tue, 24 Aug 2004 00:54:10 GMT, Richard Clark
wrote:

Now, I know that such antennas are not designed to be transmit
antennas (and again, perhaps too short to boot); so I will leave that
to others to engage as a receive antenna if they doubt reciprocity (or
I will do that later this eve for them as I often have to).


Hi All,

I've repeated the models with longer runs: 1000 meters length @ 80M.

For transmits, the single wire over ground shows a gain of 0.42dBi at
10° but with a F/B of 16.4dB. EZNEC proclaims the model exhibits 17dB
loss.

For transmits, the double wire over ground shows a gain of 1.2dBi at
10° but with a F/B of 11.7dB. EZNEC proclaims the model exhibits 17dB
loss.

However, Beverages are not typically the first choice for
transmission, but rather reception. Does reciprocity hold? As no one
has offered to help the Little Red Hen, would they care to share in
the cake?

For the receive single wire Beverage @ 10° w/600 Ohm load
Total load power = 5.543E-07 watts

For the receive double wire Beverage @ 10° w/600 Ohm load
Total load power = 6.623E-07 watts

Now, if we compare the two receive loads we find they differ by .77dB
which is the same difference for the transmission models. By most
accounts, that means reciprocity prevails. By further accounts, that
means the double wire system is superior - if you want to lay out 1000
meters of wire for less than one dB (that pesky one dB value judgment
again).

By this point, what with all the trolling going on and so little
actual technical content, What was this all about?

73's
Richard Clark, KB7QHC

"Richard Clark" asked -

Does reciprocity hold?

-------------------------------------------

How dare you question it?
----
Punchinello.

Richard Clark wrote:
. . .
However, Beverages are not typically the first choice for
transmission, but rather reception. Does reciprocity hold? As no one
has offered to help the Little Red Hen, would they care to share in
the cake?

For the receive single wire Beverage @ 10° w/600 Ohm load
Total load power = 5.543E-07 watts

For the receive double wire Beverage @ 10° w/600 Ohm load
Total load power = 6.623E-07 watts

Now, if we compare the two receive loads we find they differ by .77dB
which is the same difference for the transmission models. By most
accounts, that means reciprocity prevails. By further accounts, that
means the double wire system is superior - if you want to lay out 1000
meters of wire for less than one dB (that pesky one dB value judgment
again).
. . .

You wouldn't modify a Beverage or any HF receiving antenna to get more
gain. The whole object is directivity. If you need more gain, turn up
the receiver gain control.

Of course reciprocity prevails. But at HF, the important criteria are
different for transmitting and receiving. When transmitting, it's gain;
when receiving, it's directivity. The Beverage is poor in the first
category but good in the second -- it's a good receiving antenna but a
poor transmitting antenna.

Incidentally, Tom W8JI and I worked out a way some time ago to get
directivity information from EZNEC. You can see an example at
http://www.w8ji.com/receiving_basics.htm in the discussion about Beverages.

Roy Lewallen, W7EL

On Thu, 26 Aug 2004 21:16:14 -0700, Roy Lewallen
wrote:

Richard Clark wrote:
. . .
However, Beverages are not typically the first choice for
transmission, but rather reception. Does reciprocity hold? As no one
has offered to help the Little Red Hen, would they care to share in
the cake?

For the receive single wire Beverage @ 10° w/600 Ohm load
Total load power = 5.543E-07 watts

For the receive double wire Beverage @ 10° w/600 Ohm load
Total load power = 6.623E-07 watts

Now, if we compare the two receive loads we find they differ by .77dB
which is the same difference for the transmission models. By most
accounts, that means reciprocity prevails. By further accounts, that
means the double wire system is superior - if you want to lay out 1000
meters of wire for less than one dB (that pesky one dB value judgment
again).
. . .

You wouldn't modify a Beverage or any HF receiving antenna to get more
gain. The whole object is directivity. If you need more gain, turn up
the receiver gain control.

If you will note above, there is nothing stated in terms of gain.

Of course reciprocity prevails. But at HF, the important criteria are
different for transmitting and receiving. When transmitting, it's gain;

If you will note in the original posting (the content that has been
edited out here) I do employ the term gain - however only as an
informal comparison.

when receiving, it's directivity. The Beverage is poor in the first
category but good in the second -- it's a good receiving antenna but a
poor transmitting antenna.

That has been attended to several times.

Incidentally, Tom W8JI and I worked out a way some time ago to get
directivity information from EZNEC. You can see an example at
http://www.w8ji.com/receiving_basics.htm in the discussion about Beverages.

Hi Roy,

That's nice. Do you have anything that resolves Yuri's "problem?"
More to the matter, does anyone know what that "problem" is? If it is
merely semantics (as the discussion seems to have evolved into), then
perhaps this matter is more suitable to rec.radio.amateur.linguistics.

73's
Richard Clark, KB7QHC

Richard Clark wrote:

Hi Roy,

That's nice. Do you have anything that resolves Yuri's "problem?"
More to the matter, does anyone know what that "problem" is? If it is
merely semantics (as the discussion seems to have evolved into), then
perhaps this matter is more suitable to rec.radio.amateur.linguistics.

73's
Richard Clark, KB7QHC

I've already said all I have to say about Yuri's problems.

Roy Lewallen, W7EL